Organic carbon content and temperature as substantial factors affecting diversity and vertical distribution of Collembola on forested scree slopes

• We assessed impact of abiotic factors on the depth distribution of Collembola.
• Organic carbon content and temperature determined species diversity and distribution.
• Screes with developed organic horizons had obvious stratification of communities.
• Dominance of troglobionts increased considerably with depth.

Vertical distribution of collembolan communities along a depth gradient and the impact of temperature and chemical parameters (pH, organic carbon content) on the structure of communities were studied on three forested scree slopes differing in type of bedrock and topography in the Western Carpathians, Slovakia (Central Europe). Collembola were collected using subterranean traps at depths of 5–95 cm from the soil surface. A total of 70 species were identified at the sites, of which 20 were subterranean forms (17 eutroglophiles, 3 troglobionts). Higher organic carbon content and lower temperature in the screes resulted in distinctly higher activities of the subterranean forms. The north-exposed limestone scree slope with mesophilous linden-maple wood and sediment layers rich in organic carbon had the most pronounced community structure and a distinctly higher number of eutroglophiles and troglobionts. The south-west facing carbon-poor volcanic scree slope with xerophilous oak-hornbeam wood had a slightly higher internal temperature and distinctly lower species richness compared with the other two sites. The north-facing limestone scree slope with mesophilous beech-hornbeam wood characterized by a rather cool microclimate and low carbon content showed lower activity and a relatively uniform pattern of distribution of Collembola across the depth profile. Species richness and activity of sub- and eutroglophiles at the sites correlated significantly with the organic carbon content in the depth layers. The activity of troglobionts increased considerably with depth and negatively correlated with the temperature inside the scree. Thus, organic carbon content and the microclimate were substantial factors that determined the diversity and vertical distribution of Collembola within the forested screes. The present study implies that in forested scree deposits with well-developed upper organic horizons microarthropod communities have an obvious vertical stratification.