Temporal variation of patch connectivity determines biodiversity recovery from recurrent disturbances

Abstract

Understanding the capacity of ecological systems to withstand and recover from disturbances is a major challenge for ecological research in the context of environmental change. Disturbances have multi-scale effects: they can cause species extinctions locally and alter connectivity between habitat patches at the metacommunity level. Yet, our understanding of how disturbances influence landscape connectivity remains limited. To fill this gap, we develop a novel connectivity index that integrates the temporal variation of patch connectivity induced by disturbances, which can be applied to any spatially-structured habitat. We then combine this index with a metacommunity model to specifically investigate biodiversity recovery from drying events in river network metacommunities. We demonstrate that patch connectivity explains variations of species richness between groups of organisms with contrasting dispersal modes and captures the effect of drying intensity (i.e., fraction of patches that dry-up) and drying location on community recovery. As a general rule, loss of patch connectivity decreases community recovery, regardless of patch location in the river network, dispersal mode, or drying intensity. Local communities of flying organisms maintained higher patch connectivity in drying river networks compared to organisms with strictly aquatic dispersal, which explained the higher recovery capacity of this group from drying events. The general relationship between patch connectivity and community recovery we found can be applied to any spatial network subject to temporal variation of connectivity, thus providing a powerful tool for biodiversity management in dynamic landscapes.

Spatial heterogeneity of biomass turnover has contrasting effects on synchrony and stability in trophic metacommunities

“…For instance, spatial heterogeneity is key to ensuring species coexistence and diversity at the regional scale, which ultimately provides important ecosystem services in agricultural landscapes (Bennett et al, 2006). A large corpus of theoretical studies explored the local response of communities in a landscape receiving perturbations (Economo, 2011; Holyoak et al, 2020; Jacquet et al, 2022; Mouquet et al, 2011). However, these studies focused on extinction events recovered by dispersal events in a patch dynamics framework, and little is known about the effect of moderate or small perturbations.…”