Ecoregions of Tanzania

Ecoregions (main)

Ecoregions of Tanzania

Published: September 24, 2009, 8:02 pm

Updated: March 2, 2013, 10:35 pm

Topics:

Ecoregions (main) Ecology (main) Forests (main)

Ecoregions of Tanzania. Source: World Wildlife Fund

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 Earth.

The following WWF ecoregions are found in Tanzania.

1. Central Zambezian Miombo woodlands (AT0704) dominate the western third of Tanzania and most of its border along Lake Tanganyika. It is one of the largest ecoregions in Africa, ranging from Angola up to the southern shores of Lake Victoria. 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.
2. Albertine Rift (Albertine Rift montane forests) montane forests (AT0101) exist in three small areas near Lake Tanganyika. It is an ecoregion of exceptional faunal and moderate floral endemism. Areas of this ecoregion north of Tanzania support the Mountain gorilla, 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 northern parts of this ecoregion straddle the borders of five different nations, making effective ecoregional conservation a challenge in the area. 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.
3. Zambezian flooded grasslands (AT0907) occurs in the Kilombero Valley, Moyowosi/ Malagarasi system and the River. The ecoregion is an anomaly of productivity and abundance in a landscape characterized by nutrient poor soil and vegetation. Unlike the surrounding Central Zambezian Miombo woodlands that generally support animals only in fairly low densities, the wetlands and floodplains of this ecoregion provide habitats to large numbers of animals, as food and water are abundant throughout most of the year. Large populations of water birds gather during the rainy season and numerous herd animals and carnivores still frequent the landscape. However, in a climate of rapid population growth and increasing need for land and natural resources, this delicate ecoregion may face increasing threat. Several conservation measures are urgently required for the ongoing survival of these wetland ecosystems and their biota.
4. Southern Rift montane forest-grassland mosaic (AT1015) occurs in the south on the edge of Lake Malawi (Nyasa). Although it boasts fewer endemics than the Albertine Rift (Albertine Rift montane forests) and Eastern Arc Forests to the north, the Southern Rift Montane Forest-Grassland Mosaic ecoregion is by no means impoverished nor lacking in unique species. The Nyika Plateau is renowned for its rich orchid flora, and hosts an impressive array of wildlife, while Tanzania’s Kitulo Plateau is also botanically important. Numerous examples of endemic plant and animal taxa can be found throughout the ecoregion. With the exception of the Nyika Plateau, the ecoregion is poorly conserved, and is increasingly threatened by cultivation and overexploitation of both forest and grassland resources, activities which have already transformed large areas of the ecoregion.
5. Eastern Miombo woodlands (AT0706) cover a large swath of south Tanzania from Lake Malawi (Nyasa) in the east to close to (but not recahing) thecounty's Indian Ocean coast. Confined to the lower elevations of the Central African Plateau, this ecoregion is characterized by the low-nutrient vegetation which grows in the dry climate and poor {C}soil. However, the combination of smaller ecotonal habitats allows the area to support a variety of mammals, including possibly the largest populations of African elephant and African wild dog on the continent. Although the presence of the {C}tsetse fly and the lengthy civil war in Mozambique has left the area sparsely populated, human populations and natural resource use are increasing in the area. In addition, the Mozambican conflict has left a series of national parks and game reserves in urgent need of rehabilitation.
6. Southern Zanzibar-Inhambane coastal forest mosaic (AT0128) occurs in the south east of Tanzania along the coast, extending south of the Lukuledi River down to nearly the mouth of the Limpopo River (inMozambique). It forms the southern extension of the Northern Zanzibar-Inhambane coastal forest mosaic ecoregion and supports a mosaic of dry forest, savanna, woodland, and swamps. It falls under the influence of the Madagascar rainshadow, and hence receives typically lower rainfall than the Northern Zanzibar-Inhambane coastal forest mosaic ecoregion. The ecoregion is very poorly known due to the prolonged civil war in Mozambique, and the status of the biodiversity of the habitats of the ecoregion, especially in northern Mozambique are largely unknown. This is a priority area for further biological investigation and for the establishment of new protected areas.
