Landscape-scale connectivity and fragment size determine species composition of grassland fragments

As a consequence of agricultural intensification and habitat fragmentation since the mid-20th century, biological diversity has declined considerably throughout world, particularly in Europe. We assessed how landscape-scale heterogeneity, such as variation fragment size (small vs. large) landscape configuration (measured connectivity index), affect plant arthropod diversity. focused on arthropods with different feeding behaviour mobility, spiders (predators, moderate dispersal), true bugs (mainly herbivores omnivores wild bees (pollinators good dispersal abilities), wasps (pollinators, abilities). studied 60 dry grassland fragments same region (Hungarian Great Plain); 30 were represented by component forest-steppe stands, situated burial mounds (kurgans). Forest-steppes are mosaics grasslands small forests matrix plantation forests. Kurgans ancient moderately disturbed surrounded fields. The ranged between 0.16–6.88 ha (small: 0.16–0.48 ha, large: 0.93–6.88 ha) for forest-steppes 0.01–0.44 0.01–0.10 0.20–0.44 kurgans. Fragments also an isolation gradient from almost cleared homogenous landscapes, to landscapes relatively high compositional heterogeneity. Fragment size, connectivity, their interaction affected specialist generalist species abundances Large had higher richness ground-dwelling spiders, effect was more strongly positive negative generalists large than fragments. However, we found strong impact plants kurgans contrast larger ones. conclude that besides well-known enhancing quality, increasing restoring natural semi-natural patches would help maintain biodiversity.