Spatial relationships and occurrence patterns within a community of lemurs in a fragmented landscape
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Identifying the factors influencing species occurrence and co-occurrence are essential for understanding primate distributions and community assembly processes. Lemurs, a group of highly threatened primates, are at risk of extinction due to human-induced land use changes, forest loss, and fragmentation. Lemurs play critical roles in Madagascar’s depauperate frugivore communities. In this thesis, I use a multi-scale approach to investigate whether landscape structure and habitat characteristics influence individual and two-species occurrence of lemurs living in the fragmented Kianjavato landscape in southeastern Madagascar. I explore my research questions by integrating occurrence data derived from camera traps with predictors obtained from remotely sensed satellite imagery. I find that lemurs in a fragmentated landscape are disparately affected by landscape structure, and some of Kianjavato’s species exhibit a positive association between occurrence and fragmentation metrics. Furthermore, lemur species with large home ranges respond to landscape structure at larger spatial extents, indicating it is essential to consider spatial scale when investigating species responses to environmental factors. Additionally, I find high spatial overlap between ecologically similar species, with fragmentation increasing spatial aggregation among species that share functional traits. These results suggest fragmented forests constrain lemur habitat use and limit spatial partitioning between ecological competitors. Ongoing restoration efforts in Kianjavato should focus on increasing forest connectivity to alleviate unsustainable competition among the resident lemur community. I conclude that landscape structure is an important determinant of both occurrence and co-occurrence in Kianjavato’s lemur community. My results provide preliminary evidence for how landscape structure shapes spatial dynamics within lemur communities in a fragmented landscape. Further, they highlight the importance of spatial scale when considering species-environment relationships.