Forest soil microbial functional patterns and response to a drought and warming event: Key role of climate-plant-soil interactions at a regional scale

Little is known about how spatial and environmental patterns structure soil microbial activities. We investigated, on 47 soil samples collected in Mediterranean forests, the net and interaction effects of climatic-geographic and edaphic variables as well as vegetation cover and composition on soil microbial community-level physiological profiles (CLPPs) assessed by Microresp™. The effects of these variables were also analyzed on CLPP response to an experimental drought treatment. CLPPs were shown to be mainly driven by climate-plant-soil and plant-soil interactions; even after drought treatment, there was a decrease in microbial activity but no change in CLPPs. Our findings highlight the robustness of these relationships, which need to be assessed within different ecosystems considering various spatial scales to reliably predict climate change effects on terrestrial ecosystems.