Assistant Professor Binghamton University Binghamton, NY, United States
Background/Question/Methods Current research in invasion ecology has been guided by many of Daniel Simberloff’s contributions to population ecology, community ecology, and invasion ecology. For example, his work on biodiversity and island biogeography suggests that island communities are more vulnerable to invasion due to open niches, but can benefit from eradication programs due to isolation. Another influential concept, invasional meltdown, highlights the importance of direct and indirect interactions among multiple nonnative species in facilitating invasions. Simberloff’s reviews on invasion solutions show management such as eradication can succeed yet need to be carefully planned to reduce unintended outcomes, such as “surprise effects.” Invasive species removal is a common management practice that assumes ecological systems are resilient to invasions such that post-removal systems recover to a pre-invaded state. However, systems might not recover after removal or suffer from “surprise effects.” We seek to quantify management success by performing a meta-analysis on studies that removed invasive species and measured ecological responses. Many of Dan Simberloff’s greatest hits (such as island biogeography and multi-species invasions) inspired this work and helped us formulate hypotheses and predict outcomes.
Results/Conclusions We systematically searched for studies that removed > 90% of invasive species and measured ecological responses (native abundance, species richness, nutrient concentrations) to removal. Studies needed to measure responses for at least one year (1- 44 years) and rely on passive recovery. We found 185 studies, calculated effect sizes for 1,580 response variables, and collected management and ecological predictor variables. Here, we highlight several predictions inspired by Simberloff’s contributions. First, we predict strong effects of system connectivity on removal responses that could be negative due to reduced rates of native species colonization or positive due to low invasive species reintroduction. We expect that larger management areas will have higher rates of native species recolonization resulting in positive responses. Third, single species management in systems with multiple invasive species will likely have greater negative responses due to “surprise effects.” Finally, we expect differences in recovery due to variations in invader taxonomic group or invasion time. We will present which of these predictions and others are important in determining when removal will likely be successful. Overall, this work will help us provide meaningful guidance for managing invaded ecosystems and when additional management (active restoration) might be necessary.