Spider community structure in the natural and disturbed habitats of the West Siberian northern taiga: comparison with Carabidae community

Abstract

The structure of spider community (Arachnida: Aranei) was studied in the main types of natural (forests and bogs) and anthropogenically dis- turbed habitats (burned places and abandoned sand pits of different age) of West Siberian north taiga (vicinity of Noyabrsk city, 63°N, 74°E). Spider diversity and abundance were compared with the diversity and abun- dance of other epigeic predators: ground beetles (Co- leoptera: Carabidae). During 4 years of investigation (1999–2002), 58 spider species from 11 families were found. Contrary to carabids, spiders were most abundant and diverse in natural ecosystems. The main factor determining the spider community organization in the North Siberian taiga is the human disturbance of ecosystems: araneo- cenoses were much more similar among undisturbed habitats (regardless of the development of the forest cover or hydrological regime) than among different types of disturbed habitats. The abundance of two dom- inating spider families (Lycosidae and Gnaphosidae) was several times lower in anthropogenically altered sites than in undisturbed habitats. The occasional com- ponent of the epigeic spider community (species inhab- iting grass and forest stand) was equally abundant in natural and disturbed types of ecosystems. Both in spider and carabid communities, the forma- tion of the typical zonal taxocenes after disturbance occurred very slowly. However, carabid communities of intermediate successional stages are forming faster than those of spiders, and have higher biological diver- sity than in climax ecosystems. In climax ecosystems, the density and species richness of spiders are consid- erably higher than those of carabids. These patterns can be explained by different preferences of spiders and carabids toward particular types of biotopes, and by competitive interactions among two dominating groups of predatory arthropods.