Community‐ and species‐level responses of reptiles to an avian ecosystem engineer

Abstract Ecosystem engineers can alter the distribution and abundance of resources in a landscape, thereby impacting the distribution of other species that use those resources. Although reptiles are known to respond to the ecosystem engineering of birds, case studies are surprisingly rare. Here, we sampled reptile abundance and diversity underneath pairs of trees that do, or do not, contain the thatched colonies of sociable weavers ( Philetairus socius ) in the Kalahari. We conducted our systematic sampling both when the weavers were breeding, and again at the beginning of summer before the onset of breeding. We test the hypotheses that (1) reptile species richness and (2) overall abundance are higher under trees with weaver colonies, and whether differences in those measures vary with season. We additionally explicitly test whether colony trees hosted greater abundances of (3) Kalahari tree skinks ( Trachylepis spilogaster ), and (4) cape thick‐toed geckos ( Pachydactylus capensis )—the two most frequently detected species in our study. We find robust support for all four hypotheses. Trees with colonies had approximately twice the richness of trees without colonies when weavers were breeding but showed no difference in richness outside of the breeding period. Trees with colonies also yielded approximately twice the number of captures (from all reptile species) than did trees without colonies, but this effect was present in both seasons. We found strong support for trees with colonies hosting larger populations of Kalahari tree skinks than noncolony trees in both seasons. We also found strong support for cape thick‐toed geckos occurring at higher abundances under colony trees. Taken together, our results indicate that multiple species of reptiles are responding to the presence of sociable weaver colonies in the Kalahari, and that those species effects are summing up to detectable community‐wide effects.