Diversity of soil macro-invertebrates in grasslands under restoration succession

In grasslands under restoration succession, the effect of nutrient impoverishment on the vegetation has been intensively studied. The invertebrate soil animal community has, however, rarely been studied under such conditions. We hypothesised that a plant community in nutrient-poor grasslands supports fewer macro-invertebrate individuals than richer grasslands. We also hypothesised that the composition of the macro-arthropod community is specific for a certain stage of vegetation succession, i.e. nutrient impoverishment. A detailed sampling programme was carried out in four grasslands under restoration succession. The time since last fertilisation differed for these four grasslands (7, 11, 24 and 29 years). The lowest total number of individuals in different taxonomic groups of macro-invertebrates was found in the most impoverished field in the majority of cases. Analysis of the data set for all specimens identified to order or family level with a canonical correspondence analysis resulted in a pattern not related to successional stage. The same holds when the species composition of the ground beetles was analysed separately. Short-term abiotic factors explained a significant part of the variation in both analyses. With the same multivariate analysis, however, the adult weevils, identified to species level, showed a clear relation with nutrient status of the grasslands.