The Usangu Plain is a lowland in south-central Tanzania. It is named for the Sangu people .
28-656: The Usangu Plain covers an area of 15,500 km. It extends northeast-southwest, bounded on the south by the Udzungwa Mountains , and the Kipengere Range on the southwest. Between the two ranges the Makambako Gap opens to the south. On the north, The Mbeya Mountains rise steeply to the northwest, and the lower Lupa upland further to the east. Further east the Usangu escarpment becomes less distinct, and
56-506: A break of gauge ), Katulukilla, Mang’ula, Kiberege, Siginali, Ifakara, Idete, Ruipa, Mbinga, Mngeta, Ikule, Chita, Chisano, Mlimba , Lumumwe, Mpanga, Kitete, Kimbwe, Uchindile, Mgololo, Kiyowela, Kitandililo , and Mahongole. Rain shadow A rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds , known as its leeward side. Evaporated moisture from water bodies (such as oceans and large lakes )
84-836: A great deal of endemism , and a very diverse flora and fauna. The Udzungwa and other Eastern Arc mountains has extremely high biodiversity with numerous endemic species (more than 25 percent of the vertebrate species). 10 percent of them are protected by the Udzungwa Mountains National Park and the Udzungwa Scarp Nature Forest Reserve. The Udzungwa Mountains are covered with lowland rainforest, montane rainforest, miombo woodland, grassland, and heathland. Forests extend from 300 to 2579 meters elevation, and vary in composition and species type with elevation and rainfall. The wetter eastern and southeastern slopes receive more rain from
112-404: Is carried by the prevailing onshore breezes towards the drier and hotter inland areas. When encountering elevated landforms , the moist air is driven upslope towards the peak , where it expands, cools, and its moisture condenses and starts to precipitate . If the landforms are tall and wide enough, most of the humidity will be lost to precipitation over the windward side (also known as
140-607: Is limited to precipitation that crosses over the Continental Divide . While many locations west of the Divide may receive as much as 1,000 millimetres (40 in) of precipitation per year, some places on the eastern side, notably the cities of Denver and Pueblo, Colorado , typically receive only about 12 to 19 inches. Thus, the Continental Divide acts as a barrier for precipitation. This effect applies only to storms traveling west-to-east. When low pressure systems skirt
168-401: Is working with local communities to protect the park and provide conservation and management support, monitoring, research and ecotourism initiatives. The help of the local communities is encouraged by giving them access to resources such as the collection of firewood, harvesting medicinal plants and gathering grass for thatching. Tanzania's A104 highway runs from northeast to southwest through
196-604: The Eastern Arc Mountains , and are home to a biodiverse community of flora and fauna with large numbers of endemic species . The mountains are home to the Hehe people , and the name Udzungwa comes from the Kihehe word “Wadzungwa", which means the people who live on mountainsides. Iringa is the largest settlement in the mountains, and the regional headquarters. The Undzungwa Mountains cover an area of 16,131.40 km²,
224-606: The Southern Highlands which lie to the southwest across the Makambako Gap. Both are Afromontane regions, home to characteristic montane species and ecologically distinct from the adjacent lowlands. The Southern Highlands' climate is more influenced by Lake Malawi than by the Indian Ocean . Some limited-range montane species, including the Kipunji and Kipengere seedeater (Crithagra melanochrous) , inhabit both
252-451: The rainward side) before ever making it past the top. As the air descends the leeward side of the landforms, it is compressed and heated, producing foehn winds that absorb moisture downslope and cast a broad "shadow" of dry climate region behind the mountain crests . This climate typically takes the form of shrub–steppe , xeric shrublands or even deserts . The condition exists because warm moist air rises by orographic lifting to
280-700: The trade winds is the zone between about 30° N and 30° S, blowing predominantly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere . The westerlies are the prevailing winds in the middle latitudes between 30 and 60 degrees latitude , blowing predominantly from the southwest in the Northern Hemisphere and from the northwest in the Southern Hemisphere. Some of
308-832: The Cordillera, in the direct lee of specific mountain ranges. This includes much of the Basin and Range Province in the United States and Mexico . The Pacific Coast Ranges create rain shadows near the West Coast: Most rain shadows in the western United States are due to the Sierra Nevada mountains in California and Cascade Mountains , mostly in Oregon and Washington . The Colorado Front Range
SECTION 10
#1732780901684336-745: The Indian Ocean and support evergreen forests on the lower slopes; the drier western and northwestern slopes have deciduous miombo forests and woodlands at lower elevations and evergreen forests only at higher elevations. Broad areas of forest on the central plateau have been cleared for agriculture and pasture. An analysis of satellite images taken between 1999 and 2003 found 1353 km² of the mountains were still covered in evergreen forest. The mountains are home to many mammals , including Abbott's duiker (Cephalophus spadix) , Kipunji (Rungwecebus kipunji) , and Udzungwa red colobus (Cercocebus galeritus) . Elephants (Loxodonta africana) are found in
364-555: The Indian Ocean, and lower in the mountains' rain shadow to the north and west. Temperatures are cooler at higher elevations. The Udzungwa Mountains, along with the others in the Eastern Arc, are made up of ancient crystalline Precambrian rocks that were uplifted over millions of years along fault lines. The most recent period of uplift started 30 million years ago, but the fault system and uplift process may be far older. Soils derived from these ancient rocks are not as fertile as
392-639: The Udzungwa Mountains and the Kipengere Range . The Kihansi spray toad (Nectophrynoides asperginis) , which was found only around a waterfall on the Kihansi River, became extinct in the wild in 2009 when an upstream dam altered its habitat. The toads have since been reintroduced after a successful captive breeding program. Protected areas include Udzungwa Mountains National Park (2088.69 km²), and Udzungwa Scarp (20,220 ha), Kisinga-Rugaro (14,164 ha) and West Kilombero (c.55,000 ha outside
