Bird diversity and land use on the slopes of Mt Kilimanjaro and the adjacent plains, Tanzania

Abstract

This study of bird distribution in the main land-use categories of the slopes of Mt Kilimanjaro, Tanzania, aims at understanding potential impacts of the land-use changes on birds. A land-use map of the study area was derived from a Landsat image, and land-use change information came from an earlier study by the author. Bird data were collected by observations along timed, standardized walks. Shannon (1948) indices of bird diversity for highlands, bushland and lowlands were 3.29, 2.99, and 2.62. The highland category was divided into two subcategories, homegarden and highland garden, as bird populations of the two were distinct. Highland garden had a higher diversity (3.15) than homegarden (3.07). The lower species diversity and number of individuals in homegardens was probably due to lower niche diversity and more human disturbance. Lowland fields had low diversity indices as they are dominated by large flocks of birds. The equitability indices for highlands, bushlands and lowlands were 0.82, 0.80 and 0.65, respectively. Each land-use type had many species that were not seen in the others. As bushland is disappearing, the species currently threatened are the 15 bushland species that are not found in other land-use types. Growing population pressure leading to deagrarianization of the homegarden area is likely to affect homegarden bird populations, though it is not clear whether the very high human population density will prevent it from supporting a highland garden type of a bird population.