Lemurs are strongly affected by forest loss, fragmentation and degradation because of their high dependence on tropical forest habitat. At the same time, these primates are critical for the functioning of forest ecosystems of Madagascar. While the effects of disturbance on biodiversity are often evaluated with measures of taxonomic diversity, functional diversity takes into account a variety of traits that define species’ ecological roles, and is thus more closely linked with ecosystem function. For this thesis, I analyzed the effects of direct anthropogenic disturbance, variation in forest structure, and edge effects on the functional diversity of lemur communities in five forest fragments in the Kianjavato-Vatovavy (KV) region. I found that forest structure, measured as mean tree diameter (DBH), was positively correlated with the functional diversity of the overall lemur community. However, the variables used for anthropogenic disturbance and edge effects did not seem to affect lemur functional diversity. In addition, I studied the effects of forest fires on the functional diversity of diurnal lemur communities, as well as on the relative abundance of individual species. Lemur surveys were conducted before and after three forest fragments were partially burned in 2015. While there was not a significant difference in functional diversity between the pre- and the post-fire periods, there was a significant decrease in abundance of two frugivores, Varecia variegata editorum and Eulemur rufifrons, and one omnivore, Microcebus jollyae. Severely reduced food supply and the loss of habitat connectivity could explain these decreases in abundance for individual species. The decline in abundance may put these species at risk of extirpation, likely affecting the functional diversity of the community, and, therefore, the functioning of the ecosystem. Individual species and functional diversity studies are useful in understanding the responses of lemur communities to habitat change and disturbance.