Plains in Serengeti Endless Plains

"I do not know of any country which is, in terms of earth, of solid matter, so nearly the equivalent of the sea. There seems to be no end of it"
Laurens van der Post, Venture to the Interior, 1963

The Serengeti Plains fill the southern half of the Serengeti and are one of the reasons why the yearly Migration of Wildebeest takes place. After spending the dry season in the wetter northern woodland of Serengeti, the Wildebeest follow the seasonal rains south and move out onto the Serengeti Plains.

During the rainy season, the shallow, water-holding soil and over a million grazing mouths maintain the plains in a super-productive growing state. With ample food, the wildebeest females produce and suckle their calves. The wet season is also the time of year for predators to fatten-up. With an abundance of young and inexperienced herbivores lions, cheetahs and hyenas live in a never-never land of endless food. As the dry season approaches, the seasonal water-holes dry up and the grass begins to turn a golden color. The wildebeest then begin their annual migration. Thompson's Gazelles, Grant's Gazelles, Warthogs, and Ostrich remain behind to feed on the dried plants of the plains. Only species which can do without water for long periods and live on poor forage can get by during the dry season.

The Serengeti plains have a series of three distinct kinds of grasslands. The first is the "short grass" plains which begin in Ngorongoro, surrounds the Oldupai river, and extends into Serengeti National Park. The second area is the "intermediate grass" plains which forms a crescent north and west of the short grass plains. The third type of grassland is the "long grass" plains that occur north of the medium grass plains and around Seronera.

During the Pleistocene age, one to three million years ago, rock and ash from the volcanoes of the Ngorongoro area covered what is today the Serengeti Plains. The volcanic ash on the plains produces a very particular type of soil. The fine-grained ash contains many salts, such as potassium, sodium, and calcium. During the seasonal rains, these salts are washed down into the soil where they precipitate, or come out of solution. In the Serengeti Plains, the salts are deposited less than a meter below the surface, and form a hard, almost concrete layer called a "hardpan" or "petrocalcic horizon". This hardpan keeps trees from sending their roots down into the soil, and so keeps trees from growing on the plains. What is bad for trees, however, is great for grasses. The hardpan keeps rainwater close to the surface and thus available for grasses which grow thick, dense, and perfect for animals.

The incredibly high number of grazing animals in the Serengeti Ecosystem mean that during the wet season, most of the grasses on the Serengeti Plains are consumed. If grass is cut very short, it rapidly re-grows and is higher in water and nutrients. By repeatedly cutting the grass short and having it constantly re-growing, the animals create what is called a "grazing lawn" of very high quality, rapidly growing grass.

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