Spatial and functional components of diversity in tropical mammals

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Tropical forests are being converted to human-dominated landscapes across the planet. Nonetheless, tropical forests still contain high species diversity within communities (alpha diversity) and high species variations between communities (beta diversity). Although mammals in these tropical communities live across a range of spatial scales, most biogeographic research has focused on their alpha diversity, indicating that habitat area is typically the main factor associated with species richness (i.e. larger habitats contain more species than smaller habitats). Recent theoretical and empirical research indicates that alpha diversity is strongly related to landscape and regional species pools and that mammal functional traits, such as body mass, can influence their persistence in fragmented landscapes. However, many important research questions remain unanswered because the spatial and functional components of diversity have rarely been studied in tropical mammals. For example: Do larger, more complex habitats contain a species community more similar to that of the landscape species community than smaller, less complex habitats? Do certain functional traits of mammals result in variations in local community composition? And does beta diversity govern overall biodiversity across landscapes to a greater extent than forest fragmentation? Over the next 5 years, my students and I will study how landscape context influences diversity patterns and processes in 24 species of nonvolant mammals in northwest Madagascar. This island is a biodiversity hot spot, despite losing 44% of its forest cover from 1955-2014, making it a natural laboratory for research on landscape ecology. Our research objectives will be to determine: 1) the relationship between local and landscape species pools in human-dominated landscapes, 2) if certain functional traits result in some mammal species being more common than others in fragmented landscapes, and 3) if differences in species diversity between local communities determines landscape-wide diversity to a greater extent than forest fragmentation. We will use a combination of standard line transect surveys as well as cage, bucket, and camera traps to collect data to test our hypotheses. We will also conduct vegetation sampling and analysis of remote sensing data to update the extensive habitat mapping we have completed over the last 10 years in our study landscapes. Understanding how spatial scale influences biodiversity is critical for research in conservation biogeography, but there is a lack of data on diversity patterns and processes of nonvolant mammals in the tropics. Thus, our research will contribute to a better understanding of how spatial patterns of habitat influence mammal communities, increase effectiveness of conservation efforts for rare mammals in Madagascar, and provide extensive training and research opportunities to Canadian students interested in conservation biogeography.