Greater Scaup

Greater Scaup (Aythya marila) Vulnerability: Presumed Stable Confidence: High The Greater Scaup is the only diving duck in the genus Aythya that has a circumpolar distribution. In Alaska this species has its highest nesting densities in the Yukon-Kuskokwim Delta but they also breed in Arctic Alaska throughout the Brooks Range, foothills and Arctic Coastal Plain. Its breeding habitat is typically characterized by relatively shallow (1–2 m) lakes and large ponds with low surrounding vegetation in extensive, largely treeless, wetlands (Kessel et al. 2002). Greater Scaup have an omnivorous diet but tend to focus on more protein-rich animal foods (mostly aquatic invertebrates) during the summer. This species winters primarily in marine waters of both the Atlantic and Pacific coasts (Kessel et al. 2002). Breeding ground population estimates for this species from 1978-2011 range from 434,000 – 642,000 and there is some evidence of regional declines (Kessel et al. 2002). drying trend could limit wetland availability in northern Alaska. Current projections of annual potential evapotranspiration suggest negligible atmospheric-driven drying for the foreseeable future (TWS and SNAP), and its interaction with hydrologic processes is very poorly understood (Martin et al. 2009). This uncertainty is reflected in the range of vulnerability severity scores in this category (see table below). C. Rutt Range: We used the extant NatureServe map for this assessment as it closely matched other range map sources and descriptions (Johnson and Herter 1989, Kessel et al. 2002). However, it should be noted that this species does occasionally breed sporadically closer to the Arctic Ocean coastline and along the Dalton Highway (Kessel et al. 2002). Physiological Hydro Niche: Among the indirect exposure and sensitivity factors in the assessment (see table on next page), Greater Interactions with Other Species: In terms of Scaup ranked neutral in most categories “interactions with other species”, it is possible although they were ranked with a greater than that red fox nest predation could increase as this “slight increase” in vulnerability for species may become more numerous moving in “physiological hydrologic niche” and from boreal regions (Pamperin et al. 2006) and “interactions with other species”. For the first scaup would not be able to defend nests as category this response was driven by the scaup’s successfully as against the smaller arctic foxes. requirement for wetlands and ponds rich in However this does not seem to be a problem for aquatic invertebrates for feeding during them in the southern portion of their range. migration, nesting, and brood rearing. They need Disturbance Regime: Disturbances (e.g. large- smaller wetlands, likely with abundant emergent scale thermokarst, disease outbreaks) and human vegetation for cover and feeding, particularly for brood rearing (Kessel et al. 2002). A tundra Greater Scaup (Aythya marila) Vulnerability: Presumed Stable Confidence: High D=Decrease vulnerability, SD=Somewhat decrease vulnerability, N=Neutral effect, SI=Slightly increase vulnerability, I=Increase vulnerability, GI=Greatly increase vulnerability. mitigation activities related to climate could Literature Cited impact this species, but experts felt this to be unlikely as these types factors will likely be Johnson, S.R. and D.R. Herter. 1989. The birds of the localized or, in the case of thermokarst, could Beaufort Sea, Anchorage: British Petroleum Exploration (Alaska), Inc. potentially create habitat (Martin et al. 2009). Physical Habitat Restrictions: The Greater Kessel, B., D.A. Rocque, and J.S. Barclay. 2002. Greater Scaup’s expansive breeding range into southern Scaup (Aythya marila). In: The Birds of North America No. Alaska makes them less susceptible to 163 (Poole, A. and Gill, F. eds.). The Birds of North America, Inc. Philadelphia, PA. constraints posed by natural barriers related to dispersal/movement issues. Because this species Martin, P., J. Jenkins, F.J. Adams, M.T. Jorgenson, A.C. experiences much warmer conditions at interior Matz, D.C. Payer, P.E. Reynolds, A.C. Tidwell, and J.R. Alaska breeding sites, they would likely have no Zelenak. 2009. Wildlife response to environmental Arctic change: Predicting future habitats of Arctic Alaska. Report problem adapting physiologically to a warmer of the Wildlife Response to Environmental Arctic Change Arctic environment and perhaps could expand (WildREACH), Predicting Future Habitats of Arctic Alaska their nesting presence in far northern Alaska. Workshop, 17-18 November 2008. Fairbanks, Alaska, Phenological Response: There are no long-term USFWS, 148 pages. data sets on nesting or migration chronology for Pamerin, N.J., E.H. Follmann, and B. Petersen. 2006. Greater Scaup for the North Slope (D. Safine, Interspecific killing of an arctic fox by a red fox at Prudhoe pers. comm.) and so it is currently unknown how Bay, Alaska. Arctic 59: 361-364. they would respond to phenology changes. In summary, this assessment suggests that The Wilderness Society (TWS) and Scenarios Network for Alaska Planning (SNAP), Projected (2001-2099: A1B Greater Scaup will likely be adaptable enough to scenario) monthly total potential evapotranspiration from 5 cope with climate change and perhaps even AR4 GCMs that perform best across Alaska and the Arctic, benefit from associated habitat changes that may utilizing 2km downscaled temperature as model inputs. occur in Arctic Alaska, at least during the 50 http://www.snap.uaf.edu/data.php. year timeline of this assessment. From: Liebezeit et al. 2012. Assessing Climate Change Vulnerability of Breeding Birds in Arctic Alaska. A report prepared for the Arctic Landscape Conservation Cooperative. Wildlife Conservation Society, North America Program, Bozeman, MT., 167pp. .

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