Connectivity and bottlenecks in a migratory wildebeest Connochaetes taurinus population

Surprisingly little is known about the spatial dimensions of most tropical ungulate migrations, including that of wildebeest Connochaetes taurinus, a species famous for long-distance movements. Using non-invasive photographic identification of 834 adult wildebeest from 8,530 images collected over 4 years we characterize patterns of migratory connectivity throughout the northern Tarangire-Manyara Ecosystem, Tanzania. We document movements between Tarangire and Lake Manyara National Parks and northwards to the shore of Lake Natron, a straight-line distance of > 130 km. Fifty-six percent of observed movements occur outside the ecosystem's three main protected areas. We supplement photographic data with fine-scale movement data from two individuals with global positioning system collars, and identify three narrow bottlenecks, each vulnerable to human development. We discuss the possible consequences for the wildebeest population if these bottlenecks become impeded. Persistence of this migration alongside a growing human population and proposed road improvement will require additional measures to ensure that pathways remain open to wildlife movement and protected from illegal hunting.