2018 ESA Annual Meeting (August 5 -- 10)

PS 32-107 - Are ecological systems resilient to invasions? A systematic review of ecological response post invasive species management

Wednesday, August 8, 2018
ESA Exhibit Hall, New Orleans Ernest N. Morial Convention Center
Carmela M. Buono, Department of Biological Sciences, Binghamton University (SUNY), Binghamton, NY, Damian Adams, School of Forest Resources and Conservation, University of Florida, Kier D. Klepzig, Southern Research Station, USDA Forest Service, Jiri Hulcr, School of Forest Resources and Conservation, University of Florida, Gainesville, FL and Kirsten Prior, Department of Biological Sciences, Binghamton University (SUNY)
Background/Question/Methods

Removing invasive species is a common management practice that is often deemed successful when invaders are effectively reduced or eliminated. One broader goal of invasive species management is to reduce the impacts of invaders on ecosystems. However, the success of removal on alleviating impacts and facilitating recovery is not always evaluated and can lead to a spectrum of ecological responses, not all of which are positive. The various outcomes of invader removal lead us to ask how often and in what contexts does invasive species removal reduce impacts and allow for the recovery of ecological systems? To address this, we conducted a global comprehensive, systematic review of published studies that removed invasive species and measured ecological responses with the invader present and removed (after at least one year) (N=163 studies). We scored the ecological response of each study and selected best-fit models of several predictor variables pertaining characteristics of management, invaders, or invaded ecosystems to uncover contexts in which positive responses were most likely. We calculated effects sizes (lnR) and confidence intervals for different ecological responses (e.g., plant abundance, animal richness, total carbon) within studies (N = 1,114 comparisons) to determined which responses most strongly responded to invader removal.

Results/Conclusions

Our systematic review retained 163 studies, of which 51% had a clear positive outcome post-invader removal, 18% a mixed outcome, and 31% had a negative or no response. These results suggest that in many cases invasive species removal leads to conservation gains and is an effective management practice, but also that it should be viewed as a part of more comprehensive and integrative conservation and restoration strategies. When plotting effect sizes (lnR) of the effect of invader removal on different ecological responses (N=1,114), we found significant positive changes (i.e., increase in native species) in 75% of response types at the population-level. In contrast, for more complex ecological responses, such as community-level (e.g., change in species richness), and ecosystem-level (e.g., change in nitrogen) responses there were fewer and weaker changes (18% of responses). This suggests that while simple ecological systems might be resilient to invaders, more complex systems might not be resilient. Our synthesis provides important guidance for managing invaded ecosystems, suggesting that invader removal alone is often not sufficient to manage invaded ecosystems if the goal is to alleviate impacts to facilitate ecological recovery, especially if the conservation goal is to promote the recovery of community or ecosystem-level processes.