Landscape heterogeneity and species richness and composition: a middle scale study

The aim of this study was to confirm and prove the influence of habitat heterogeneity to species composition and richness of 4 taxa: higher plants, spiders, butterflies and true bugs. We also wanted to analyze the role of a biotope identity in species richness and composition of observed taxa on various biotopes, e.g. whether the biotope itself weakens or forcens the effect of habitat heterogeneity.The research was taken place in the years 2003–2004 in Bochov in Doupovske vrchy, a military training zone in Western Bohemia. 4 transect lines (each 6 km long) were established here and each transect was divided into 20 rectangles, each 300 m long. True bugs, spiders and butterflies were collected here using swepping net, ground traps and transect walks. The data about higher plants were collected using classical vegetational relevés.Habitat heterogeneity strongly affects the species richness of the observed taxons, especially butterflies and true bugs. After adding the biotope identity to the model the impact of habitat heterogeneity dies away. But, on the contrary, species richness of higher plants and spiders were not so affected by the biotope identity. From heterogeneity predictors, the species richness of higher plants was mainly affected by number of segments and borders and butterfly species richness was strongly affected by number of segments and diversity. By true bugs the strongest impact had number of segments and diversity, similarly as by spiders, which species richness was also strongly affected by borders. Habitat heterogeneity also affects the species composition of the taxons. In large distance the most affected taxons were true bugs and plants even after adding the effect of biotope identity. The effect of biotope is very important in assessing the species richness and it can strongly affect the results.