Edge effect on carabid assemblages along forest-grass transects

摘要

During 1997 and 1998, we have tested the edge-effect for carabidsalong oak-hornbeam forest-grass transects using pitfall traps in Hungary. Ourhypothesis was that the diversity of carabids will be higher in the forest edgethan in the forest interior. We also focused on the characteristic species ofthe habitats along the transects and the relationships between theirdistribution and the biotic and abiotic factors.Ourresults proved that there was a significant edge effect on the studied carabidcommunities: the Shannon diversity increased significantly along the transectsfrom the forest towards the grass. The diversity of the carabids weresignificantly higher in the forest edge and in the grass than in the forestinterior. The carabids of the forest, the forest edge and the grass areseparated from each other by principal coordinates analysis and by indicatorspecies analysis (IndVal), suggesting that each of the three habitats has adistinct species assemblages. There were 5 distinctive groups of carabids: 1)habitat generalists, 2) forest generalists, 3) species of the open area, 4)forest edge species, and 5) forest specialists. It was demonstrated by multipleregression analyses, that the relative air moisture, temperature of the ground,the cover of leaf litter, herbs, shrubs and canopy cover, abundance of thecarabids’ preys are the most important factors determining the diversityand spatial pattern of carabids along the studied transects.