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Loss functions and posterior distributions of population growth rate (r) generated from state-space models of abundance for spectacled eiders breeding on the Arctic Coastal Plain (ACP) and Yukon Kuskokwim Delta (YKD) Loss functions were generated using the probability of quasi-extinction given population size, growth rate, and process variation. The dotted line represents the under-protection loss function (i.e., loss if decision were to delist given negative population growth) and the solid line is the over protection loss function (i.e., loss if the decision were to maintain status given positive population growth). Gray distributions show the posterior density of population growth rate (r) estimated by a Bayesian state-space model for the time series from 2007 to 2019. As part of the recovery criteria, spectacled eiders will be considered for delisting if overprotection (value in solid line box) is greater than underprotection (value in dashed line box). Greater overprotection error indicates that we are more likely to provide too much protection to the species than we are to provide too little protection to the species.
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Assessing species status and making classification decisions under the Endangered Species Act is a critical step towards effective species conservation. However, classification decisions are liable to two errors: i) failing to classify a species as threatened or endangered that should be classified (underprotection), or ii) classifying a species as...
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Citations
... The regions accounting for most of the waterfowl egg harvest were Y-K Delta Coast (56%), Bering Strait Mainland (16%), and Y-K Delta Inland (11%) (Fig 3B). Alaska abundance index [43,[53][54][55][56][57][58][59]: Abundance indices are heterogenous among species depending on the geographic area, demographic contingents (e.g., breeding, non-breeding, hatch-year birds), and populations represented in different estimates as well as whether estimates are corrected for incomplete detection. Additional information for population data is available in S1 Dataset. ...
We estimated the annual harvest of waterfowl and Sandhill Crane Grus canadensis and their eggs by Alaska’s rural residents and described seasonal and geographic patterns. Subsistence in Alaska refers to patterns of resource use typical of rural, remote regions where Indigenous people are a high proportion of the population. Rural communities in Alaska rely on the legally-allowed spring-summer harvest of migratory birds for food and socio-cultural wellbeing, in addition to harvests in the fall-winter general hunting season. We based harvest estimates on a large dataset (637 community-years) composed from multiple sources. The estimated annual average harvest of waterfowl and Sandhill Crane by rural residents was 270,641 birds/year (68% in spring-summer, 32% in fall-winter) and 36,692 eggs/year in the 2004–2015 reference period. Harvest estimates for ducks, swans, and Sandhill Crane were lower than in the 1980s–1990s. Harvest amounts, seasonality, and species composition distinguished regional patterns for the Pacific-Aleutian mainland and islands, Bering Sea mainland, St. Lawrence-Diomede islands, North Slope, and Interior Alaska-Upper Copper River. Rural residents accounted for 79% of the total waterfowl harvest in Alaska and high proportions of the total Pacific Flyway harvest for several species of sea ducks, geese, swans, and Sandhill Crane. Alaska’s Indigenous people are important partners in harvest management and conservation of migratory birds. Harvest data are needed to inform efficient and appropriate decisions to achieve management goals. This study can facilitate collaboration for harvest management and conservation across Alaska and the flyways by helping diverse users to understand their contributions to the total harvest.
... Several studies have examined effects of life history, model complexity, process error, measurement error, and decision rules on the distribution and magnitude of misclassification errors for classification decisions (Connors et al., 2014;Dunham et al., 2021;Regan et al., 2013;Rueda-Cediel et al., 2015Taylor et al., 1996). Classification decisions varied in sensitivity to each of these components and these studies highlight the considerable consequences associated with misclassification for species conservation. ...
... In particular, sea ducks (Mergini) that nest in the North American Arctic have shown major declines from historic levels (Bowman et al., 2015;Suydam et al., 2000), with some evidence for recent increases especially on the subarctic Yukon-Kuskokwim Delta (Amundson et al., 2019;Bowman et al., 2015;Dunham et al., 2021). ...
