Effects of Grazing Intensity on Diversity of Ground-dwelling Spiders of Grassy and Shrubby Habitats

The main objective of this paper is to report the effect of grazing intensity on the diversity of grounddwelling spiders. The study was conducted in grassy and shrubby habitats of the Somhegy-Bukk pasture of the Matra Mountains in Hungary, where grazing is considered as an experimental management. We found significant effects of grazing on spider communities. Meadow diversity increased during moderate grazing compared to the pre-treatment diversity. Species diversity decreased during intensive grazing. Spider diversity of shrub decreased during both moderate and intensive grazing. We compared grazing in shrub and meadow habitats with control habitats in case of intensive grazing. Our result showed that the control habitats had higher diversity than the grazing habitats. Spider species had narrow tolerance for habitat naturalness in the moderately grazed habitats. We could conclude that grazing is an effective grassland management action to increase spider diversity in the Somhegy-Bukk pasture. Lowering the grazing intensity is necessary in order to save and maintain the high spider diversity. Finally, there is no optimal grazing intensity for all habitats because spiders of shrubs and meadows responded differently to grazing.