Anthropogenic climate change poses a challenge to populations, species, and natural communities. Relative to the last several hundred years, rates of sea-level rise and climate change are dramatic, but relative to the last several hundred thousand years, even the most rapid rates of anthropogenic climate change do not exceed “natural” rates. Whereas species and natural communities have responded to and persisted through rapid environmental change in the past, what makes anthropogenic climate change so challenging today is that it is happening in the context of dramatic and pervasive human land-use change that may limit resilience and adaptability. Conservation priorities should account for the challenges from current and future climate change/sea-level rise, but also for the legacy impacts of human land-use change. We assessed the current and future threats from sea-level rise, climate change, and human land-use change for 20 natural communities and for 50 species distributed along the coastal counties of Georgia. Our goals are to assess impacts quantitatively using GIS overlays and qualitatively using the Standardized Index of Vulnerability and Value (SIVVA) and to make suggestions for prioritizing both individual species and assemblages in the form of natural communities.
Results/Conclusions
Overall, we find that natural communities are likely to lose between 10% and 85% of their current distribution by 2100 to the combination of sea-level rise and land-use change as predicted from overlays with conservative future projections modelled under SLAMM (sea-level rise) and SLEUTH (land-use change) scenarios. Despite these dramatic losses, qualitative surveys consistently point to greater threats from the legacy effects of land-use change than from projected threats either from land-use change or sea-level rise/climate change. Our conservation prioritization results for natural communities ranked tidal freshwater marshes and sandy beaches as among the most at-risk natural communities in coastal Georgia. Results from our analysis of coastally distributed species reveal dramatic projected losses of habitat for those species associated with coastal marshes, particularly where those habitats are unable to “migrate inland” due to coastal development. We also find that experts lack the information necessary to confidently project how marine, brackish and freshwater species will respond to sea-level rise, which is an area that needs further research.