420-552: The central plateau of the mountains, extending northeastwards to Dodoma and southwestwards to Makambako , Mbeya , and the border with Zambia . The A7 highway meets the A104 at Iringa , and extends eastwards through the mountains to Morogoro and Dar es Salaam . The Tazara Railway passes along the southern escarpment of the Udzungwa Mountains, passing through Kidatu (where it meets the Misuku branch of Tanzania's Central Line at
448-507: The forests along the southern escarpment. The grey-faced sengi (Rhynchocyon udzungwensis) is a species of elephant shrew endemic to the mountains. The Udzungwa forest partridge ( Xenoperdix udzungwensis ) is also endemic, and its closest relatives appear to be the hill partridges of Asia. Although the two mountain groups are ecologically distinct, the Eastern Arc Mountains share many species and plant communities with
476-570: The largest of the Eastern Arc ranges. The highest peak in the range is Luhombero at 2,579 metres (8,461 ft). The mountain range extends generally northeast-southwest. The Usangu Plain lies to the northwest, drained by the Great Ruaha River and its tributaries. The Great Ruaha River separates the Udzungwa Mountains from the Rubeho Mountains and Uvidunda Mountains to the northeast. The Kilombero River valley lies to
504-561: The middle of the plain. Ruaha National Park occupies the eastern and central portion of the plain. Until the 1960s, the Sangu people were mostly pastoralists , grazing cattle on the plain with a communal form of land ownership. The Sangu were concentrated in the southern part of the plain, which was more amenable to cattle grazing. In the 1960s the Tanzanian government organized an irrigation project and developed three large rice farms on
532-463: The mountain. The air descends on the leeward side, but due to the precipitation it has lost much of its moisture. Typically, descending air also gets warmer because of adiabatic compression (as with foehn winds) down the leeward side of the mountain, which increases the amount of moisture that it can absorb and creates an arid region. There are regular patterns of prevailing winds found in bands round Earth's equatorial region. The zone designated
560-594: The national park) forest reserves It is possible to visit the Udzungwa Mountains National Park and go hiking and trekking. The park has no roads passable by vehicle and is accessible only by foot. The trekking routes vary, from the short and easy one-hour Sonjo Waterfall hike to the extremely difficult 6 day trek the Lumemo Trail. The most popular route is the Sanje Waterfalls trail, taking about four hours to complete. The World Wide Fund for Nature
588-585: The northern edge of the Kipengere and Udzungwa mountains. Most of the region is in the Southern Acacia-Commiphora bushlands and thickets ecoregion , with extensive grasslands punctuated by woodlands of Acacia and Commiphora trees. There are areas of dry miombo woodland along the southern end of the plain, on the lower slopes of the plateaus and the Makambako Gap. The Great Ruaha River forms extensive wetlands, some seasonal, in
SECTION 20
#1732780901684616-533: The plain transitions into the plateau of central Tanzania. The plain is drained by the Great Ruaha River and its tributaries. The Usangu Plain is the eastern branch of the East African Rift . The Usangu Fault scarp runs along the northern edge of the plain, where the Mbeya Mountains and Lupa upland meet the plain. The Chimala fault scarp marks the southern edge of the Usangu basin, defining
644-626: The plain, watered by streams originating in the western mountains. Some former communal grazing lands have been brought under state control. Now many Sangu make a living in agriculture. Many people from elsewhere in Tanzania have moved to the region to farm or graze livestock. Udzungwa Mountains The Udzungwa Mountains are a mountain range in south-central Tanzania . The mountains are mostly within Iringa Region , south of Tanzania's capital Dodoma . The Udzungwa Mountains are part of
672-524: The south and southeast. To the southwest the Makambako Gap separates the Udzungwa Mountains from the Kipengere Range . Both the Great Ruaha and Kilombero rivers are tributaries of the Rufiji River , which empties into the Indian Ocean. The Lukosi River originates in the central part of the range, and empties eastwards into the Great Ruaha. The Little Ruaha River and its tributaries drain much of
700-697: The strongest westerly winds in the middle latitudes can come in the Roaring Forties of the Southern Hemisphere, between 30 and 50 degrees latitude. Examples of notable rain shadowing include: On the largest scale, the entirety of the North American Interior Plains are shielded from the prevailing Westerlies carrying moist Pacific weather by the North American Cordillera . More pronounced effects are observed, however, in particular valley regions within
728-419: The top of a mountain range. As atmospheric pressure decreases with increasing altitude, the air has expanded and adiabatically cooled to the point that the air reaches its adiabatic dew point (which is not the same as its constant pressure dew point commonly reported in weather forecasts). At the adiabatic dew point, moisture condenses onto the mountain and it precipitates on the top and windward sides of
756-491: The western portion of the range, emptying northwards into the Great Ruaha. The Udzungwa Mountains intercept moisture-laden winds from the Indian Ocean, and receive more rainfall than the surrounding lowlands. Most of the rainfall occurs in the November-to-May wet season, although mist and light rain occur at higher elevations during the dry season months. Rainfall is higher on the southern and southeastern slopes facing
784-443: The younger volcanic soils of mountains to the north and west. About thirty million years ago, the area was covered by extensive rainforest . During a cooler and drier period some ten million years ago, the lowland forests were converted to savanna , leaving the mountain ranges as "islands" where the tropical forests continued to flourish. The long-term persistence of a humid climate and the isolation of each mountain range has led to
#683316