Soil pore volume and the abundance of soil mites in two contrasting habitats

Microarthropods are mainly found in the organic layer of soils but show high spatial variability in abundance that remains poorly understood. A factor that could be influencing the abundance of microarthropods is the soil pore volume. Consequently, we tested the hypothesis that mite abundance is related to soil pore volume in two contrasting habitats. Heather moorland and birch woodland, with contrasting humus forms, showed high within-habitat variation in soil pore volume and mite abundance. The abundance of oribatid mites in both habitats and the abundance of mesostigmatid mites in heather moorland were strongly and positively related to the volume of pores in the range 60-300 μm. This supports the hypothesis that mite abundance is influenced by soil pore volume and we stress that soil structure should be considered as an explanatory variable when studying microarthropod communities.