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Ecoregions of Côte d'Ivoire

EoE - September 6, 2012 - 5:41pm

Côte d'Ivoire has six ecoregions that occur partly within its borders:

  1. Guinean mangroves
  2. Eastern Guinean forests
  3. Western Guinean lowland forests
  4. Guinean montane forests
  5. Guinean forest-savanna mosaic
  6. West Sudanian savanna


Guinean mangroves

The Guinean Mangroves, influenced by a large tidal range and high inputs of freshwater, contain stands that are more than 25 m in height. As the best developed mangroves in western Africa, this ecoregion provides important habitat for migratory birds and endangered species such as the West African manatee and the pygmy hippopotamus. However, the mangrove habitat is threatened by agriculture and urban development and has been affected by poor rainfall over the entire region during the past three decades.

Eastern Guinean forests

The Eastern Guinean Lowland Forest extends from the east banks of the Sassandra River in western Côte d’Ivoire (06° 05’ W) to the edge of Lake Volta (01° 50’ W) in Ghana. There is a small extension of this ecoregion east of Lake Volta into the Togo Hills, which lie mostly in Togo but extend across the border to easternmost Ghana, with one outlier in Benin. The dry lowland area on the eastern edge of the ecoregion is termed the Dahomey Gap and is a major biogeographical barrier. In the border areas between Ghana and Côte d’Ivoire, the ecoregion extends to 8° N and gradually fades into a mosaic of forest patches and tall grasslands of the Guinea Forest-Savanna Mosaic.

There is a high diversity of non-human primates here, including western chimpanzee (Pan troglodytes verus). Thirteen amphibians are strictly endemic to the ecoregion and, together with plants and butterflies, these groups illustrate the clearest difference from the contiguous lowland forests further west.

The threats facing this ecoregion are numerous and diverse. Considerable areas of forestland have been converted to farmlands, often using a rotation ‘farmbush’ farming system. The total area under protection is relatively small, and pressure to extract forest resources, especially timber, fuel wood, and charcoal remains high due to a ready timber export market and increasing urban population centers such as Abidjan and Accra. Habitat loss and hunting for bushmeat has recently caused the extinction of one non-human primate subspecies, Miss Waldron’s colobus (Piliocolobus badius waldroni), and the endemic Togo mouse (Leimacomys buettneri) may also be extinct.

Western Guinean lowland forests

The Western Guinean Lowland forest stretches from eastern Guinea, across Sierra Leone and Liberia, to the Sassandra River in southwestern Côte d’Ivoire. It is the most westerly tropical rainforest block on the African continent.

The flora and fauna is distinctive, with larger numbers of narrowly endemic species than in the contiguous Eastern Guinean lowland forests ecoregion to the east. The two endemic duikers, Jentink’s duiker (Cephalophus jentinki) and zebra duiker (Cephalophus zebra), 13 strictly endemic amphibians, and three strictly endemic birds illustrate the distinctive species-composition of the ecoregion. Non-human primates are also diverse and include the Diana monkey (Cercopithecus diana diana), Campbell’s monkey (Cercopithecus mona campbelli) and western red colobus (Piliocolobus badius badius.

Much of the natural forest in this ecoregion has been lost to human activities, with almost all remaining forest modified by past human disturbance. The loss has been severe in Côte d’Ivoire, where the national priorities favored export crops, which led to vast forests being cleared. Sierra Leone has also experienced severe loss of its natural forest, dating back to the 19th century when timber was exported during British colonial administration. Subsistence agriculture in the wake of commercial logging has reduced the area of primary forest in Sierra Leone from more than 70 percent to just under 6 percent. Further losses in forest coverage are projected at five percent should the trend in deforestation continue. Both Côte d’Ivoire and Sierra Leone show the greatest level of fragmentation of natural forests, while Liberia still retains large forest blocks. The largest stands of high forest in all of these countries are found within so-called ‘protected areas’ and ‘forest reserves’. Despite these titles, the management of protected areas and reserves is currently poor or non-existent, especially in Guinea, Sierra Leone and Liberia where civil conflicts drain resources to other areas. The total area of protected forest in this ecoregion is just under 3 percent for all National Parks and other reserves (IUCN levels II-IV) with international designations.

Guinean montane forests

The Guinean Montane Forest ecoregion consists of scattered mountains and high plateau areas that rise out of a gently undulating landscape. Parts of the ecoregion are found in four West African countries, from Guinea in the west to Côte d’Ivoire in the east. Some landscapes rise precipitously (e.g., Loma Mountains and Tingi Hills in Sierra Leone, and Mount Nimba on the border between Liberia, Guinea, and Côte d’Ivoire) while others are more gentle such as the Fouta Djallon in Guinea, a heavily eroded plateau with an elevation of 1,100 meters (m).

One of the peaks, Bintumani (on the Loma Mountains of Sierra Leone), is the highest peak west of Mount Cameroon. The broad range of elevation, coupled with the underlying geology and anthropogenic activities, have given rise to different plant associations on several of the mountains. Although details of the number of endemic plants are not fully compiled, 35 plant species are known to be strictly endemic, with several mountains containing their own unique plant species, such as the orchid Rhipidoglossum paucifolium, known only from Mount Nimba. The fauna is also diverse with close to 15 strictly endemic vertebrate species, including species found on single mountains, such as the Mount Nimba endemic toad, Nimbaphrynoides occidentalis.

Mining on Mount Nimba, slash and burn farming, and human-made fires were the major threats prior to a decade of civil conflicts in Sierra Leone and Liberia.

In general this ecoregion is not well protected in formal conservation areas. In total, there are two Biosphere Reserves (Monts Nimba in Liberia, Guinea, and Côte d’Ivoire and Massif du Ziama in Guinea) and two World Heritage Reserves (Mount Nimba in Côte d’Ivoire and Mount Nimba in Guinea). The current status of this ecoregion is poorly known because of continuing civil war in the region. A conservation assessment should be done immediately following cessation of fighting, and efforts made to declare the Loma Mountains and Tingi Hills as national parks.

Guinean forest-savanna mosaic

The Guinean Forest-Savanna Mosaic runs through West Africa, dividing the Guinean rain forest from the Sudanian savanna. The interlacing forest, savanna, and grassland habitats are highly dynamic, and the proportion of forest versus other habitat components has varied greatly over time.

These forest-savanna ecotones may offer critical habitat for differentiation and speciation. A number of large charismatic mammal species are found here, but national parks attract few visitors.

The protected areas system is under funded and only covers two percent of the area of this ecoregion.

West Sudanian savanna

The West Sudanian Savanna stretches in a band across West Africa south of the Sahel, from Senegal and Gambia to the eastern border of Nigeria. It lies between the Guinean Forest-Savanna Mosaic to the south, and the Sahelian Acacia Savanna to the north.

The West Sudanian Savanna is a hot, dry, wooded savanna composed mainly of large tree species and long "elephant" grass.

The habitat has been greatly reduced, degraded, and fragmented by agricultural activities, fire, and clearance for wood and charcoal, while populations of most of the larger mammal species have been decimated by over-hunting. Although many protected areas exist, most are under-resourced "paper parks" with little active enforcement on the ground.

The hot climate and poor infrastructure have resulted in little development of tourism in the region.

The habitats of the ecoregion are principally threatened by the agricultural and herding activities of the local populations. There are considerable pressures on the land from seasonal farming, grazing animals, cutting trees and bushes for wood, burning woody material for charcoal, and from wild fires. All of these pressures have reduced and degraded natural habitats. Climatic desiccation is a further threat, exacerbating human pressures, as the ability of the ecosystem to recover from overuse is reduced when there is little rainfall.

The main threats to the animal species of the ecoregion come from human use of the habitat and especially from hunting. For the larger mammals, hunting for food and for sport has removed many species over wide areas; species such as giraffe, wild dog, lion, and elephant are now much reduced (some to single viable populations). The black rhinoceros (Diceros bicornis) was extirpated decades ago. Even within protected areas, commercial and subsistence poaching is rife, and illegal grazing of livestock occurs extensively.

A particular threat to the migratory wildlife (especially birds) is the drainage and pollution of wetlands. Large-scale agricultural initiatives, dams, and river diversion schemes are proposed, and in some cases have been completed. These can change or reduce flood regimes of inland wetlands, which are generally seasonal and dependent on rainfall. In Nigeria, in particular, some of the agricultural schemes have damaged these wetlands, with potential negative consequences for the wildlife and the people's whose livelihoods depend on fishing or seasonal farming related to the floods.


Ecoregions are areas that:

[1] share a large majority of their species and ecological dynamics;
[2] share similar environmental conditions; and,
[3] interact ecologically in ways that are critical for their long-term persistence.

Scientists at the World Wildlife Fund (WWF), have established a classification system that divides the world in 867 terrestrial ecoregions, 426 freshwater ecoregions and 229 marine ecoregions that reflect the distribution of a broad range of fauna and flora across the entire planet.

National Parks:

  1. Assagny National Park
  2. Banco National Park
  3. Comoé National Park
  4. Îles Ehotilés National Park
  5. Marahoué National Park
  6. Mont Nimba National Park
  7. Mont Péko National Park
  8. Mont Sângbé National Park
  9. Taï National Park

See also:

Tropical coral reefs and environmental stress

EoE - September 6, 2012 - 5:41pm

Corals that host fewer species of algae appear less sensitive to disturbances. The following article is part ten in a series on the National Science Foundation's Long-Term Ecological Research (LTER) Network. Visit parts one, two, three, four, five, six, seven, eight and nine in this series.

Tropical Reefs' Surviving Environmental Stresses:
Corals' Choice of Symbiotic Algae May Hold the Key

Symbiodinium, it's technically called, but more popularly it's known as zooxanthellae. Either way, these microscopic algae that live within a coral's tissues hold the key to a tropical reef's ability to withstand environmental stresses.

The effects on tropical corals of global warming, ocean acidification, pollution, coastal development and overfishing may all come down to how choosy the corals are about their algae tenants.

Reef corals are the sum of an animal and the single-celled algae that live inside its tissues. The animal is called the host and the algae are called endosymbionts. It's a mutually beneficial arrangement. The corals provide the algae with protection in sunlit, shallow seas. The algae produce large amounts of energy through photosynthesis, which the corals use to survive and to build their skeletons. The stability of this symbiotic relationship is critical to corals' survival. When corals lose their algae, they bleach out and often die.

Researchers at the University of Hawaii and other institutions have found that the more flexible corals are about their algal residents, the more sensitive they are to environmental changes.

"It's exactly the opposite of what we expected," says Hollie Putnam of the University of Hawaii and lead author of a paper published in the journal Proceedings of the Royal Society B.

"The finding was surprising; we thought that corals exploited the ability to host a variety of Symbiodinium to adapt to climate change." But more is not always better, say Putnam and co-authors Michael Stat of the University of Western Australia and the Australian Institute of Marine Science; Xavier Pochon of the Cawthron Institute in Nelson, New Zealand; and Ruth Gates of the University of Hawaii. "The relationship of corals to the algae that live within them is fundamental to their biology," says David Garrison, program director in the National Science Foundation's (NSF) Division of Ocean Sciences, which funded the research.

"This study gives us an important new understanding of how corals are likely to respond to the stresses of environmental change." The research was conducted at NSF's Moorea Coral Reef Long-Term Ecological Research (LTER) site, one of 26 such NSF LTER sites around the globe in ecosystems from deserts to freshwater lakes, and from forests to grasslands.

Putnam and colleagues took samples from 34 species of corals at the Moorea LTER site. By analyzing the DNA from the algae in the samples, they identified the specific species of Symbiodinium. The findings reveal that some corals host a single Symbiodinium species. Others host many.

"We were able to link, for the first time, patterns in environmental performance of corals to the number and variety of endosymbionts they host," says Putnam. The patterns show that corals termed generalists--those that are flexible in their choice of algae residents--are more environmentally sensitive. In contrast, environmentally resistant corals--termed specifists--associate with only one or a few specific species of Symbiodinium.

Generalists such as Acropora and Pocillopora are some of the most environmentally sensitive corals. Conversely, specifists such as Porites harbor few Symbiodinium species and are environmentally resistant.

"Coral reefs are economically and ecologically important, providing homes for a high diversity of organisms and are necessary for food supplies, recreation and tourism in many countries," says Gates. "The better we understand how corals respond to stress, the more capable we will be of forecasting and managing future reef communities."

It's likely that the reefs of tomorrow, say Putnam and co-authors, will be shaped by the coral-Symbiodinium assemblages of today. In the roulette of coral species on a tropical reef, Porites may be the clear winner.

August 29, 2012

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Ecoregions of Costa Rica

EoE - September 6, 2012 - 5:41pm

Costa Rica has eight ecoregions that occur entirely or partly within its borders:

  1. Central American dry forests
  2. Southern Mesoamerican Pacific mangroves (Moist Pacific Coast mangroves and Southern Dry Pacific Coast mangroves)
  3. Mesoamerican Gulf-Caribbean mangroves (Rio Negro-Rio San Sun mangroves)
  4. Costa Rican seasonal moist forests
  5. Talamancan montane forests
  6. Isthmian-Atlantic moist forests
  7. Isthmian-Pacific moist forests
    and off shore:
  8. Cocos Island moist forests

While the country has only about 0.1% of the world's landmass, it contains 5% of the world's biodiversity. All of Costa Rica is included in the subtropical and tropical Mesoamerica Biodiversity Hotspot.

Central American dry forests

The Central American dry forests is an interesting dry forest ecoregion, which stretches along the Pacific Coast, corresponds to a tropical habitat that has a prolonged dry season of five to eight months and is home to important plant and animal species, as well as a significant degree of endemism.

This totally fragmented ecoregion, represented in less than two percent of the original habitat (up to the middle of the 20th century, the ecoregion of the dry tropical forest of Central America extended in a continuous strip from the Pacific Coast of southwestern Mexico, through Guatemala, El Salvador, Honduras and Nicaragua to northwestern Costa Rica.) It is threatened by strong pressures from man, cattle overgrazing, burning, agricultural expansion, and hunting operations.

The dry tropical forests are now much more rare than tropical rain forests, although the latter are also disappearing at a very rapid rate.

Costa Rica is the country that has implemented the most conservation strategies for this ecoregion, although very little of the original habitat is protected.  In 1989 the Government of Costa Rica established the Guanacaste National Park, part of the Area de Conservación Guanacaste World Heritage Site as a protected habitat in northwestern Costa Rica, This unit effectively serves as a biological corridor connecting moist forested topography on the slopes of the Orosí and Cacao Volcanoes west to the Pan-American Highway, where it joins Santa Rosa National Park. This migration corridor between the dry forest and rain forest areas allows many fauna species to move seasonally. This protected area embodies a holding of about 340square kilometers, and boasts 140 species of mammals, more than 300 bird species, 100 amphibian and reptile taxa, and over 10,000 species of insects.

This forest is affected primarily by the extraction of precious woods and many agricultural activities.

The highest priority in the ecoregion is the need for rehabilitation, formulation of management strategies including fire control and prevention, and absolute protection of the last remaining fragments, as small as they may be. If an action plan is not established according to each country’s socioeconomic and political structures, the dry forests could be wiped out completely in a short time, leaving only tiny remnants. The action plan should not only conserve but also work on the recovery of contiguous areas in the ecoregion.

Southern Mesoamerican Pacific mangroves

Within this ecoregions are two subregions in Costa Rica:

The Moist Pacific Coast mangroves ecoregion runs along thepPacific coast of Central America from near the town of Jaco, Costa Rica to the southwestern corner of the Peninsula de Azuero, Panama, with a large number of embayments that provide shelter from wind and waves, favoring mangrove establishment. Tidal fluctuations also directly affect the mangrove ecosystem health. This ecoregion shows a mean tidal amplitude of 3.5 meters (m) but may range from two to six meters. Mangroves are more developed in this ecoregion than those further north due to the higher rate of freshwater inflow that reduces salt accumulation in the mangroves by increasing evapotranspiration.

A large area is protected in Costa Rica as Corcovado National Park on the Osa Peninsula. This park is also the largest tract of protected land on the Pacific side of Central America.


The Southern Dry Pacific Coast mangroves ecoregion runs along the Pacific coast of Central America beginning just south of the Golfo de Fonseca in Nicaragua then continuing south to the Gulf of Nicoya in Costa Rica. This southern dry pacific coast ecoregion encompasses the Gulfo de Nicoya that marks the transition zone from dry to moist on the pacific coast.

Vegetation zones can be divided into external and internal areas, and vegetation is characterized by the geneses Rhizopora and Avicennia. The ecoregion serves as an important nesting site for a number of bird species as well as providing habitat for such fauna species as mantled howler monkey, spectacled caiman, and the largest bat species in the New World, the false vampire bat. The main threat to this region is the conversion of habitat for agricultural development.

Areas with the highest remaining concentrations of mangroves in this ecoregion, in Costa Rica are Puerto Soley (near NI border; Tamarindo (400 hectares (ha)), Golfo de Nicoya (15,173 ha), and Puntarenas.

Mesoamerican Gulf-Caribbean mangroves

Within this ecoregions are the Rio Negro-Rio San Sun mangroves which consist of a coastal ecoregion in Costa Rica, extending to the north slightly into Nicaragua and south into Panama.

Mangroves are sparse in this ecoregion, and are primarily found in estuarine lagoons and small patches at river mouths growing in association with freshwater palm species including Raphia taedigera, which has some salt tolerance and can be considered an element of mangrove forest.

These mangrove communities are also part of a mosaic of several habitats that include mixed rainforest, wooded swamps, coastal wetlands, estuarine lagoons, sandy beaches, sea grasses, and coral reefs.

This coastal area generally consists of low alluvial floodplain (sea level to 20 meters above sea level), in which there is a network of black-water canals and creeks. In between are beaches that are important nesting areas for endangered sea turtles that feed in the seagrass beds and visit mangrove areas.

The protected areas in this region include the Tortuguero National Park and the Humedal Caribe Noreste in Costa Rica, are part of a network of Caribbean sites linked by a Meso-American Biological Corridor intended to insure continuity of biogeographical links between North and South America. The Humedal Caribe Noreste is also considered a wetland of international importance under the RAMSAR convention.

Deforestation in the upper watershed has resulted in drainage and sedimentation problems. Also associated with these problems are the acceptable management practices used on banana plantations. The redirection of surface water flow as a result of dam construction is changing the mangrove habitat by either adding or removing the natural amount of freshwater inflow to the ecoregion. A list of other threats includes land use changes as a result of unplanned settlements, illegal hunting, development of an international port, plans for another canal between the Caribbean Sea and the Pacific Ocean, gold mining on the Nicaraguan side of the border, sewage contamination from towns, runoff of agricultural chemicals, and erosion. For lack of a unified management plan, these threats appear to vary depending on the side of the border and are more acute in Costa Rica.

Costa Rican seasonal moist forests

This relatively small ecoregion lies on the Pacific Ocean slope, spanning the borders of northwestern Costa Rica and Nicaragua, between the crests of Costa Rica's central chain of volcanoes on the east and the Pacific Ocean on the west. The rain shadow created by Tilaran Mountain Range gives this ecoregion's climate significant seasonal variability.

The Costa Rican seasonal moist forests ecoregion is quite different from the surrounding dry and moist forest habitat types. Deciduous trees that lose their leaves during the distinct dry season make up the dominant vegetation in these forests. The flora are more adapted and capable of surviving in such a seasonally based ecoregion. Animals also are adapted to this fluctuation between wet and dry and the subsequent changes in the plants.

The Costa Rican seasonally moist forests have been extensively altered by human intervention. Lowland areas have been cleared for cattle, while mountain slopes, regardless of their steepness, have been cleared to grow beans, corn, coffee, as well as to support dairy cattle; most of Costa Rica's population and a significant portion of Nicaragua's lives within this ecoregion. During the past 100 years, virtually the entire ecoregion has been stripped of its native vegetation, with only small forest fragments remaining, totaling less than 10% of the ecoregion's original forest cover. The lack of lower and middle-elevation Pacific Slope forests threatens both the species that reside in these habitats and the altitudinal migrants the breed in the neighboring highlands. The small protected areas in the ecoregion total less than 30,000 hectares (ha), or around 3% of the ecoregion. In addition, this ecoregion is considered one of the least represented by National Parks within Central America.

