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

Greater White-fronted Goose (Anser albifrons)Vulnerability: Presumed StableConfidence: ModerateThe Greater White-fronted Goose, with a nearly circumpolar distribution, has the most expansiverange of any species in its genus. In Alaska, this species breeds in large numbers in both theYukon-Kuskokwim Delta and also on the Arctic Coastal Plain, but they will also nest in theinterior. On the coastal plain breeding habitat ranges from lowland wet to upland dry tundraoften near ponds or lakes (Ely and Dzubin 1994). The Greater White-fronted Goose diet isdominated by vegetative matter, primarily grass and sedge rhizomes, tubers, and berries (Ely andDzubin 1994). Arctic Alaskan populations winter on the Gulf Coastal plain in Louisiana andTexas as well as northern Mexico (Ely and Dzubin 1994). The Alaskan Arctic Coastal Plainpopulation is estimated at 200,000 and population growth has been rapid in the past decade buthas recently leveled off (Larned et al. 2012).J. Liebezeit @ WCSRange: We used the extant NatureServe map forthe assessment as it matched other range mapsources and descriptions (Johnson and Herter1989, Ely and Dzubin1994).Physiological Hydro Niche: Among the indirectexposure and sensitivity factors in theassessment (see table on next page), GreaterWhite-fronted Goose ranked neutral in mostcategories with the exception of physiologicalhydrologic niche for which they were evaluatedto have a “slightly to greatly increased”vulnerability. This response was drivenprimarily by this species reliance on waterbodies for breeding and foraging. A drying trendcould have negative impacts by reducingavailability of suitable habitats. 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.Human Response to CC: All-weather roads(necessitated by a warming climate andshortened ice road season) associated withenergy extraction activities could impact GreaterWhite-fronted Geese, particularly nearTeshekpuk Lake, however other sources ofhuman activity related to climate changemitigation will be much less pervasive in thenear future so would likely only slightly increasevulnerability.Disturbance Regime: Climate-mediateddisturbance processes, namely thermokarst,could both create and destroy foraging andnesting habitats through both ice wedgedegradation and draining of thaw lakes (Martinet al. 2009). Likewise, predicted increasedcoastal erosion and resulting salinization (Joneset al. 2009) could both negatively and positivelyaffect post-breeding aggregations of stagingbirds by destroying and creating foraging /molting habitat.42