The Sahara desert, as defined by the World Wide Fund for Nature (WWF), includes the hyper-arid center of the Sahara, between latitudes 18° N and 30° N. It is one of several desert and xeric shrubland ecoregions that cover the northern portion of the African continent.
The Belizean pine forests is an ecoregion that represents an example of lowland and premontane pine forests in the Neotropical realm, where the dominant tree species is Caribbean pine. The vegetation here is generally adapted to the xeric, acidic and nutrient-poor conditions along the Belizean near coastal zone of the Caribbean versant.
The Caspian lowland desert ecoregion covers the north and southeast coasts of the Caspian Sea, including the deltas of the Volga River and Ural River in the northern region. While the region gets relatively low amounts of precipitation, wildlife is supported by the river estuaries and the sea itself. The wetlands are an internationally important area for bird nesting and migratory resting. The ecoregion is in the Palearctic realm, and the deserts and xeric shrublands biome. It has an area of 267,300 square kilometres (103,200 sq mi).
The Central Tibetan Plateau alpine steppe ecoregion covers the high alpine plateau that stretches over 1,600 kilometres (1,000 mi) across the Tibetan Plateau to Qinghai Lake in China. Because of the high altitude—much it over 5,000 metres (16,000 ft)—the region is a cold, arid desert that is only 20% covered with steppe and meadow vegetation. The area has been relatively free from human development due to the hostile climate and unsuitability for agriculture. The ecosystem is relatively intact, and supports herds of wild antelope, sheep, deer, and gazelles.
The Yarlung Tsangpo arid steppe ecoregion covers the river valley of the Yarlung Tsangpo River on the southern edge of Tibet. The river runs parallel to the northern borders of Nepal, Bhutan and India, between the Himalayas to the south and the Tibet Plateau to the north. The river valleys are the most populated areas of Tibet, putting pressure on wildlife. The area ranges from cold desert in the west to steppe shrub land in the east; the few trees are in the lowest river valleys to the east.
The Tonle Sap freshwater swamp forests ecoregion covers the seasonally flooded forests surrounding Tonlé Sap, the largest lake in Cambodia, and the floodplains of its connections to the Mekong River. Over 35% of the ecoregion experiences flooding during the wet season.
The East Afghan montane conifer forests ecoregion covers a series of unconnected conifer forests along the border between Afghanistan and Pakistan, at elevations of 2,000 metres (6,600 ft) to 3,400 metres (11,200 ft) above sea level. The ecoregion supports the near-threatened Markhor (Capra falconeri chiltanensis), known as the Screw-horned goat, the national animal of Pakistan. The forests of the ecoregion have been heavily thinned for timber.
The Afghan Mountains semi-desert ecoregion covers three disconnected interior valleys in the north of the mountains of Afghanistan. These valleys are arid, and covered mostly in thorny shrubs. Overgrazing by livestock has put pressure on the grasses and the wild animals dependent on them.
The Ghorat-Hazarajat alpine meadow ecoregion covers the high mountainous elevations of central Afghanistan. The ecoregion fans out to the west from the capital city of Kabul at the eastern point. Vegetation is thornbush meadows and alpine grassland. The region is the home of the critically endangered Afghan brook salamander, which depends on the cold waters of the high streams of the ecoregion.
The Hindu Kush alpine meadow ecoregion covers a portion of the Hindu Kush Mountain Range in northern Afghanistan. Most of the terrain is between 3,000 and 4,000 meters in elevation. This portion of the Hindu Kush is very mountainous, with steep slopes. About half of the alpine meadow is bare rock or gravely soils with sparse vegetation. The remainder supports herbaceous cover of grasses and cushion plants. Human habitation is scarce and follows the river courses in the valleys.
The Central American Atlantic moist forests ecoregion covers the lowland coastal forests of Honduras, southeast Guatemala, and the eastern forests of Nicaragua. Half of the ecoregion is closed-canopy tropical broadleaf evergreen forest, with tree heights reaching 50 meters. This ecoregion has the largest single fragment of natural forest in Central America, with a size of 14,629 square kilometres (5,648 sq mi). The total area is 89,979 square kilometres (34,741 sq mi).
