Landscape structure is a major driver of plant and arthropod diversity in natural European forest fragments

Abstract

AbstractDisentangling the effects of different landscape and local attributes on the biota of habitat patches is often challenging. In Central European forest‐steppe ecosystems the high number of forest fragments and the relatively homogenous matrix between them offer the opportunity to disentangle the effects of habitat size and landscape structure (both landscape composition and landscape configuration) on plant and arthropod biodiversity. We selected 40 forest fragments: 20 forest fragments in extensive, dry, sandy forest‐steppe region and 20 fragments in a mesic forest‐steppe region of Hungary. We classified the detected plant and arthropod species according to their habitat association as forest specialist species or open habitat species. We then tested the effect of fragment size, landscape composition, and landscape configuration on their species richness and abundances. We found that increasing forest fragment size, forest habitat amount, and forest edge length had in general positive effects on forest spider abundance, but negative on open‐habitat arthropod abundances and plant species richness, varying a little among the studied taxa. Most interestingly, the effects of fragment size were often moderated by both landscape composition and landscape configuration, as well as habitat association of species. The fragment size effect was more pronounced in landscapes with low forest habitat amount having positive effects on forest spiders and negative effects on open‐habitat plants. An effective conservation strategy should take into account not only the presence of forest fragments, but also the size and configuration as well as the connectivity of forest fragments, to maximize diversity benefits of forest patches.