Diversity, structure and endemicity of earthworm and springtail communities of a softly managed beech forest in the pyrenees (France)

Abstract

We assessed and compared patterns of biodiversity and the composition of two soil invertebrate communities (Collembola and Lumbricidae) in three slightly managed plots in a beech forest of the French Pyrenees. The plots were managed in three different ways: an even-aged (REG), a closed unevenaged stand (NAT), and an open uneven-aged full-grown stand (IRR). At each sampling point, earthworms and Collembola from litter, soil, and pitfall traps were collected, and nine edaphic and environmental parameters were measured. The fauna collected was rich in species, and endemic and rare taxa. No clear-cut differences in species richness appeared between plots. Nevertheless, (1) the less disturbed plot, i.e. NAT, hosted a slightly larger number of endemic and rare species than IRR and REG; (2) the structure of both communities in NAT, REG and IRR differed significantly depending on the site elevation and organic nitrogen content (higher in NAT), soil surface temperature and soil pH level (higher in IRR), and humus index and soil water content (higher in REG). Those factors, except elevation, may be explained by the canopy opening partly controlled by management practices; (3) a side aspect of the study was to show that sampling exhaustiveness required more sampling effort for soil than for litter, and more for Lumbricidae than for Collembola. In a broader context, the case documented in this study suggests that management practices with limited clearing of forest cover affect soil biodiversity only slightly, which is in sharp contrast with the collapse in endemic biodiversity induced by reafforestation.