THE IMPACT OF HUMAN LAND USE ON THE COMPOSITION AND RICHNESS OF GROUND AND DUNG BEETLE ASSEMBLAGES

Abstract

This paper presents the results of a survey on the habitat and seasonal variation in activity density and richness of ground and dung beetle assemblages in a heterogeneous landscape of central Greece. Beetles were collected using 2,646 pitfall traps across an area of 138 ha representative of the Mediterranean mountainous landscape. Sampling was performed in cereal fields, corn fields, fallow land, grassland, Robinia pseudoacacia plantations, oak forest - farmland ecotone and oak forest using pitfall traps. A total of 18,275 individuals belonging to 38 species were collected, whereas only seven species constituted the 82.64% of the overall captures. Onthophagus ovatus was the most common species in all habitats. Beetle assemblages varied markedly regarding the number of species, while higher densities were reported during June. Significant differences in beetle richness were found considering habitat preferences with the lowest species richness in corn fields. Carabidae assemblages were both most abundant and diverse in plantations, whereas Scarabaeidae assemblages were most abundant and diverse in fallow land. Among estimated diversity indices, Margalef's index generated similar results with the observed diversity, likewise non parametric estimators. Overall, the results obtained in the present study suggest that agricultural areas in mountainous heterogeneous landscape might be the important factor for conserving rich beetle diversity, whereas supplementary biotic factors should be explored.