Tropical forests are facing an unprecedented number of threats worldwide and many species are in decline. The survival of lemurs, a diverse group of primates in Madagascar, is highly threatened by human disturbances. I examined the responses of these endemic primates to forest logging. Although anthropogenic disturbances have long-lasting effects on forest structure and composition, regenerating forests have considerable conservation potential as lemur habitat and facilitate coexistence of closely-related lemur species. However, disturbances may exert stress on lemurs and influence the presence of nematodes and microbiota composition and can affect the animals’ resistance against diseases. Some lemur species only appear to survive in undisturbed forests, others prefer selectively-logged forests. But very few can live without forests. Proper conservation actions, based on the results of this thesis, can help to ensure the long-term viability of lemurs, keeping the raft called Madagascar, including its unique flora and fauna, afloat.