Secondary succession of terrestrial isopod,centipede, and millipede communities in grasslands under restoration

The aim of this study was to investigate the impact of restoration management on the composition of a macro-invertebrate community in a formerly, nutrient-poor grassland. Four grassland plots were selected that were last fertilised 7, 11, 24 or 29 years before sampling in 1996. In the same plots it was observed that nutrient impoverishment as a restoration tool resulted in a decrease in primary production and a directional shift in vegetation composition after cessation of fertiliser application. Terrestrial isopods, millipedes, and centipedes were sampled with pitfall traps in the four plots. The directional shift observed in vegetation composition before this study was not accompanied by a directional change in macro-invertebrate composition. Both the field poorest in nutrients and the one richest in nutrients showed the lowest density and species richness, while the species composition was similar across intermediate succession stages. By far the most specimens and species were caught in the field that had not received fertilisers for 24 years. Succession theory could only partly explain the observed results. Canonical correspondence analysis of the data revealed that only a small part of the pattern could be explained by the nutrient status of the grasslands. The C accumulation due to secondary succession of plants was hypothesised to influence the densities and diversity of macro-invertebrate communities in these grasslands.