In the past decade, there has been substantial regeneration of lower-elevation hillsides following the collapse of Costa Rica's cattle industry due to rising labor costs and decreasing yields after soils gave out from annual burning, over grazing, and resulting erosion. However, above 800 meters, the situation remains critical as a growing human population puts ever-increasing demands for living space and agricultural products that grow well in the moderate mid-elevation climate.

Talamancan montane forests

The Talamancan montane forests is an ecoregion situated along the mountainous spine of the Cordillera Talamanca within Costa Rica and Panama. These forests represent one of Central America’s most intact habitats.

The steep slopes, remoteness and relatively cool temperatures have limited the impact of agriculture and human development in most of this area.

This region provides habitat for considerable floral and faunal species diversity, many of which taxa are endemic. Over 30 percent of the ecoregion's flora, including over 10,000  vascular and 4000 non-vascular plant species, are endemic to this area, as are a number of fauna species.

The Talamanca ecoregion presently retains almost 75 percent of its original forest cover, which is distributed patchily over the isolated highland zones of the Tilaran and Talamanca Ranges. The largest forest block occurs in and around the La Amistad Biosphere Reserve. Deforestation, even in the Talamancan highland oak forests, has proceeded since the 1950s at an extremely high rate. The endemic oak species are also valued for their excellent properties to produce charcoal, while rare tree species such as Podocarpus are very sensitive to exploitation.

The Talamanca montane ecoregion's high biological diversity and endemism, as well as its steep topography have encouraged the Costa Rican and Panamanian governments to establish a series of reserves with varying degrees of protection. A full 40 percent of the ecoregion is under protection, in national parks such as the La Amistad, Chirripó, Braulio Carrillo, Volcán Poas, Volcán Baru, Rincón de la Vieja, and the Monteverde cloud forest reserve complex. Like most protected areas in Mesoamerica, the montane parks of the Talamancan forests lack full edological connectivity and regulatory oversight, and do not represent the gamut of ecosystems needed to support altitudinal migrants. For example, they do not allow for altitudinal movement of species. Even La Amistad protects primarily highland habitats over 2000 m while largely missing Pacific slope middle and lower elevations.

However, the clearing of forest for crops and cattle pastures have begun to alter the unprotected habitat, as has timber harvesting. Because of the archipelago-like distribution of these montane patches along the Cordillera Central, beta-diversity is high between mountains and ranges, as well as along an elevational gradient.

Isthmian-Atlantic moist forests

Covering the lowland Atlantic slopes at chiefly below 500 meters (m) elevation in southern Nicaragua, northern Costa Rica, and most of Panama, the Isthmian-Atlantic moist forests represent the epitome of wet, tropical jungle. This forest ecoregion evolved from unique combinations of North American and South American flora and fauna, which came together with the joining of these continents three million years ago. Currently, much of this ecoregion has been converted to subsistence and commercial agriculture.

Although a few large blocks of intact habitat still exist, the once vast Atlantic lowland forests have been seriously fragmented in recent years. The tropical evergreen forests are among the least well represented in Costa Rica's protected areas system, although large reserves exist in southern Nicaragua and eastern Panama. Only about 130,000 (ha) in the lowland Atlantic zone are currently protected and difficult economic conditions offer little likelihood that the area in protection will be significantly expanded.

The lack of protection of the Atlantic lowlands and the heavy bias toward deforestation at elevations of < 1,000 (m) contribute to the fragmentation and elimination of these forests. With gradual slopes and relatively good access, much of Costa Rica's remaining Atlantic slope forest has been intervened or exists in small fragments. Nicaragua's lack of access and the until-recently inaccessible steeper slopes of western Panama's Atlantic lowlands and foothills have left these areas

Isthmian-Pacific moist forests











Cocos Island moist forests

Cocos Island in the central eastern Pacific Ocean (5º32’N-86º59’W) lies 523 kilometers (km) southwest of Cabo Blanco, in Costa Rica; the country to which it has belonged since 1869, and 665 km northeast of the Galapagos Islands, in Ecuador. This small island measures 7.6 km long and 4.4 km across with a surface area of approximately 24,000 hectares (ha). There are also small islets nearby such as Dos Amigos, Rafael and Juan Bautista.

Cocos Island is the only island in the eastern Pacific with very moist tropical flora and fauna, and the only Pacific oceanic island off Central America. In addition to the very moist tropical forest, this small island has a tropical cloud forest, the highest parts of which are undisturbed, and represent the only ecosystem of this type on an eastern Pacific island. The various ecosystems and microclimates provide numerous niches with relatively high levels of insular endemism (nearly 30% of plant species and nearly 20% of insect species). The small islands and rocks around Cocos Island and within this ecoregion also maintain important nesting colonies of migratory seabirds such as the brown booby (Sula leucogaster), red-footed booby (Sula sula), Fregata minor, Gygis alba and Anous stolidus. The high biological wealth and endemism present in the coastal and oceanic ecosystems of the island should also be noted. The island’s conservation status is good, although introduced species threaten the balance of natural processes.

The entire island was declared a National Park and Biological Reserve by the government of Costa Rica in 1978, a World Heritage Site by UNESCO in 1997 and a Wetland of International Importance. Most of the island natural habitat can be considered intact, despite the negative influence of introduced plants and animals. The low relative biodiversity and isolation of this ecoregion make it particularly vulnerable to disturbances.


Ecoregions are areas that:

[1] share a large majority of their species and ecological dynamics;
[2] share similar environmental conditions; and,
[3] interact ecologically in ways that are critical for their long-term persistence.

Scientists at the World Wildlife Fund (WWF), have established a classification system that divides the world in 867 terrestrial ecoregions, 426 freshwater ecoregions and 229 marine ecoregions that reflect the distribution of a broad range of fauna and flora across the entire planet.


Ecoregions of the Democratic Republic of the Congo

EoE - September 6, 2012 - 5:41pm

The Democratic Republic of the Congo  has fourteen ecoregions that occur entirely or partly within its borders: [1] Central African mangroves; [2] Atlantic Equatorial coastal forests; [3] Western Congolian forest-savanna mosaic; [4] Angolan Miombo woodlands; [5] Southern Congolian forest-savanna mosaic; [6] Central Congolian lowland forests; [7] Eastern Congolian swamp forests; [8] Western Congolian swamp forests; [9] Northeastern Congolian lowland forests; [10] Northern Congolian forest-savanna mosaic; [11] East Sudanian savanna; [12] Ruwenzori-Virunga montane moorlands; [13] Albertine Rift montane forests; and, [14] Central Zambezian Miombo woodlands.


Central African mangroves

These mangroves flank the coastline of western and central Africa, in suitable low energy marine environments. The largest mangrove stand is found in the Niger Delta, which supports the most extensive area of mangrove in Africa. These mangroves also occur at the mouth of the Congo River in the Democratic Republic of Congo. The mangroves of this region have no endemic species but support some endangered species, such as manatees and perhaps pygmy hippopotamuses in the Niger Delta. Mangroves are important as nursery and feeding areas for marine fishes, and they trap large amounts of sediment. The oil industry, clearance for salt pans, and overcutting by an increasing human population pose serious threats to these mangroves, but some are contained within protected areas.

Atlantic Equatorial coastal forests

This ecoregion extends from the Sanaga River in west-central Cameroon south through Equatorial Guinea into the coastal and inland areas of Gabon, the Republic of Congo, and the Cabinda Province of Angola, ending in the extreme west Democratic Republic of Congo, just north of the mouth of the Congo River. At its southern extremity, the last 400 kilometers (km) of the ecoregion is a tongue of forest lying inland of the coastal plain and surrounded by the Western Congolian Forest-Savanna Mosaic.

The Atlantic Equatorial Coastal Forests ecoregion has exceptionally high levels of species richness and endemism, contains large blocks of evergreen lowland moist forest, and the central portion has one of the lowest human population densities in Africa. Most of the floral and faunal assemblages are intact, including assemblages of threatened large mammals, such as the western lowland gorilla (Gorilla gorilla gorilla), mandrill (Mandrillus sphinx), and sun-tailed monkey (Cercopithecus solatus). Important centers of endemism are found in this ecoregion, particularly in some of the coastal mountain ranges.

Western Congolian forest-savanna mosaic

Western Congolian forest-savanna mosaic (AT0723) covers most of western DRC where large dissected plateaus frame the lower Congo River, separated by spectacular canyons that plunge down to depths of 980 ft (300 m). Around the river, and extending further south into Angola, this ecoregion is a mix of dry and moist forests, savanna, and grasslands. A number of primates can be found here, including the endangered Bouvier’s red colobus and the Black mangabey, which lives in the forest canopy along waterways. Other mammals found here include elephants, lions, forest buffaloes, warthogs, and a variety of antelopes such as waterbuck, reedbuck, common duiker, and even the swamp-dwelling sitatunga, the most aquatic of the antelopes. A number of bird species are endemic here, including the [White-headed robin-chat]] and the Orange-breasted bush-shrike, two species threatened by forest clearing. Major urban centers, such as Kinshasa and Brazzaville, hold human populations that still depend on the forest for resources such as bushmeat and wood for construction. The Congo River and local roads provide easy access to the forest. In more rural areas, vegetation is often converted to agriculture. But perhaps the biggest threat of all has been civil wars plaguing Angola, the DRC, and the Republic of Congo which produce massive movements of refugees and devastate the environment.

Angolan Miombo woodlands

Covering all of central Angola and extending into the Democratic Republic of Congo, the extensive Angolan miombo woodlands are part of an even larger miombo ecosystem that covers much of eastern and southern Africa. The miombo is characterized by several unique ecological factors, including its propensity to burn, the importance of termites, and the unusual browsing conditions found here. While only poor-quality browsing is available, this ecoregion hosts a rich assortment of large mammals, some bulk feeders like the African elephant (Loxodonta africana), some specialized feeders such as the sable antelope (Hippotragus niger), and some, such as the tsessebe (Damaliscus lunatus), that utilize the wetlands scattered throughout this ecoregion. However, large mammal populations and all conservation activities have been severely affected by the decades-long civil war in Angola since 1974.

The ecoregion lies mainly in the Cubango-Zambezi Basin, which is an extensive area of gently undulating hills drained by rivers that flow eastwards into the Zambezi River. It is also drained by the endorheic Kwando-Cubango system and the Kunene River. The northern portion of the ecoregion is part of the Congo Basin, while in the west, it extends onto the Old Plateau which includes the highlands of Huíla, Huambo, and Bié.

Southern Congolian forest-savanna mosaic

Covering a broad area of southern Democratic Republic of Congo, the Southern Congolian Forest-Savanna Mosaic is a blend of forest, woodland, shrubland and grassland habitats. While the forests here boast only a few endemic species, they have a rich fauna, including a number of different antelope species and high numbers of African elephants. This rich blend of habitats provides key insights into the biogeography of Central Africa, which has experienced large climatic fluctuations over the last 10 million years. While there is only one protected area in this ecoregion, the human population is low. However, the civil war in the Democratic Republic of Congo has had unknown effects on this ecoregion and, until stability returns, no significant conservation work is likely to be accomplished.

Central Congolian lowland forests

The Central Congolian Lowland Forests ecoregion lies in the central part of the Congo Basin, south of the wide arc formed by the Congo River. The network of rivers function as distribution barriers to many species, thereby isolating this lowland basin along its northern, eastern, and western limits. The headwaters of the Lopori, Maringa, Ikelemba, Tshuapa, Lomela, and Lokoro Rivers lie within this ecoregion, while their lower drainage basins are included in the Eastern Congolian Swamp Forests ecoregion. Because of the relatively flat topography of the area, most of these rivers are slow flowing with heavy sediment loads, and numerous alluvial islands.

The Central Congolian Lowland Forests ecoregion is globally recognized for its intact assemblages of rainforest flora and fauna, particularly the bonobo (Pan paniscus). Apart from primates, however, very little biological information exists. The northern, eastern, and western limits of the ecoregion are bound by the Congo River and swamp forest while in the south there is a gradual transition to savanna-forest mosaic. There are few threats at present, with most of the area remaining largely intact. Scientific research is a priority, together with the enhanced management of existing protected areas.

Eastern Congolian swamp forests

The Eastern Congolian Swamp Forests are found on the left bank (facing downriver) of the Congo River and its tributaries, forming a large arc across the central portion of the Congo Basin. The ecoregion is located wholly within the Democratic Republic of Congo.

Topographically, the area is almost entirely flat and occurs between 350 and 400 meters (m) in elevation. It is a part of the wet tropics, with mean annual rainfall over 2 meters. There is little seasonality, as the area is close to the equator, and the humidity level is high. Human population densities average around 12 persons per km2, and are generally concentrated in villages along the major river systems.

This ecoregion encompasses a number of the Congo River's largest tributaries. The most dramatic change in topography and the largest riparian barrier is the Stanley Falls, located near Kisangani. The most important tributaries and other waterbodies are the following (from west to east): Lake Ntomba, Lake Tumba, the Ruki-Momboyo, and Ruki-Busira-Tshuapa-Lomela systems, the Lulonga-Maringa-Lopori system, and the Lomami system.

The Eastern Congolian swamp forest, combined with the neighboring Western Congolian swamp forest, contain some of the largest areas of swamp forest on the planet. Although not known to be particularly outstanding in either species richness or endemism, these forests are largely intact. Poaching is likely to have reduced populations of forest elephants (Loxodonta africana cyclotis) along the main rivers, especially close to any navigable waterways. Biologically, this is one of the least known ecoregions in the world, and surveys are urgently needed. Conservation efforts are required to safeguard populations of bonobos (Pan paniscus), and to assist the management of protected areas.

It has been recently estimated that about 124,000 km2 of swamp forests remain in the Congo Basin, with perhaps half in this ecoregion. The Congo River is a highly navigable waterway, making most of the area accessible to poachers. Salonga National Park, Lomako Reserve, and Lomami Lualaba Forest Reserve all fall within this ecoregion, although Salonga N.P. contains the largest area of swamp forest under formal protection. Tumba is another area that has been proposed for protection, as have other priority areas for biodiversity conservation.

Logging and associated poaching are the major threats in this ecoregion due to the ease of access through the Congo River and its tributaries. The Service Permanent d'Inventaire d'Amenagement Forestier has noted that extensive areas along the left bank of the Congo River has been allocated as concessions for logging.

Hunting is a major threat. Larger species are hunted for bushmeat, elephants are hunted for ivory and meat, and bonobos are hunted for meat, fetishes and the pet trade. Anecdotal information suggests that elephants have disappeared from large areas. Elephant hunting in the Democratic Republic of Congo is extremely well organized and professional. Areas close to the Congo River and other major waterways may have also suffered reduction in other wildlife populations, including bonobos.
Satellite view of the central Congo basin, Democratic Republic of the Congo Photograph by National Geographic Society

Western Congolian swamp forests

Western Congolian Swamp Forests ecoregion stretches from eastern Republic of Congo through to the western portion of the Democratic Republic of Congo (DRC), and into the Central African Republic. This ecoregion lies on the western bank of the Congo River, which forms a major biogeographic barrier to the Eastern Congolian Swamp Forests and Central Congolian Lowland Forests. The river in this section can be up to 15 kilometers (km) wide, and becomes braided in a maze of alluvial islands. The Western Congolian Swamp Forests have an irregular shape (reflecting riparian habitats) bounded by the right bank of the Congo River between the confluence of the Lualaba (Upper Congo) and the Lomami Rivers to the confluence of the Lefini and the Congo Rivers.

This ecoregion, combined with the neighboring Eastern Congolian Swamp Forests, contains one of the largest continuous areas of swamp forest in the world. Although relatively few species have been recorded, it remains largely intact and contains large populations of western lowland gorilla (Gorilla gorilla gorilla). Poaching is thought to have reduced populations of forest elephants (Loxodonta africana cyclotis) along the navigable waterways. Little research has focused on this region, and further efforts are necessary to better understand these forests and their species composition. There are no protected areas.

Northeastern Congolian lowland forests

The Northeastern Congolian Lowland Forest is located in the northeastern portion of the Democratic Republic of Congo (DRC) and extends into the Southeastern portion of the Central African Republic (CAR). It occupies a roughly triangular area of land supporting lowland and sub-montane rainforest vegetation. The northern margin fixed by the transition to savanna and woodland habitats, the eastern border is bounded by the Albertine Rift Montane Forests, and the southern and western margins are delimited by the Congo River and its tributaries, primarily the Elila River.

The ecoregion declines in elevation from east to west, from the Albertine Rift Mountains towards the Congo River.

The Northeastern Congolian Lowland Forests contains endemic species and large areas of forest wilderness with intact animal and plant assemblages. Endemic species include the okapi (Okapia johnstoni), aquatic genet (Osbornictis piscivora), and the Congo peacock (Afropavo congensis). The forests also provide critical habitat for endangered species such as eastern lowland gorilla (Gorilla gorilla graueri). There are some protected areas, but the recent military conflicts in Rwanda, Burundi, and the Democratic Republic of Congo have made these difficult to manage. Threats come from mining, logging, hunting, and agricultural clearance of forest, often by refugees.

In the DRC, an important part of the Ituri forest is now protected within the Okapi Faunal Reserve (see map below). Other lowland forest areas are protected within the Kahuzi-Biega National Park, the Maïko National Park and the Yangambi Reserve. At present the Yangambi reserve is seriously compromised, and of uncertain conservation value. Further reserves which should be assessed to determine their values are the Rubi Tele Domaine de Chasse, the Maika Penege Reserve (near Isiro), and on the ecoregions northern border, the Bili-Uere Domaine de Chasse. The total area under protection is roughly 31,000 km2, representing around 6 percent of the ecoregion. Lowland forest of the Itombwe Massif is currently unprotected, but of high conservation value.

The ecoregion contains part of one of the great rain forest wildernesses in the world. This is particularly true in the central part of the ecoregion where the extensive forests support a low density of forest dwelling Mbuti pygmies, and associated agricultural peoples. Soils and agriculture potential are better in the east and south of the ecoregion, especially in Kivu Province. This land is suitable for cattle ranching and plantation agriculture, including coffee. The wars in Rwanda and Burundi and in eastern Congo have displaced many people into the eastern part of the ecoregion. However, these wars have also led to the depopulation of other areas, allowing for potential regrowth of forest cover in the future.

Northern Congolian forest-savanna mosaic

The Northern Congolian Forest Savanna Mosaic ecoregion includes the northernmost savanna woodlands in Africa. Forming the northern border of the Congo watershed, it begins east of the Cameroon highlands and extends east through the Central African Republic, northeastern Democratic Republic of Congo and into southwestern South Sudan and a sliver of north-western Uganda. The Ubangi and Uele Rivers demarcate the central and eastern borders with the northeastern Congo rain forest, while the Bar al Ghazall, part of the Upper Nile drainage, delineates the transition to the Saharan flooded grasslands to the east.

Unlike the Zambezian forest-savanna mosaics south and west of the Congo Basin, this narrow transition zone marks an abrupt habitat discontinuity between the extensive Congolian rain forests and Sudanian/Sahelian grasslands. With their characteristically diverse habitat complexes, forest savanna mosaics support a high proportion of ecotonal habitats, which have high species richness and are possible locii of tropical differentiation and speciation. The gallery forests of Garamba National Park in northeastern DRC shelter the last known populations of northern white (square-lipped) rhinoceros (Ceratotherium simum cottoni) and at the western extreme of this ecoregion is the last population of the western black rhino, (Diceros bicornis longipes). However, political and economic instability and population growth throughout Central Africa exert intense pressure on parts of this ecoregion, especially in the eastern portion. The Garamba rhinos had plunged to a record low of 15 individuals in 1984 as a result of intensive poaching. By 1996, their numbers doubled under conservation efforts (WCMC), but continuing regional instability could eliminate this remnant population.

East Sudanian savanna

This ecoregion lies south of the Sahel in central and eastern Africa, and is divided into a western block and an eastern block by the Sudd swamps in the Saharan Flooded Grasslands ecoregion. The western block stretches from the Nigeria/Cameroon border through Chad and the Central African Republic to western Sudan. The eastern block is found in eastern Sudan, Eritrea, and the low-lying parts of western Ethiopia, and also extends south through southern Sudan, into northwestern Uganda, and marginally into the Democratic Republic of Congo around Lake Albert.

