Investigations on the potential of woodlice as bioindicators of grassland habitat quality

As intensive land-use practices may reduce available leaf litter, woodlice—important decomposers of leaf litter—may show a loss of biomass and a decrease in number of species. Their diversity as grassland detritivores could thus be a potential guide to ecosystem activity in natural and cultivated grasslands. Woodlice diversity was studied in different grassland types at three sites in Western France: Avon, with semi-natural grasslands; Fors, with mixed farming; Lusignan, with intensive farming. Woodlice were collected by hand in plot centres, borders and field boundaries. Isopod numbers were higher at Fors than at Lusignan; species assemblages were dominated by Philoscia muscorum at Lusignan whereas this species is less numerous at Fors than Armadillidium vulgare and Armadillidium nasatum. These results also differ with grassland type, with higher species diversity or number of individuals in temporary and permanent grasslands at Fors. Hedges were important in increasing isopod diversity within plots. Assemblages reflect grassland quality with high densities and diversity of woodlice in the permanent grasslands at Avon.