Assessing Climate Change Vulnerability of Breeding Birds in Arctic ...

Executive SummaryClimate change is occurring at anaccelerated rate in the Arctic compared tomost other places on the earth. Temperatureand moisture changes are leading towarming permafrost, increased coastalerosion, more frequent fires, and shrubinvasion, altering geomorphology,hydrology, and habitat structure. These rapidchanges in habitats, especially thoseassociated with hydrology, are ultimatelyinfluencing wildlife populations. ArcticAlaska harbors some of the most importantbreeding and staging grounds for millions ofbirds representing over 90 species. Many ofthese species are migratory, wintering atdisparate sites across the planet, and someare already experiencing population declinesand/or are species of conservation concern.As climate change has become a focal issuefor agencies and other institutions in recentyears, one of the recognized needs is theapplication of science-driven assessments toreconsider landscape management, wildliferesearch, and conservation priorities in thiscontext. To help address these emergingneeds the Wildlife Conservation Societyconducted a climate change vulnerabilityassessment for arctic breeding birds to helpguide climate-informed wildlifemanagement in the region. The specificgoals of this assessment were to: 1) providea climate change vulnerability ranking for54 Arctic Alaskan breeding bird species; 2)evaluate the relative contribution of specificsensitivity and exposure factors to individualspecies rankings; 3) consider how thisassessment may be integrated with otherapproaches; and 4) appraise theeffectiveness of the NatureServe ClimateChange Vulnerability Index (CCVI) tool.The CCVI tool was developed byNatureServe specifically to compare theadded vulnerability posed by climate changeto species in a region. We assessedvulnerability with reference to changesprojected for 2050 and restricted ingeographic scope to the Alaska portion ofthe Arctic LCC region. The CCVI is aspreadsheet based algorithm that integratesinformation on species sensitivity, directexposure to projected atmospheric changesin climate, and indirect exposure factors.Direct exposure factors, temperature andmoisture balance change, were incorporatedas geospatial inputs. We ran the tool withdata from five global circulation models,two emissions scenarios, and at two spatialresolutions. Indirect exposure factorsincluded sea-level rise, dispersal relative tobarriers, and human mitigation in responseto climate change. Sensitivity factors (lifehistory traits making a species more or lessvulnerable) were scored by species expertson survey forms based on publishedliterature and their personal knowledge.The CCVI results ranked two species ashighly vulnerable (Gyrfalcon, CommonEider), seven as moderately vulnerable(Brant, Steller’s Eider, Pomarine Jaeger,Yellow-billed Loon, Buff-breastedSandpiper, Red Phalarope, RuddyTurnstone), and five as likely to increase(Savannah Sparrow, Lapland Longspur,White-crowned Sparrow, American TreeSparrow, Common Redpoll). Theassessment outcome suggests that the mostimportant contributions to the climatechange vulnerability for the 54 bird speciesinclude: 1) being a specialists in at least onelife history trait and/or having a strongcoastal orientation; 2) the quality and natureof interactions with other species; 3)restrictions associated with physical habitatand diet; 4) dependence on other species tomeet habitat needs; and 5) changes indisturbance regimes that would negativelyaffect the speices. Physiologicalhydrological niche (i.e., dependence onwetland habitats in the arctic) was thought to1