Effect of Microhabitat Complexity on the Local Distribution of Arthropods in Clear-Cuts

Abstract

Structural complexity may affect activity and abundance of ground-dwelling arthropods. In this field experiment, the short-term effect on abundance of ground-active carabid beetles (Coleoptera: Carabidae) and lycosid spiders (Araneae: Lycosidae) from slash (logging residue) on the ground was studied. Arthropods were collected by pitfall trapping in three clear-cuts in southwest Sweden. The distribution of slash on the ground was manipulated, and two types of microhabitats were created adjacent to traps, i.e., either slash was cleared (bare ground traps) or slash was aggregated in heaps (slash-covered traps). Overall, carabids were significantly less abundant on the bare ground compared with the slash covered ground. For lycosids, no difference in abundance between the two microhabitat types was found. In reference plots, where no manipulation of microhabitat complexity was carried out, an overall positive relationship between structural complexity (slash height) and abundance of carabids was found. For lycosids, however, no correlations in reference plots were found. Bare ground microhabitats are mimicking structural complexity in clear-cuts after commercial slash harvest for biofuel. Large-scale removal of structural elements in clear-cuts might have short-term local effects, such as altered composition of arthropod communities.