What can ants tell us about ecological restoration? A global meta-analysis

The development of easily observable measures of restoration success is essential for monitoring of the ambitious proposed global restoration targets (e.g. The Bonn Challenge; New York Declaration on Forests). Systematic reviews with meta-analyses are a good way to evaluate the performance of different organisms in the monitoring of ecological restoration. Among the arthropods, ants have a long history in environmental monitoring. We compiled a data set and performed a global meta-analysis encompassing studies conducted in different ecosystems around the world to investigate whether richness and composition of species or functional groups (FG) of ant communities can be predicted during the restoration process. Moreover, we aimed to understand the influence of restoration technique (natural regeneration or active restoration), ecosystem type (temperate or tropical), and past land use (mining or pasture) on ant communities in areas undergoing restoration processes. Notwithstanding the varied conditions in which the studies were carried out, our meta-analysis showed that reestablishment of ant FG takes place more quickly than species richness. The recovery of ant diversity is faster in tropical ecosystems and areas under natural regeneration can have higher ant diversity than the reference areas. In temperate ecosystems, mined areas under restoration are less likely to recover the number of species than FG richness. Both species and FG composition were less predictable in our meta-analysis. As the publication of new datasets is increasing, we hope that future meta-analyses can build on the present study to further describe and understand the patterns in ant communities to be used as indicators of ecosystem restoration.