The consequences of global changes on biodiversity dynamics are still poorly understood. Traditionally, ecological studies have either focused on how individual species respond to specific pressures or on the spatial distribution of more integrative descriptors such as species richness. But whether and how global changes are shaping the structure and composition of local assemblages in space and time and across large areas remain poorly analysed. We investigate the synergies among several candidate variable of environmental perturbations to understand the magnitude and direction of changes in the “interaction milieu” defined as the specific interrelations among species within communities. We apply a network approach to a large and high resolution dataset in birds collating co-occurrences of more than 100 species for 16 years in 1,977 sites monitored with a standardized protocol across France.
Results/Conclusions
We propose new metrics reflecting three aspects of the relationships among species to describe the interaction milieu of bird communities. We then test the relative contribution of random processes versus more deterministic filters to explain the state and fate of bird communities facing climate and anthropogenic stressors. Overall, we found that global changes are most likely responsible for homogenising the diversity of interrelations among species. This study opens new avenues for bridging the gap between network ecology and community ecology under global changes and highlight a neglected issue for conservation science.