Predicting the relative vulnerability of near-coastal species to climate change using a rule-based ecoinformatics approach

Background/Question/Methods

Near-coastal species are threatened by multiple climate change drivers, including temperature increases, ocean acidification, and sea level rise.  To identify vulnerable habitats, geographic regions, and species, we developed a sequential, rule-based approach to predict vulnerability based on species’ distributions, life history attributes, and habitat specific climate alterations. This framework is being implemented in a web-based tool, the Coastal Biogeographic Risk Analysis Tool (CBRAT), which maps near-coastal species’ distributions using the “Marine Ecoregions of the World” (MEOW) schema. This sequential three-tiered approach allows initial vulnerability assessments for species with limited data and more accurate predictions for the handful of better studied species. The first tier is the “rarity matrix” based on Rabinowitz’s (1981) concept that there are three components of rarity: extent of a species’ geographic distribution, maximum population abundance within some region, and degree of specialization. Rarity is used as a first-order prediction, assuming that rare species are more vulnerable. The second tier utilizes life history attributes that alter a species’ exposure to a climate driver and/or its susceptibility to the specific climate alteration. The third, and most data intensive, tier overlays regional climate projections on specific habitats and relates these environmental changes to species’ tolerances.  

Results/Conclusions

The current analysis focuses on using rarity and life history rules to assess the brachyuran and lithodid crabs, bivalves, chitons, and rock fish from the Gulf of California through the Beaufort Sea (>1500 species). Among the brachyuran crabs, the pinnotherid crabs (ca. 57 species) will be highly vulnerable to climate change due to: 1) specialized commensal habitat relationships, 2) generally low abundances, 3) generally limited geographic ranges, and 4) presence of lightly calcified carapaces which makes them more susceptible to ocean acidification. Of the 167 chitons, 42 have been reported from only a single MEOW ecoregion and are presumably at greater risk due to their limited distribution. Additionally, 11 of these endemics are only found in the intertidal, making them more vulnerable to increases in air temperature compared to subtidal species. These results indicate that a rule-based approach can be used to generate first-order estimates of the relative vulnerability for multiple species with readily available data. Incorporation of additional life-history attributes, habitat-specific climate changes, and interacting rule sets should generate more precise estimates of vulnerability for the better studied species as well as identifying the major climate driver(s) by habitat and geographical region.