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The Flora & Fauna of East Africa

Written by  John C. Cannon 2/9/2016
Mention “East Africa” and the first thoughts that pop into one’s mind are probably the animals of the Serengeti. And perhaps no country identifies more closely with the great mammals – the charismatic mega fauna that grace the pages of National Geographic so frequently – than Tanzania. Primatologist and conservationist Jane Goodall calls the Serengeti “the essence of Africa” (16).

Nearly too numerous to count, the mammals that inhabit Serengeti National Park in Tanzania and Maasai Mara National Park in Kenya, as well as surrounding protected areas, include gazelle, buffalo, impala, topi, hartebeest, giraffe, eland, lion, spotted hyena, cheetah, rhinoceros, African hunting dog, crocodile, hippo, warthog, bush pig and giant forest hog, not to mention 500 species of birds (1).

But underpinning this ecosystem is the annual Great Migration taken by up to 1.5 million wildebeest – the region’s keystone species – and hundreds of thousands of zebra and gazelle. The 40,000 square kilometers of the Serengeti Ecosystem is “pretty much defined by the dominant migration routes of the white-bearded wildebeest (Connochaetes tuarinus mearnsiI)” (12). Part moving buffet for the region’s predators, part gardeners in maintaining the vast grassland, these large mammals, which undertake the longest land migration on earth, directly or indirectly impact nearly all of the life around them.

The dry season, which typically begins in May, launches the movement of the wildebeest on a grand scale. With little water and only dry, stubbly grass to feed upon at this time of year, they head north from Ngorongoro Crater and the southern Serengeti Plains toward scrubby woodlands in the north dominated by iconic flat-topped Acacia species, following the rains that occur there (2,3). The 800-kilometer migration takes them across the Mara River and into Kenya. Then, in December, monsoon rains begin again in the southern Serengeti and Ngorongoro Crater, and the great herds make their way back to the region’s rich volcanic soil (5).

The wildebeest’s lifecycle involves synchronized birthing as a strategy for survival. Every February, around half a million calves are born. This deluge of babies at the same time ensures that, while some will perish to feed the lions, leopards, hyenas and other predators that depend on the wildebeest for sustenance, there will be animals that survive to adulthood (2, 3). In all, about 250,000 wildebeest die each year, though only about a third are killed by predators (2,6).

The mix of wildebeest, zebra and gazelle plays a critical role in maintaining the ecosystem. Each species graze on different parts of the grass and some prefer other plants, which helps sustain the diversity of plants that make up the region. Scientific studies from the 1980s and 1990s found that if these herbivores weren’t part of the equation, parts of the plains wouldn’t be as botanically productive, and some species of grass might disappear entirely (2).

The migration plays a critical roll in replenishing the volcanic soils of the East African Plains. Research suggests that the moving herd dumps “500 truckloads” of manure and “125 road tankers of urine” on the grasslands each day, cycling vital nutrients back into the soil (3).

These huge aggregations of watchable wildlife form the backbone in many ways of the economies of Tanzania and Kenya, valued at more than US$1.2 billion for each country in 2012, according to the UN Environmental Programme (9). More than a million visitors per year enter Tanzania’s borders, many intent upon a life-list safari to see the country’s animal wealth (15). About 12 percent of jobs in Tanzania are connected to travel and tourism in some way, according to a 2015 trade association report (17).

Although the governments of Kenya and Tanzania appear committed to the protection of Serengeti and Maasai Mara, both UNESCO World Heritage sites, the ecosystems and the animals themselves are not immune from the pressures of sharing space with humans.

Scientists and conservationists have raised concerns about a road in Tanzania, designed to connect the Rift countries of Uganda, Rwanda, Burundi and the Democratic Republic of Congo with the coast of Tanzania, that would bisect the migration and potentially disrupt the critical process that the migration drives (3,8). The road has been discussed for decades, though it is still unclear whether it will ultimately be built. Opponents worry about more accidents involving wildlife and vehicles if it comes to fruition, as well as easier access for poachers to the animals.

Some of the region’s longest-term human inhabitants have also begun to transition from pastoral to sedentary lifestyles, threatening to upset a balance between people and wildlife that has existed for thousands of years. As pastoralists, the Maasai, as well as the Tatoga and Hadzabe tribes, have moved their cattle around for hundreds of years, so that no one place bore too much of the impact of their grazing. But now, as more Maasai settle into “Group Ranches” to farm, the increased intensity of their new livelihoods could impact the greater ecosystem. A trend toward sedentary agriculture has not, however, led to fewer livestock: Tanzania has more than 21 million cows, leading to intense grazing pressure on the land (4, 13, 14, 18, 19).

Scientists have also suggested that earth’s changing climate, and the accompanying effects on rain patterns, droughts, and flooding, could challenge the Great Migration. They don’t have conclusive proof, but climate change, along with development and poaching, could be contributing to the 20 percent decline in wildebeest numbers observed between 2000 and 2010, though numbers in 2013 seem to have climbed back up a bit (7, 9, 10).

Citation list

1. The African Great Rift Valley - The Maasai Mara, UNESCO World Heritage Centre, 2010.
2. Eastern Africa: the Greater Serengeti grassland ecosystem in northern Tanzania, WWF.
3. Road will ruin Serengeti, Nature, 2010.
4. Wildlife and the Maasai, Cultural Survival.
5. Great Migration,
6. The Serengeti: Plain Facts about National Park & Animals,
7. For Wildebeests, Danger Ahead, Smithsonian Magazine, 2010.
8. Highway Development Threatens Serengeti, Serengeti Watch, 2012.
9. Saving the Great Migrations: Declining wildebeest in East Africa? UNEP, 2013.
10. Epic Animal Migrations Could Change with Global Warming, Scientific American, 2014.
11. Serengeti wildebeest migration, Expert Africa.
12. Great Wildebeest Migration,
13. Human population increases, hard edges and the resulting trends and conflicts,, 2000.
14. Cows Are the Next Great Threat to Tanzania's Endangered Species, VICE News, 2015.
15. Tourism in Tanzania Tanzania tourist arrivals reach 1 million mark, EturboNews, 2013.
16. Jane Goodall on Why We Should Help the Serengeti, National Geographic News, 2013.
17. Travel and Tourism, Economic Impact, 2015, World Travel & Tourism Council, 2015.
18. “ The African Great Rift Valley - The Maasai Mara.” UNESCO World Heritage Centre, 2010.
19. “ Maasai People, Kenya.” Maasai Association.