7. Northern Zanzibar-Inhambane coastal forest mosaic (AT0125) covers most of the Tanzanian coast north of the Lukuledi River. Together with the Eastern Arc montane forests this ecoregion harbors densities of plant species that are among the highest in the world. The great diversity of habitats contributes to the species richness of the area, although the levels of species endemism, most notably among the plants, is also high in this ecoregion. Natural habitats, especially small forest patches, are highly threatened along the Kenyan coast, and only slightly less threatened in coastal Tanzania. This has resulted primarily from conversion to agricultural land, although various forms of extraction also pose significant threats.
8. East African mangroves (AT1402) occurs along Tanzania's coast. Highly productive nurseries for fish and prawns, these mangroves significantly enhance the biodiversity of surrounding marine habitats while providing vital habitat for migratory birds, marine turtles, dugongs and porpoises. The most developed mangroves in this ecoregion extend as far as 50 kilometers inland, with canopy heights up to 30 meters. However, Eastern African mangroves are threatened in many areas by overuse and conversion by a growing human population that utilizes the mangroves for rice farming, shrimp aquaculture, and for construction materials and the timber trade.
9. Eastern Arc forests (AT0109) occur in elevational patches along a chain of isolated mountain ranges, from the Taita Hills, just across the border in Kenya, down through the eastern part of Tanzania to the gap between the Udzungwa Mountains and Mt. Rungwe (Makombako Gap). The Eastern Arc Mountains possess large numbers of endemic plants and animals at some of the highest densities in the world. The endemism comprises both newly evolved species, as well as those with an ancient history. Globally recognized plant groups such as African violet and ‘Busy Lizzie’ have their center’s of radiation in this ecoregion. The unique biogeography, and the disjunct nature of this ecoregion in elevational patches makes species distributions and ranges more similar to true islands than to mainland regions. The main threats to the ecoregion are the expansion of agriculture into the remaining areas of forest, mostly in the village-owned lands, but also into the forest reserves, which protect the majority of the remaining forest areas.
10. Itigi-Sumbu thicket (AT0708) is a unique but poorly understood ecoregion, best known for its impenetrably dense deciduous vegetation. It is found in two small areas in center of Tanzania and Zambia. The thick, primarily vegetation is so dense that elephants forcing their way through these thickets barely leave tracks, as the shrubs spring back to their original positions. While little research has been conducted, the Itigi-Sumbu Thicket’s vegetation is unique and contains a number of endemic plants. It was once vital habitat for the black rhino, although poachers have eradicated the rhino in this ecoregion. Human populations in the area are rapidly increasing and even the thicket contained in protected areas is converted for agricultural purposes. In fact, the Itigi-Sumbu Thicket is being transformed so quickly that the Zambian portion is predicted to disappear in the next twenty years if urgent conservation action is not taken.
11. Southern Acacia-Commiphora bushlands and thickets (AT0716) cover much of northern and central Tanzania, extending into southwestern Kenya, around the eastern margins of Lake Victoria. In the heart of these wide-sweeping grasslands and associated Acacia-Commiphora woodlands, the world’s most spectacular migration of large mammals occurs each year. Wildebeests, plains zebras, and Thomson’s gazelles traverse the Greater Serengeti Ecosystem, triggered by cyclical wet and dry seasons. Parts of the world famous Serengeti National Park and the Ngorongoro Conservation Area are located in this ecoregion; both have been designated as World Heritage Sites and Biosphere Reserves. Of the three Acacia-Commiphora Bushland and Thicket ecoregions, this southern unit receives the most rain and is closely associated with the Serengeti Volcanic Grasslands. The main threats to the ecoregion are the same as other savanna areas in the region, poaching of large mammals for body parts and meat, and expansion of pastoralism and agricultural use of the area with associated loss of tree cover.
12. Serengeti volcanic grasslands (AT0714) occur in two swaths just south of the Kenyan border.This world-renowned ecoregion is a stage for some of the most spectacular mass game migrations in the world. Although populations fluctuate, there are an estimated 1.3 million blue wildebeest, 200,000 plains zebra, and 400,000 Thomson’s gazelle migrating between this ecoregion and the Southern Acacia-Commiphora bushlands ecoregion each year. The migrations continue despite a devastating rinderpest outbreak in the late 19th century and indiscriminate hunting by European settlers in the early 20th century. The area represents the last remnant of a large mammal dominated ecosystem which has existed in African at least since the Pleistocene. It is relatively well protected within National Parks and Game Reserves, but populations of black rhinoceros have been extirpated by illegal hunting, and there is some evidence that illegal hunting of animals for meat is increasing.
