Protecting Wildlife Corridors in the Greater Tarangire Ecosystem
Zoo conservationists work with partners in the Greater Tarangire Ecosystem to protect the main migration corridors for African buffalo, elephants, giraffes, wildebeests, zebras, Grant’s gazelles, Coke’s hartebeests, elands, impalas, and other important species.
The Tarangire ecosystem in northern Tanzania supports the third-largest movement of large mammals in East Africa, surpassed only by the wildebeest migration in the Serengeti ecosystem and the white-eared kob movement in South Sudan. The most recent aerial count, conducted across the Tarangire ecosystem in the dry season of 2016, suggests that approximately 78,000 animals disperse and migrate across the ecosystem annually. This includes large populations of African buffalos, elephants, giraffes, wildebeests, zebras, Grant’s gazelles, Coke’s hartebeests, elands, and impalas.
The ecosystem is also a stronghold for fringe-eared oryxes and nationally important populations of lions, and wild dogs, while leopards, striped hyaenas, and spotted hyaenas are also common. In total, the ecosystem protects no less than 26 species of carnivores and 24 species of hoofed animals, making this one of the most diverse ecosystems for large mammals globally.
In order to protect these wildlife areas—and the grazing areas for local Maasai—zoo conservationists work with a local partner organization, the Ujamaa Community Resource Team, and other partners to zone an area exclusively for livestock grazing and wildlife using Certificates of Customary Rights of Occupancy. These certificates are provisioned for under the Tanzania land law, allowing a community to retain ownership and create by-laws that allocate specific land uses for the area. It’s a win-win for wildlife and the local communities, who are eager to protect their dry season grazing land from agricultural expansion.
To date, more than one million acres of community land has been set aside via these certificates. The ultimate goal of the project is to ensure that the main migration corridors in the ecosystem are protected through a contiguous set of Certificates of Customary Rights of Occupancy, allowing for uninterrupted movement of livestock and wildlife across the greater Tarangire ecosystem.
During the dry season, wildlife concentrates in Tarangire National Park, which provides the only major dry season water supply along the Tarangire River. In the wet season, wildlife disperses widely outside the park onto community lands. The key factor driving this migration is water availability and the variability in mineral content of the soils in the ecosystem.
Studies have shown that the soils of Tarangire National Park are deficient in phosphorus, which is an important mineral for lactating female animals. By contrast, the soils and grasses in the dispersal areas outside the park, notably the Simanjiro plains, are rich in both phosphorus and crude protein, making them ideal calving grounds for the large ungulates. The soils in Tarangire National Park are so mineral deficient that they are unable to maintain lactating female ungulates, such as wildebeests.
When the standing water in the surrounding dispersal areas dries up, the wildlife is forced to return to Tarangire National Park. During very wet years, as witnessed in 1998 in the aftermath of El Niño, this return migration does not take place—the wildlife simply stayed on the community lands year-round. Access to dispersal areas outside the Park is therefore essential; if the large ungulate species were restricted to Tarangire National Park’s less nutritious grasslands for any lengthy period, their populations would eventually crash.
This large-scale movement of wildlife is increasingly threatened from land-use change outside Tarangire National Park. Agricultural expansion, particularly to the west and north of Tarangire, has led to the disappearance of five of the nine major wildlife corridors connecting Tarangire to surrounding dispersal areas in the past 40 years. The land to the east and south is predominately used by the livestock-herding Maasai tribe, who have traditionally tolerated and co-existed with wildlife on their land. However, recent changes in their land-use and pastoral traditions have led to an expansion of agriculture or to leasing communal grazing land to immigrant farmers. This expansion now threatens the integrity of two of the most important remaining corridors to the north and east of the park.