country : Tanzania
place : north of the country, east of Victoria lake
The Serengeti ecosystem is a geographical region in Africa. It is located in north Tanzania and extends to south-western Kenya between latitudes 1 and 3 S and longitudes 34 and 36 E. It spans some 30,000 km2 (12,000 sq mi). The Kenyan part of the Serengeti is known as Maasai (Masai) Mara.
The Serengeti hosts the largest terrestrial mammal migration in the world, which helps secure it as one of the Seven Natural Wonders of Africa, and one of the ten natural travel wonders of the world.[2] The Serengeti is also renowned for its large lion population and is one of the best places to observe prides in their natural environment. The region contains the Serengeti National Park in Tanzania and several game reserves.
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. Blue wildebeests, gazelles, zebras and buffalos are some of the commonly found large mammals in the region.
Currently there is controversy surrounding a proposed road that is to be built through the Serengeti.
Serengeti is derived from the Maasai language, Maa; specifically, "Serengit" meaning "Endless Plains".
Much of the Serengeti was known to outsiders as Maasailand. The Maasai are known as fierce warriors, and live alongside most wild animals with an aversion to eating game and birds, subsisting exclusively on their cattle. Historically, their strength and reputation kept the newly arrived Europeans from exploiting the animals and resources of most of their land. rinderpest epidemic and drought during the 1890s greatly reduced the numbers of both Maasai and animal populations. The Tanzanian government later in the 20th century re-settled the Maasai around the Ngorongoro Crater. 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.
By the mid-1970s wildebeest and the Cape buffalo populations had recovered, and were increasingly cropping the grass, reducing the amount of fuel available for fires. The reduced intensity of fires has allowed Acacia to once again become established.
Great migration
Migrating wildebeests
Wildebeests crossing the river during the Serengeti migration
Each year around the same time the circular great wildebeest migration begins in the Ngorongoro area of the southern Serengeti of Tanzania. A natural phenomenon determined by the availability of grazing. It is January to March when the calving season begins. A time when there is plenty of rain ripened grass available for the 750,000 zebra that precede 1.2 million wildebeest and the following hundreds of thousands of other plains game.
During February the wildebeest spend their time on the short grass plains of the south eastern part of the ecosystem, grazing and giving birth to approximately 500,000 calves within a 2 to 3 week period: a remarkably synchronized event. Few calves are born ahead of time and of these, hardly any will survive. (Estes 1992)[citation needed] The main reason for this being that very young calves are more noticeable to predators when mixed with older calves from earlier in the previous year, and so are easier prey. As the rains end in May the animals start moving north west, into the areas around the Grumeti River, where they typically remain until late June. July sees the main migration of wildebeest, zebra and eland heading north, arriving on the Kenyan border late July / August for the remainder of the dry season (the Thomson's and Grant's Gazelles move only east/west). In early November with the start of the short rains the migration starts moving south again, to the short grass plains of the south east, usually arriving in December in plenty of time for calving in February.
Some 250,000 wildebeest die during the journey from Tanzania to Maasai Mara Reserve in lower Kenya, a total of 800 kilometres (500 mi). Death is usually from thirst, hunger, exhaustion, or predation. The migration is chronicled in the 1994 documentary film, Africa: The Serengeti. The second-largest is the South Sudan animal migration.
Ecology
Maasailand has East Africa's finest game areas. The governments of Tanzania and Kenya maintain a number of Protected Areas: parks, conservation areas, game reserves, etc. that give legal protection to over 80% of the Serengeti.
Ol Doinyo Lengai, the only active volcano in the area of the Serengeti, is the only volcano that 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 being rained upon. OL Doinyo Lengai is also a Maasai holy site.
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. gradient of soil depth northwestward across the plains results in changes in the herbaceous community and taller grass. Some 70 km (43 mi) west, Acacia woodlands appear suddenly and stretch west to Lake Victoria and north to the Loita Plains, 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.
Altitudes in the Serengeti range from 920 to 1,850 metres (3,020 to 6,070 ft) with mean temperatures varying from 15 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 (20 in) in the lee of the Ngorongoro Highlands to a high of 1,200 mm (47 in) on the shores of Lake Victoria. 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 and gneiss outcroppings known as kopjes. These outcroppings are the result of volcanic activity. Kopjes provide a microhabitat for non-plains wildlife. One kopje likely to be seen by visitors to the Serengeti is the Simba Kopje (Lion Kopje). The Serengeti was used as inspiration for the animated Disney feature 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.
Ngorongoro Conservation Area
The Ngorongoro Conservation Area (NCA) is a conservation area and a UNESCO World Heritage Site located 180 km (110 mi) west of Arusha in the Crater Highlands area of Tanzania. Ngorongoro Crater, a large volcanic caldera within the area, is recognized by one private organization as one of the seven natural wonders of Africa. The conservation area is administered by the Ngorongoro Conservation Area Authority, an arm of the Tanzanian government, and its boundaries follow the boundary of the Ngorongoro Division of the Arusha Region.