The Central Afghan Mountains xeric woodlands ecoregion covers the xeric (dry) eastern and southern slopes of the central mountain range of Afghanistan, between the sandy desert to the south and the alpine meadows in the higher, wetter region to the north. Despite the 'woodlands' in the ecoregion name, very little of the territory is forested – less than 1% – but is instead sparse vegetation or herbaceous cover.
The Red Sea Nubo–Sindian tropical desert and semi-desert ecoregion covers extremely arid land along the northeastern Red Sea, the southern Sinai Peninsula, and on a thin strip along the Israel-Jordan border. Most of the coastal land is flat, but there are high mountains in southern Sinai. Biodiversity is limited by the low moisture levels – some areas go for years without significant rain. Portions of the area support a thin savannah-like cover of widely scattered trees and scrub, surrounded by grasses that briefly flourish after a rainfall. Biodiversity is highest in the mountains of Sinai, and in the wadis and gullies that retain moisture.
The Paropamisus xeric woodlands ecoregion covers the portion of northeastern Afghanistan north of the central mountain range and the Hindu Kush Mountains. The name is derived from the Old Persian name for the region, Parupraesanna. While there are low canopy woodlands in the northeast of the ecorgegion, most of the territory is desert or xeric (dry) scrubland.
The Baluchistan xeric woodlands ecoregion covers the middle elevations of a series of mountain ranges of western Pakistan and northeastern Afghanistan, reaching 1,200 kilometres (750 mi) from the Arabian Sea in the south to the Hindu Kush Mountains and the Himalayas in the north. The characteristic vegetation is xeric (dry) woodlands of shrubs and herbaceous cover. The region has rich biodiversity but relatively few endemic species.
The Sulaiman Range alpine meadows ecoregion covers a series of higher altitude mountain ranges along the crest of the Sulaiman Mountains, a southerly extension of the Hindu Kush Mountains along the Afghanistan-Pakistan border. The area is relatively undeveloped, with about a third of the terrain either forested or in 'alpine steppe' shrub or herbaceous cover.
The Torngat Mountain tundra ecoregion covers the Torngat Mountains on the northeastern tip of the Labrador Peninsula where the provinces of Quebec and Newfoundland and Labrador meet. The mountains feature glacially carved U-shaped valleys and deep fjords. The vegetation over most of the territory is that of arctic tundra, herbaceous cover, or bare rock. The region supports seasonal polar bears, black bears, and caribou. The Atlantic coast is on the Atlantic Flyway for migratory birds.
The Magdalena-Santa Marta mangroves ecoregion covers the mangrove forests along the coast of Colombia on the Caribbean Sea, from Gulf of Urabá in the west at the Colombia-Panama border to the Guajira Peninsula in the east. The region is relatively dry, with low precipitation and high evapotranspiration, so the mangroves depend for water and nutrients on the rivers flowing across the estuarine plain from the Sierra Nevada de Santa Marta mountains to the east. Efforts are currently underway to restore mangroves degraded by development and road building from the 1950s to 1980s.
The Northern Dry Pacific Coast mangroves ecoregion covers the mangrove habitats in a series of sites along the Pacific Ocean coast of Guatemala and El Salvador. This part of Central America is relatively dry compared to higher elevations or more southerly areas, so the wetland mangroves serve as a refuge for animals of the interior during the winter dry season. The mangroves only extend a few kilometers inland to where the salt water influence is gone; the ecoregion surrounding the mangroves is the Central American dry forests ecoregion.
The Windward Islands xeric scrub ecoregion covers the relatively small areas of the Windward Islands that receive low levels of precipitation. The dry areas of these islands are the low coastal areas that receive less precipitation. Because the dry scrub land is generally flat, near the coast, and not as obviously in need of conservation as the upland forests of the interior, they are more vulnerable to human settlement and development for agriculture.