The East Sudanian Savanna is a hot, dry, wooded savanna composed mainly of Combretum and Terminalia shrub and tree species and tall elephant grass (Pennisetum purpureum). The habitat has been adversely affected by agricultural activities, fire, clearance for wood and charcoal, but large blocks of relatively intact habitat remain even outside protected areas. Populations of some of the larger mammal species have been reduced by hunting, but good numbers of others remain. Although numerous protected areas exist, most are under-resourced "paper parks" with little active enforcement on the ground, and some have suffered from decades of political instability and civil unrest. The poor infrastructure and inaccessibility of the region have resulted in little development of tourism and wildlife-related revenue generation schemes, with the notable exception of sport hunting in the Central African Republic. Considerable external support to this ecoregion from multilateral and bilateral aid agencies is likely to be needed for many years to maintain or improve current levels of biodiversity.

Ruwenzori-Virunga montane moorlands

Ruwenzori-Virunga montane moorlands occurs in two mall border areas mostly above 9,800 feet (3,000 m) atop the Ruwenzori and Virunga mountains. Habitat types include lakes at various altitudes, marshy deltas and peat bogs, open montane grasslands, areas of scrub, patches of high elevation forest, glaciers, and even snow fields. It include habitat for the vulnerable mountain gorilla, the Ruwenzori-Virunga Montane Moorlands contain two World Heritage Sites--areas set aside for protection by international treaties.

Albertine Rift montane forests

The Albertine Rift is dominated by a series of mountain chains, originating on the Lendu Plateau in northern Uganda and the Democratic Republic of the Congo (DRC), and running south through the Ruwenzori mountains of Uganda and the eastern part of the Democratic Republic of Congo (03°N, 30°E), western Rwanda and Burundi, to some isolated massifs on the shores of Lake Tanganyika (to 08 °S).

The Albertine Rift forms the epicenter of Africa’s montane rainforest circle. Both its fauna and flora have links to the west and southwest with Cameroon and Angola, to the northeast with the Kenyan Highlands, and the southeast with the Eastern Arc Mountains, and ultimately via the Malawi Rift with southern Africa. On the western side it abuts the Guinea-Congolian lowland rainforest. Collectively, its central location within Africa, juxtaposition of habitats, and prevalent altitudinal zonation, makes the Albertine Rift globally outstanding for its high species diversity and large numbers of endemics; highlighted by the ecoregion containing the world’s last population of Mountain Gorilla.

The Albertine Rift Mountains ecoregion is an area of exceptional faunal and moderate floral endemism. These mountains also support the Mountain gorilla (Gorilla gorilla beringei), which is one of the most charismatic flagship species in Africa, and an effective target for much of the current conservation investment in the area. The mountain chain comprising the Albertine Rift straddles the borders of five different nations, and this makes effective ecoregional conservation a challenge in the area. Although there are a number of National Parks and Forest Reserves in the area, the recent wars have made their management difficult over much of the ecoregion. Additional threats include conversion of most forest areas outside reserves into farmland, together with logging, firewood collection, and bushmeat hunting within the remaining forest areas.

The Albertine Rift is one of Africa’s most species rich and endemic-rich regions, despite being one of its most poorly documented.

Some of the highest population pressures in Africa are to be found within the Albertine Rift with many families living on small farms originally cleared from the forest. Consequently, remaining blocks of habitat range from undisturbed to highly disturbed. For Rwanda alone, 1998 logged a minimum of 55% of the original extent of afromontane forest in 1934.

The forests of the Lendu Plateau in the northern reaches of the Albertine Rift have almost completely disappeared.

The farming activities of rural people are destroying and fragmenting habitats of this ecoregion in many areas, and this issue is the largest and most overriding concern for conservation in the area. Coupled to high human population density and destruction of habitat, is hunting and poaching, which is causing major problems in several protected areas and is even more intense outside these areas. Firewood collection is also a serious problem in several areas.

Populations of elephant (Loxodonta africana), as well as many other large mammal species, have been decimated during the regions turbulent political past. This is especially the case in the DRC Virunga national park.

Central Zambezian Miombo woodlands

The Central Zambezian Miombo Woodland is one of the largest ecoregions in Africa, ranging from Angola up to the shores of Lake Victoria in Tanzania. This ecoregion covers the southeastern third of the Democratic Republic of Congo (DRC).

All the typical miombo flora are represented here, but this region has a higher degree of floral richness, with far more evergreen trees than elsewhere in the miombo biome. The harsh dry season, long droughts, and poor soils are ameliorated by the numerous wetlands spread throughout the ecoregion, covering up to 30 percent of the region’s total area. As a result, a diverse mix of animals is found here, from sitatunga (swamp-dwelling antelopes), to chimpanzees, in the world-famous Gombe Stream Reserve. The bird life is also exceptionally rich, as is the fauna of some amphibian groups. The ecoregion contains areas of near-wilderness with exceptionally low human populations and extensive protected areas. Other parts of the ecoregion, typically close to lakes and mountains, have higher population densities and the miombo is much more degraded. Bushmeat hunting, dryland agriculture, deforestation especially for charcoal production near larger towns, and mining are increasing threat in this ecoregion.


Ecoregions are areas that:

[1] share a large majority of their species and ecological dynamics;
[2] share similar environmental conditions; and,
[3] interact ecologically in ways that are critical for their long-term persistence.

Scientists at the World Wildlife Fund (WWF), have established a classification system that divides the world in 867 terrestrial ecoregions, 426 freshwater ecoregions and 229 marine ecoregions that reflect the distribution of a broad range of fauna and flora across the entire planet.

National parks and preserves

Source: Protected Planet.

  1. Salonga National Park
  2. Sankuru Nature Reserve
  3. Ngiri-Tumba-Maindombe Wetlands
  4. Réserve de Abumonbazi
  5. Bomu Wildlife Reserve
  6. Garamba National Park
  7. Okapi Faunal Reserve
  8. Virunga National Park
  9. Maiko National Park
  10. Kahuzi-Biéga National Park

See also:

Further Reading
  1. Bailey, Robert G. 2002. Ecoregion-Based Design for Sustainability. Springer-Verlag. New York, New York. 240pp., 100 illus. ISBN 0-387-95430-9
  2. Bailey, Robert G. 1998. Ecoregions: The Ecosystem Geography of the Oceans and the Continents. Springer-Verlag. New York, New York. 192pp., 107 illus., 10 tables. ISBN 0-387-98305-8
  3. Bailey, Robert G. 1996. Ecosystem Geography. Springer-Verlag. New York, New York. 216pp., 122 illus., 14 tables. ISBN 0-387-94586-5
  4. Omernik, James M., 1995. Ecoregions: A spatial framework for environmental management. In: Biological Assessment and Criteria: Tools for Water Resource Planning and Decision Making. Davis, W.S. and T.P. Simon (eds.) Lewis Publishers, Boca Raton, FL. Pp. 49-62. ISBN: 0873718941.

Urban yards as birds' refuges

EoE - September 6, 2012 - 5:41pm

Urban yards with plants that mimic native vegetation offer birds "mini-refuges" and help to offset losses of biodiversity in cities,. Such purposeful landscaping with native vegetation helps local bird species.

Native Plants in Urban Yards Offer Birds "Mini-Refuges"

Yards with plants that mimic native vegetation offer birds "mini-refuges" and help to offset losses of biodiversity in cities, according to results of a study published in the journal PLOS ONE.

"Native" yards support birds better than those with traditional grass lawns and non-native plantings.

Researchers conducted the study through the National Science Foundation's (NSF) Central Arizona-Phoenix Long-Term Ecological Research (LTER) site, one of 26 such sites around the globe in ecosystems from coral reefs to deserts, from forests to grasslands.

"To a desert bird, what's green is not necessarily good," says Doug Levey, program director in NSF's Division of Environmental Biology. "Arizona birds don't view lush urban landscapes as desert oases. The foraging behavior of birds in greener yards suggests that there's less food for them there than in yards with more natural vegetation."

The research, led by scientists Susannah Lerman and Paige Warren of the University of Massachusetts-Amherst, and Hilary Gan and Eyal Shochat of Arizona State University, looked at residential landscape types and native bird communities in Phoenix, Ariz.

It's among the first to use quantitative measures and a systematic approach--including 24-hour video monitoring--in yards to assess and compare foraging behavior of common backyard birds.

The scientists found that desert-like, or xeric, yards had a more even bird community and superior habitat compared with moist, or mesic, grass lawns.

"We already know that bird communities differ, and that there are more desert birds found in a desert-type yard," says Lerman.

"With this study, we're starting to look at how different yards function--whether birds behave differently by yard type. We're doing that using behavioral indicators, especially foraging, as a way of assessing birds' perceptions of habitat quality between differing yard designs."

Lerman and colleagues conducted the experiment in 20 residential yards at least 1.8 miles apart, making it unlikely that the same birds would visit more than one study yard.

Half the yards were desert-like, while the others had green lawns.

From February through April 2010, homeowners removed bird feeders before and during a 24-hour experimental data collection period.

The researchers set up feeding stations--seed trays--in each yard to simulate resource patches similar to ones where birds feed in the wild. Plastic trays contained 0.70 ounces of millet seed mixed into six pounds of sand. The trays were placed on low stools and left out for 24 hours.

Later, Lerman removed the trays, sifted out and weighed uneaten seed to the nearest 0.01 gram. The amount of seed remaining quantified the giving-up densities (GUD), or the foraging decision and quitting point for the last bird visiting a seed tray.

Trays were videotaped for the entire 24-hour experiment.

The experiment assumed that an animal behaving optimally would stop foraging from a seed tray when its energy gains equal the "costs" of foraging, Lerman says.

Costs include predation risk, digestion and missed opportunities to find food elsewhere.

As time spent foraging at a seed tray increases, so do the costs associated with foraging. When a bird first arrives at the tray, seeds are easy to find, but that gets harder as the tray becomes depleted.

Each bird makes a decision about whether to spend time searching in the tray or to move on to a new patch in the yard.

The "giving up" point will be different for different species and in different environmental conditions. Birds visiting seed trays in yards with more natural food available will quit a tray sooner than birds in resource-poor yards.

Since the method only measures the foraging decisions for the last species visiting the seed tray, the researchers devised a mathematical model for estimating the foraging decisions for all visiting species.

Using the videotapes, they counted every peck by every bird for each tray to calculate the relationship between the number of pecks and grams of seed consumed for each seed tray. This was the GUD-peck ratio for the last species visiting the seed tray.

They then estimated the seed consumption--GUD ratio for all other species visiting the seed tray based on the number of pecks per tray when each species quit.

"We know how many pecks each species had and can put that number into the model and calculate the number of grams at that point," Lerman says. This greatly enhances the GUD method by expanding the ability to assess foraging decisions for all species visiting trays.

In all, 14 species visited the trays, 11 of which visited both yard types. Abert's towhee, curve-billed thrasher (a species unique to the Sonoran desert), house finch and house sparrow were the most widespread tray visitors.

Species that visited trays in both yard designs consumed more seed from trays placed in mesic yards, indicating lower habitat quality compared with xeric yards.

Similarly, foragers in the desert-like yards quit the seed trays earlier due to greater abundance of alternative food resources in those yards, spending more time foraging in the natural yards and less at the seed trays.

Lerman says that by videotaping the trays, counting pecks and measuring giving-up points by species, the research also advanced the GUD method, allowing researchers to disentangle some of the effects of bird community composition and density of competitors, and how these factors affect foraging decisions between two different landscape designs.

The results build upon evidence that native landscaping can help mitigate the effects of urbanization on common songbirds, she says.

August 22, 2012

Read the PLos One Study

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West Nile Virus

EoE - September 6, 2012 - 5:41pm

Since 1999, more than 30,000 people in the United States have been reported as getting sick with West Nile virus. Infected mosquitoes spread West Nile virus (WNV) that can cause serious, life altering disease.

West Nile Virus: What You Need To Know CDC Fact Sheet

Download PDF version formatted for print [PDF - 2 pages]

  What Is West Nile Virus?


West Nile virus (WNV) is a potentially serious illness. Experts believe WNV is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall. This fact sheet contains important information that can help you recognize and prevent West Nile virus.


What Can I Do to Prevent WNV?


New! Prevention measures consist of community-based mosquito control programs that are able to reduce vector populations, personal protection measures to reduce the likelihood of being bitten by infected mosquitoes, and the underlying surveillance programs that characterize spatial/temporal patterns in risk that allow health and vector control agencies to target their interventions and resources.


The easiest and best way to avoid WNV is to prevent mosquito bites.


  • When you are outdoors, use insect repellent containing an EPA-registered active ingredient. Follow the directions on the package.
  • Many mosquitoes are most active at dusk and dawn. Be sure to use insect repellent and wear long sleeves and pants at these times or consider staying indoors during these hours.
  • Make sure you have good screens on your windows and doors to keep mosquitoes out.
  • Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets and barrels. Change the water in pet dishes and replace the water in bird baths weekly. Drill holes in tire swings so water drains out. Keep children's wading pools empty and on their sides when they aren't being used.
What Are the Symptoms of WNV?


  • Serious Symptoms in a Few People. About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.
  • Milder Symptoms in Some People. Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.
  • No Symptoms in Most People. Approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.
How Does West Nile Virus Spread?


  • Infected Mosquitoes. Most often, WNV is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.
  • Transfusions, Transplants, and Mother-to-Child. In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding and even during pregnancy from mother to baby.
  • Not through touching. WNV is not spread through casual contact such as touching or kissing a person with the virus.
An enlarged view of a Culex quinquefasciatus mosquito larva. The C. quinquefasciatus mosquito is known as one of the many arthropodal vectors responsible for spreading the arboviral encephalitis, West Nile virus (WNV) to human beings through their bite when obtaining a blood meal. Source: CDC; Credit: Harry Weinburgh.


How Soon Do Infected People Get Sick?


People typically develop symptoms between 3 and 14 days after they are bitten by the infected mosquito.


How Is WNV Infection Treated?


There is no specific treatment for WNV infection. In cases with milder symptoms, people experience symptoms such as fever and aches that pass on their own, although even healthy people have become sick for several weeks. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment including intravenous fluids, help with breathing and nursing care.


What Should I Do if I Think I Have WNV?


Milder WNV illness improves on its own, and people do not necessarily need to seek medical attention for this infection though they may choose to do so. If you develop symptoms of severe WNV illness, such as unusually severe headaches or confusion, seek medical attention immediately. Severe WNV illness usually requires hospitalization. Pregnant women and nursing mothers are encouraged to talk to their doctor if they develop symptoms that could be WNV.


What Is the Risk of Getting Sick from WNV?


People over 50 at higher risk to get severe illness. People over the age of 50 are more likely to develop serious symptoms of WNV if they do get sick and should take special care to avoid mosquito bites.


Being outside means you're at risk. The more time you're outdoors, the more time you could be bitten by an infected mosquito. Pay attention to avoiding mosquito bites if you spend a lot of time outside, either working or playing.


Risk through medical procedures is very low. All donated blood is checked for WNV before being used. The risk of getting WNV through blood transfusions and organ transplants is very small, and should not prevent people who need surgery from having it. If you have concerns, talk to your doctor.


Pregnancy and nursing do not increase risk of becoming infected with WNV.


The risk that WNV may present to a fetus or an infant infected through breastmilk is still being evaluated. Talk with your care provider if you have concerns.


What Is the CDC Doing About WNV?


CDC is working with state and local health departments and other government agencies, as well as private industry, to prepare for and prevent new cases of WNV.


Some things CDC does with respect to WNV include:


  • Manage and maintain ArboNET, a nation-wide electronic surveillance system where states share information about WNV and other arboviral diseases;
  • Support states develop and carry out improved mosquito prevention and control programs;
  • Develop better, faster tests to detect and diagnose WNV;
  • Prepare updated prevention and surveillance information for the media, the public, and health professionals; and
  • Work with partners on the development of vaccines.
What Else Should I Know?


If you find a dead bird: Don't handle the body with your bare hands. Contact your local health department for instructions on reporting and disposing of the body. They may tell you to dispose of the bird after they log your report.


For more information call the CDC public response hotline

at (888) 246-2675 (English), (888) 246-2857 (Español), or (866) 874-2646 (TTY)




Human Microbiome Project

EoE - September 6, 2012 - 5:41pm

The Human Microbiome Project (HMP) aims to characterize the microbial communities found at several different sites on the human body, including nasal passages, oral cavities, skin, gastrointestinal tract, and urogenital tract, and to analyze the role of these microbes in human health and disease.

Human Microbiome Project

Within the body of a healthy adult, microbial cells are estimated to outnumber human cells ten to one. This community, however, remains largely unstudied, leaving their influence upon human development, physiology, immunity, and nutrition almost entirely unknown. To take advantage of recent technological advances and to develop new ones, the NIH Common Fund Human Microbiome Project (HMP) was established with the mission of generating resources enabling comprehensive characterization of the human microbiota and analysis of their role in human health and disease.

Traditional microbiology has focused on the study of individual species as isolated units. However the vast majority of microbial species have never been successfully isolated as viable specimens for analysis, presumably because their growth is dependent upon a specific microenvironment that has not been, or cannot be, reproduced experimentally. Advances in DNA sequencing technologies have created a new field of research, called metagenomics, allowing comprehensive examination of microbial communities, even those comprised of uncultivable organisms. Instead of examining the genome of an individual bacterial strain that has been grown in a laboratory, the metagenomic approach allows analysis of genetic material derived from complete microbial communities harvested from natural environments. In the HMP, this method will complement genetic analyses of known isolated strains, providing unprecedented information about the complexity of human microbial communities.

The NIH Human Microbiome Project is one of several international efforts designed to take advantage of metagenomic analysis to study human health. The HMP expects to continue the practice established by the Human Genome Project of international collaboration to generate a rich, comprehensive, and publicly available data set. This information will be available worldwide for use by investigators and others in efforts to understand and improve human health.

HMP includes the following initiatives.

For more information on the Human Microbiome Project, e-mail [email protected] or visit http://www.hmpdacc.org

Temperature rise 'slows economy in poor countries'

EoE - September 6, 2012 - 5:41pm

Paula Park reports in SciDev.Net on August 16, 2012, that [s]mall increases in temperature may have reduced the industrial and agricultural production of poor countries, according to a study by Melissa Dell and Benjamin A. Olken at MIT and Benjamin F. Jones at Northwestern University.

Temperature rise 'slows economy
in poor countries'

Higher temperatures may also have contributed to political instability in these countries — defined as those with below-median per capita income, adjusted for the purchasing power of the country's currency — according to the study published in the American Economic Journal: Macroeconomics last month. In contrast, rich countries have so far shown no measurable economic or political consequences resulting from temperature change.

"Temperature fluctuations can have large negative impacts on poor countries," said Benjamin Olken, an economics professor at the Massachusetts Institute of Technology, and one of the authors of the study. "If fluctuations affect the growth rate each year, over time that adds to a really big impact."

The authors compared annual temperature and precipitation changes from 1950 to 2003 with aggregate economic output data. Based on the data, the researchers estimated that a one degree Celsius rise in temperature in a given year had reduced economic growth by about 1.3 percentage points on average. By correlating the temperature and precipitation data with regular changes of government, such as elections, and irregular changes, such as coups, the researchers found that higher temperatures are also associated with political instability in poor countries.  

The impact of temperature on political instability may be "one mechanism through which temperature might affect productivity growth", according to the paper. But further work is needed to determine why both a country's economy and its political stability are affected by temperature, the authors said. The findings could be used to tweak the traditional climate change models, allowing them to better distinguish the effects of climate from other factors influencing economies, the paper said.

"There is a huge amount of literature looking at the [impact of temperature] fluctuations," said Melissa Dell, one of the authors of the paper. "We're more able [than before] to convincingly isolate the temperature and not just something that's correlated with it."

Previous findings published in American Economic Review: Papers & Proceedings in 2010 also found that a one degree Celsius warming in a poor country had reduced the growth of all exports by between two and 5.7 percentage points.

Rich countries had not experienced such slowdowns that could be correlated with temperature increases, although the decline in imports from poor countries might have led to consumers in rich countries paying higher prices for commodities, the researchers speculated.

"It has generally been a reasonable assumption that poor countries are disproportionately affected by climate change, which is what the study showed," said Saleemul Huq, a senior fellow in the climate change group at the International Institute for Environment and Development, in United Kingdom. Huq said there was now a need to analyse the impact that severe temperature fluctuations in major food-producing countries may have on developing countries. For example, high temperatures in the United States have resulted in sharp price increases in corn around the world this year.

