Christoph Hrad

Effects of landscape structure on dung removal of coprophagous beetles

A well functioning dung beetle community promotes important ecological services such as facilitating soil aeration, natural manuring by dung burying, enhancing nutrient cycling, promoting mycorrhizal associations, reducing parasite populations and secondary seed dispersal. This study examines the dung removal in several different structured agro landscapes. It was hypothesized that dung removal coheres with structural complexity of landscapes hence dung beetle abundance. Cultivated landscapes with higher structural diversity should have a higher abundance of dung beetles thus higher dung removal of animal droppings. Therefore measured amount of dung pats were placed in prepared plastic boxes and exposed in the 15 study fields. The selected areas represent landscapes characterized by different complexities ranging from very homogeneous landscapes predominated by uniform annual cultures to landscapes with a diverse mosaic of different habitats. Dung removal for each exposed dung pat was calculated as the difference between the dry mass of re-collected dung pats and the average dry weight of 20 control samples. In the calculations of the generalized linear model as well as in the analysis of the correlation of dung removal, NSCP -index (as a measure for landscape complexity) and the abundance of dung beetles of the genus Onthophagus made an univariat significant contribution to dung removal. The hypothesis that dung removal increases with the structural complexity of landscapes hence dung beetle abundance could be proved in this thesis.