Integrating aquatic species, assemblage, and habitat climate change vulnerabilities into a watershed-scale decision support framework

Abstract

Climate change is increasingly recognized as a serious threat to ecological systems, particularly freshwater systems. As a result, climate adaptation planning is more common in natural resource management. Because conservation resources are limited, decision support tools can help managers prioritize actions. We created the Species and Habitat-based Ecological Decision Support tool (wtrSHEDS) for conservation managers by integrating two distinct indices: one biologically based on aquatic watershed-scale species assemblages and the other a habitat climate change vulnerability index. To do this, we evaluated 60 crayfish and fish species in West Virginia, USA, using the NatureServe Climate Change Vulnerability Index under an A1B emissions scenario. The species vulnerability assessment results indicated that most species we assessed are vulnerable to climate change. Four species of fish and two species of crayfish had extremely high vulnerability due to their dependence on a specific hydrological cycle, sensitivity to barriers, and reproductive dependence on a thermal niche. Aggregating species at the watershed scale (8-digit hydrological unit code [HUC]) using an adapted weighted sum indicated which assemblages were the most and least vulnerable to climate change. Secondly, we created a unique habitat vulnerability index using the established Northeast Association of Fish and Wildlife Agencies habitat vulnerability index and an index of land cover vulnerability from the Forecast Scenario model’s land cover change projections under the A1B emissions scenario to incorporate potential synergistic impacts of land use. Land cover projections were reclassified based on the assumption that developed land would have a higher potential to interact with climate change than forested lands synergistically. We combined the two habitat indices at the watershed scale (HUC 8) and performed a Hot Spot Analysis to 1) combine the assemblage and habitat vulnerability indices and 2) identify watersheds of conservation priority. This assessment methodology illustrates a means of identifying priority conservation areas in West Virginia that utilize pre-existing data, can be modified to suit management needs, and, therefore, one that managers across regions can readily apply to their system.