NSF Award
2504233
Climate change is increasing the amount of salt of coastal freshwater habitats, driven by sea-level rise and intensified storm surges. Anurans (frogs and toads) play a pivotal role in wetland ecosystems and are presumed to be intolerant of saltwater, but recent syntheses indicate more salt tolerance than previously thought. This project improves our understanding of the limits of salt tolerance in anuran species occupying coastal habitats on two sea level rise fronts (Gulf and Atlantic coasts). The project uses an experimental approach that investigates multiple salinities, species, life stages, and levels of biological organization, providing data that can guide coastal managers and practitioners in improving coastal resilience and preventing biodiversity loss. Specifically, the study will identify life stage-specific mortality from salt stress across species to predict vulnerable life stages and breeding times. This research will determine whether species relatedness and ecological traits can predict salinity vulnerability and characterize the extent that the effects of saltwater at one life stage cascade across life stages. Finally, this study aims to understand how saltwater affects amphibian physiology across species and life stages, focusing on membrane permeability, hormones, and cellular processes. In summary, this research will produce diverse physiological, life history, phylogenetic, and genomic datasets that span across life stages and species to determine the salinity tolerance of anuran species that occupy coastal habitats with the goal of informing conservation actions and predicting climate change impacts. The project will also educate students and the public on various topics such as conservation and physiology.<br/> <br/>Climate change-driven sea level rise is increasing salinization of coastal habitats. Sea levels along the United States coastlines are predicted to rise between 50 and 100 cm in the next 70 years, with the east and gulf coasts facing intensified impacts. Anurans, or frogs and toads, are expected to be severely affected by salinity increases, as they are considered largely saltwater intolerant. However, salinity tolerance among amphibians is more variable than commonly considered, leaving uncertainty in the predictions of seawater inundation effects on coastal communities. To address these gaps, this research will focus on 10 anuran species with known populations within five miles of coastlines near Houston, Texas and Sapelo Island, Georgia. These locations are dual sea level rise fronts with low-elevation coastlines and freshwater wetlands expected to be inundated by the year 2050 under moderate sea level rise scenarios. The project will use a comparative approach to investigate how life history traits and evolutionary history affect stage-specific survival in higher salinities, how chronic saltwater exposure affects long-term growth, development, and fitness, and the physiological responses to saltwater exposure. This research will inform questions on how complex life cycles affect persistence in novel environments, how physiological mechanisms facilitate saltwater tolerance, and how chronic versus acute exposure affect survival and persistence. Additionally, this research will provide baselines for predicting how different coastal species will fare as sea level rise pushes saltwater further upriver and inland, which can guide coastal managers and practitioners to improve coastal resiliency and prevent biodiversity losses.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
