Effects of patch type and food specializations on fine spatial scale community patterns of nocturnal forest associated Lepidoptera

Abstract

Species groups at different sites may build a meta-community that owns characteristic patterns of species distribution. Local differences, species interactions, random effects and dispersal characteristics can influence the diversity of local insect communities. We measured the diversity of nocturnal Lepidoptera at 12 sites of a temperate mixed forest that represented different patch types. To analyze causes of community structures, we tested for nestedness, checkerboards, clementsian, gleasonian, or evenly spaced gradients, and for random distribution as hypothetical patterns of a meta-community. The most diverse sites were patches at outer and inner edges of the forest. Lowest diversity was observed at a clearance inside the forest, and at three of four grove patches outside the forest. A cluster analysis of the similarity of Lepidoptera communities at different sites showed that the patch type and location, inside the forest (clearings, inner edge) or outside the forest (groves, outer edge), influenced the community structure. With increasing similarity of plant species growing at two sites, the faunal similarity of those two sites increased not significantly, indicating that differences of local plant communities caused a minor part of the faunal variation. The Lepidoptera communities were clearly nested, and different forms of gradients were detected in various subgroups of the Lepidoptera communities. Whereas nestedness indicated that patches were statistically depauperate subsets of the regional fauna, gradients showed that environmental changes between patches were responsible for different communities at that patches. Checkerboards and random distribution were not observed at all. This showed that interspecific competitions, as well as purely stochastic factors were not the driving forces in community regulation.