A new method for assessing vulnerability of species and communities to combined impacts of sea-level rise, climate change, and land-use change

Background/Question/Methods

With limited resources for conservation, agencies and researchers must focus on the species and ecosystems most vulnerable to anthropogenic threats and/or most important ecologically or economically. Vulnerability Assessments (VAs) are one of many tools used to prioritize species and geographic areas. In Florida and other low-lying coastal regions, sea-level rise is one of the most immediate and severe threats to natural and human communities. Nevertheless, existing VAs do not adequately account for the unique problems associated with sea-level rise in combination with climate and human land-use change. The goal of our study was to evaluate species of plants, vertebrates and invertebrates and terrestrial, freshwater, and marine natural communities in Florida, in terms of their vulnerability to these combined threats. We developed a novel assessment tool based on 30 criteria distributed across four types of information: Vulnerability, Adaptive Capacity, Conservation Value, and Information Availability. We applied this assessment to 300 species and 30 natural communities identified as being at risk of extinction or substantial reduction in population or distribution over the next century. We used both quantitative and fuzzy-logic class membership ranking schemes to assign risk and prioritize species and ecosystems.

Results/Conclusions

First, we identify the overarching threat as the intersection between sea-level rise and coastal development, with species caught ‘between the devil and the deep blue sea.’ Second, we provide a list of 300 species and 30 natural communities, which can be ranked by vulnerability, adaptive capacity, conservation value, or information availability, or by an average of all criteria, while also accounting for uncertainty in those rankings. This allows managers to prioritize according to different values. Third, we identify key information gaps for insects and mollusks (distributional data); birds and mammals (influence of sea level, climate, and land-use on biotic interactions); amphibians (tolerance of increasing salinity); reptiles (tolerance of temperature and rainfall changes); and fish (ability to shift distributions in response to sea-level rise). Uncertainty about the ability to disperse through fragmented landscapes is common to all taxa. Finally, we use scores on information availability to identify species with sufficient data available for spatially explicit niche and population modeling, in response to combined threats, and for development of detailed adaptation strategies. Our assessment provides a flexible tool for rapidly evaluating a large number of species and communities for vulnerability to interacting threats, and for prioritizing by user-defined values.