Integrating ecosystem functions into restoration ecology-recent advances and future directions

Abstract

Including ecosystem functions into restoration ecology has been repeatedly suggested; yet there is limited evidence that this is taking place without bias to certain habitats; species; or functions. We reviewed the inclusion of ecosystem functions in restoration and potential relations to habitats and species by extracting 224 publications from the literature (2004–2013). Most studies investigated forests; fewer grasslands or freshwaters; and fewest wetlands or marine habitats. Of all studies; 14% analyzed only ecosystem functions; 44% considered both biotic composition and functions; 42% exclusively studied the biotic component; mostly vascular plants; more rarely invertebrates or vertebrates; and least often microbes. Most studies investigating ecosystem functions focused on nutrient cycling (26%); whereas productivity (18%); water relations (16%); and geomorphological processes (14%) were less covered; carbon sequestration (10%); decomposition (6%); and trophic interactions (6%) were rarely studied. Monitoring of ecosystem functions was common in forests and grasslands; but the functions considered depended on the study organisms. These associations indicate research opportunities for certain habitats; species; and functions. Overall; the call to include ecosystem functions in restoration has been heard; however; a lack of clarity about the ecosystem functions to be included and deficits offeasible fieldmethods aremajor obstacles for a functional approach. Restoration ecology should learn from recent advances in rapid assessment of ecosystem functions; and by a closer integration with biodiversity–ecosystem functioning research. Not all functions need to be measured in all ecosystems; but more functions than the few commonly addressed would improve the understanding of restored ecosystems.