"I would like to see more about how changes in temperature in one part of the world have repercussions in another part of the world," said Huq. "Climate change in one part of the world can have a tremendous impact in another, that we are not yet aware of."

Link to article abstract in American Economic Journal: Macroeconomics


American Economic Journal: Macroeconomics doi:10.1257/mac.4.3.66 (2012)

American Economic Review: Papers & Proceedings doi:10.1257/aer.100.2.454 (2010)


U.S. carbon dioxide emissions from energy use fell in 2011

EoE - September 6, 2012 - 5:41pm

After an increase in 2010 of 3.3 percent, energy-related carbon dioxide emissions declined in 2011 by 2.4 percent and were 526 million metric tons (9 percent) below the 2005 level. Energy-related carbon dioxide emissions have declined in the United States in four out of the last six years. Main Image Credit: Vitaly Krivosheev-Fotolia.

U.S. Energy-Related Carbon Dioxide Emissions, 2011

Release Date: August 14, 2012   |  Next Release Date: August 2013

U.S. carbon dioxide emissions from energy use fell in 2011

Read the Analysis

After two years of declining carbon dioxide emissions (2008 and 2009) and one year of increasing emissions (2010), carbon dioxide emissions in 2011 fell, but at a less dramatic rate than in 2009. Unlike 2009, the 2011 decline occurred during a year of positive growth in the Gross Domestic Product (GDP).1

Energy-related carbon dioxide emissions, 1990-201119901991199219931994199519961997199819992000200120022003200420052006200720082009201020110-10-5510percent change02468billion metric tons CO2Source: U.S. Energy Information Administration, Monthly Energy Review (July 2012), Table 12.1.energy-related CO2percent change

1For a full definition of Gross Domestic Product, see the end of this analysis.
Note: this analysis examines the level and sources by sector and fuel of energy-related carbon dioxide emissions in 2011 as presented in Section 12: Environment of the Monthly Energy Review (MER).


Part of the 2011 emissions decrease is due to slower economic growth

In 2011, GDP grew by 1.8 percent, but emissions decreased by 2.4 percent (136 million metric tons). This indicates that the carbon intensity of the economy declined by about 4.2 percent.2 The 2011 decrease is only the fourth year since 1990 to experience a decline in carbon intensity of greater than 3.5 percent for the economy as a whole and only the sixth year since 1990 to experience an emissions decline. Since 1990, energy-related carbon dioxide emissions in the United States have grown much more slowly than GDP – in 2007 emissions were 19 percent greater than their 1990 level, but by 2011 were only about 9 percent above the 1990 level. GDP has increased by 66 percent over that same time period.

Percent change in GDP and energy-related carbon dioxide since 199019901991199219931994199519961997199819992000200120022003200420052006200720082009201020110-25255075percentSources: U.S. Energy Information Administration, Monthly Energy Review (July 2012), Table 12.1; Bureau of Economic Analysis, www.bea.gov, as of 7/27/2012. GDPenergy-related CO2 emissions

2The carbon intensity of the economy is carbon dioxide per unit of economic output (CO2/GDP). The carbon intensity of the energy supply is carbon dioxide per unit of energy consumption (CO2/Btu). 


Various factors combine to produce changes in energy-related carbon dioxide emissions

Using the “Kaya Identity,” changes in energy-related carbon dioxide can be understood in terms of economic output (the total change in output as measured by the GDP is the growth in per capita output multiplied by the growth in population), the energy intensity of the economy and the carbon intensity of the fuel mix to meet the demand for energy.3 Since 2000 the population growth rate has declined slowly and annual swings in GDP growth are largely attributed to changes in per capita output.4 Since 2000, only three years have achieved growth in per capita output above 2 percent (2000, 2004, and 2005). Energy-related carbon dioxide emissions increased in all those years. In 2011, growth in population (0.7 percent) and output per capita (1.1 percent), combined to produce GDP growth of 1.8 percent. This was more than offset by a decline in carbon intensity of the energy supply (CO2/Btu) of 1.9 percent. This meant that the decrease in energy intensity of 2.3 percent yielded a decrease in energy-related carbon dioxide of about 2.4 percent.

Percent changes in Kaya factors (2000 - 2011)2000200120022003200420052006200720082009201020110-10-55percent changeSources: U.S. Energy Information Administration, Monthly Energy Review (July 2012), Table 12.1; U.S. Energy Information Administration, Annual Energy Review (October 2011), Table D1; Census Bureau for 2010 and 2011; Bureau of Economic Analysis, www.bea.gov as of 07/27/2012.populationper capita outputenergy intensitycarbon intensityenergy-related CO2
3For a full definition of Kaya Identity, energy intensity, carbon intensity of the energy supply and carbon intensity of the economy see the end of this analysis.
4Population source: Table 1. Annual Estimates of the Population for the United States, Regions, States, and Puerto Rico: April 1, 2010 to July 1, 2011 (NST-EST2011-01), U.S. Census Bureau, Population Division, Release Date: December 2011 http://www.census.gov/popest/data/national/totals/2011/index.html.


Energy use changes in main sectors in 2011

The industrial sector experienced energy consumption growth of 0.7 percent in 2011.5 The commercial sector fell slightly (0.3 percent). Energy consumption in the residential sector fell by 1.1 percent and in the transportation sector by 1.4 percent. The sum of these sector changes meant that total energy consumption fell by 0.5 percent – this coupled with economic growth of 1.8 percent meant that the energy intensity of the economy fell by 2.3 percent.

Energy consumption by end-use sectors, 1990-20111990199119921993199419951996199719981999200020012002200320042005200620072008200920102011010203040quadrillion BtuSource: U.S. Energy Information Administration, Monthly Energy Review (July 2012), Table 2.1.residentialcommercialindustrialtransportation
5End-use sector energy consumption allocates primary energy used in the electric power sector to the end-use sectors based on their share of electricity use.


Special factors drove the consumption decreases in the residential and transportation sectors

Weather is an important factor in residential energy consumption variations from one year to the next. In 2011, cooling degree-days (CDD) were slightly higher than in 2010 (0.7 percent). This would tend to put upward pressure on electricity demand and related emissions. On the other hand, heating degree-days (HDD) fell by 3.2 percent and residential sector energy consumption declined by 1.1 percent.6 In the figure below, the monthly change in heating degree-days and cooling degree-days is weighted by the proportion of degree-days for that month in the prior year (2010). In 2011, transportation-related carbon dioxide emissions fell primarily due to higher fuel costs, improvements in fuel efficiency, and a reduction in miles traveled. In 2010, the price of regular gasoline averaged $2.78 per gallon. In 2011, the average price rose to $3.53 per gallon – an increase of 27 percent. It is estimated that the miles per gallon (mpg) of light duty vehicles improved by 1.0 percent (20.4 to 20.6 mpg) from 2010 to 2011.7 Vehicle miles traveled fell from an average of 8,127 million miles per day in 2010 to 8,029 million miles per day in 2011 (1.2 percent). This contributed to a decline in gasoline consumption of 2.9 percent which, in conjunction with changes in other transportation fuels, resulted in a decline in total energy consumption in the transportation sector of 1.4 percent.

Weighted percent change by month from 2010 for heating and coolingdegree-days in 2011JanFebMarAprMayJunJulAugSepOctNovDec0.0-5.0- changeSources: U.S. Energy Information Administration, Short-Term Energy Outlook, Monthly Energy Review, Tables 2.2, 2.3, 2.5 (July 2012).weighted percent HDD change from prior yearweighted percent CDD change from prior year
6For a full definition of cooling and heating degree-days see the end of this analysis.
7Estimate from the National Energy Modeling System AEO2012.


Role of electricity in the carbon intensity of the energy supply decreases in 2011

The carbon intensity of the energy consumed declined in every sector of the economy. A carbon intensity decline in the electric power sector (-4.0 percent) which accounted for 40 percent of total U.S. primary energy use in 2011, helped achieve the lower carbon intensity of the energy supply. Because primary energy use in the electric power sector is allocated to the end-use sectors based on their share of electricity use, the drop in reported carbon intensity for the end-use sectors was greatest in the residential and commercial sectors (3.1 percent and 3.2 percent, respectively) as these sectors rely heavily on electricity to meet their energy needs.

Change in energy carbon intensity by sector from previous year, 2000-20112000200120022003200420052006200720082009201020110.0-5.0- change Sources: U.S. Energy information Administration, Monthly Energy Review (July 2012), Tables 12.2 to 12.5. Energy carbon intensity values (CO2/Btu) calculated by EIA.residentialcommericalindustrialtransportation


Impact of fuel supply mix in the electric power sector on the carbon intensity of energy supply in 2011

As mentioned above, the carbon intensity of the energy supply (CO2/Btu) declined in every sector in 2011. With the exception of the transportation sector, this decline was influenced by the decline in the carbon intensity of the electric power sector. The share of non-carbon emitting generation in the electric power sector grew from 30 percent in 2010 to 31 percent in 2011. It was a particularly good year for hydropower as generation increased by 25 percent from 2010. Wind power generation increased by 26 percent and solar energy from both thermal and photovoltaic systems increased by 49 percent, but from a small base. Geothermal generation rose about 10 percent. Natural gas generation (the lowest carbon intensity per Btu of the fossil fuels) increased 3 percent and coal (almost twice as carbon intensive as natural gas) declined by 6 percent.

Million kWh change in generation in 2011HydroWindCoalNatural gasAll otherTotal-150,000-100,000-50,000050,000100,000million kWhSource: U.S. Energy Information Administration, Monthly Energy Review (July 2012), Table 7.2b.


Unusual decline in coal generation in 2011

Since 1949, the 2011 decline in coal generation of over 6 percent is second only to the decline in 2009 of almost 12 percent. As recently as 2005, coal's share of electric power sector generation was over 51 percent. By 2011 that share had declined to just over 43 percent. Petroleum generation, which was small to begin with, has also lost share. Natural gas, on the other hand, has steadily grown in market share. The introduction of new, efficient gas-fired capacity and a recent decline in the price of natural gas has helped boost natural gas' share from 14 percent in 2000 to 24 percent in 2011.

Share of generation by major fossil fuel for selected years (1990 - 2011)1990199520002005201020110102030405060percentSource: U.S. Energy Information Administration, Monthly Energy Review (July 2012), Table 7.2b.coalpetroleumnatural gas


Energy-related carbon dioxide emissions in 2011 compared to the last several years on a month-by-month basis

Total monthly emissions show some seasonality with peaks at the beginning and end of each year. There is also a summer peak at a lower level than the winter peak. While all three years (2009-2011) show the same peaks and valleys, the economic slowdown is evident throughout 2009. The decline in heating degree-days in December 2011 is also evident in the data as the December emissions are well below the prior two years.

Monthly total energy-related carbon dioxide emissions, 2009-2011JanFebMarAprMayJunJulAugSepOctNovDec300350400450500550600million metric tons CO2Source: U.S. Energy Information Administration, Monthly Energy Review (July 2012), Table 12.1.200920102011


Emissions by major fuels compared to their consumption

While coal provides 20 percent of U.S. primary energy consumption, it contributes to 34 percent of energy-related carbon dioxide emissions. Petroleum provides 36 percent of the energy consumption, but 42 percent of the emissions. Natural gas, on the other hand, provides 26 percent of the energy consumed but 24 percent of the emissions. About 18 percent of total U.S. energy consumption was from sources that either do not emit carbon dioxide such as nuclear, hydropower, wind and solar or emit carbon dioxide as part of the natural carbon cycle (biomass). Other energy sources, e.g., plastics in municipal solid waste facilities that convert waste to energy, emit small amounts of carbon dioxide but they are less than one percent of the total.

2011 energy consumption and energy-related CO2 emissions share by fuelEnergy consumption,share by fuelEnergy-related CO2 emissions,share by fuelSources: U.S. Energy Information Administration, Monthly Energy Review (July 2012), Table 1.3 and Table 12.1. natural gaspetroleumothercoal


Implications of the carbon dioxide emissions decrease in 2011 for future emissions

It is difficult to draw conclusions from one year of data. Just as 2009 was an atypical year in terms of the magnitude of the emissions decline, and 2010 did not signal a new trend in emissions growth, there are specific circumstances (for example, the large increase in hydropower generation) that contributed to the decline in emissions in 2011. Other factors, such as improvements in vehicle fuel efficiency, abundant supplies of natural gas, and increased use of non-hydro renewable generation, however, could play a continuing role in 2012 and subsequent years.

For the Energy Information Administration's (EIA) projections on emissions and the factors that contribute to their underlying trends, see either our short-term forecast through 2013 that is updated monthly at www.eia.gov/forecasts/steo, or longer-term projections through 2035 that are updated annually at www.eia.gov/forecasts/aeo. EIA's projections of international energy consumption and emissions to 2035 can be found at http://www.eia.gov/forecasts/ieo/.

Starting in the fall of 2010, EIA expanded its reporting of energy-related carbon dioxide emissions in both the Monthly Energy Review (MER) and the Short-Term Energy Outlook (STEO). The MER reports monthly energy-related carbon dioxide emissions derived from our monthly energy data in Chapter 12, while the STEO forecasts these emissions to accompany its traditional forecasts of energy use. For the full range of EIA's emissions products see: http://www.eia.gov/environment/.


Terms used in this analysis:

British thermal unit (Btu): The quantity of heat required to raise the temperature of 1 pound of liquid water by 1 degree Fahrenheit at the temperature at which water has its greatest density (approximately 39 degrees Fahrenheit).

Carbon intensity (economy): The amount of carbon by weight emitted per unit of economic activity. It is most commonly applied to the economy as a whole, where output is measured as the gross domestic product (GDP). The carbon intensity of the economy is the product of the energy intensity of the economy and the carbon intensity of the energy supply. Note: this value is currently measured in the full weight of the carbon dioxide emitted.

Carbon intensity (energy supply): The amount of carbon by weight emitted per unit of energy consumed. A common measure of carbon intensity is weight of carbon per Btu of energy. When there is only one fossil fuel under consideration, the carbon intensity and the emissions coefficient are identical. When there are several fuels, carbon intensity is based on their combined emissions coefficients weighted by their energy consumption levels. Note: this value is currently measured in the full weight of the carbon dioxide emitted.

Cooling degree-days (CDD): A measure of how warm a location is over a period of time relative to a base temperature, most commonly specified as 65 degrees Fahrenheit. The measure is computed for each day by subtracting the base temperature (65 degrees) from the average of the day's high and low temperatures, with negative values set equal to zero. Each day's cooling degree-days are summed to create a cooling degree-day measure for a specified reference period. Cooling degree-days are used in energy analysis as an indicator of air conditioning energy requirements or use.

Energy intensity: A measure relating the output of an activity to the energy input to that activity. It is most commonly applied to the economy as a whole, where output is measured as the gross domestic product (GDP) and energy is measured in Btu that allow for the summing of all energy forms. On an economy-wide level, it is reflective of both energy efficiency as well as the structure of the economy. Economies in the process of industrializing tend to have higher energy intensities than economies that are in their post-industrial phase. The term energy intensity can also be used on a smaller scale to relate, for example, the amount of energy consumed in buildings to the amount of residential or commercial floor space.

Gross domestic product (GDP): The total value of goods and services produced by labor and property located in the United States. As long as the labor and property are located in the United States, the supplier (that is, the workers and, for property, the owners) may be either U.S. residents or residents of foreign countries.

Heating degree-days (HDD): A measure of how cold a location is over a period of time relative to a base temperature, most commonly specified as 65 degrees Fahrenheit. The measure is computed for each day by subtracting the average of the day's high and low temperatures from the base temperature (65 degrees), with negative values set equal to zero. Each day's heating degree-days are summed to create a heating degree-day measure for a specified reference period. Heating degree-days are used in energy analysis as an indicator of space heating energy requirements or use.

Kaya Identity: An equation stating that total energy-related carbon dioxide emissions can be expressed as the product of four inputs: 1) population, 2) GDP (output) per capita, 3) energy use per unit of GDP, and 4) carbon emissions per unit of energy consumed.  The change in the four inputs can approximate the change in energy-related carbon dioxide emissions.

Primary energy: Energy in the form that it is first accounted for in a statistical energy balance, before any transformation to secondary or tertiary forms of energy. For example, coal can be converted to synthetic gas, which can be converted to electricity; in this example, coal is primary energy, synthetic gas is secondary energy, and electricity is tertiary energy. In the context of this analysis it would mean energy consumed directly by a home, business or industrial operation as opposed to electricity generated elsewhere and supplied to the end-user.

For other definitions see the EIA glossary: http://www.eia.gov/tools/glossary/.


Changing climate, changing forests

EoE - September 6, 2012 - 5:41pm

The report focuses on established science and offers recommendations for decision-makers on steps that will make forests more resilient to the effects of climate change. It is a General Technical Report, published by the U.S. Forest Service, and was authored by Lindsey Rustad, John Campbell, Jeffrey S. Dukes, Thomas Huntington, Kathy Fallon Lambert, Jacqueline Mohan, and Nicholas Rodenhouse. The report concludes that the climate of the Northeast has changed and is likely to change more.

The report's Abstract is presented here, and the full document may be downloaded at the link at the end of this page.

Changing climate, changing forests: The impacts of climate change on forests of the northeastern United States and eastern Canada

Key Words: temperate forests, biogeochemistry, carbon cycle, water cycle, climate models, invasive species, wildlife, climate adaptation, climate mitigation


Decades of study on climatic change and its direct and indirect effects on forest ecosystems provide important insights for forest science, management, and policy. A synthesis of recent research from the northeastern United States and eastern Canada shows that the climate of the region has become warmer and wetter over the past 100 years and that there are more extreme precipitation events. Greater change is projected in the future. The amount of projected future change depends on the emissions scenarios used. Tree species composition of northeast forests has shifted slowly in response to climate for thousands of years. However, current human-accelerated climate change is much more rapid and it is unclear how forests will respond to large changes in suitable habitat. Projections indicate significant declines in suitable habitat for spruce-fir forests and expansion of suitable habitat for oak-dominated forests. Productivity gains that might result from extended growing seasons and carbon dioxide and nitrogen fertilization may be offset by productivity losses associated with the disruption of species assemblages and concurrent stresses associated with potential increases in atmospheric deposition of pollutants, forest fragmentation, and nuisance species. Investigations of links to water and nutrient cycling suggest that changes in evapotranspiration, soil respiration, and mineralization rates could result in significant alterations of key ecosystem processes. Climate change affects the distribution and abundance of many wildlife species in the region through changes in habitat, food availability, thermal tolerances, species interactions such as competition, and susceptibility to parasites and disease. Birds are the most studied northeastern taxa. Twenty-seven of the 38 bird species for which we have adequate long-term records have expanded their ranges predominantly in a northward direction. There is some evidence to suggest that novel species, including pests and pathogens, may be more adept at adjusting to changing climatic conditions, enhancing their competitive ability relative to native species. With the accumulating evidence of climate change and its potential effects, forest stewardship efforts would benefit from integrating climate mitigation and adaptation options in conservation and management plans.

Last Modified: 8/13/2012

Editor's Notes:
  • The Authors are: Rustad, Lindsey; Campbell, John; Dukes, Jeffrey S.; Huntington, Thomas; Fallon Lambert, Kathy; Mohan, Jacqueline; Rodenhouse, Nicholas.
  • Year: 2012
  • Publication: Gen. Tech. Rep. NRS-99. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 48 p.
  • View or print this publication (PDF) 2,211 KB's

Effects of household sprays and scented products on heart rate

EoE - September 3, 2012 - 5:34pm

Household cleaning products have been associated with adverse respiratory health outcomes, but their cardiovascular health effects largely are unknown. The goal of the study was to determine if long-term use of household sprays and scented products at home was associated with reduced heart rate variability (HRV), a marker of autonomic cardiac dysfunction.

This Research article, written by Amar J. Mehta, Martin Adam, Emmanuel Schaffner, Jean-Claude Barthélémy, David Carballo, Jean-Michel Gaspoz, Thierry Rochat, Christian Schindler, Joel Schwartz, Jan-Paul Zock, Nino Künzli, Nicole Probst-Hensch, SAPALDIA Team* appeared first in Environmental Health Perspectives—the peer-reviewed, open access journal of the National Institute of Environmental Health Sciences.

