Climate and topography rather than tree species affect mite communities (Mesostigmata) in severe conditions - Studies from sandstone rocky islands of the Szczeliniec Wielki Plateau (Poland)

Relationships between certain plant species and soil fauna assemblages in severe climatic conditions require scientific attention due to reported climatic changes. We investigated density, diversity, and community structure of soil mites (Mesostigmata) in tree biogroups of Betula pendula, Picea abies, and Pinus sylvestris with microhabitats represented by Calluna vulgaris, Dicranum scoparium, Vaccinium myrtillus, and Vaccinium vitis-idaea plant patches and accumulated litter in humid and cold rock crevices a few meters deep. We analyzed the effects of climatic (light availability, precipitation, temperature) and environmental (litter pH, organic matter thickness, microhabitat type) conditions on mite communities based on 1080 samples collected during two vegetation periods (2004–2005). Results revealed that litter pH was shaped by microhabitat type (plant patches and rock crevices) whereas organic matter thickness depended on tree species and microhabitat type. Also, light availability differed between tree biogroups and microhabitats. This study documented that Mesostigmata abundance was shaped by maximum daily temperature while species richness was also affected by total monthly precipitation, tree species (P. sylvestris) and microhabitat (rock crevices). Results revealed that mite density ranged from 3001 ± 213 ind./m2 in the P. abies biogroup to 3310 ± 350 ind./m2 in P. sylvestris. On the microhabitat level, mite density ranged from 2571 ± 170 ind./m2 in V. myrtillus patches to 4137 ± 463 ind./m2 in rock crevices. Total number of recorded species was highest in rock crevices (41 species), and lowest in C. vulgaris (19). In conclusion, results indicated that climatic conditions modulate mite communities on an isolated rocky island. This study documented that maximum daily temperature during the vegetation period affected Mesostigmata abundance, whereas species richness and diversity were also shaped by total monthly precipitation and tree species (P. sylvestris). In addition, the community was also affected by litter acidity, organic matter and tree species.