Data Sheet 1_Multidimensional spatial niche differentiation promotes coexistence in a Malagasy lemur community.pdf

Understanding why only certain species coexist within ecological communities is a central question in ecology and evolution, as community membership reflects both contemporary ecological processes and deeper evolutionary histories. Interspecific competition and the resulting niche differentiation are frequently proposed as mechanisms that promote coexistence, yet these processes remain difficult to test empirically in species-rich systems. Malagasy lemur communities provide a powerful model for examining these dynamics, as their evolutionary diversification is thought to have been shaped in part by competition and spatial niche partitioning. Here, we conducted nocturnal line transect surveys totaling 342 km in Zombitse-Vohibasia National Park, Madagascar, to investigate vertical and horizontal space use in four sympatric cheirogaleid lemurs (Cheirogaleus medius, Mirza coquereli, Microcebus murinus, Phaner pallescens) and one outgroup species (Lepilemur hubbardorum), using a combination of traditional analyses and joint species distribution modeling. We observed patterns consistent with spatial differentiation across the community. Most species occupied different vertical strata, while species that overlapped showed greater horizontal separation. In contrast, several species exhibited strong vertical stratification but were broadly distributed across the forest with limited horizontal differentiation. Plant community composition explained more variation than weather or structural variables at the local scale, although a substantial proportion of variation remained unexplained. Vertical niches shifted seasonally, while horizontal niches remained comparatively stable. Together, these results are consistent with spatial differentiation contributing to coexistence and highlight the importance of considering multiple processes operating across spatial and temporal scales.