Effects of topsoil transposition on the taxonomic and functional diversity of macrofauna of highly degraded soil

Abstract

AbstractTopsoil transposition has been identified as an environmental restoration technique capable of accelerating regeneration in degraded areas. In addition to the seed bank, topsoil contains invertebrates and microorganisms essential in ecological succession. This study evaluated the temporal variation in the macrofauna community structure in an experiment with topsoil transposition. We hypothesized that the morphospecies richness, functional groups and macrofauna biomass would be higher in the plots with topsoil and native vegetation compared with plots with no topsoil. We further hypothesized that the composition of macrofauna community and the proportion of functional groups in the topsoil and the reference plots would become more similar over time. The community was compared between plots that received topsoil, plots that did not receive topsoil and plots in a natural vegetation, over 14 months. The macrofauna biomass and the diversity of functional groups were equivalent in the degraded area and the topsoil. The effect of treatment on richness depended on time, and it was possible to observe higher values of macrofauna richness in the topsoil compared with the degraded area in some months. The compositions of the macrofauna communities in the degraded area and the topsoil showed greater similarity to each other. In contrast, the reference area showed the greatest dissimilarity with the other treatments. In general, the macrofauna community in the topsoil remained more similar to the degraded area. However, in the topsoil plots, we found higher macrofauna richness during rainy months and an increase in predator biomass. In conclusion, the macrofauna community in the topsoil, which has changed over time, presented higher values of morphospecies richness in some months and the increase in predator biomass, indicating an increase in the complexity of the community. Besides, the topsoil can improve biodiversity, but this does not produce the natural communities found at reference sites, in a small‐time scale experiment.