Competition and Seasonal Co-Existence of Coprophagous Scarabaeoidea (Coleoptera) in Differently Managed Habitat Patches of Sub-Mediterranean Grasslands in Slovenia

Abstract

We studied species composition and seasonal co-existence of coprophagous Scarabaeoidea from two study sites in karst meadows in sub-Mediterranean Slovenia. Each site consisted of three habitat patches with different impact of grazing (S1, the active part of the pasture; S2, the overgrown part of the pasture, mainly spiny shrubs; S3, a meadow with some overgrown patches of shrubs outside the fenced pasture). Four pitfall trapping events per month were conducted from March until November to test for temporal, spatial and habitat-related segregation of species. Primary results show a high level of temporal segregation of species within and between the guilds (Aphodiidae – dwellers, Geotrupidae – tunnelers, Scarabaeidae – tunnelers, Scarabaeidae – rollers). Temporal segregation of monthly samples was evident between Aphodiidae – dwellers (most active at the beginning and end of the season, with a month of complete inactivity during hot summer) and Scarabaeidae – tunnelers (present all the time, but with least species and specimens at the beginning and end of season). Intra-guild competition was most prominent for Aphodiidae – dwellers and Geotrupidae – tunnelers, where species show high rate of temporal avoidance to minimize interspecies competition for the same food source. Finally, geographical (site-related) and habitat-related (S1, S2, S3) differences were found in species composition, species richness and abundance, however for the latter two parameters only at habitat level (more species at S1, but higher abundances at S2 and S3). The results imply that the pronounced temporal and spatial segregation facilitate higher biodiversity in space and time, and allow more species to co-exist at the same sites over time.