The article is a verbatim version of the original and is not available for edits or additions by Encyclopedia of Earth editors or authors. Companion articles on the same topic that are editable may exist within the Encyclopedia of Earth.

Heart Rate Variability in Association with Frequent Use of
Household Sprays and Scented Products in SAPALDIA Abstract

Background: Household cleaning products are associated with adverse respiratory health outcomes, but the cardiovascular health effects are largely unknown.

Objective: We determined if long-term use of household sprays and scented products at home was associated with reduced heart rate variability (HRV), a marker of autonomic cardiac dysfunction.

Methods: We recorded 24-hr electrocardiograms in a cross-sectional survey of 581 Swiss adults, ≥ 50 years of age, who answered a detailed questionnaire regarding their use of household cleaning products in their homes. The adjusted average percent changes in standard deviation of all normal-to-normal intervals in 24 hr (24-hr SDNN) and total power (TP) were estimated in multiple linear regression in association with frequency [< 1, 1–3, or 4–7 days/week, unexposed (reference)] of using cleaning sprays, air freshening sprays, and scented products.

Results: Decreases in 24-hr SDNN and TP were observed with frequent use of all product types, but the strongest reductions were associated with air freshening sprays. Compared with unexposed participants, we found that using air freshening sprays 4–7 days/week was associated with 11% [95% confidence interval (CI): –20%, –2%] and 29% (95% CI: –46%, –8%) decreases in 24-hr SDNN and TP, respectively. Inverse associations of 24-SDNN and TP with increased use of cleaning sprays, air freshening sprays, and scented products were observed mainly in participants with obstructive lung disease (p < 0.05 for interactions).

Conclusions: In predominantly older adult women, long-term frequent use of household spray and scented products was associated with reduced HRV, which suggests an increased risk of cardiovascular health hazards. People with preexisting pulmonary conditions may be more susceptible.

Keywords: airway irritants, autonomic nervous system, epidemiology, heart rate variability, observational studies.


The health hazards associated with household cleaning products are a growing public health concern. Although earlier studies identified the use of cleaning products to be a risk factor for work-related asthma among cleaners employed in industrial and domestic settings (Medina-Ramón et al. 2005; Nielsen and Bach 1999; Rosenman et al. 2003; Zock et al. 2001), more recent studies have observed that nonprofessional use of household cleaning products and air fresheners in domestic settings may be a risk factor for developing asthma (Zock et al. 2007) and breast cancer in females (Zota et al. 2010).

The indoor use of household cleaning products and air fresheners, including products with spray application, may result in inhalational exposures to toxic volatile product constituents [e.g., volatile organic compounds (VOCs)], which are emitted during application, and to secondary pollutants that are formed when these primary constituents react with the indoor environment (e.g., with ozone and secondary organic aerosols) (Bello et al. 2010; Singer et al. 2006; Wolkoff et al. 1998). A wide range of adverse health effects has been observed with indoor exposure to VOCs in nonindustrial environments, including mucosal membrane irritation and systemic effects such as fatigue and poor concentration (Bernstein et al. 2008). A recent statement by the American Heart Association (AHA) on air pollution and cardiovascular disease summarized the role of ambient particles, gases, and chemical substances, including VOCs, in the development of cardiovascular disease (Brook et al. 2010). However, it is largely unknown whether indoor aerosol exposures from household cleaning and air freshening products affect cardiovascular health.

The objective of this study was to examine whether long-term nonprofessional use of household cleaning sprays, air freshening sprays, and scented products in domestic settings was associated with reduced heart rate variability (HRV), an established marker of cardiac autonomic dysfunction and increased cardiovascular events and mortality (Dekker et al. 1997; Kleiger et al. 1987; Tsuji et al. 1996), among participants in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA). SAPALDIA participants who participated in the present study were predominantly women, many of whom were full-time homemakers, which provided a unique opportunity to carry out our objective.


Study population. SAPALDIA is a multicenter, population-based prospective cohort study consisting of a random sample of 9,561 adults who were 18–60 years of age when they were recruited from eight regions in Switzerland (Martin et al. 1997). The baseline survey was conducted in 1991 when participants were administered medical examinations, including spirometry testing, and a detailed health questionnaire. The second assessment (SAPALDIA 2) of 8,047 study participants (84.2%) was conducted from 2001 to 2003 and also included HRV measurements and special questionnaires on work-related exposures (Ackermann-Liebrich et al. 2005). From these participants who were ≥ 50 years of age at the time of SAPALDIA 2 (n = 4,645), 1,846 individuals (955 women, 891 men) were randomly selected for 24-hr electrocardiogram (ECG) monitoring to assess HRV (Felber Dietrich et al. 2006).

In addition, a detailed questionnaire on household cleaning activities was administered to all SAPALDIA 2 participants who responded positively (n = 3,255) to the following question from the health questionnaire, “Have you been the person doing the cleaning and/or washing in your home in the last ten years?” This cross-sectional analysis was restricted to 851 individuals ≥ 50 years of age who had valid HRV measurements and who had completed the household cleaning questionnaire [for a flow chart describing participation, see Supplemental Material, Figure 1 (http://dx.doi.org/10.1289/ehp.1104567)]. Of these 851 participants, 188 were excluded for reporting either occupations that used cleaning products at work (n = 166) or that involved metalworking, welding, or soldering (n = 22). After further exclusion of participants with insufficient exposure or covariate information (n = 82), a total of 581 participants contributed to the analyses. The distributions of basic characteristics were similar between the 581 participants included in this analysis and the 808 nonparticipants, who were also ≥ 50 years of age and reported cleaning activities at their homes, but who were not selected for HRV assessment (see Supplemental Material, Table 1).

  Figure 1. Click for Larger Image.

Adjusted average percent change (95% CIs) in 24-hr SDNN, TP, LF, and HF associated with the use of cleaning sprays (A), air freshening sprays (B), scented products (C), and the number of sprays used weekly (D). Twenty-four-hour SDNN, TP, LF, and HF were modeled on the logarithmic scale in multiple linear regression as a function of each exposure in separate models and then transformed into average percent change relative to unexposed participants (n = 66), after adjusting for sex, age, age2, BMI, BMI2, alcohol consumption, physical activity, smoking status, environmental tobacco smoke exposure, education, employment status, cardiovascular medication intake, uric acid levels, street and railway noise, traffic-related PM10, seasonal effects, and study area. *Ordinal exposure variable p < 0.05. **Ordinal exposure variable p < 0.10.

    Table 1. Click for Larger Image.

Characteristics of participants who reported cleaning in their homes (n = 581).

Ethical approval for the study was given by the central Ethics Committee of the Swiss Academy of Medical Sciences and the Cantonal Ethics Committees for each of the eight examination areas (Aarau, Basel, Davos, Geneva, Lugano, Montana, Payerne, and Wald, Switzerland) and participants signed an informed consent at the examination.

HRV measurements and analyses. Holter recordings, described elsewhere by Felber et al. (2006), were made between August 2001 and March 2003. Recorders were placed on participants who had given consent after a detailed health interview. Participants were asked to follow their regular daily routine during the recording period. To avoid a biased result due to methacholine challenge, which was part of the SAPALDIA lung function testing and which, for practical reasons, was performed before the Holter recording, we excluded the first 2 hr of all recordings. The mean ± SD duration of the Holter recordings was 22.4 ± 2.1 hr. The summary measures of HRV were selected as the primary outcomes of interest in this analysis and included the 24-hr value of the SD of all normal RR (NN) intervals (msec 24-hr SDNN), and the following frequency domain variables: total power (TP; ≤ 0.40 msec2/Hz), low-frequency (LF) power (0.04–0.15 msec2/Hz), and high-frequency (HF) power (0.15–0.40 msec2/Hz). The evaluation of SDNN and TP was also limited to nighttime, which was defined as the time when subjects indicated in the diary that they where sleeping (see Felber et al. 2008; Probst-Hensch et al. 2008). To improve normality of the residuals, each HRV parameter was log transformed in this analysis.

Spirometry testing. The spirometry protocol was equivalent to that of the European Community Respiratory Health Survey (ECRHS) (Burney et al. 1994). No bronchodilation was applied. Participants performed three to eight forced expiratory lung function maneuvers with the spirometer (model 2200; Sensormedics Yorba Linda, CA, USA), and at least two acceptable measurements of forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1) were obtained, complying with the American Thoracic Society criteria (American Thoracic Society 1995).

Respiratory symptoms and medication use. Presence of asthma was based on positive responses to the questions “Have you ever had asthma?” and, if yes, “Was this confirmed by a doctor?” Shortness of breath was defined as a positive response to the question “Are you troubled by shortness of breath when hurrying on level ground or walking up a slight hill?” Chronic bronchitis was defined as self-reported cough or phlegm during the day or at night on most days for as much as 3 months each year for ≥ 2 years. Medication use for asthma or breathing problems was defined by a positive response to either of the following questions: “Has your doctor ever prescribed medicines, including inhalers, for your breathing?”; “Are you currently taking any medicines, including inhalers, aerosols, or tablets for asthma?”; or “Have you taken medicine for asthma during the last 3 days?”

Exposure assessment. The questionnaire module on cleaning and washing in the home, which was adopted from the ECRHS, asked about the frequency of using of 16 different products for domestic cleaning and washing over a period of at least 3 consecutive months since the baseline survey in 1991 (ECRHS 2002). In a previous analysis of Spanish housewives, Medina et al. (2000) compared the frequency responses in this module with a 1-week diary as the gold standard, and the median specificity was 94% across the different cleaning products. We hypothesized that use of products with spray application would better facilitate respiratory exposure to irritants than would nonspray products. Thus, we mainly focused on several spray products used for cleaning glass, furniture, rugs/curtains/carpets, or ovens and on products for ironing, air freshening, and other unspecified purposes. We also examined the use of scented products, which could either be in spray or nonspray form. For each product, the frequency of use was recorded as never, < 1, 1–3, or 4–7 days/week and assigned a score from 0 to 3, respectively. In a preliminary factor analysis, it was determined that the use of cleaning sprays for glass, furniture, and rugs/carpets/curtains contributed to most of the variation in the reported use of spray products in the study sample. A composite score variable for cleaning sprays was subsequently constructed, which was the sum of individual frequency scores for using glass, rug/carpet/curtain, and furniture cleaning sprays with a value ranging from 1 to 9, and divided into four categories (1, 2, 3, ≥ 4). To evaluate the number of sprays used weekly (accounting for all types of sprays, including air freshening sprays), another composite score variable was developed with a value of 1–3 (1, any spray < 1 day/week; 2, 1 spray ≥ 1 day/week; 3, ≥ 2 sprays ≥ 1 day/week).

Statistical analysis. Statistical analyses were performed using SAS software (version 9.2; SAS Institute Inc., Cary, NC, USA). Log-transformed 24-hr SDNN, TP, LF, and HF were regressed separately against the different categorical variables of cleaning spray, air freshening spray, scented products, and number of different sprays used weekly in multiple linear regression (PROC GLM). Effect estimates for each exposure frequency category were first expressed as geometric mean ratios, with unexposed participants as the reference group, and then converted into average percent changes. We also evaluated ordinal exposure–response trends by treating exposure variables as continuous, where unexposed participants were assigned a score of zero. Because 24-hr SDNN and TP are in theory mathematically correlated, the Wilks’ lambda test was used to evaluate the overall association between exposure and both outcomes 24-hr SDNN and TP using the MANOVA procedure, which handles multiple correlated outcomes (Scheiner 2001); only p-values indicating statistically significant deviation (p < 0.05) from the null hypothesis of no association are reported.

All models were adjusted for individual-level covariates that were considered potential confounders of the association between long-term use of household sprays and scented products and HRV including sex (female as reference), age (years), age2, body mass index (BMI; kilograms per meter squared), BMI2, smoking status [former, current, never (reference)], tertiary education level [high, medium, low (reference)], employment status [retired, sick/disabled, or other; fully/partially employed, in military, or student; unemployed housewife/househusband (reference)], weekly physical activity [to the point of getting out of breath or sweating for < 30 min (reference), between 30 min and 2 hr, or > 2 hr], daily alcohol consumption [≥ 1, < 1 drink (reference)], daily exposure to environmental tobacco smoke [ETS, < 3, ≥ 3, 0 hr (reference)], uric acid concentration measured in serum (micromoles per liter), current cardiovascular medication intake [yes, no (reference)], seasonal effects (based on sine and cosine function of day of examination), street-related noise, train-related noise, average traffic-related particulate matter with aerodynamic diameter < 10 μm (PM10) concentration, and study area. The measurement and analysis of personal noise and traffic-related PM10 exposures have been described in detail elsewhere (Dratva et al. 2012; Künzli et al. 2009; Liu et al. 2007).

Having ever smoked, obesity (BMI ≥ 30 kg/m2), cardiovascular medication intake, and markers or symptoms of obstructive lung disease (OBS) were evaluated as potential effect modifiers. We constructed multiplicative interaction terms between each effect potential modifier and ordinal exposure variables (e.g., exposure scores modeled as continuous variables), and included them in separate multiple linear regression models. Only interactions with p-values < 0.05 are reported. In addition, we evaluated interactions with 24-hr SDNN and TP as a combined outcome using the MANOVA procedure described above. OBS was defined as the presence of any of the following markers or symptoms: ratio of forced expiratory volume in 1 sec over forced vital capacity (FEV1:FVC) < 0.70, self-reported symptoms of chronic bronchitis, or self-reported shortness of breath. To evaluate effect modification by OBS as distinct from asthma, we excluded all participants who reported an occurrence of asthma or asthma medication intake from the analysis. We did not evaluate self-reported asthma, diabetes, or heart disease for effect modification because of insufficient numbers of observations for statistical comparisons.

Secondary analyses. Specific cleaning activities were not recorded in the time activity diaries; thus, we were not able to evaluate the acute effect of household sprays and scented products on HRV. Because HRV during nighttime is less likely to be influenced by short-term disturbances, we estimated adjusted average percent changes of (log-transformed) nighttime SDNN and TP in association with the frequency of use of each product type in multiple linear regression. Linear regression models were also repeated with the reference category for each exposure variable comprising both unexposed participants and those who used the product of interest < 1 day/week.


Of the 581 participants, 515 reported using any spray or scented product, and 66 reported using neither any spray nor scented product, the latter of whom were considered unexposed in all analyses (Table 1). Both groups were primarily female and were similar with regard to age, BMI, alcohol consumption, employment status, and education level. However, exposed participants included a significantly larger proportion of ever smokers compared with unexposed participants.

Of the 515 exposed participants, 362 reported using cleaning sprays, 175 reported using air freshening sprays, and 318 reported using scented products [see Supplemental Material, Table 2 (http://dx.doi.org/10.1289/ehp.1104567)]. Among participants who used cleaning sprays, 46 were in the highest frequency category (composite score ≥ 4, 12.7%). Approximately 22% and 24% of participants who reported using air freshening sprays and scented products, respectively, used these products 4–7 days/week. The prevalence of current smokers was highest among participants in the most frequent categories for use of cleaning sprays and air freshening sprays and among participants who reported using scented products ≥ 1 day/week. Exposure to ETS ≥ 3 hr/day was highest among participants who used air freshening sprays 4–7 days/week, among those who used scented products ≥ 1 day/week, and among participants with a composite score ≥ 3 for using cleaning sprays. Finally, minimal physical activity (< 0.5 hr/week) was highest in the most frequent categories of all product types.

Unadjusted average percent changes of each summary HRV measure in association with frequency of using cleaning sprays, air freshening sprays, scented products, and number of sprays used weekly are summarized in Supplemental Material, Table 3 (http://dx.doi.org/10.1289/ehp.1104567). Overall, there is a general pattern of reduction in HRV, particularly for TP, with increased usage of all products. The adjusted effect estimates for TP were not considerably different from the corresponding unadjusted estimates, particularly in the highest frequency categories (Figure 1; see also Supplemental Material, Table 4). Decreases in TP were largest for those who used air freshening sprays 1–3 days/week [–23% (95% CI: –39, –2%)] and 4–7 days/week [–29% (95% CI: –46, –8%)] compared with unexposed participants after adjusting for all other covariates. Compared with unexposed participants, similarly large reductions in TP were also observed in the highest frequency categories for use of cleaning sprays and scented products, and number of sprays used weekly, with average decreases in TP ranging between 17–21%. Finally, ordinal trends for lowered TP (p < 0.05) were also observed with increased use of cleaning sprays, air freshening sprays, and with the number of sprays used weekly (see Supplemental Material, Table 4).

Compared with unexposed participants, the largest decreases in 24-hr SDNN were associated with using air freshening sprays 1–3 days/week [–12% (95% CI: –20, –4%)] and 4–7 days/week [–11% (95% CI: –20, –2%)] [Figure 1; see also Supplemental Material, Table 4 (http://dx.doi.org/10.1289/ehp.1104567)]. Overall (inverse) associations between both outcomes 24-hr SDNN and TP and using air freshening sprays 1–3 days/week and 4–7 days/week were statistically significant (Wilks’ lambda p = 0.02 and p = 0.03, respectively). The inverse ordinal trend of the association between air freshening sprays and both outcomes for 24-hr SDNN and for TP was also statistically significant (Wilks’ lambda p = 0.02; data not shown). Participants who used scented products 4–7 days/week also had reduced 24-hr SDNN [–9% (95% CI: –16, –1%)] compared with unexposed participants.

Similar to TP, an ordinal trend for decreased LF was observed with the number of sprays used weekly [Figure 1; see also Supplemental Material, Table 4 (http://dx.doi.org/10.1289/ehp.1104567)]. Associations with lower frequency categories of all product types were larger for LF than for HF, but associations with HF were comparable to or larger than associations with LF for the highest frequency categories. Compared with unexposed participants, all discrete comparisons between exposures and LF and HF were not statistically significant with the exception of associations between LF and a composite score of 2 for cleaning spray use, and ≥ 2 sprays used weekly (see Supplemental Material, Table 4).

We found no major exposure–response differences in 24-hr SDNN and TP for ever smoking and obesity status [see Supplemental Material, Figures 2 and 3 (http://dx.doi.org/10.1289/ehp.1104567)]. However, for all products of interest, negative associations with 24-hr SDNN and TP were observed mainly among participants with markers or symptoms of OBS (Figure 2). Statistically significant interactions between OBS and air freshening sprays, scented products, and the number of spray products used weekly were present for 24-hr SDNN and TP as separate outcomes (all p < 0.05) and for 24-hr SDNN and TP as combined outcomes (all Wilks’ lambda p < 0.01). The inverse associations of cleaning spray use with 24-hr SDNN and TP were also present mainly among participants with OBS, but a statistically significant interaction was only observed for TP (p = 0.10 and p = 0.02 for interactions with 24-hr SDNN and TP as separate outcomes, respectively). Associations with air freshening sprays and number of sprays used weekly and LF were also modified so that inverse associations were mainly observed among participants with OBS. Inverse associations between LF and cleaning sprays, air freshening sprays, scented products, and multiple sprays were also larger among participants who reported taking cardiovascular medication (see Supplemental Material, Figure 4), but only for the highest frequency categories of each exposure. A significant interaction was also observed between cardiovascular medication intake and the use of cleaning sprays on both 24-hr SDNN and TP (Wilks’ lambda p = 0.03).

  Figure 2. Click for Larger Image.

Adjusted average percent changes (95% CIs) in 24-hr SDNN, TP, LF, and HF associated with the use of cleaning sprays (A), air freshening sprays (B), scented products (C), and the number of sprays used weekly (D) after stratification by OBS. Twenty-four-hour SDNN, TP, LF, and HF were modeled on the logarithmic scale in multiple linear regression as a function of each exposure in separate models and then transformed into average percent change relative to unexposed participants (n = 34, OBS; n = 23, no OBS), after adjusting for OBS, sex, age, age2, BMI, BMI2, alcohol consumption, physical activity, smoking status, environmental tobacco smoke exposure, education, employment status, cardiovascular medication intake, uric acid levels, street and railway noise, traffic-related PM10, seasonal effects and study area. Participants who reported doctor-diagnosed asthma or asthma medication use were excluded from this analysis.

Secondary analyses. Overall, percent decreases in nighttime SDNN and TP in association with the frequency of household spray and scented product use [see Supplemental Material, Table 5 (http://dx.doi.org/10.1289/ehp.1104567)] were smaller than the percent decreases estimated for the 24-hr period. Decreases in nighttime SDNN in association with use of air freshening sprays 1–3 days/week and 4–7 days/week [–10% (95% CI: –20, 0.6%) and –11% (95% CI: –21, 1.2%), respectively)] were comparable to the average percent changes in 24-hr SDNN.