Wetlands in Arctic tundra support abundant breeding waterbirds. Wetland types differing in area, depth, vegetation, and invertebrate biomass density may vary in importance to birds, and in vulnerability to climate change. We studied availability and use of different wetland types by prelaying females of four species of sea ducks (Mergini) breeding on the Arctic Coastal Plain of Alaska, USA: long-tailed ducks (Clangula hyemalis) and Steller's (Polysticta stelleri), spectacled (Somateria fischeri), and king eiders (Somateria spectabilis). All four species preferred shallow vegetated wetlands versus deeper lakes. The ducks spent almost all their active time feeding, but their occurrence in different wetland types was not affected by the relative biomass density of known prey or of all invertebrates that we sampled combined. Sea ducks strongly preferred wetlands dominated by emergent and submersed Arctophila fulva over those dominated by the sedge Carex aquatilis, despite the much greater number , total area, and invertebrate biomass density of Carex wetlands. The hens depend heavily on local invertebrate prey for protein to produce eggs; thus, their preference for Arctophila wetlands likely reflects greater accessibility of prey in the near-surface canopy and detritus of Arctophila. Such shallow wetlands decreased substantially in number (−17%) and area (−30%) over 62 years before 2013 and appear highly susceptible to further declines with climate warming. Impacts on sea ducks of climate-driven changes in availability of important wetland types will depend on their adaptability in exploiting alternative wetlands.
... Spectacled eiders use remote areas throughout the annual cycle making it particularly challenging to conduct comprehensive surveys or studies of demography. Several studies have focused on independent analyses of data sets to model population dynamics and demography of spectacled eiders (e.g., Christie et al., 2018;Dunham et al., 2021;Flint et al., 2016); however, estimating abundance and demographic rates has remained challenging. Evidence suggests that all four eider species demonstrate demographic responses, changes in abundance, and distribution shifts related to climate change and environmental conditions encountered throughout the annual cycle (e.g., Barry, 1968;Christie et al., 2018;Fournier & Hines, 1994;Frost et al., 2013;Sexson et al., 2016;Žydelis et al., 2006). ...
... Breeding abundance increased substantially over our study period (Figure 3), and our abundance estimates and trend were largely consistent with recent analyses of the abundance data alone (Dunham et al., 2021;Fischer et al., 2018). Eiders exhibit a slow "pace of life" strategy, which often includes high variance ("boom and bust") in annual reproductive success and first-year survival (Orzack & Tuljapurkar, 2001). ...
The Arctic is undergoing rapid and accelerating change in response to global warming, altering biodiversity patterns, and ecosystem function across the region. For Arctic endemic species, our understanding of the consequences of such change remains limited. Spectacled eiders (Somateria fischeri), a large Arctic sea duck, use remote regions in the Bering Sea, Arctic Russia, and Alaska throughout the annual cycle making it difficult to conduct comprehensive surveys or demographic studies. Listed as Threatened under the U.S. Endangered Species Act, understanding the species response to climate change is critical for effective conservation policy and planning. Here, we developed an integrated population model to describe spectacled eider population dynamics using capture–mark–recapture, breeding population survey, nest survey, and environmental data collected between 1992 and 2014. Our intent was to estimate abundance, population growth, and demographic rates, and quantify how changes in the environment influenced population dynamics. Abundance of spectacled eiders breeding in western Alaska has increased since listing in 1993 and responded more strongly to annual variation in first-year survival than adult survival or productivity. We found both adult survival and nest success were highest in years following intermediate sea ice conditions during the wintering period, and both demographic rates declined when sea ice conditions were above or below average. In recent years, sea ice extent has reached new record lows and has remained below average throughout the winter for multiple years in a row. Sea ice persistence is expected to further decline in the Bering Sea. Our results indicate spectacled eiders may be vulnerable to climate change and the increasingly variable sea ice conditions throughout their wintering range with potentially deleterious effects on population dynamics. Importantly, we identified that different demographic rates responded similarly to changes in sea ice conditions, emphasizing the need for integrated analyses to understand population dynamics.