History and geography
Based on fossil evidence found at the Olduvai Gorge, various hominid species have occupied the area for 3 million years.
Hunter-gatherers were replaced by pastoralists a few thousand years ago.[citation needed] The Mbulu came to the area about 2,000 years ago and were joined by the Datooga around the year 1700.[citation needed] Both groups were driven from the area by the Maasai in the 1800s.
Massive fig trees in the northwest of the Lerai Forest are sacred to the Maasai and the Datooga. Some of them may have been planted on the grave of a Datago leader who died in battle with the Maasai around 1840.
No Europeans are known to have set foot in the Ngorongoro Crater until 1892, when it was visited by Oscar Baumann. Two German brothers (Adolph and Friedrich Siedentopf) farmed in the crater until the outbreak of World War I, after leasing the land from the administration of German East Africa. The brothers regularly organized shooting parties to entertain their German friends. They also attempted to drive the wildebeest herds out of the crater.
In 1921, the first game preservation ordinance was passed, which restricted hunting to permit holders throughout Tanzania. In 1928, hunting was prohibited on all land within the crater rim, except the former Siedentopf farms. The National Park Ordinance of 1948 (implemented in 1951) created the Serengeti National Park (SNP). This, however, caused problems with the Maasai and other tribes, resulting in the NCA Ordinance (1959) that separated the NCA from the SNP.The Ngorongoro Conservation Area Authority was established by the Game Park Laws (miscellaneous amendments) Act, 1976 and owns the majority of NCA land, including the crater. The area became a UNESCO World Heritage Site in 1979.
Land in the conservation area is multi-use and unique because it is the only conservation area in Tanzania that protects wildlife while allowing human habitation. Land use is controlled to prevent negative effects on the wildlife population. For example, cultivation is prohibited at all but subsistence levels.
The area is part of the Serengeti ecosystem and, to the northwest, adjoins the SNP and is contiguous with the southern Serengeti plains. These plains also extend to the north into the unprotected Loliondo division and are kept open to wildlife through transhumance pastoralism practiced by the Maasai. The south and west of the area are volcanic highlands, including the famous Ngorongoro Crater and the lesser known Empakaa Crateri. The southern and eastern boundaries are approximately defined by the rim of the East African Rift wall, which also prevents animal migration in these directions.
Ngorongoro Crater
The main feature of the Ngorongoro Conservation Authority is the Ngorongoro Crater, the world's largest inactive, intact, and unfilled volcanic caldera. The crater, which formed when a large volcano exploded and collapsed on itself two to three million years ago, is 610 metres (2,000 feet) deep and its floor covers 260 square kilometres (100 square miles). Estimates of the height of the original volcano range from 4,500 to 5,800 metres (14,800 to 19,000 feet) high. The elevation of the crater floor is 1,800 metres (5,900 feet) above sea level.
The crater highlands on the side facing the easterly trade winds receives 800 to 1,200 millimetres (31 to 47 inches) of rain a year and are covered largely in montane forest. The less-steep west wall receives only 400 to 600 millimetres (16 to 24 inches) and is grassland and bushland dotted with Euphorbia bussei trees. The crater floor is mostly open grassland with two small wooded areas dominated by Acacia xanthophloea.
The Munge Stream drains Olmoti Crater to the north, and is the main water source draining into the seasonal salt lake in the center of the crater. This lake is known by two names: Makat as the Maasai called it, meaning salt; and Magadi. The Lerai Stream drains the humid forests to the south of the Crater, and it feeds the Lerai Forest on the crater floor - when there is enough rain, the Lerai drains into Lake Magadi as well. Extraction of water by lodges and NCA headquarters reduces the amount of water entering Lerai by around 25 percent.
The other major water source in the crater is the Ngoitokitok Spring, near the eastern crater wall. There is a picnic site here open to tourists and a huge swamp fed by the spring, and the area is inhabited by hippopotamus, elephants, lions, and many others. Many other small springs can be found around the crater's floor, and these are important water supplies for the animals and local Masaai, especially during times of drought.
Following the recommendations of the ad hoc committee of scientists convened after the year 2000 drought, an ecological burning program was implemented in the crater, which entails annual or biannual controlled burns of up to 20 percent of the grasslands. Maasai are now permitted to graze their cattle within the crater, but must enter and exit daily.
The Ngorongoro Conservation Area also protects Olduvai Gorge, situated in the plains area. It is considered to be the seat of humanity after the discovery of the earliest known specimens of the human genus, Homo habilis as well as early hominidae, such as Paranthropus boisei.
