Effect of restoration and surrounding grassland proportion on the dung beetle metapopulation abundance in the fragmented semi-natural grasslands : dung beetles in restored semi-natural grasslands

Abstract: The importance of landscape composition surrounding the local habitats is increasingly recognized, especially with goal of enhancing the understanding about its role in various conservation frameworks. The dung beetles which depend on human mediated ephemeral resources (Dung from domestic animal) gives a valuable opportunity for understanding landscape moderated effects of both the landscape structure as well as sensitive grazing management on the local populations of semi-natural grasslands in Sweden. The objectives of this study was to investigate the influence of surrounding landscape grassland proportion gradient and grassland management history on dung beetle species richness and composition. Dung pats (n=200) where collected from the 10 pairs (restored and continuously managed) of pastures. The local abundance and species richness was statistically tested using GLM and regression analysis for the effect of habitat type (restored or continuously grazed grassland) &/or grassland proportion (at 1km & 5km scale) and time since restoration respectively. The field sampling yielded 4784 beetles of 17 species (Aphodius and Geotrupes) belonging to 14 functional guilds of which two generalist species A. rufipes and A. rufus itself contributed 2664 individuals. The total abundance was higher in restored pastures and total species richness was higher in continuously managed pastures. GLM analysis showed that independent of surrounding landscape grassland proportion the habitat type had an effect on abundance of A. fossor (Pasture specialist) and domestic feeder guild positively on continuously managed pastures. The 1km scale surrounding grassland proportion had positive influence on total abundance and abundance of various functional guilds confounded by metapopulation dynamics of generalist species in respective guilds. Whereas 5km scale grassland proportion had both independent and interactive (with habitat management) positive influence on species specific models. This study concludes surrounding grassland proportion influences the local dung beetle abundance and the restored pastures has a delay in recovery of the population abundance of pasture specialists and intermediate species guild similar to continuously managed pastures. Further research is needed to increase the understanding about the persistence of species and species guilds which experience narrow niches in their life history.