Serengeti

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This article is about a geographical region; for the National Park see Serengeti National Park

A zebra and wildebeests during migration

The Serengeti ecosystem is located in north-western Tanzania and extends to south-western Kenya between latitudes 1 and 3 S and longitudes 34 and 36 E. It spans some 30,000 km.^[1]

The Serengeti hosts the largest and longest overland migration in the world,^[2] a semi-annual occurrence. This migration is one of the ten natural travel wonders of the world.

The region contains several national parks and game reserves. Serengeti is derived from the Maasai language, Maa; specifically "Serengit", meaning "Endless Plains".^{[3] [4]}

Approximately 70 larger mammal and some 500 avifauna species are found there. This high diversity in terms of species is a function of diverse habitats ranging from riverine forests, swamps, kopjes, grasslands and woodlands. ^[5] Blue Wildebeests, gazelles, zebras and buffalos are some of the commonly found large mammals in the region.

Around October, nearly 2 million herbivores travel from the northern hills toward the southern plains, crossing the Mara River, in pursuit of the rains. In April, they then return to the north through the west, once again crossing the Mara River. This phenomenon is sometimes called the Circular Migration. Over 250,000 wildebeest alone will die along the journey from Tanzania to Masai Mara Reserve in upper Kenya, a total of 500 miles. Death is often caused by injury, exhaustion, or predation.^[2] The migration is chronicled in the 1994 documentary film, Africa: The Serengeti.

[edit] History and Ecology

A young Maasai man (moran or warrior) walks into the Serengeti with the Ngorongoro Highlands as a backdrop.

Much of the Serengeti was known to outsiders as Maasailand. The Maasai were known as fierce warriors, and lived alongside most wild animals with an aversion to eating game and birds, subsisting exclusively on their cattle. Their strength and reputation kept the newly arrived Europeans from exploiting the animals and resources of most of their land. A rinderpest epidemic and drought during the 1890s greatly reduced the numbers of both Maasai and animal populations. Poaching and the absence of fires, which had been the result of human activity, set the stage for the development of dense woodlands and thickets over the next 30-50 years. Tsetse fly populations now prevented any significant human settlement in the area. Fire, elephants, and wildebeest were influential in determining the current character of the Serengeti.^[6] [4] By the 1960s, as human populations increased, fire, either intentionally set by the Maasai to increase area available for pasture, or accidentally, scorched new tree seedlings. Heavy rainfall encouraged the growth of grass, which served as fuel for the fires during the following dry seasons. Older Acacias, which live only 60 to 70 years, began to die. Initially elephants, which feed on both young and old trees, had been blamed for the shrinking woodlands. But experiments showed that other factors were more important. Meanwhile, elephant populations were reduced from 2,460 in 1970 to 467 in 1986 by poaching.^[7] [5] By the mid 1970s wildebeest and African buffalo populations had recovered, and were increasingly cropping the grass, reducing the amount of fuel available for fires.[6] The reduced intensity of fires has allowed Acacia to once again become established.^[8] [7]

Maasailand now has East Africa's finest game areas.^[9] The governments of Tanzania and Kenya maintain a number of Protected Areas: parks, conservation areas, game reserves, etc, which give legal protection to over 80% of the Serengeti.[8]

Ol Doinyo Lengai, the only active volcano in the area of the Serengeti, is the only volcano which still ejects carbonatite lavas. This material, upon exposure to air, changes from black to white and resembles washing soda. A thick layer of ash can turn into a calcium rich hardpan as tough as cement after rained upon. Tree roots cannot penetrate this layer, and the essentially treeless plains of the Serengeti, which lie to the west and down wind of Ol Doinyo Lengai, are the result.^[10]

A rock outcropping, or koppes, on the Serengeti plain.

The southeastern area lies in the rain shadow of the Ngorongoro highlands and is composed of shortgrass treeless plains with abundant small dicots. Soils are high in nutrients, overlying a shallow calcareous hardpan. A gradient of soil depth northwestward across the plains results in changes in the herbaceous community and taller grass. Some 70 km west, Acacia woodlands appear suddenly and stretch west to Lake Victoria and north to the Loita Plains,[9] north of the Maasai Mara National Reserve. The 16 Acacia species vary over this range, their distribution determined by edaphic conditions and soil depth. Near Lake Victoria there are flood plains developed from ancient lakebeds. In the far northwest, Acacia woodlands are replaced by broadleaved Terminalia-Combretum woodlands, determined by a change in geology. This area has the highest rainfall in the system and forms a refuge for the migrating ungulates at the end of the dry season. [10]

Altitudes in the Serengeti range from 920 to 1,850 meters with mean temperatures varying from 15 degrees to 25 degrees Celsius. Although the climate is usually warm and dry, rainfall occurs in two rainy seasons: March to May, and a shorter season in October and November. Rainfall amounts vary from a low of 508 mm in the lee of the Ngorongoro Highlands to a high of 1,200 mm on the shores of Lake Victoria.[11] The highlands, which are considerably cooler than the plains and are covered by montane forest, mark the eastern border of the basin in which the Serengeti lies.

The Serengeti plain is punctuated by granite outcroppings known as koppes. These outcroppings are the result of volcanic activity. Koppies provide a microhabitat for non-plains wildlife. One koppe likely to be seen by visitors to the Serengeti is the Simba Koppe (Lion Koppe). The Serengeti was used as inspiration for the animated Disney film The Lion King and subsequent theatrical production.

The area is also home to the Ngorongoro Conservation Area, which contains the Olduvai Gorge, where some of the oldest hominid fossils are found, as well as the Ngorongoro Crater, the world's largest unbroken volcanic caldera.

[edit] See also

• Serengeti National Park
• Maasai tribe
• Animals of the Serengeti
• Plants of the Serengeti

[edit] References

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