Convergences and divergences between two European mountain dung beetle assemblages (Coleoptera, Scarabaeoidea)

We analyzed the altitudinal change in dung beetle species richness and the relative proportion of higher taxa, as well as the turnover in the type of distribution and range size of species in two mountain chains located at the two extremes of Europe (Western Rhodopes Mountains and the Iberian Central System). Both mountain ranges showed a clear substitution among higher taxa (Aphodiinae–Geotrupinae vs. Scarabaeidae) and species richness variation with the altitude was similar. We suggest that East European dung beetle assemblages are conditioned by a horizontal colonization process in which mountains had been reached in relatively recent geological time by elements coming from different latitudes. In spite of these convergences, Rhodopes dung beetle assemblages are characterized by a significantly lower proportion of narrowly distributed species and a lower relevance of Aphodiinae species in lowland places. Although these divergences can be partially attributed to the dissimilar sampling effort accomplished in both regions, we suggest that the low number on narrowly distributed species could be due to the different role of these two mountain zones as refuges during glaciar–interglaciar Pleistocene cycles.

Key words: Scarabaeoidea, Dung beetles, Altitudinal variation, Rhodopes mountain range, Iberian Central System, Refuges.