The Uluguru Mountains of eastern Tanzania: are we loosing their globally significant biodiversity values?

Abstract

The Uluguru Mountains in eastern Tanzania contain at least 15 vertebrate and 100 plant species as strict endemics, and hundreds more which are shared only with other Eastern Arc Mountains in eastern Tanzania. The high numbers of restricted range taxa in a small area is exceptional in tropical Africa and the area is one of the 10 most important tropical forest sites for conservation on the continent. Recent surveys in the Ulugurus have tried to establish the area of habitat remaining, the number of the endemics that can be confirmed to still exist, and the number of the endemics that might be in danger of extinction given current deforestation patterns. The forest area between 500 m and 2600 m altitude has declined from around 300 sq km in 1955, to 220 sq km today. Almost all the forest now remains within Forest Reserves managed by the Tanzanian Government. The loss of forest has been greatest between 600 m and 1600 m, which is largely in the range of sub-montane forest on the Ulugurus. These sub-montane forests contain a number of strict endemics, and species shared only with other Eastern Arc Mountains. Recent biological surveys have located most of the endemic and near-endemic vertebrate species in the Ulugurus, but have failed to locate three strict endemic vertebrate species, and two near-endemic bird species that have been recorded as occurring in the Ulugurus. Nearly all of the species which have not been found prefer a forest habitat at the elevation where deforestation has been greatest. It is likely that deforestation is the cause of the loss of these species.