Temporal dynamics and stability of Collembola communities in central European forests : the roles of forest management, climate and regional factors

Collembola are among the most dominant groups of soil arthropods in temperate forests and contribute to essential ecosystem processes such as decomposition and nutrient cycling. However, their temporal dynamics and stability across forest management gradients remain poorly understood. We analysed Collembola communities sampled at three-year intervals from 2008 to 2020 in 48 forests of varying management intensity across three regions of Germany. Based on a dataset comprising 18,617 individuals and 101 species, we found that density and species number declined in years with low spring precipitation but recovered in wetter years. Unmanaged beech forests maintained higher species number during dry years and harboured the highest proportion (53 %) of hemiedaphic Collembola dwelling in organic layers. Coniferous forests supported significantly higher density (51,298 vs. 32,923 ind. m⁻² in young managed beech forests) and showed greater temporal variability in species composition. However, stability was similar across forest types. Instead, stability decreased significantly in northern forests with sandy soils of low water-holding capacity, coinciding with higher synchrony in species fluctuations, likely driven by variations in spring precipitation. Stability was weakly related to species number, as community dynamics across forests and years were largely determined by a few dominant species. The three most abundant taxa accounted for 60 % of all individuals. While dominant species currently maintain the stability of Collembola communities in Central European beech and coniferous forests, future increases in drought frequency may impair population recovery, particularly in sandy soils. Therefore, undisturbed organic layers with high structural diversity in unmanaged beech forests could serve as important refuges for Collembola during future dry periods.