Spatiotemporal patterns in an Afrotropical montane forest bird community

Understanding how species richness and diversity patterns vary across time and space is essential for predicting how biodiversity will respond to anthropogenic threats and for effective conser-vation planning. Tropical montane forests are among the most biodiverse places in the world, yet high rates of endemism and narrow physiological tolerances place tropical montane species among the most vulnerable to anthropogenic impacts. Therefore, it is of the utmost importance to understand how ecological communities are structured along elevational and spatial gradients, particularly in the Afrotropics, which are historically understudied despite their unique climate and rich biodiversity. Here we examine how the Afrotropical montane bird community of Nyungwe National Park in Rwanda is spatially and temporally structured with respect to eleva-tion and geography. We show that despite the absence of geographic barriers, avian communities are spatially structured across the elevational gradient with significant regional differences in both species composition and richness, and that high elevation assemblages are comprised of fewer species compared to lower and middle elevations. We find evidence for overall stability in species richness during this study period (2001-2011) yet differing season-specific trends across the elevational range of the study. Specifically, the high elevation assemblage exhibited a wet season-specific increase in richness, congruent with predicted upslope elevational shifts for low and middle elevation species. Our findings suggest that anthropogenic factors may have different effects on richness patterns depending on elevation and region, and that protected areas large enough to encompass the full range of geographic and elevation gradients are required to effectively conserve Afromontane bird communities.

Automated summary

Understanding the spatial and temporal structure of ecological communities along elevational and geographic gradients is important for predicting biodiversity conservation and identifying the impacts of anthropogenic factors. In this study, we examined the Afrotropical montane bird community in Rwanda and found that avian communities are spatially structured across elevational gradient, with regional differences in species composition and richness. We also observed season-specific trends in species richness, with a wet season-specific increase in the high elevation assemblage.