Meredith Happold

Biogeography of montane small mammals in Malawi, Central Africa

Small mammals were surveyed in montane forests and grasslands on Zomba Plateau, Nyika Plateau and Mulanje Mountain in Malawi. Nine species were recorded, all confined in Malawi to montane habitats. Community densities varied from 20/ha on Nyika Plateau to 29/ha on Zomba Plateau. Five or six species were livetrapped in each region, but only four species (Lophuromys flavopunctatus Thomas, Mus triton (Thomas), Thamnomys sp. and Praomys delectorum (Thomas)) occurred in all regions. Each species has a different habitat preference. Tests of similarity between these small mammal faunas showed that each region was different but with considerable similarity between them. There was little difference between similar habitats within a region. Each species has had a different evoluti9nary history and pattern of dispersal, and the present mixture of species is a result of these differences and the past changes in climate and vegetation. The present species composition may be explained by the continuous presence of a forest-grassland mosaic which must have shown altitudinal change in response to changing climates in the past.

The bats of Malawi

— This paper gives an account of the 55 species of bats currently known to occur in Malawi. Six species are recorded for the first time, together with 86 new species-locality records which increase the records for Malawi by approximately 44 percent. Data were obtained from 1489 specimens (36 species) collected from 13 localities by DCDH and MH (August 1984 to June 1985), and museum specimens in Malawi. The account of each species includes measurements, localities, and brief notes on distribution, status, habitat, domiciles and behaviour. The bat faunas of Malawi and 13 other African countries are compared to reveal patterns and trends in the zoogeography and geographical ecology of the bats of Malawi.

SMALL MAMMALS IN PINE PLANTATIONS AND NATURAL HABITATS ON ZOMBA PLATEAU, MALAWI

(1) The effects of Pinus patula plantations on the populations of small terrestrial mammals were investigated on Zomba Plateau in Malawi, central Africa. Twelve study areas were live-trapped for seventy-five trap-nights each; nine were pine plantations (ages 1-32 years), one was a cypress plantation, and two were natural habitats. (2) A total of 113 small mammals representing eight species was captured; six species were rodents (Lophuromys fiavopunctatus, Mus triton, Otornys angoniensis, Praaomvs delectorum, Thamnomys dolichurus, Rattus rattus), and two were shrews (Crocidura luna, Crocidurafiavescens). The numbers of species and individuals varied considerably between the study areas, but only Lophuromysfiavopunctatus, Mus triton, Otomys angoniensis and the two species of Crocidura were found in the plantations. Other species, known from the montane grasslands on the plateau, were not present in the plantations. (3) Several habitat characteristics, which changed in relation to the age of the plantation, were measured, and correlations were sought between these characteristics and the numbers of small mammals. Numbers declined with decreasing number of trees per ha, increasing tree height, increasing height of the lowest branches, and increasing amount of pine-needle litter. Each species of small mammal responded in a different way to these agerelated changes. (4) The two natural habitats, a Mulanje cedar (Widdringtonia nodifora) forest and a secondary tangle, supported more individuals (36 5 per 100 trap-nights) than any of the pine plantations (7 2 per 100 trap-nights, range 0-14 per 100 trap-nights). (5) Lophuromys fiavopunctatus, Mus triton, and Crocidura tuna had wide habitat breadths and were able to adjust to the changing conditions associated with the plantations. In contrast, Praomys delectorurm, Thanmnomys dolichurus and Otomnys angoniensis were unable to adapt. (6) Four published reports on the responses of small mammals to coniferous plantations were compared with the present study. The principal responses, regardless of species or locality, were (a) an increase in numbers after clear-felling, (b) a decline in numbers and species diversity with increasing age of the plantation, (c) maintenance of numbers by some species in localities where coniferous trees were indigenous, and (d) local extinction of some species when the plantation was established. (7) Zomba Plateau and the adjacent Malosa Mountain are one of a series of isolated montane habitats which extend from north to south in Malawi, and consequently the montane mammals on Zomba-Malosa are isolated from other such communities. The establishment of pine plantations destroys the natural habitats and communities and, therefore, it is important to conserve the remnants of natural habitats on the Plateau, and all of Malosa Mountain.