Overall, the exposure–response patterns were unchanged when the reference category for exposure included both unexposed participants and participants who used products < 1 day/week [see Supplemental Material, Table 6 (http://dx.doi.org/10.1289/ehp.1104567)]. The average percent changes in 24-hr SDNN and TP were not as strongly inverse as the corresponding effect estimates presented in the Supplemental Material, Table 2, where the reference category included unexposed participants only.


Potential health hazards associated with household cleaning products are a growing public health concern, but the effects of regular use on cardiovascular health are largely unknown. In this cross-sectional analysis of predominantly older Swiss women who reported cleaning their own homes, we observed that long-term frequent use of household sprays and scented products was associated with reduced HRV, with the strongest inverse associations observed with air freshening sprays. OBS modified the observed associations, such that participants with either airflow obstruction or self-reported chronic respiratory symptoms (in absence of asthma) appeared to be more susceptible to exposure-associated reductions in HRV than other participants.

Reduced HRV is a marker of cardiac autonomic dysfunction and may increase the risk of all-cause mortality in the general population (Dekker et al. 1997; Tsuji et al. 1996) and in patients with heart failure (Task Force of the European Society of Cardiology 1996), as well as increase the risk of nonfatal cardiovascular events, including myocardial infarction and new-onset hypertension (Singh et al. 1998; Tsuji et al. 1996). Reduced HRV has been described as an intermediate factor between air pollution and cardiovascular morbidity and mortality (Pope et al. 2004; Utell et al. 2002); however, the clinical implications of the associations observed between HRV and the use of household sprays and scented products among older adults are not clear. To our knowledge, this is the first study to evaluate the effect of long-term use of household sprays and scented products on cardiovascular health. The present findings should be verified in other study populations before addressing the clinical implications.

Numerous epidemiologic studies have examined the association between ambient air pollution and HRV, and the general pattern suggests that exposure to particulate matter is associated with increased heart rate and reductions in most indices of HRV among older or other susceptible individuals (Brook et al. 2010), but the biological mechanisms linking ambient air pollution and reduced HRV are not fully understood. The recent AHA statement suggests that inhalation of particulate matter may result in disturbance of the autonomic nervous system balance or heart rhythm by particle interactions with lung receptors or nerves (Brook et al. 2010). We hypothesize a similar mechanism applies to exposures from long-term use of household sprays and scented products, which may result in exposure to VOCs or other toxic air contaminants (Bello et al. 2010; Singer et al. 2006; Wolkoff et al. 1998). Ambient VOCs have been shown to increase the risk of cardiovascular mortality (Theophanides et al. 2007; Tsai et al. 2010), and, in a recent occupational study of healthy young adult females (n = 62) working in hair salons, Ma et al. (2010) observed that indoor exposure to nonspecific VOCs was associated with reduced HRV. Mizukoshi et al. (2010) also observed a strong correlation between personal exposure to nonspecific VOCs and a reduction in HRV, particularly HF, in their recent panel study of seven healthy adults who were monitored under usual daily life conditions. Indoor VOCs, particularly the ones from air fresheners, have been shown to interact with ozone to produce secondary organic aerosols indoors. Hence, this may be an additional mechanism of action that could explain stronger effects of air fresheners (Chen and Hopke 2009).

The findings also suggest that those with OBS are more strongly affected by the use of household sprays and scented products, which is of interest. OBS was defined based on symptoms and markers commonly associated with chronic obstructive pulmonary disease (COPD). Although COPD is characterized by chronic airway inflammation, systemic effects have been observed including decreases in HRV and raised systemic inflammation (Sinden and Stockley 2010; Stein et al. 1998; Volterrani et al. 1994). It has been proposed that chronic pulmonary inflammation, by contributing to subclinical systemic inflammation, plays a pivotal role in atherosclerosis and acts as a primary underlying mechanism of cardiovascular morbidity and mortality in association with air pollution exposures (Künzli and Tager 2005). This hypothesis might also apply to effects of long-term exposures to household sprays and scented products. Postbronchodilator spirometry was not performed in this study, so it is possible that some participants classified as having OBS may have had conditions more consistent with asthma (in which airflow obstruction is generally reversible) than with COPD. However, we excluded participants who reported doctor-diagnosed asthma or asthma medication use from the analysis.

Our study has several limitations that should be considered. This was a cross-sectional analysis. Thus, the temporality of exposure–response relations could not be evaluated. The observed findings may also be explained by selection bias should the inclusion of participants in this analysis be associated with both the exposures and outcomes of interest. However, the overall distributions of household spray and scented product use and other characteristics, including smoking and cardiovascular medication intake, were similar between participants and nonparticipants not selected for HRV assessment [see Supplemental Material, Table 1 (http://dx.doi.org/10.1289/ehp.1104567)].

Data collected on the use of household cleaning products were based on self-report, which may result in exposure misclassification. Bias from exposure misclassification is likely nondifferential with respect to HRV, an objective measure, typically leading to a bias towards the null and thus likely resulting in an underestimation of the true association. Exposures resulting from the use of household sprays and scented products also may be modified by home characteristics, such as room size, humidity, ventilation, and temperature, but this information was not collected.

There was also no information available on specific cleaning activities in the time activity diaries recorded during ECG monitoring. Thus, we were not able to estimate acute effects of household sprays and scented products on HRV. It is possible that frequent use of household sprays and scented products over a long duration was associated with an increased likelihood of use of these products immediately before or during ECG monitoring. With the exception of air freshening sprays and nighttime SDNN, average percentage decreases in nighttime HRV in association with exposure were smaller than in corresponding percent decreases in 24-hr HRV, which also raises the question whether principal findings reflect long-term or short-term use of household sprays and scented products.

Although we attempted to control for multiple potential confounders, the observed associations may be biased by residual confounding, such as confounding by sources of indoor air pollution that are known to impair cardiovascular health, including ETS exposures (Barnoya and Glantz 2005) and biomass burning (Baumgartner et al. 2011; McCracken et al. 2011). Indoor measurements of particulate matter and gaseous pollutants were not available in this study, but self-reported information on daily ETS exposure was collected and adjusted for. Additional adjustment for exposure to biomass smoke—which we defined as present if the participant reported use of a wood fireplace, wood burning oven, or either coal, coke, or wood fuel for heating—did not result in any meaningful change in the effect estimates presented (data not shown). Other factors for which we have no available data, such as psychosocial conditions, including anxiety and depression, may also increase the risk of coronary heart disease (Hemingway and Marmot 1999). It is possible that the findings may be explained by unmeasured confounding by these conditions (and other unknown factors) if they increase the risk of reduced HRV and are more prevalent among adults who use household sprays and scented products most frequently. Residual confounding by cigarette smoking, socioeconomic status, and other covariates is also possible. Additional adjustment for cumulative pack-years smoked did not result in any considerable changes in the effect estimates presented (data not shown). Aside from education level, SAPALDIA did not collect information on other proxies for socioeconomic status, such as personal income. Finally, the most frequent users of sprays and scented products tended to be the least physically active on a weekly basis. Although we adjusted for weekly physical activity in our analysis, we cannot exclude the possibility of residual confounding by a hypothetical association between frequent use of sprays and scented products and physical activity on the day of ECG monitoring.

Considering the strength of the observed associations and perceived public health impact, we believe further investigation of the potential effects of exposures to household sprays and scented products on HRV and other cardiovascular outcomes in other study populations is warranted, with emphasis on direct exposure assessment and longitudinal observation of exposures and outcomes. In conclusion, long-term frequent use of household spray and scented products was associated with reduced HRV in a predominantly older population of women, and preexisting pulmonary conditions appeared to increase susceptibility.

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Wolkoff P, Schneider T, Kildesø J, Degerth R, Jaroszewski M, Schunk H.. 1998. Risk in cleaning: chemical and physical exposure. Sci Total Environ 215:135–156. Find this article online

Zock JP, Kogevinas M, Sunyer J, Almar E, Muniozguren N, Payo F, et al. 2001. Asthma risk, cleaning activities and use of specific cleaning products among Spanish indoor cleaners. Scand J Work Environ Health 27:76–81. Find this article online

Zock JP, Plana E, Jarvis D, Antó JM, Kromhout H, Kennedy SM, et al. 2007. The use of household cleaning sprays and adult asthma: an international longitudinal study. Am J Respir Crit Care Med 176:735–741. Find this article online

Zota AR, Aschengrau A, Rudel RA, Brody JG. 2010. Self-reported chemicals exposure, beliefs about disease causation, and risk of breast cancer in the Cape Cod Breast Cancer and Environment Study: a case–control study. Environ Health 9:40.; doi:10.1186/1476-069X-9-40 [Online 20 July 2010] Find this article online

Editor's Notes
  • *The Authors and their Affiliations: Amar J. Mehta1,2,3, Martin Adam1,2, Emmanuel Schaffner1,2, Jean-Claude Barthélémy4, David Carballo5, Jean-Michel Gaspoz5, Thierry Rochat5, Christian Schindler1,2, Joel Schwartz3, Jan-Paul Zock6,7,8, Nino Künzli1,2, Nicole Probst-Hensch1,2, SAPALDIA Team
    1 Swiss Tropical and Public Health Institute, Basel, Switzerland,
    2 University of Basel, Basel, Switzerland,
    3 Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA,
    4 SNA-EPIS (Système Nerveux Autonome, Epidémiologie, Physiologie, Exercice, Santé) Research Team (EA 4607), Department of Clinical and Exercise Physiology, University Hospital of Saint-Etienne, PRES (Pole Research and Higher Education), Lyon, France,
    5 Divisions of Cardiology and Primary Care Medicine, University Hospitals and Faculty of Medicine, Geneva, Switzerland,
    6 Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain,
    7 Hospital del Mar Research Institute (IMIM), Barcelona, Spain,
    8 CIBER Epidemiología y Salud Pública (CIBERESP), Spain
  • Citation: Mehta AJ, Adam M, Schaffner E, Barthélémy J-C, Carballo D, Gaspoz J-M, et al. 2012. Heart Rate Variability in Association with Frequent Use of Household Sprays and Scented Products in SAPALDIA. Environ Health Perspect 120:958-964. http://dx.doi.org/10.1289/ehp.1104567
  • Received: 02 October 2011; Accepted: 10 April 2012; Online: 22 April 2012
  • Address correspondence to A.J. Mehta, Harvard School of Public Health, Landmark Center, West 415, 401 Park Dr., Boston, MA 02215 USA. Telephone: (617) 384-8754. Fax: (617) 384-8745. E-mail: [email protected]
  • We thank the entire SAPALDIA team for their contribution to the study. The study could not have been conducted without the help of the study participants, technical and administrative support, and the medical teams and field workers at the local study sites. C.S., J.C.B., J.M.G., N.K., N.P.H., and T.R. made substantial contributions to the conception and design and to the acquisition of data. A.J.M., C.S., D.C., E.S., J.S., J.P.Z., M.A., N.K., and N.P.H contributed to the analysis and interpretation of the data. A.J.M., C.S., D.C., E.S., J.C.B., J.M.G., J.S., J.P.Z., M.A., N.K., N.P.H., and T.R. assisted in the drafting or the revising of the manuscript. A.J.M., C.S., D.C., E.S., J.C.B., J.M.G., J.S., J.P.Z., M.A., N.K., N.P.H., and T.R. approved the final version of this manuscript.
  • This study was supported by grants from the Swiss National Science Foundation (33CSCO-108796, 3247BO-104283, 3247BO-104288, 3247BO-104284, 3247-065896, 3100-059302, 3200-052720, 3200-042532, and 4026-028099); the Federal Office for Forest, Environment and Landscape; the Federal Office of Public Health; the Federal Office of Roads and Transport; the cantons of Aargau, Basel-Stadt, Basel-Land, Geneva, Luzern, Ticino, Valais, and Zurich; the Swiss Lung League; the canton’s Lung League of Basel Stadt/Basel Landschaft, Geneva, Ticino, Valais, and Zurich; and the Autonomic Nervous System nonprofit organization, Saint-Etienne, France.
  • The authors declare they have no actual or potential competing financial interests.

NIEHS Strategic Plan 2012-17

EoE - August 31, 2012 - 5:17pm

This Editorial, introducing the 2012-2017 Strategic Plan for the National Institute for Environmental Health Sciences, was written by Linda S. Birnbaum*. The Editorial appeared first in Environmental Health Perspectives—the peer-reviewed, open access journal of the National Institute of Environmental Health Sciences. The Strategic Plan is attached at the bottom of this page as a PDF Document.

The article is a verbatim version of the original and is not available for edits or additions by Encyclopedia of Earth editors or authors. Companion articles on the same topic that are editable may exist within the Encyclopedia of Earth.

NIEHS's New Strategic Plan

I am pleased to present “our” new strategic plan for the National Institute of Environmental Health Sciences (NIEHS 2012). I say that it’s “our” plan because the entire document reflects tremendous thought, discussion, and sharing of ideas by hundreds of scientists and community stakeholders, and it speaks to the entire field of environmental health research. This plan is about what we will strive to accomplish together as we devote ourselves to research that, in my opinion, has the greatest chance for preventing disease and for improving health throughout the world.

As reflected in the new strategic plan (NIEHS 2012), the NIEHS has a fresh vision, not because our values have changed but because our research has been so successful—and many of you have made a huge contribution to that progress.

New technologies and increasing knowledge bring exciting new opportunities each and every year. The NIEHS’s new strategic plan builds upon the accomplishments and vision that came before.

The NIEHS has come a long way in making environmental health research responsive to the needs and concerns of the American people—
to make environmental health part of the public health debate. This continues to be a source of motivation and purpose for NIEHS staff and our research partners. Environmental justice is an everlasting core value for NIEHS research.

In the past few years, we at the NIEHS have made some important progress in exposure science, supporting new technologies for sensor devices and bioinformatics. We have been embracing new science such as epigenetics and exposure phenotyping, focusing on interdisciplinary research and translational research. In addition, our clinical research unit is now up and running.

As the NIEHS moves forward, our overall goal is to make the institute, including the National Toxicology Program (NTP), the foremost trusted source of environmental health knowledge, leading the field in innovation and the application of research to solve health problems.

Our new vision statement (NIEHS 2012) captures our collective dreams and aspirations, and reflects our strong commitment to making a real difference:

The vision of the National Institute of Environmental Health Sciences is to provide global leadership for innovative research that improves public health by preventing disease and disability from our environment.

What this means in practical terms is that we are pursuing some of the “big influences” that have been understudied, all of which interact with traditional environmental exposures: the microbiome, for example, and inflammation pathways, immunological pathways, nutrition, and epigenetic processes. We also want to lead the process of defining the “exposome,” which is the totality of exposure encountered by humans.

We have elevated the NTP to the divisional level within the NIEHS. And we will continue to integrate our toxicology research with our excellent basic and translational science programs, not because I am a toxicologist but because the NTP is a problem-solving program—a truly translational component of the NIEHS. For example, the NTP is part of our consortium on bisphenol A, contributing to the scientific deliberations, right along with our intramural scientists and our grantees.

The NTP is leading the Tox21 initiative along with the National Institute of Health’s National Center for Comparative Genomics, the U.S. Environmental Protection Agency, and the Food and Drug Administration. This high throughput testing program shows great promise not only as a new and faster method but also for moving toxicology into a predictive science.

The NTP is moving beyond the traditional approaches of testing one chemical at a time and are taking on the significant challenge of evaluating mixtures. We are also looking at the effects of exposures throughout the life span, expanding our research and testing to include prenatal exposures and how they may link to adult disease. It is clear that there are multiple windows of susceptibility and that exposures early in life may have long-lasting consequences to both health and disease.

Finally, the antiquated idea that the dose makes the poison is overly simplistic. The newest research clearly shows that biology is affected by low doses of chemicals, often within the range of general population exposure, and that these biological changes can be harmful, especially during periods of development. Therefore, low-dose research must go hand in hand with our life-span approach.

The NIEHS’s job doesn’t stop with the publication of scientific results. We also have an obligation to help translate the nation’s research investment into public health intervention, new policy, and preventive clinical practice.

To be successful, we at the NIEHS need to conduct and support the best science, whether it is led by an individual researcher or a multidisiplinary team, and this means working together with all of our partners. We thank everyone who joined us in our strategic planning process. We appreciate your commitment and support.

  1. NIEHS (National Institute of Environmental Health Sciences) 2012. NIEHS Strategic Plan.
    Available: http://niehs.nih.gov/about/strategicplan​/index.cfm [accessed 19 July 2012]
Editor's Notes
  • *Linda S. Birnbaum is Director, NIEHS and NTP, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, E-mail: [email protected]
  • Citation: Birnbaum LS 2012. NIEHS's New Strategic Plan. Environ Health Perspect 120:a298-a298.
  • Online: 01 August 2012
  • Linda S. Birnbaum, director of the NIEHS and the NTP, oversees a budget that funds multidisciplinary biomedical research programs and prevention and intervention efforts that encompass training, education, technology transfer, and community outreach. She recently received an honorary Doctor of Science from the University of Rochester, the distinguished alumna award from the University of Illinois, and was elected to the Institute of Medicine. She is the author of > 900 peer-reviewed publications, book chapters, abstracts, and reports. Birnbaum received her M.S. and Ph.D. in microbiology from the University of Illinois, Urbana. A board-certified toxicologist, she has served as a federal scientist for > 32 years, 19 with the U.S. EPA Office of Research and Development, preceded by 10 years at the NIEHS as a senior staff fellow, a principal investigator, a research microbiologist, and a group leader for the institute’s Chemical Disposition Group.
  • The author declares she has no actual or potential competing financial interests.


Species range limits

EoE - August 26, 2012 - 4:57pm

Species range limits (SRLs) are defined as the spatial boundaries beyond which no living individuals of a given species occur.  Populations occurring near or at SRLs are often referred to as “marginal,” “peripheral,” “edge,” or “border” populations.  SRLs may represent areas beyond which individuals cannot physiologically tolerate ecological conditions or areas where they have not yet dispersed.  SRLs may be stable (i.e., at equilibrium) or may represent areas where range expansion through migration or population growth is in the process of occurring.  SRLs are significant to ecology, evolution, and conservation for several reasons.  They provide opportunities to understand the conditions under which populations expand or contract, and the conditions under which populations may evolve new forms. Additionally, SRLs can provide clues about how species may respond in the face of rapid environmental change.

Characteristics of Species Range Limits

Biologists have long been interested in whether populations near SRLs possess predictable properties, such as differences in abundance or genetic variation when compared to more central populations.  Two general patterns have emerged by reviewing patterns of DNA variation across a broad set of species, mostly from the Northern Hemisphere.  Genetic differentiation levels (defined as the degree to which populations differ in their genes to one another) among nearby populations are higher approaching SRLs than genetic differentiation levels among populations more centrally located within species ranges.  Also, genetic diversity levels (defined as the diversity or variety of genes within a population) are generally lower near SRLs.  These patterns are not especially strong, and their general causes are still not understood, but the following factors may contribute: stronger natural selection near SRLs, increased isolation or genetic drift near SRLs, or greater fluctuations in environmental suitability near SRLs that translate into unstable population dynamics. Importantly, despite the general genetic signature of decreased diversity in the majority of species examined, exceptions to this pattern are common.  Additionally, populations near SRLs, even those having lower genetic diversity than interior populations, can host unique genes and adaptations that can have high conservation value.

Causes of species range limits

SRLs can be maintained by a variety of interacting factors.  Barriers may cause range limits, such as a rapid transition in ecological suitability (e.g., a land to sea transition) that prevents individuals from establishing elsewhere. Non-biological environmental factors, termed abiotic factors (e.g., climate, soil type, etc.), explain large biogeographic divisions such as biomes (deserts, tropical forests, etc.) and often determine the occurrence of SRLs.  Species interactions, often termed biotic factors, include predation, parasitism, mutualisms, competition, and hybridization and can also cause SRLs.  Abiotic and biotic factors can interact, and any one range-limiting factor, or set of interacting factors, may change gradually or abruptly across space to determine SRLs.  Evolutionary constraints, or the failure of a given species to adapt to all conditions on earth, are the ultimate cause of SRLs. 

