Intra-annual activity patterns of terrestrial isopods are tempered in forest compared to open habitat

Abstract

Forests exhibit lower inter-seasonal climatic variation compared to open landscape types. Because fauna activity is influenced by a site's microclimate, we expect these more stable conditions translate into smaller intra-annual variation in activity patterns of soil fauna in forests. We assessed differences in activity of terrestrial isopods across more open (open landscape and anthropogenic habitat) and closed (forest) habitat based on recent field observations in Belgium. We related the species detectability chance (as a proxy for activity) to monthly average temperatures to establish linear relationships. The slopes of these relationships are combined in a meta-analytical model to investigate how species' responses relate to habitat type. We found that terrestrial isopod activity was more tempered in forests than in open landscape habitats, suggesting that climate stability in forests leads to more stable levels of terrestrial isopod activity. We also found that activity patterns in anthropogenic habitat are tempered compared to open landscape habitat but highly variable and more research is needed to unravel underlying mechanisms.