Restoration of ecological interactions: Metrics and outcomes at the community scale

Abstract

The restoration of ecological interactions is key for recovering the biodiversity and other attributes of degraded ecosystems. In particular, each interaction has the potential to alter the structure of the resulting community through direct and indirect effects (e.g., predation), which may result in changes in community stability or resilience against perturbations. In this study, we analyze using theoretical models how the restoration of ecological interactions in a multitrophic community modifies 1) the feasibility domain of the community, 2) the average number of species that persist in it, and 3) the importance of indirect effects on species dynamics. We simulate the progressive establishment of floral, frugivore and predator visitants in a community and measure its impact on such metrics. Our results show the overall complex effect of restoring interactions at the top of the trophic chains. Communities with higher trophic structure are in average more persistent, whereas their feasibility domain is lower than in plantonly communities. This apparent dichotomy is explained by the dual role of the introduced interactions: an increase in the number of interactions is destabilizing, but it simultaneously mitigates destabilizing variations on demographic rates. Overall, our results emphasize the need to integrate communitylevel metrics, such as those proposed here, in studies aiming at improving our understanding of the restoration of ecological interactions and ecosystems trajectories.