Dung beetle community patterns in Western Europe : responses of Scarabaeinae to landscape and environmental filtering

Abstract

Context Mediterranean landscapes from Europe have undergone recent biodiversity changes. The intensification of human activities and the fragmentation of open habitats now affect many taxonomic groups, such as dung beetles, which have benefited from centuries of extensive herding. Nevertheless, dung beetles’ responses to landscape composition have been rarely investigated in this context. Objectives We explored how dung beetle communities (species occurrences, abundances and traits) were influenced by temperature and by soil and landscape characteristics and examined residual co-occurrence patterns that may reflect interspecific interactions. Methods We used an extensive dataset on Scarabaeinae dung beetles from southern France (31 species, 117 sites) to evaluate how landscape composition and fragmentation, climate and soil characteristics jointly influence dung beetle communities across this region. We used hierarchical joint species distribution models to characterize (co)variation in the responses of species and to connect such responses to species-specific traits. Results Temperature, soil and landscape characteristics shape dung beetle communities and species’ thermal tolerance was connected to their soil preferences. Fragmentation was negatively associated with beetle abundance while forest cover was positively associated with species richness and with abundance. There was little evidence of residual associations among dung beetle species, suggesting that species interactions do not play a major role in community assembly. Conclusion K-selected species were over-represented among the rarest species. The effects of fragmentation and forest cover indicate that a conservation plan based on connected, heterogeneous habitats with low-density grazing should be promoted to preserve ecological functions linked to these insects.