Effects of urbanization on ground-dwelling spiders in forest patches, in Hungary

Effects of urbanization on ground-dwellingspiders (Araneae) were studied using pitfall trapsalong an urban-suburban?rural forest gradient inDebrecen (Hungary). We found that overall spiderspecies richness was significantly higher in the urbansites compared to the suburban and rural ones. Theincreased diversity was due to the significantly moreopen-habitat species in the assemblages at the urbansites. This suggests that species from the surroundingmatrix (grasslands and arable lands) penetrated thedisturbed urban sites. The ratio of forest species wassignificantly higher in the rural sites than in thesuburban and urban ones, suggesting that forestspecies are indeed sensitive to the disturbance causedby urbanization. Canonical correspondence analysisrevealed that the species composition changedremarkably along the urbanization gradient. Openhabitatspiders were associated with the urban sites ofhigher ground and air temperature. Forest spiderswere characteristic of the rural sites with higheramount of decaying woods. Our findings suggest thatthe overall diversity was not the most appropriateindicator of disturbance; species with differenthabitat affinity should be analyzed separately to getan ecologically relevant picture of the effect ofurbanization.