Functional traits and ecosystem services in ecological restoration

The application of a functional trait-based approach to ecological restoration is receiving growing attention worldwide, but lack of knowledge on functional traits and how they link to ecosystem services imposes a major barrier to operationalize such approach. Synthesizing the existing knowledge on functional trait-based restoration is thus a timely and important challenge. We systematically reviewed the literature to assess how ecosystem services are associated to functional traits across organisms, ecosystem types, and continents. We also assessed the existing trait-based frameworks to target ecosystem services in restoration ecology. Then, we discussed future perspectives for the field, especially the challenges of applying trait-based frameworks in megadiverse tropical ecosystems, which have ambitious restoration commitments. Most papers focused on plants (72%), terrestrial habitats (69%), and non-tropical ecosystems (68%) and monitored ecosystem services and functional traits after restoration started rather than using them as previous targets. Only 12% of the papers targeted the restoration of both services and traits a priori, and 3.8% presented a clear trait-based framework to target ecosystem services in restoration. The possibility of selecting alternative subsets of complementary species in their provisioning of ecosystem services should make functional restoration more feasible than traditional approaches in species-rich tropical ecosystems. With this review and our critical insights on the perspectives of applying functional trait-based restoration widely, we hope to assist broad-scale restoration programs to obtain higher levels of benefits for nature and human well-being per unit of area undergoing restoration, going beyond the area-based approach that has dominated restoration commitments.