Contrasted Successional Trajectories in a Mediterranean Wetland Due to Geomorphic- and Human-Induced Perturbations

Abstract

Wetland ecosystems in water-limited environments locally boost biotic interactions, habitat diversity, and species concentrations, but little knowledge exists on their long-term functioning and susceptibility to regime shifts that might influence conservation and reclamation actions. Here we used a historical ecology approach on a rare Mediterranean peat-bog to reconstruct ecological successions for the last 4 millennia. The reconstruction is used to explore the role of geomorphic thresholds, climate changes, and anthropogenic perturbations as drivers of the ecosystem trajectory in the frame of the projected aridification of the climate. Our findings highlight how the superimposition of pastoral disturbances to river incision, has exacerbated ecosystem sensitivity to climate changes. Considering the long-term trajectory, the disappearance of the ecosystem might occur independently of changes in the precipitation regime. Insights given by Historical Ecology have implications for our understanding of ecosystem responses to perturbations, demonstrating that long-term dynamics must be considered before engaging in strict conservation action.