Fieldwork in Tanzania suggests that soil chemistry—influenced by local volcanism and tectonic activity—might help dictate the record-setting migration of over a million wildebeests.The most famous migration in the animal kingdom is undoubtedly that of wildebeests. While the Serengeti boasts hundreds of mammal and bird species — 800 to be exact — many travelers head here to see the "big five" in the wild: lion, rhino, leopard, elephant and Cape buffalo.Spotting these animals is exhilarating, particularly the elusive leopard and rhino, but these hardly scratch the surface of animals you'll see in the Serengeti. That fingerprint would allow the team to determine how factors such as geology, volcanism, and tectonic activity might be affecting soil chemistry and nutrient availability, which in turn influence vegetation growth and therefore migration patterns.Most of the samples are still awaiting analysis in a laboratory in Arusha, Tanzania, said Kübler. Researchers now have preliminary evidence that this record-setting migration is dictated by more than just precipitation patterns: Soil chemistry is also a likely driver.Every year, the animals journey roughly 500 kilometers through wide plains covered with short grasses, as well as through wooded areas and landscapes with mixed grasses and shrubs. Starting in the southeastern part of the park, the researchers spent 2 weeks in a beige Toyota Land Cruiser retracing the wildebeests’ clockwise migration route.Along the way, Kübler and his collaborators collected samples of rock, soil, and vegetation. In November, the short rains bring them south back into the Serengeti to start the process all over. Every year, roughly 1.2 million of the ungulates wind their way through Africa’s Serengeti ecosystem.
In the southern short grass plains, they give birth, from January through to March. They’re following the route that their ancestors did, and that movement merits study, said Scientists have often studied wildebeest migration from a climatic perspective but rarely from the angle of rock chemistry and weathering, said Kübler. During late December, the animals arrive within the Serengeti Plains all the way to the Northern part of the Ngorongoro Conservation Area. Because of high precipitation levels in this area, rocks experience more chemical weathering, the team hypothesized, which releases nutrients into the soil and promotes vegetation growth. Chemical analyses are still in progress, but “we believe that the nutrient levels in the soils [here] are probably the lowest,” said Kübler. Much of their journey passes through various parts of the Serengeti eco-system. The annual migration of the wildebeest is one of the most impressive sights in Africa. The animals stay in the same area, with most wildebeest calves born in February. Around 1.5 million wildebeest—translating to “wild cattle” in Afrikaans—travel around the Serengeti plains for about seven months every year in search of pasture and water.
June: The animals congregate on the south side of the Grumeti River, in the Western Corridor. About 1 million wildebeest are constantly on the move following the path of the rains and the new grass. April, May: The animals start their great migration north in search of fresh grazing and water. Every day for about three weeks, an estimated 8000 foals are born. The Animals of the Serengeti.
Ol Doinyo Lengai, roughly 50 kilometers east of Serengeti National Park, holds a unique honor among volcanoes: It produces Ash from Ol Doinyo Lengai rains down on the southeastern part of the park and sprinkles calcium into the soil, Kübler said. “The geological system that’s underlying the entire ecosystem might be stable for longer periods of time.” Furthermore, there’s a source of fresh rock because tectonic activity and uplift are occurring near this part of the park, said Kübler.
A UNESCO World Heritage Site and home to the Great Migration . Much of their journey passes through various parts of the Serengeti eco-system. “Wildebeest can only stay for a limited amount of time until they migrate farther north.” Water-induced erosion likely contributes to the poor soil quality in this region, the team concluded.The third and final site the scientists analyzed was near the northernmost border of the park, where wildebeests spend the late summer and early fall.