Adaptation at species range limits

Why do species fail to adapt to conditions at SRLs?  The main reason for evolutionary constraints at SRLs, or anywhere, is a lack of genetic variation to respond to natural selection.  This lack of genetic variation to adapt to novel conditions may be a characteristic of populations approaching SRLs or a characteristic of the species as a whole.  In this vein, species with very limited levels of genetic variation (contained within their populations) may have smaller range sizes.

Adaptation to conditions at SRLs can result in a species range expansion as newly adapted populations spread into new areas.  This process of species range expansion through adaptation at SRLs is essentially niche evolution, or the evolutionary broadening of niche breadth (e.g., an increase in the range of growing degree days in which a plant can grow and produce viable seeds).  As genetic mutations arise within a species’ range, and as populations trade these new genes through gene flow, genetic variation may accumulate and increase over time, allowing a gradual increase in range size known as secular migration.  When genetic variation is not limited at range limits, beneficial traits can evolve quickly.  This phenomenon has been observed at the spatial margins of recent biological invasions.  For example, dispersal speed (through increased leg length) has rapidly evolved in edge populations of the cane toad invasion in Australia.


Gene flow between populations can have negative and positive consequences on adaptation to novel conditions, and these consequences can depend on the environmental source of gene flow. Gene flow between very different environments may increase genetic variation within populations, but this gene flow may also disrupt the process of adaptation by natural selection by mixing adapted genes with maladapted genes.  In this vein, gene flow could stall adaptations occurring near SRLs, thereby contributing to the maintenance of SRLs.  Alternatively, gene flow may introduce beneficial genes to stressful environments near SRLs, especially if originating from similar environments where beneficial adaptations already exist.  Gene flow between similar environments of ecological gradients may be an important force in adaptation at species range limits. In this vein, populations occupying similar environments should be considered collectively for their potential to share genes with adaptive results, and not just as a set of populations that are individually high or low in adaptive and conservation value.

Shifting limits under climate change?

The extent to which SRLs are at equilibrium is unknown for most species. If SRLs are in tight equilibrium with current climates, we may expect a rapid shift in range limits with rapid climate change.  This would result in leading-edge and rear-edge portions of species ranges where adjustments to climate change are occurring.  Leading-edge areas are those that become more favorable during climate shifts and where populations will migrate towards through a process of niche tracking.  Rear-edge areas are expected to become unsuitable during climate shifts as the species niche moves away from populations inhabiting environmental extremes that are becoming even more extreme (e.g., warming of the current hottest areas inhabited by a species). Indeed, many species have already responded to recent human-linked climate warming during the past few decades by expanding their geographic ranges towards the poles. An important question is, which species will be most vulnerable to range shifts under modern climate change? The challenge of conservation efforts during climate shifts is to assist populations in tracking their species niche as it moves away from them, or to promote rapid climate adaptation in cases where individuals are unable to migrate due to habitat requirements unrelated to climate (e.g., species restricted to certain soils or bodies of water).

Further reading
  • Frankham, R., Ballou, J.D., Eldridge, M.D.B., Lacy, R.C., Ralls, K., Dudash, M.R., et al. (2011). Predicting the Probability of Outbreeding Depression. Conservation Biology, 25, 465–475.
  • Gaston, K.J. (2003). The Structure and Dynamics of Geographic Ranges. Oxford University Press.
  • Hampe, A. & Petit, R.J. (2005). Conserving biodiversity under climate change: the rear edge matters. Ecology Letters, 8, 461–467.
  • Hoffmann, A.A. & Blows, M.W. (1994). Species borders: Ecological and evolutionary perspectives. Trends in Ecology & Evolution, 9, 223–227.
  • Kellermann, V., van Heerwaarden, B., Sgro, C.M. & Hoffmann, A.A. (2009). Fundamental evolutionary limits in ecological traits drive Drosophila species distributions. Science, 325, 1244–1246.
  • Loarie, S.R., Duffy, P.B., Hamilton, H., Asner, G.P., Field, C.B. & Ackerly, D.D. (2009). The velocity of climate change. Nature, 462, 1052–1055.
  • Lomolino, M., Riddle, B.R. & Brown, J.H. (2005). Biogeography. third. Sinauer Associates, Sunderland, MA.
  • Phillips, B., Brown, G., Webb, J. & Shine, R. (2006). Invasion and the evolution of speed in toads. Nature, 439, 803–803.
  • Rubidge, E.M., Patton, J.L., Lim, M., Burton, A.C., Brashares, J.S. & Moritz, C. (2012). Climate-induced range contraction drives genetic erosion in an alpine mammal. Nature Climate Change, 2, 285–288.
  • Parmesan, C. & Yohe, G. (2003). A globally coherent fingerprint of climate change impacts across natural systems. Nature, 421, 37–42.
  • Sexton, J.P., Strauss, S.Y. & Rice, K.J. (2011). Gene flow increases fitness at the warm edge of a species’ range. Proceedings of the National Academy of Sciences, 108, 11704–11709.
  • Sexton, J.P., Mcintyre, P.J., Angert, A.L. & Rice, K.J. (2009). Evolution and ecology of species range limits. Annual Review of Ecology, Evolution, and Systematics, 40, 415–436.



International Food Security Assessment: 2012-22

EoE - August 24, 2012 - 4:39pm

Food security is estimated to improve slightly in 2012 as the number of food-insecure people in the 76 countries covered in this report declines from 814 million in 2011 to 802 million in 2012. The share of the population that is food insecure remains at 24 percent. Over the next decade, the share of the population that is food insecure is projected to decline from 24 percent in 2012 to 21 percent in 2022, but the number of food insecure people is projected to increase by 37 million. Regionally, food insecurity is projected to remain most severe in Sub-Saharan Africa. Food-insecure people are defined as those consuming less than the nutritional target of roughly 2,100 calories per day per person.

International Food Security Assessment: 2012-22

The U.S. Department of Agriculture's Economic Research Service (ERS) has, since the late 1970s, reported annually on food security in a number of developing countries. A key indicator is the number of food-insecure people (those who each consume less than a nutritional target of 2,100 calories per day). In the latest report in PDF format (International Food Security Assessment: 2012-22), ERS estimates food security in 76 countries, in four regions.

For 2012, ERS estimates the situation overall to improve slightly, with the number of food-insecure people declining to 802 million people, from 814 million in 2011.  The decade ahead presents a different picture, with food-insecure numbers rising by 37 million, although this 4.6 percent increase is below the 16.7-percent rise in population.

The key factors ERS measures in determining the level of food security are countries’ domestic food production and their import capacity. In the Asian and Sub-Saharan African regions studied, domestic food production generally plays the most critical role in food security, so increasing output of staple crops will be crucial in improving food security. The countries studied in Latin America and North Africa import a large share of their food supplies, so the capacity to pay for imports is more significant.

In Sub-Saharan Africa, the region where food insecurity is generally more concentrated, the number of food-insecure people is estimated to decline by 4.3 percent between 2011 and 2012.  That slight improvement can be almost entirely attributed to higher expected food production levels. But over the next decade a sizable increase in food insecure people – 15 percent – is projected for the region. The bright spot for the decade is that the share of the population that is food insecure in sub-Saharan Africa is projected to fall from about 42 percent in 2012 to 38 percent in 2022.

Conditions vary within regions, and even within Sub-Saharan Africa, the food security situation is expected to improve for some countries. Among the factors in raising food production levels are a country’s ability to make needed investments in new technologies, and farmers’ skills and willingness to adopt the provided technologies.

ERS's latest International Food Security Assessment contains data on another key indicator of food security: the distribution gap, or the quantity of food needed for each income decile within a country to reach the nutrition target of about 2,100 calories per day. Overall, the distribution gap is projected to hold constant over the next decade. ERS's report also points out differences among and within regions.

Further Reading

Botulism and home canning

EoE - August 22, 2012 - 4:26pm

Home canning is an excellent way to preserve garden produce and share it with family and friends, but it can be risky or even deadly if not done correctly and safely.

Home Canning and Botulism

It's summer, and home gardeners may already be harvesting—or thinking about harvesting—the delicious produce they've been growing this year. Food gardening and home canning are becoming increasingly popular in the United States. According to one survey, 1 in 5 U.S. households can their own food, and 65% of those households can vegetables.

If canning is done improperly, the vegetables you worked so hard to grow, harvest, and preserve could become contaminated with germs that cause serious illness. In fact, a study shows that many home canners are not aware of the risk of botulism, a rare and potentially fatal foodborne illness that has been linked to improperly canned food. By knowing about the risks and learning the safe way to can, you can protect yourself, your family, and others when you share your home-canned goodies.

Home-canned vegetables are the most common cause of botulism outbreaks in the United States. From 1996 to 2008, there were 116 outbreaks of foodborne botulism reported to CDC. Of the 48 outbreaks that were caused by home-prepared foods, 18 outbreaks, or 38%, were from home-canned vegetables. These outbreaks often occur because home canners did not follow canning instructions, did not use pressure cookers, ignored signs of food spoilage, and were unaware of the risk of botulism from improperly preserving vegetables.

For more information, see:

Botulism, rare but deadly

Botulism is a rare, but serious illness caused by a germ called Clostridium botulinum. The germ is found in soil and can survive, grow, and produce toxin in a sealed jar of food. This toxin can affect your nerves, paralyze you, and even cause death. Even taking a small taste of food containing this toxin can be deadly.

Botulism is a medical emergency. If you have symptoms of foodborne botulism, seek medical care immediately. 

Symptoms may include the following:

  • Double vision
  • Blurred vision
  • Drooping eyelids
  • Slurred speech
  • Difficulty swallowing
  • Dry mouth
  • Muscle weakness
Keep your vegetables safe from contamination

Here are some tips to keep your canned vegetables safe and keep them from spoiling.

Use proper canning techniques

Make sure your food preservation information is always current with up-to-date, scientifically tested guidelines. Don't use outdated publications or cookbooks, even if they were handed down to you from trusted family cooks.

You can find in-depth, step-by-step directions from the following sources:

Make your home-canned vegetables safe
  • Use a pressure canner or cooker.
  • Be sure the gauge of the pressure canner or cooker is accurate.
  • Use up-to-date process times and pressures for the kind of food, the size of jar, and the method of packing food in the jar.

Use the right equipment for the kind of foods that you are canning.

Use a pressure canner or cooker. Pressure canning is the only recommended method for canning vegetables, meat, poultry, and seafood. The germ bacterium that causes botulism is destroyed when these foods are processed at the correct time and pressure in pressure canners or cookers. Do not use boiling water canners because they will not protect against botulism poisoning.

Any food that may be contaminated with the germs that cause botulism should be thrown out. If you suspect that you have contaminated food, see "Safely dispose home-canned foods."

Protect yourself from botulism: When in doubt, throw it out!
  • Any food that may be contaminated with the germs that cause botulism should be thrown out. If you suspect that you have contaminated food, see "Safely dispose home-canned foods."
  • Never taste the product to determine if it is safe. Do not taste or eat foods from containers that are leaking, have bulges or are swollen, or look damaged, cracked, or abnormal.
  • When you open a jar of home-canned food, thoroughly inspect the product. Do not taste or eat foods that are discolored, moldy, or smell bad.
    Do not use products that spurt liquid or foam when the container is opened.
Inspect your home-canned foods before consuming.
  • Suspect contamination if
    • The container is leaking, bulging, or swollen
    • The container looks damaged, cracked, or abnormal
    • The container spurts liquid or foam when opened
    • The food is discolored, moldy, or smells bad
  • Don’t open or puncture any unopened cans, commercial
    or home-canned, if you suspect contamination.
Safely dispose of food and cans that may be contaminated

If a home-canned food that may be contaminated is spilled, wipe up the spill using a dilute bleach solution (1/4 cup bleach for each 2 cups of water).

Online Resources General Information Home Canning


Geophony, Biophony, and Anthrophony

EoE - August 22, 2012 - 4:26pm

What do these words mean? Biophony is the melodic sound created by such organisms as frogs and birds; geophony, the composition of non-biological sounds like wind, rain and thunder; and anthrophony, the conglomeration of noise spawned by human activity.

Studying Nature's Rhythms:
Soundscape Ecologists Spawn New Field

The following Discovery article is part is part four in a series on the National Science Foundation's Science, Engineering and Education for Sustainability (SEES) investment. Visit parts one, two, three, five, six and seven in this series.

Listen to biophony, geophony, anthrophony: the 'music' of Planet Earth

The following is part four in a series on the National Science Foundation's Science, Engineering and Education for Sustainability (SEES) investment. Visit parts one, two, three, five, six and seven in this series.

Geophony. Biophony. Anthrophony.

Unfamiliar words. But they shouldn't be. We're surrounded by them morning, noon and night, say ecologist Bryan Pijanowski of Purdue University and colleagues. The evening "singing" of frogs. Burbling brooks, breaking waves and the whistling wind. Planes, trains and automobiles. Biophony is the music created by organisms like frogs and birds; geophony, the composition of non-biological sounds like wind, rain and thunder; and anthrophony, the conglomeration of noise from humans.

What they add up to is a cacophony--a mix of sounds made by the environment, and by people; a background to which most have become tone-deaf. "Another word for it is 'soundscape,'" says Pijanowski.

He and colleagues are leading an effort to spawn a new field called soundscape ecology. It uses "nature's music" to understand the ecological characteristics of a landscape. It also reconnects people with Earth-sounds. "Natural sound could be the 'canary in the coal mine,'" says Pijanowski. "Sound might be the critical first indicator of changes in climate and weather patterns, or the presence of pollution."

The dawn and dusk choruses of birds, for example, are characteristic of a certain location. If the intensity or frequency of these melodies change, "there's likely something causing it," says Pijanowski. "Ecologists have largely ignored the ways in which sound can help determine what's happening to an ecosystem."

Pijanowski and colleagues have received a grant from the National Science Foundation's (NSF) Dynamics of Coupled Natural and Human Systems (CNH) Program to study soundscapes. NSF CNH awardees work to provide a better understanding of natural processes and cycles, and of human behavior and decisions--as well as understanding how and where they intersect. NSF's Directorates for Biological Sciences (BIO), Geosciences (GEO) and Social, Behavioral & Economic Sciences (SBE) support the CNH program. CNH is part of NSF's Science, Engineering and Education for Sustainability (SEES) initiative.

"CNH highlights the need for scientists from different fields to work together and benefit from each other's perspectives to gain an understanding of the complex ways people interact with Earth's natural systems," says Tom Baerwald, CNH program director in SBE. "Findings from these projects will help individuals and groups address environmental problems more effectively." "By bringing together researchers from a wide variety of academic fields," adds Sarah Ruth, CNH program director in GEO, "the projects are providing valuable new insights into the ways in which we, our environment, and the natural resources we rely on act as one interconnected system." "CNH addresses societal challenges in the management of 'ecosystem services' and in adaptation to climate change," says Alan Tessier, CNH program director in BIO. "The soundscapes project is one such effort."

Since Rachel Carson's far-reaching 1962 book Silent Spring, the sounds of nature have been linked with environmental quality. "Over increasingly large areas of the United States," wrote Carson in Silent Spring, "spring now comes unheralded by the return of the birds. The early mornings are strangely silent where once they were filled with the beauty of bird song." Carson's observations turned out to be right.  What began as her observation of sound--or its absence--ultimately led to the ban of DDT, the insecticide responsible for precipitous drops in numbers of bald eagles and their avian relatives.

The study of soundscapes can yield valuable information about very different landscapes, say Pijanowski and colleagues like Bernie Krause of Wild Sanctuary, Inc., in Glen Ellen, California, and Almo Farina of Urbino University in Italy. Pijanowski has mapped soundscapes in wetlands and agricultural fields in Tippecanoe County, Indiana; near burbling streams and in high-wind chaparral in Sequoia National Park, California; and in the bird-song-filled forests of Italy and Costa Rica.

The ecosystem that surrounds the La Selva Biological Station in Costa Rica, for example, is home to more than 5,000 species of plants, 500 species of birds, three dozen frogs and kin and hundreds of species of insects. All these animals--including poison dart frogs, cicadas, great green macaws and howler monkeys--contribute to the La Selva biophony.

"Geophony is a hallmark of this landscape, too, with strong winds moving through trees, raging rivers audible from far away, and intense tropical rain showers that fill the 'acoustic spaces,'" says Pijanowski. Acoustic spaces are equally "noisy" in the beech forests of Italy's Apennine National Park. There Pijanowski and other scientists collected three-hour recordings from 6 a.m. to 9 a.m. each day. Data from the acoustic recorders were used to construct "soundtopes"--three-dimensional maps of acoustics plotted across the landscape. The daily maps show that large seasonal changes happen in this beech forest. "We anticipated that the maps would be similar," says Pijanowski. "But that wasn't the case."

Recordings like those made in Apennine National Park will become tomorrow's "acoustic fossils," says Pijanowski, "possibly preserving the only evidence we have of ecosystems that may vanish in the future."

Soundscapes, he believes, represent the heritage of our planet's acoustic biodiversity and reflect Earth's assemblages of organisms. "Natural sounds are an auditory link with our environment, one we need. Society's growing 'nature deficit disorder' is likely to increase as we replace these sounds with the din made by humans."

Almost 50 years ago, Rachel Carson highlighted the dangers of pesticides and their potential threats to wildlife, and to us. A half-century later, "the unintended silencing of organisms by human activities is an indication of our continued effect on the planet's ecosystems," says Pijanowski. Through soundscape ecology, he hopes to record and study Earth-music--while there's still time.

While frogs yet sing, waves break, and the wind whistles through the forest.

February 6, 2012

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Ocean acidification troubles

EoE - August 22, 2012 - 4:26pm

The seas in which corals and other calcifying species dwell are turning acidic, their pH slowly dropping as Earth's oceans acidify in response to increased carbon dioxide in the atmosphere.

Trouble in Paradise:
Ocean Acidification This Way Comes

Sustainability of tropical corals in question, but some species developing survival mechanisms

The following Discovery article is part two in a series on the National Science Foundation's Science, Engineering and Education for Sustainability (SEES) investment. Visit parts one, three, four, five, six and seven in this series.

The following is part five in a series on the National Science Foundation's Long-Term Ecological Research (LTER) Network. Visit parts one, two, three, four, six, seven, eight and nine in this series.

Double, double toil and trouble;
Fire burn, and caldron bubble.
—Shakespeare, Macbeth

Something wicked this way comes: ocean acidification arrives in paradises like Mo'orea.

Mo'orea, it's called--this island in French Polynesia that's been dubbed the most beautiful island in the world. Here Tahitian breezes dance across crystal blue waters and beneath the tropical seas lies a necklace of coral reefs that encircles Mo'orea like a string of brightly colored jewels.

Extensive reefs of a coral named Porites and other species form atolls, or reefs that ring Mo'orea's lagoons. Porites are colonial corals, also known as Scleractinians, found in shallow tropical waters throughout the Indo-Pacific and Caribbean regions. Think tropical reef and your mind's eye is likely seeing Porites.

These corals and other calcifying marine life, such as coralline algae, are also the world's primary reef-builders.  And therein lies the trouble.

The seas in which these calcifying species dwell are turning acidic, their pH slowly dropping as Earth's oceans acidify in response to increased carbon dioxide in the atmosphere. As atmospheric carbon rises in response to human-caused carbon dioxide emissions, carbon in the ocean goes up in tandem. Marine life that depends on calcium carbonate can no longer form shells or, in the case of coral reefs, skeletons.  Such marine life are found in waters that are more basic with a higher pH rather than a lower pH, which is more acidic.

Porites reefs, say scientists Peter Edmunds and Robert Carpenter of California State University at Northridge, are among the most sensitive of all corals. Carpenter and Edmunds are two of the lead scientists at the National Science Foundation's (NSF) Mo'orea Coral Reef Long-Term Ecological Research (LTER) site, one of 26 such LTER sites around the globe.

Mo'orea is the only coral reef site in NSF's LTER network. It is funded by NSF's Divisions of Ocean Sciences and Environmental Biology. To study the effects of ocean acidification on corals and other calcifying organisms, the biologists have been awarded an NSF SEES (Science, Engineering, and Education for Sustainability) Ocean Acidification grant.

We need to understand the chemistry of ocean acidification and its interplay with other marine processes--while Earth's seas are still hospitable to life as we know it, according to David Garrison, director of NSF's Biological Oceanography Program.

