The impact of grazing on dung beetle diversity depends on both biogeographical and ecological context

Aim We analysed the effects of grazing on the diversity and structure of dung beetle communities to see whether the biogeographical and ecological contexts influence dung beetle responses. We hypothesized that the responses of dung beetle communities are modulated by both the ecological conditions resulting from the transformation of native vegetation into grazing areas, and the history of the species inhabiting different biogeographical provinces. Location The state of Hidalgo, in the Mexican Transition Zone, central Mexico. Methods We used a standardized hierarchical sampling procedure in three biogeographical provinces located in Hidalgo. Within each province, we identified the dominant vegetation types, and within these we identified the sites with native vegetation and those modified by grazing. The design included 800 baited pitfall traps, and allowed us to study the response of dung beetle communities with different biogeographical histories to ecological context. Results We captured 8707 beetles belonging to 37 species and 17 genera in the subfamily Scarabaeinae. We found that grazing areas only had a negative effect on dung beetle diversity in tropical forest; conversely, in dry environments (pine–oak forest and xerophilous scrubland) diversity in grazing areas was higher than in the native vegetation sites. We did not detect a clear effect in cloud forest sites. Species turnover between the native vegetation and pastures was high locally, and low over larger spatial scales (vegetation type or biogeographical province). In all four vegetation types grazing was associated with differences in dung beetle community composition. Main conclusions The impact of grazing on dung beetle diversity is dependent to a considerable degree on the local ecological conditions and the biogeographical context that has shaped the composition of communities over time.