Identifying new invasives in the face of climate change: A focus on sleeper species

Ayodele Ouhuru, Department of Environmental Conservation, University of Massachusetts, Amherst, MA, Bethany A. Bradley, Environmental Conservation, University of Massachusetts, Amherst, Amherst, MA and Toni Lyn Morelli, U.S. Geological Survey, Northeast Climate Adaptation Science Center, Amherst, MA

Background/Question/Methods
As climate change makes sweeping adjustments to landscapes and ecosystems, there is increasing concern that new invasive species threats will arise. Some non-native but currently non-invasive species could find conditions more suitable with climate change. However, given the large pool of non-native species, it is critical that we identify those most likely to be ‘sleeper’ invasive species. Sleeper species are naturalized species that could become invasive (i.e. begin spreading and having negative impacts) with climate change. Because sleeper species are not currently invasive, managing high-risk naturalized populations now is a priority. To focus limited resources on non-native species posing the greatest threats, we assessed the potential that naturalized plants could become invasive using a list from the US Department of Agriculture PLANTS Database. We assessed the potential impacts of all non-native plants in the northeastern US (New England plus New York) based on Web of Science literature reviews and the IUCN- supported Environmental Impact Classification of Alien Taxa (EICAT) protocol.

Results/Conclusions
We identified a list of 1795 unique species that are non-native and naturalized in North America and in the lower 48 states. 102 of these species were already regulated in at least one northeastern state and were excluded from further analysis. For our initial assessment, we focused on the 179 species regulated outside of the northeast, and currently found in the study location, and those that were invasive or listed as a noxious weed in at least one lower 48 states. We excluded fifty-eight species that were previously evaluated in one or more northeastern states and thirty-six species that went through the EICAT protocol. The remaining 85 species became the priority list for further assessment. Using the EICAT scale assessing the magnitude of ecological impacts from minimal (1) to major (4) concern, we identified sleeper plant species that could become invasive to this region due to climate change. The goal of this research is to conduct risk assessments for sleeper species and allow for management actions such as early detection and rapid response (EDRR). Creating and sharing this information about sleeper species will allow managers to prioritize species for monitoring, treatment, regulation, and communication with the public. Understanding where there are sleeper species will provide support to vulnerable native ecosystems threatened by climate change to better protect them now and in the future.