Effects of forest fragmentation, introduced Rattus rattus and the role of exotic tree plantations and secondary vegetation for the conservation of anendemic rodent and a small lemur in littoral forests of southeastern Madagascar

We sought to assess the effects of forest fragmentation, introduced Rattus rattus, exotic tree plantations and secondary vegetation on the endemic rod ent Eliurus webbi (Nesomyinae) and the lemur Microcebus murinus in the litt oral forests of southern Madagascar. For E. webbi the number of individuals caught, the body mass of males and the percentage of females in the popula tion were positively correlated with the size of the forest fragments. Capt ure rates and population characteristics of the other two species were unco rrelated with fragment size. None of the endemic species was caught outside the native forest while R. rattus inhabited all vegetation formations exce pt for a newly planted corridor of tree saplings. Capture rates of both end emic species were uncorrelated with the number of R. rattus caught at the s ame site and thus did not indicate replacement of native species by R. ratt us. The study demonstrated negative effects of fragmentation on capture rat es of E. webbi and changes in their population characteristics. Exotic tree plantations or secondary vegetation seem to represent unsuitable or margin al habitats for the endemic species.