Community of Mesostigmata (Acari) in experimental habitat patches of forest floor

The aim of the study was to test whether populations and communities of predatory microarthropods (Mesostigmata) are differentiated between different habitat patches of the forest floor, whether there are migrations between patches according to time of day or prevailing weather, and what is the large-scale (''global'') heterogeneity of the community. Artificial patches were created by removing dwarf shrubs and herbs from test plots, and introducing coniferous or deciduous litter, faecal material or rotten wood. Samples (0-3 cm) were taken in summer and autumn in dry and moist conditions. The communities of different patches were significantly different. Several species were more numerous in the faecal treatment, though few ''dung specialists'' were present. Some species showed affinity to plots with additional litter, but communities from spruce and birch litter treatments did not differ from each other in total composition. There was little difference between seasons. The data give evidence of horizontal movements between patches depending on moisture. Population densities of several species differed significantly between blocks inside the 0.5 ha study area, but the average total community was similar to that in another forest 70 km north of this.