Carpenter and Edmunds hope to learn how fast--and the specific mechanisms by which--ocean acidification is affecting Mo'orea's corals and calcified algae, before the island's pristine reefs join dead and dying corals lining tropical coastlines around the world.

"Is there a way of sustaining healthy coral reefs when our oceans are acidifying?" asks Edmunds. "Marine animals and plants from pteropods--delicate, butterfly-like plankton--to hard corals and coralline algae are affected by ocean acidification, as are the microbes that fuel ocean productivity and influence the chemical functioning of seawater." "Corals like Porites, with their extensive distribution in tropical waters, may be ocean 'canaries in the coal mine."

At the current rate, he and Carpenter believe, coral reefs could disappear by the turn of the next century.

"The loss of biodiversity," says Carpenter, "would be devastating to the world's oceans--and to all of us. Tourism and fishing, in fact, entire economies, depend on coral reefs."

The scientists' recent findings are cause for hope, however. Porites, it turns out, may be developing an ability to counteract the effects of ocean acidification.

When Edmunds exposed Porites to different water temperatures and pH levels, and to plankton called brine shrimp as a food source, he found that increasing the amount of plankton in the coral's diet reduced the effects of ocean acidification. (The results have been published in the journal Limnology and Oceanography [See the PDF: Zooplanktivory ameliorates the effects of ocean acidification on the reef coral Porites spp.].)

"It's an intriguing mechanism," says Edmunds. "As seawater became more acidic, the corals continued to deposit calcium carbonate [new hard skeleton]. Although ocean acidification reduced the overall ability of coral tissue to calcify, the corals responded to more food by adding more tissue." Edmunds thinks that the extra plankton food may allow the coral to "bulk up," thereby changing its internal structure and increasing its ability to manufacture skeleton even in acidifying waters. "It's a very important finding that corals can mitigate the effects of ocean acidification," says Garrison. "It will be important to uncover the specific mechanism, and to establish whether other species have this ability."

And whether, says Edmunds, it might allow Porites to survive in the more acid oceans of the future.

Edmunds and Carpenter found that the response of tropical reefs to ocean acidification may be species-specific, with some species of corals and coralline algae affected more than others. They've also discovered that more acid oceans may lead to changes in patterns of biodiversity in a high-carbon dioxide world.

If the tropical seas cauldron continues to bubble with waters turning to acid, the scientists say, it will indeed lead to double, double toil and trouble—for the most beautiful island in the world, and for coral reefs around the globe.

Ultimately, it will affect the sustainability of life on a planet that—made up of 70 percent oceans—might better be called Water than Earth.

January 4, 2012

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Marcellus Shale Gas Development and Healthy Waterways?

EoE - August 20, 2012 - 4:19pm

The following Discovery article is part one in a series on the National Science Foundation's Science, Engineering and Education for Sustainability (SEES) investment. Visit parts two, three, four, five, six and seven in this series.

The following is part one in a series on the National Science Foundation's Critical Zone Observatories (CZO). View part two in this series.

Can Marcellus Shale Gas Development
and Healthy Waterways Sustainably Coexist?

Sustainability Research Coordination Network is Providing Answers

Amity, Pennsylvania. Epicenter of the natural gas-containing geological formation known as the Marcellus Shale. Amity lies in Washington County near Anawanna, Pa. Once, Native Americans lived there. They named it Anawanna, or "the path of the water," in recognition of its many rivers and streams. Today the Native American Anawanna is but a whisper in tales of the past, but the path of the water for which it's named is making headlines.

The Marcellus Shale Formation underlies some 95,000 square miles of land, from upstate New York in the north to Virginia in the south to Ohio in the west. The bull's-eye, however, is under Pennsylvania in places like Amity. There the gas-bearing thickness of the shale reaches 350 feet; it thins to less than 50 feet in other areas. The Marcellus Shale gas reservoir may contain nearly 500 trillion cubic feet of technically-recoverable gas. At current use rates, that volume could meet the U.S. demand for natural gas for more than 20 years. The shale's proximity to the heavily populated mid-Atlantic and Northeast makes its development economically advantageous. Already, more than 4,000 shale gas wells have been drilled in Pennsylvania.

But the Marcellus Shale has a bête noire. With such rapid development, gas exploitation is creating environmental challenges for Pennsylvania--and beyond. Retrieving the Marcellus Shale's gas requires a process known as hydraulic fracturing, hydrofracking or simply fracking.

Fracking involves the use of large quantities of water, three to eight million gallons per well, mixed with additives, to break down the rocks and free up the gas. Some 10 to as much as 40 percent of this fluid returns to the surface as "flowback water" as the gas flows into a wellhead.

Once a well is in production and connected to a pipeline, it generates what's known as produced water. "Flowback and produced water," says Susan Brantley, a geoscientist at Penn State University, "contain fluid that was injected from surface reservoirs--and 'formation water' that was in the shale before drilling."

Enter the bête noire.

These flowback fluids carry high concentrations of salts, and of metals, radionuclides and methane. "Such chemicals," says Brantley, "can affect surface and groundwater quality if released to the environment without adequate treatment."

The rapid pace of Marcellus Shale drilling has outstripped Pennsylvania's ability to document pre-drilling water quality, even with some 580 organizations focused on monitoring the state's watersheds. More than 300 are community-based groups that take part in volunteer stream monitoring. Pennsylvania has more miles of stream per unit land area than any other state in the United States. "It's overwhelming to keep track of," says Brantley. "These community organizations have identified a need for scientific and technical assistance to carry out accurate stream assessments."

Working through the National Science Foundation's (NSF) Susquehanna Shale Hills Critical Zone Observatory (CZO), one of six such observatories in the continental U.S. and Puerto Rico, Brantley studies the "critical zone" where water, atmosphere, ecosystems and soils interact. Now, with a grant from NSF's Science, Engineering and Education for Sustainability (SEES) Research Coordination Networks (RCN) activity, Brantley is developing a Marcellus Shale Research Network.

The network will identify groups in Pennsylvania that are collecting water data in the Marcellus Shale region; create links among these organizations to meld the resulting data; and organize a water database through the NSF-funded Consortium of Universities for the Advancement of Hydrologic Sciences. The database will be used to establish background concentrations of chemicals in streams and rivers, and ultimately to assess changes throughout the Marcellus Shale area.

The results, Brantley hopes, will help community groups evaluate hydrogeochemical data. The network will use geographic information systems that incorporate population and economic data to evaluate the potential for public health risks. "An outcome of the NSF investment in the Susquehanna Shale Hills Critical Zone Observatory has been a better interpretation of the chemistry and flow of groundwater in shale," says Enriqueta Barrera, program director in NSF's Division of Earth Sciences, which funds the CZOs. "The SEES-RCN project will use this information in assembling data collected by watershed associations, government agencies, and water scientists to further knowledge on the effect of hydrofracking on groundwater properties."

The Marcellus Shale RCN, says Brantley, "is designed to act as an 'honest broker' that collates datasets and teaches ways of synthesizing the data into useful knowledge. The approach stresses that volunteer data acts as a 'canary in a coal mine' to inform agencies about when and where they need to intensify water quality monitoring."

Of particular concern are concentrations of salts such as barium and strontium, high in some discharges as a result of the mixing of gas drilling fluids with naturally-occurring barium-strontium-containing waters. "Barium can cause gastrointestinal problems and muscular weakness," says Brantley, "when people are exposed to it at levels above the EPA drinking water standards, even for relatively short periods of time. "Animals [such as cows, pigs, sheep] that drink barium-laced waters over longer periods sustain damage to kidneys and have decreases in body weight, and may die of the effects."

The waterways of Pennsylvania have recorded many of the important human activities in the history of the United States, Brantley says. "It's expected that they will record the development of the Marcellus Shale gas as well."

The rise and fall of coal mining is found in concentrations of dissolved sulfates in the state's rivers. Pennsylvania's air, water and soils retain the signature of the steel industry and of coal-burning over the last century in their low-level manganese contamination. Documenting the effects of shale gas extraction, says Brantley, requires extensive water sampling and a database of long-term records.

In the past, monitoring sometimes has not begun until after effects were noticed.  But times are changing. "In the future," says Brantley, "many monitoring networks of all kinds will need to include citizen scientists to keep costs down, and research scientists will need to learn to use such networks to the best outcome."

Can we have natural gas development and clean waterways?

The Marcellus Shale Research Network will provide much-needed answers, says Barrera. "Successfully developing new energy resources while maintaining healthy ecosystems," she says, "is the very heart of sustainability."

December 9, 2011

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Ecoregions of the Republic of Congo

EoE - August 19, 2012 - 4:12pm

The Republic of Congo has four ecoregions that occur partly within its borders as show in the figure below:

  1. Western Congolian forest-savanna mosaic

  2. Atlantic Equatorial coastal forests

  3. Northwestern Congolian lowland forests

  4. Western Congolian swamp forests

Western Congolian forest-savanna mosaic

This ecoregion covers 159,700 square miles of critical/endangered tropical and subtropical grasslands, savannas, and shrublands in Angola, the Democratic Republic of the Congo, western Republic of Congo, and Gabon.

Atlantic Equatorial coastal forests

This ecoregion extends from the Sanaga River in west-central Cameroon south through Equatorial Guinea into the coastal and inland areas of Gabon, the Republic of Congo, and the Cabinda Province of Angola, ending in the extreme west Democratic Republic of Congo, just north of the mouth of the Congo River. At its southern extremity, the last 400 kilometers (km) of the ecoregion is a tongue of forest lying inland of the coastal plain and surrounded by the Western Congolian Forest-Savanna Mosaic.

The Atlantic Equatorial Coastal Forests ecoregion has exceptionally high levels of species richness and endemism, contains large blocks of evergreen lowland moist forest, and the central portion has one of the lowest human population densities in Africa. Most of the floral and faunal assemblages are intact, including assemblages of threatened large mammals, such as the western lowland gorilla (Gorilla gorilla gorilla), mandrill (Mandrillus sphinx), and sun-tailed monkey (Cercopithecus solatus). Important centers of endemism are found in this ecoregion, particularly in some of the coastal mountain ranges.

Although considerable areas of rainforest still remain in southern Cameroon, Gabon, and the Republic of Congo, most of these areas have been selectively logged, some several times over.

The Republic of Congo contains the Conkouati and Dimonika-Mayombe Reserves. However, given the vast forest areas remaining in the ecoregion and its exceptional importance, the number of protected areas is insufficient, their level of legal protection too low, and they are not representative of the entire range of existing habitats. Proposals have been made as to where additional protected areas should be located within areas of high biological priority.

Northwestern Congolian lowland forests

The Northwestern Congolian Lowland Forests ecoregion stretches across four countries - Cameroon, Gabon, Republic of Congo, and the Central African Republic (CAR). It is bordered to the north and south by forest-savanna mosaics and to the east by swamp forest, while the western limit grades gradually into the lowland rain forests of the Atlantic Equatorial coastal forest ecoregion.

The Northwest Congolian Lowland Forest ecoregion contains vast tracts of lowland forest, supporting core populations of the western lowland gorilla (Gorilla gorilla gorilla) and large numbers of forest elephant. Species richness and endemism are both high. Logging concessions and associated bushmeat hunting and agricultural expansion are the main threats to the habitats and species. There are some established protected areas, and the gazettement of new protected areas offers good potential for biodiversity conservation in the region.

This ecoregion contains large areas of forest and forms a part of one of the world's last remaining tropical forest wildernesses. Around one third of the forest is classified as "frontier forests" that are largely in their natural state.

In Congo, Odzala–Koukoua National Park (over 13,000 km2) has recently been extended.

Most of the ecoregion has been allocated to forestry concessions. Even within protected areas, logging is a concern. Although logging in the region is selective and habitat conversion is limited, the major issue is the depletion of wildlife in logging concessions through hunting for bushmeat and poaching for ivory. There are also technical problems with the sustainability of logging operations and also of the political will both of regional governments and the logging industry to operate sustainably.

Logging roads and other infrastructure developments are contributing to the uneven loss of habitat throughout the ecoregion, with more accessible regions most affected. Although the impact of this fragmentation on biodiversity is still poorly understood, the population densities of sensitive species (e.g. chimpanzees) are known to decline.

Western Congolian swamp forests

Western Congolian Swamp Forests ecoregion stretches from eastern Republic of Congo through to the western portion of the Democratic Republic of Congo (DRC), and into the Central African Republic. This ecoregion lies on the western bank of the Congo River, which forms a major biogeographic barrier to the Eastern Congolian Swamp Forests and Central Congolian Lowland Forests.

The river in this section can be up to 15 kilometers (km) wide, and becomes braided in a maze of alluvial islands. The Western Congolian Swamp Forests have an irregular shape (reflecting riparian habitats) bounded by the right bank of the Congo River between the confluence of the Lualaba (Upper Congo) and the Lomami Rivers to the confluence of the Lefini and the Congo Rivers.

This ecoregion, combined with the neighboring Eastern Congolian Swamp Forests, contains one of the largest continuous areas of swamp forest in the world. Although relatively few species have been recorded, it remains largely intact and contains large populations of western lowland gorilla (Gorilla gorilla gorilla). Poaching is thought to have reduced populations of forest elephants (Loxodonta africana cyclotis) along the navigable waterways. Little research has focused on this region, and further efforts are necessary to better understand these forests and their species composition.

Together, the Eastern and Western Congolian Swamp Forest ecoregions contain approximately 124,000 km2 of swamp forests habitats. Perhaps half of this area remains in this ecoregion.

The ecoregion contains one large (4,390 km2) Ramsar site in the Republic of Congo, Lac Tl-Likouala-aux-Herbes Community Reserve, which was gazetted in 1998. The reserve is located along the River Likouala-aux-herbes, with four major tributaries Tanga, Mandoungouma, Bailly, and Batanga and the lake, Lac Tl, which is the home of the mythical giant dinosaur-like animal called Mokele Mbembe. The area is a good example of a freshwater tropical African wetland ecosystem with a diversity of habitats, including swamp forest, inundated savannas and floating prairies along the watercourses. The site is public property, owned by the local communities. A special zone of firm land and seasonally flooded forests, named Zone d'Utilisation Rationelle (ZUR, zone with sustainable use) is used for hunting.

The remote and difficult nature of the swamp forest makes many human activities difficult, and hence the habitats are regarded as largely intact.


Ecoregions are areas that:

[1] share a large majority of their species and ecological dynamics;
[2] share similar environmental conditions; and,
[3] interact ecologically in ways that are critical for their long-term persistence.

Scientists at the World Wildlife Fund (WWF), have established a classification system that divides the world in 867 terrestrial ecoregions, 426 freshwater ecoregions and 229 marine ecoregions that reflect the distribution of a broad range of fauna and flora across the entire planet.

Linking extreme heat events to global warming

EoE - August 16, 2012 - 3:49pm
An analysis by James Hansen and colleagues suggests that recent episodes of extremely warm summers, including the intense heat wave afflicting the U.S. Midwest this year, very likely are the consequence of global warming.   Research Links Extreme Summer Heat Events to Global Warming A statistical analysis (Perception of climate change) by NASA scientists has found that Earth's land areas have become much more likely to experience an extreme summer heat wave than they were in the middle of the 20th century. The research was published August 6, 2012, in the journal Proceedings of the National Academy of Sciences.
  Earth's Northern Hemisphere over the past 30 years has seen more "hot" (orange), "very hot" (red) and "extremely hot" (brown) summers, compared to a base period defined in this study from 1951 to 1980. This visualization shows how the area experiencing "extremely hot" summers grows from nearly nonexistent during the base period to cover 12 percent of land in the Northern Hemisphere by 2011. Watch for the 2010 heat waves in Texas, Oklahoma and Mexico, or the 2011 heat waves the Middle East, Western Asia and Eastern Europe.
Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio
› Download hi-res visualization

The statistics show that the recent bouts of extremely warm summers, including the intense heat wave afflicting the U.S. Midwest this year, very likely are the consequence of global warming, according to lead author James Hansen of NASA's Goddard Institute for Space Studies (GISS) in New York.

"This summer people are seeing extreme heat and agricultural impacts," Hansen says. "We're asserting that this is causally connected to global warming, and in this paper we present the scientific evidence for that."

Hansen and colleagues analyzed mean summer temperatures since 1951 and showed that the odds have increased in recent decades for what they define as "hot," "very hot" and "extremely hot" summers.

The researchers detailed how "extremely hot" summers are becoming far more routine. "Extremely hot" is defined as a mean summer temperature experienced by less than one percent of Earth's land area between 1951 and 1980, the base period for this study. But since 2006, about 10 percent of land area across the Northern Hemisphere has experienced these temperatures each summer.

James Hansen and colleagues use the bell curve to show the growing frequency of extreme summer temperatures in the Northern Hemisphere, compared to the 1951 to 1980 base period. The mean temperature for the base period is centered at the top of the green curve, while hotter than normal temperatures (red) are plotted to theright and colder than normal (blue) to the left. By 1981, the curve begins to shift noticeably to the right, showing how hotter summers are the new normal. The curve also widens, due to more frequent hot events.
Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio
› Download hi-res visualization

In 1988, Hansen first asserted that global warming would reach a point in the coming decades when the connection to extreme events would become more apparent. While some warming should coincide with a noticeable boost in extreme events, the natural variability in climate and weather can be so large as to disguise the trend.

To distinguish the trend from natural variability, Hansen and colleagues turned to statistics. In this study, the GISS team including Makiko Sato and Reto Ruedy did not focus on the causes of temperature change. Instead the researchers analyzed surface temperature data to establish the growing frequency of extreme heat events in the past 30 years, a period in which the temperature data show an overall warming trend.

NASA climatologists have long collected data on global temperature anomalies, which describe how much warming or cooling regions of the world have experienced when compared with the 1951 to 1980 base period. In this study, the researchers employ a bell curve to illustrate how those anomalies are changing.

A bell curve is a tool frequently used by statisticians and society. School teachers who grade "on the curve" use a bell curve to designate the mean score as a C, the top of the bell. The curve falls off equally to both sides, showing that fewer students receive B and D grades and even fewer receive A and F grades.

Hansen and colleagues found that a bell curve was a good fit to summertime temperature anomalies for the base period of relatively stable climate from 1951 to 1980. Mean temperature is centered at the top of the bell curve. Decreasing in frequency to the left of center are "cold," "very cold" and "extremely cold" events. Decreasing in frequency to the right of center are "hot," "very hot" and "extremely hot" events.

Plotting bell curves for the 1980s, 1990s, and 2000s, the team noticed the entire curve shifted to the right, meaning that more hot events are the new normal. The curve also flattened and widened, indicating a wider range of variability. Specifically, an average of 75 percent of land area across Earth experienced summers in the "hot" category during the past decade, compared to only 33 percent during the 1951 to 1980 base period. Widening of the curve also led to the designation of the new category of outlier events labeled "extremely hot," which were almost nonexistent in the base period.

Hansen says this summer is shaping up to fall into the new extreme category. "Such anomalies were infrequent in the climate prior to the warming of the past 30 years, so statistics let us say with a high degree of confidence that we would not have had such an extreme anomaly this summer in the absence of global warming," he says.

Other regions around the world also have felt the heat of global warming, according to the study. Global maps of temperature anomalies show that heat waves in Texas, Oklahoma and Mexico in 2011, and in the Middle East, Western Asia and Eastern Europe in 2010 fall into the new "extremely hot" category.

Related Links 08.06.12  

Kathryn Hansen
NASA’s Earth Science News Team
Goddard Space Flight Center, Greenbelt, Md.

Editor's Note

Abstract: (Perception of climate change)

“Climate dice,” describing the chance of unusually warm or cool seasons, have become more and more “loaded” in the past 30 y, coincident with rapid global warming. The distribution of seasonal mean temperature anomalies has shifted toward higher temperatures and the range of anomalies has increased. An important change is the emergence of a category of summertime extremely hot outliers, more than three standard deviations (3σ) warmer than the climatology of the 1951–1980 base period. This hot extreme, which covered much less than 1% of Earth’s surface during the base period, now typically covers about 10% of the land area. It follows that we can state, with a high degree of confidence, that extreme anomalies such as those in Texas and Oklahoma in 2011 and Moscow in 2010 were a consequence of global warming because their likelihood in the absence of global warming was exceedingly small. We discuss practical implications of this substantial, growing, climate change.

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