Morphological traits reflect dung beetle response to land use changes in tropical karst ecosystems of Vietnam

Abstract

Abstract Dung beetles (Coleoptera, Scarabaeidae) are known to respond sensitive to habitat changes, but difficulties in the delineation of species together with their high local diversity have hindered the generalization of results. Morphological traits instead may better reflect species’ adaptations to habitat changes. We investigated changes in morphological traits of 41 tunnelling dung beetle species in a sequence of land use change from primary forests, to secondary forests and meadows in a tropical karst mountain ecosystem in Vietnam (South East Asia). Tunnellers were by far the dominant functional group of dung beetles in these ecosystems. In addition, we measured dung removal rate as a key ecosystem service of these beetles. By combining RLQ and fourth-corner methods to characterize shifts in morphological species traits, we identified three distinct morphological trait clusters of dung beetles, reflecting distinct community adaptations to land use changes. Meadows, despite harbouring highest dung beetle abundance and species richness were severely impoverished in large-bodied dung beetles. The large-bodied dung beetles however, turned out to play crucial roles for dung removal. These data indicate that land use change led to significant changes of species traits in dung beetle communities which in turn fed back on critical ecosystem services. Our data demonstrate that trait-based approaches are well suited to describe the functional implications of environmental changes on species-rich arthropod communities and may better allow generalizations of adaptive responses between ecosystems.