Introduction

Aims

It is the purpose of this chapter to list and identify the mammalian forest fauna of eastern Africa, updating the list with new information. We provide some simple measures of affinity and distinctness in the forest mammal communities of far eastern Africa. We consider to what extent the affinities might reflect eastward dispersal from a westerly focus or a residual forest fauna impoverished by climatic degradation. Two principal levels of endemism are identified: those species that are broadly distributed in the forests of eastern Africa and those that have a very restricted distribution within this region. Further categories of endemics are also identified, restricting species to (i) montane, (ii) lowland and (iii) coastal forest types, including those found on Zanzibar, Pemba and Mafia Islands. The possible importance of colonisation, competition and isolation in the evolution of distinct species or subspecies is discussed.

A list of forest-dependent mammals from eastern and southwestern Tanzania has been assembled and is compared with a list of comparable mammals from western Uganda (Budongo, Kibale, Kalinzu, Kayonza and Bwindi). Those species held in common are listed in Table 11.1, with local subspecies shown separately under their regional heading. From these lists some simple measures of endemism have been estimated.

The interest of mammals

There are indisputably far fewer species in the East African forests than in Central and West Africa. Furthermore, the shared occurrence of various rodent, insectivore and primate species, blue duiker Cephalophus monticola, palm civet Nandinia binotata, and the anomalure Anomalorus derbianus has encouraged the view that these forests are merely impoverished outliers of the Guineo–Congolian block.