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

Brant (Branta bernicla)Vulnerability: Moderately VulnerableConfidence: ModerateThe Brant is a small goose well known in Alaska for the tens of thousands of individuals thatmolt in the Teshekpuk Lake area of the coastal plain during the late summer. In ArcticAlaska, this species typically nests within 8 km of the coast although in the NationalPetroleum Reserve – Alaska (NPR-A) can nest up to 30 km inland (Reed et al. 1998, D.Ward, pers. comm.). Brant often nest in colonies near the upper edge of salt marshes alongsloping seacoasts or on estuarine deltas, although in areas where salt marshes are lesscommon, they will be more dispersed, nesting near small ponds and freshwater marshes (Reedet al. 1998). Brant subsist on a vegetarian diet and during breeding primarily focus on just afew species of sedges and grasses (Reed et al. 1998). Alaskan breeders spend their wintersalong the Pacific Coast of North America as far down as Baja California (Reed et al 1998).Current Pacific Brant population (which includes the sizeable Y-K delta breeders) isestimated at approximately 125,000 (Arctic Goose Joint Venture 2008).climate change mitigation (e.g. wind farms) willbe much less pervasive in the near future sowould likely only slightly increase vulnerability.S. Zack @ WCSRange: For this assessment, we adjusted theNatureServe Map to more closely reflect therange map depicted in the Birds of NorthAmerica account as the latter more accuratelyrepresented this species’ range based on multipleaccounts and expert opinion (Johnson and Herter1989, Reed et al. 1998, D. Ward, pers. comm.).Sea Level Rise: Because Brant rely on coastalareas for breeding, foraging, and especiallymolting/staging in the Arctic LCC area, theywould most likely be negatively impacted bypredicted sea level rise and a disturbance regimeof increased storm surge frequency and saltwater intrusion (IPCC 2007, Jones et al. 2009).Their ability to shift to nesting habitats that areless susceptible to such phenomena is possibleas they are known to nest further inland in someplaces, albeit in lower numbers than near thecoast (Reed et al. 1998).Human Response to CC: All-weather roads(necessitated by a warming climate andshortened ice road season) associated withenergy extraction activities could impact Brant,particularly near Teshekpuk Lake, howeverother sources of human activity related toPhysiological Hydro Niche: Brant response tochanging hydrological conditions could rangefrom slight to greatly increased vulnerability(see table below) as they are reliant on coastalwetlands that are periodically inundated by saltwater and nesting areas could be negativelyimpacted directly through potential tundradrying and indirectly as some nest predators maybe able to more readily access nesting sitespreviously surrounded by water. Currentprojections of annual potential evapotranspirationsuggest negligible atmosphericdrivendrying for the foreseeable future (TWSand SNAP). Thus atmospheric moisture, as anexposure factor (most influential on the“hydrological niche” sensitivity category), wasnot heavily weighted in the assessment.46