13. Northern Acacia-Commiphora bushlands and thickets (AT0711) dominate much of lowland Kenya and extend across the border to cover a small area of northern Tanzania. The ecoregion, comprised of semi-arid mixed woodland, scrub and grassland, is reasonably protected within a well-functioning system of national parks and other reserves. However, numbers of humans and livestock are increasing outside protected areas, and nomadic pastoralism is declining in favor of settlement, causing environmental degradation through heavy grazing and agricultural expansion. Water is always in short supply in this region, where one or both rainy seasons commonly fail. Certain species such as Grevy’s zebra have undergone severe declines because of competition with livestock for, and often exclusion from, water supplies. Poaching also threatens some of the large herbivores found here, particularly the black rhinoceros and, until recently, the African elephant.
14. East African montane forests (AT0108) are situated on continuous and isolated mountain ranges including several in northern Tanzania including includes the forests of Mt. Kilimanjaro, Mt. Meru, and Ngorongoro. The ecoregion is rich in endemic species, although the numbers of endemics are lower here than in other eastern African mountain ecoregions. The primary threats to the ecoregion come from forest clearance due to an expanding population needing new farmland, and from forest degradation due to a number of exploitative activities, including timber logging.
15. East African montane moorlands (AT1005) cover high elevation areas surrounded by East African montane forests, including Mount Kilimanjaro, Mount Meru, and Ngorongoro. The East African montane moorlands is a relatively small alpine ecoregion in eastern Africa. The habitat is virtually treeless since it occupies a zone above the treeline. This ecoregion, classified as an element of the montane grasslands and scrublands biome, has a land area measuring only about 1300 square miles. The ecoregion, lying at the upper zones of ancient volcanoes, exhibits low species richness of higher level faunal organisms, but manifests moderate plant and animal endemism, including support of certain extremophiles. There is particularly high endemism among amphibians and small mammals of the ecoregion. Many of the plant species that occur in the ecoregion have adapted interesting morphological features to allow survival in the extreme cold here.
16. East African halophytics (AT0901) encompass two saline (soda) lakes, Lake Natron and Lake Bahi, both situated in the eastern arm of the Great Rift Valley in Tanzania. These lakes are an inhospitable environment for most plants and animals as the water is saline, extremely hot, and subject to rapid salinity changes following [[rain]s]. However, the lakes are home to huge flocks of lesser and greater flamingos that breed on the mud flats that surround the lakes. The lesser flamingos filter the blue-green algae out of the salty waters and the greater flamingos feed on copepod larvae that live in the shallow waters of the lakes. The East African Halophytics are threatened by active development and are not protected in any way. As a consequence, the long-term future of the flamingos that use the lakes as a principal breeding ground is also threatened.
17. Victoria Basin forest-savanna mosaic (AT0721)occurs in the north east of Tanzania on the southern shores of Lake Victoria. The ecoregion is most noted for its high species diversity and endemism resulting from the mixture of habitat types and species from both western and eastern Africa. Add the scattered wetland habitat, and you get an abundance of animals representing different habitat types. These include more than 310 species of trees and shrubs, 280 species of birds, 220 species of butterflies, and 100 species of moths. The tropical moist climate here has two rainy seasons--one in April and May and another in October and November. These help replenish the waters for the many wetland areas of the ecoregion.

See also:

Ecoregions (collection)
Ecoregions of Uganda (WWF)
Ecoregions of Rwanda (WWF)
Ecoregions of Burundi (WWF)
Ecoregions of Zambia (WWF)
Ecoregions of Congo, Democratic Republic of (WWF)

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.
5. World Wildlife Fund, Ecoregions homepage, Accessed 1 May 2009.

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Citation

Fund, W. (2013). Ecoregions of Tanzania . Retrieved from http://editors.eol.org/eoearth/wiki/Ecoregions_of_Tanzania