Grazing abandonment and dung beetle assemblage composition: Reproductive behaviour has something to say

摘要

Grazed pastures are important habitats that support high biodiversity. However, in recent decades pasture management practices have experienced drastic changes. To identify better management practices that permit the coupling of productivity and biodiversity conservation, attention must be given to the intensity of grazing management. By using a recognized bio-indicator group such as dung beetles, we analysed the impact of grazing intensity on assemblage composition in a gradient from abandoned grazing to low and moderate grazing levels. Moreover, we studied whether or not assemblage composition shifts are related to species-specific responses or to more generalized effects by categorizing dung beetles into functional groups. We found differential effects on dung beetle communities depending on their feeding and reproductive behaviour; “no-nest building” species were the functional group most affected because of their inability to relocate food. Moreover, the decreased level of herbivory in abandoned areas led to shrub and tree encroachments. We demonstrated that dung beetles from abandoned areas were sensitive to this incipient habitat change due to the presence of indicator species associated with shrub and woodland habitats. Therefore, community composition varies depending on both species-specific and generalized responses due to the sensitivity of “no-nest building” species. From a management standpoint, we suggest maintaining a low to moderate level of grazing intensity to conserve a well-structured functional assemblage of dung beetles.