It will be important for land managers, ecological researchers and policymakers to understand how predicted climate changes may affect the flora of Illinois. A climate change vulnerability assessment was completed in 2011 for the162 Animal Species in Greatest Need of Conservation using NatureServe’s Climate Change Vulnerability Index (CCVI) tool. Here we selected 73plant species found in Illinois and calculated their relative vulnerabilities to predicted climate changes, also using the NatureServe CCVI tool. We selected species from several groups that we felt would be broadly representative of the Illinois flora. These groups included: rare plants, invasive plants, important prairie species, important woodland/savanna species, important forest species, and plants important to society. We compiled and entered data regarding both the species’ exposures to predicted climate changes and their sensitivities to those changes. Exposures were determined by overlapping species range maps for Illinois with maps of temperature and moisture (AET:PET) predictions for the middle of this century. Species sensitivities were determined by interviewing between 4 and 12 experts for each plant species. Experts answered questions found in the CCVI tool regarding the species’ biologies, ecologies and behaviors. Results for each individual survey were averaged for each species. Results fell into one of five vulnerability categories: Extremely Vulnerable, Highly Vulnerable, Moderately Vulnerable, Not Vulnerable/Presumed Stable, and Not Vulnerable/Increase Likely. Results for these 73species in Illinois fell into all 5 vulnerability categories, with the majority (67%) falling into the Presumed Stable category. The species most vulnerable to predicted climate changes were all of conservation concern; most were federal or state listed species. Native species tended to be more vulnerable than non-natives, and plants important to prairies, savannas and forests were equally vulnerable to predicted changes. The four species were ranked as likely to increase in population size or range extent due to predicted climate changes were: Ailanthus altissima(tree of heaven), Ambrosia artemisiifolia(ragweed), Microstegium vimineum(Japanese stiltgrass) and Toxicodendron radicans(poison ivy). We advocate for 8 important next-steps to ensure adequate conservation of Illinois plants in a future with climate change, based on the findings of this report: 1) Investigate the climate change vulnerabilities of all rare plants in Illinois. Rare plants are the most vulnerable group of species in this report. 2) Prioritize research on plants’ abilities to phenologically track changes in seasonality, population genetics, species interactions, dispersal distances, thermal and hydrological tolerancesand soil preferences/tolerances. 3) Continue to monitor population trends. Increase capacity to monitor species with the most uncertain responses to climate changes, the most vulnerable species, and all rare species. 4) Monitor invasive speciesfor changes in populations and behavior. Assess all invasive species using NatureServe’s CCVI tool or another tool. 5) Increase connectivity between natural areas. Increase acreage of natural areas. 6) Managers, policymakers, researchers and the public shouldwork together to fully consider the role that assisted migration should or should not play in Illinois plant conservation. 7) Compile work done by various agencies and NGOs on the climate change vulnerabilities of Illinois species and ecosystems to detect trends, and to identify appropriate research, management and policy priorities. 8) Use adaptive management approaches to care for natural areas in Illinois in order to best achieve land management goals in an uncertain future.Illinois Natural History SurveyIllinois Department of Natural ResourcesIllinois Department of Transportationunpublishednot peer reviewedOpe