The Olduvai Gorge or Oldupai Gorge is a steep-sided ravine in the Great Rift Valley, which stretches along eastern Africa. Olduvai is in the eastern Serengeti Plains in northern Tanzania and is about 30 miles long. It lies in the rain shadow of the Ngorongoro highlands and is the driest part of the region. The gorge is named after 'Oldupaai', the Maasai word for the wild sisal plant, Sansevieria ehrenbergii.
It is one of the most important prehistoric sites in the world and research there has been instrumental in furthering understanding of early human evolution. Excavation work there was pioneered by Mary and Louis Leakey in the 1950s and is continued today by their family. Some believe that millions of years ago, the site was that of a large lake, the shores of which were covered with successive deposits of volcanic ash. Around 500,000 years ago seismic activity diverted a nearby stream which began to cut down into the sediments, revealing seven main layers in the walls of the gorge.
Wildlife
Inside Ngorongoro Crater
The Ngorongoro Crater includes most of the animal species found in East Africa.
Approximately 25,000 large animals, mostly ungulates, live in the crater. Large animals in the crater include the black rhinoceros (Diceros bicornis), the local population of which declined from about 108 in 1964-66 to between 11-14 in 1995, and the hippopotamus (Hippopotamus amphibius). There also are many other ungulates: the wildebeest (Connochaetes taurinus) (7,000 estimated in 1994), Burchell's zebra (Equus burchelli) (4,000), the common eland (Taurotragus oryx), and Grant's (Nanger granti) and Thomson's gazelles (Eudorcas thomsonii) (3,000). Waterbuck (Kobus ellipsiprymnus) occur mainly near Lerai Forest. There are no topis (Damaliscus lunatus), oribis (Ourebia oribi), or crocodiles (Crocodylus niloticus). Impala (Aepyceros melampus) are absent because the open woodland they prefer does not exist. Giraffe also are absent, possibly because of a lack of browse species. Cheetah (Acinonyx jubatus), African wild dog (Lycaon pictus), and leopard (Panthera pardus) are rarely seen.
Although thought of as "a natural enclosure" for a very wide variety of wildlife, 20 percent or more of the wildebeest and half the zebra populations vacate the crater in the wet season. Buffalo (Syncerus caffer) and eland do the opposite. Their highest numbers are during the rains.
Since 1986, the crater's wildebeest population has fallen from 14,677 to 7,250 (2003-2005). The numbers of eland and Thomson's gazelle also have declined while the buffalo population has increased greatly, probably due to the long prevention of fire which favors high-fibrous grasses over shorter, less fibrous types.
Servals (Leptailurus serval) occur widely in the crater.
Lake Magadi, a large lake in the southwest of the crater, is often inhabited by thousands of mainly Lesser Flamingoes.
Crater lions
The crater has one of the densest known population of lions, numbering 62 in 2001.
A side effect of the crater being a natural enclosure is that the lion population is significantly inbred. This is due to the very small amount of new bloodlines that enter the local gene pool, as very few migrating male lions enter the crater from the outside. Those who do enter the crater are often prevented from contributing to the gene pool by the crater's male lions, who expel any outside competitors.
Long-term data imply that lions in the crater were struck by four deadly disease outbreaks between 1962 and 2002. Drought in 1961 and rains throughout the 1962 dry season caused a massive build-up of blood-sucking stable flies (Stomoxys calcitrans) by May 1962. They drained blood and caused painful skin sores that became infected, causing lion numbers to crash from 75-100 to 12. The population recovered to around 100 by 1975 and remained stable until 1983, when a persistant decline began. Numbers have generally remained below 60 animals since 1993, reaching a low of 29 in 1998. In 2001, 34 percent of the lion population died between January and April from a combination of tick-borne disease and canine distemper.
The lion population is also influenced to some extent by the takeover of prides by incoming males, which typically kill small cubs. The biggest influence, however, appears to be disease, particularly canine distemper.
Inside the crater:
Wildebeest and zebra in a herd.
Female lions on the hunt in the crater.
Lioness, zebras, and wildebeest in the crater.
Outside Ngorongoro Crater:
The Ngorongoro Conservation Area (NCA) has a healthy resident population of most species of wildlife. The Ndutu Lake area to in the west of the NCA has particularly strong cheetah and lion populations. Common in the NCA are hartebeest (Alcelaphus buselaphus), spotted hyenas (Crocuta crocuta), and jackals. The population of African Wild Dog in the NCA may have declined recently.[when?] Servals occur widely on the plains to the west of the Ngorongoro Crater.
The annual ungulate migration passes through the NCA, with 1.7 million wildebeest, 260,000 zebra, and 470,000 gazelles moving south into the area in December and moving north in June. This movement changes seasonally with the rains, but the migration traverses almost the entire plains in search of food.
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