Variability of Carabidae in time and space in open areas

The temporal and spatial variability of carabid fauna was studied on a colliery spoil heap area in Germany and on an area of post-agricultural soil in Poland using pitfall traps. Applying Mean Individual Biomass (MIB) of carabids as an indicator of environmental quality, all plots were assessed as being young stages of succession. Species richness and total carabid abundance fluctuated remarkably among different plots and study years. Total numbers of individuals fluctuated significantly in time, whereas species richness remained strikingly constant. The Jaccard’s index ofspecies similarity was low for the level of individual sampling plots but high for the total catches when comparing different years. Individual species showed asynchronicity of fluctuations in numbers of individuals at the level of individual plots. Based on these results we suggest that the observed patterns can be explained by the ‘spreading of risk’ hypothesis.