Effects of different grazing intensities on the composition and diversity of Collembola communities in southern Brazilian grassland

Abstract

Most studies evaluating the effects of grazing intensities on soils in Brazilian grasslands have focused on abiotic parameters, especially chemical or physical properties. In this context, soil arthropods have been largely unexplored, especially Collembola. This research addressed the effect of different grazing intensities on the composition and structure (abundance, richness, diversity, and evenness) of Collembola communities under different grazing intensity levels. Collembola were collected at different cattle grazing intensity level treatments (high, moderate, and low) in southern Brazilian native grasslands (also known as Campos). Our findings indicated significant changes in the composition of Collembola communities through grazing intensities. The treatment with the lowest grazing intensity was found to be substantially different from all others, probably because of a high abundance of some taxa (i.e. Entomobrya spp). We also observed that morphospecies richness and diversity tended to peak at moderate grazing intensities, whereas total abundance was higher in the lowest grazing intensity treatment. This study provides experimental evidence that disturbances caused by cattle grazing in native grasslands might impact soil faunal communities: increases in grazing intensity affected soil arthropod composition and structure by reducing their abundance, richness and diversity. It is important to highlight taxonomical richness and diversity as an intrinsic characteristic of communities insuring their functionality as a consequence of niche occupation and complementarity.