Biological invasions and climate change pose two of the most important challenges facing global biodiversity. Of particular importance are aquatic invasive plants, which have caused extensive economic and environmental impacts by drastically altering native biodiversity and ecosystem services of freshwater wetlands. Here, we used the maximum entropy model, Maxent, to model the potential range expansion of three nonnative aquatic invasive plants: alligatorweed, limnophila, and giant salvinia, throughout the continental United States under current, 2030 to 2059 (2040), and 2070 to 2099 (2080) climate scenarios. Maxent is a popular method to model predicted current and future species distributions based on biogeography and climate. Alligatorweed, limnophila, and giant salvinia are noxious invaders of freshwater habitats in the southeastern United States and cause economic and ecological loss. In addition, we analyzed each species' habitat preference based on wetland type, occurrence in man-made habitats, and distance to the nearest stream to better understand what future habitats are at risk and how these species spread. Our results show that in 2040 and 2080 climate scenarios, all three species have the potential to increase their range throughout the northeastern United States and as far as New York and Massachusetts. The spatial distribution of alligatorweed was primarily determined by precipitation of the warmest quarter (15.8%), limnophila was primarily determined by precipitation of the warmest quarter (52.2%) and mean temperature of the coldest quarter (21.8%), and giant salvinia was primarily determined by the mean temperature of the coldest quarter (24.3%). All three species were found significantly more frequently in lakes and ponds than in other freshwater habits. Giant salvinia was found significantly more often in man-made wetland habitats. In order to reduce the detrimental impacts of these species, land managers in the northeastern United States should concentrate early detection and rapid response management in lakes, ponds and man-made wetland habitats.
Nomenclature: Alligatorweed, Alternanthera philoxeroides (Mart.) Griseb; giant salvinia, Salvinia molesta Mitchell; limnophila, Limnophila sessiliflora (Vahl) Blume.
Management Implications: Aquatic invasive plant species are well known to have dramatic impacts on the habitats they invade. The impacts of these species include decreases in plant and animal biodiversity, altered nutrient cycling, and impact navigation and recreation of inland waterways. Climate change is expected to amplify the number of aquatic biological invasions by changing climatic conditions, particularly by warmer temperatures, increasing the likelihood that previously climatically restricted species will be successful in northern latitudes. Because of the serious consequences aquatic invasive plants pose to aquatic and wetland habitats, understanding the future range expansion of these species is imperative for early detection and management. Alligatorweed, limnophila, and giant salvinia are noxious invaders of freshwater habitats in the southeastern United States. In this study, we ask the following questions: What is the potential for range expansion of three highly invasive plant species in current and future climate scenarios? and What are the aquatic and wetland habitat preferences of these three species? Our results show that with future climate change, and consequently, warmer temperatures, these three species will have the potential to expand their ranges into the mid-Atlantic and northeastern United States. Lakes and ponds are at increased risk for future invasion because all three species were more frequently found in these habitats over other freshwater wetland types. Furthermore, giant salvinia was found significantly more often in man-made wetland habitats, which co