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Christina A D Semeniuk - One of the best experts on this subject based on the ideXlab platform.

  • increasing nest predation will be insufficient to maintain polar bear body condition in the face of sea ice loss
    Global Change Biology, 2017
    Co-Authors: Evan Richardson, David Mcgeachy, Samuel A Iverson, Hugh G Gilchrist, Christina A D Semeniuk
    Abstract:

    Climate change can influence interspecific interactions by differentially affecting species-specific phenology. In seasonal ice environments, there is evidence that polar bear predation of Arctic bird eggs is increasing because of earlier sea ice break-up, which forces polar bears into near-shore terrestrial environments where Arctic birds are nesting. Because polar bears can consume a large number of nests before becoming satiated, and because they can swim between island colonies, they could have dramatic influences on seabird and seaduck reproductive success. However, it is unclear whether nest foraging can provide an energetic benefit to polar bear populations, especially given the capacity of bird populations to redistribute in response to increasing predation pressure. In this study, we develop a spatially explicit agent-based model of the predator-prey relationship between polar bears and Common Eiders, a Common and culturally important bird species for northern peoples. Our model is composed of two types of agents (polar bear agents, and Common Eider hen agents) whose movements and decision heuristics are based on species-specific bioenergetic and behavioral ecological principles, and are influenced by historical and extrapolated sea ice conditions. Our model reproduces empirical findings that polar bear predation of bird nests is increasing, and predicts an accelerating relationship between advancing ice break-up dates and the number of nests depredated. Despite increases in nest predation, our model predicts that polar bear body condition during the ice-free period will continue to decline. Finally, our model predicts that Common Eider nests will become more dispersed and will move closer to the mainland in response to increasing predation, possibly increasing their exposure to land-based predators, and influencing the livelihood of local people that collect Eider eggs and down. These results show that predator-prey interactions can have non-linear responses to changes in climate, and provides important predictions of ecology change in Arctic ecosystems. This article is protected by copyright. All rights reserved.

Mark L Mallory - One of the best experts on this subject based on the ideXlab platform.

  • annual movement patterns of american Common Eiders somateria mollissima dresseri
    Wildlife Biology, 2020
    Co-Authors: Mark L Mallory, Randy G Milton, Chris Dwyer, Robert A Ronconi, Bradford R Allen, Stephane Lair, Conor D Mallory, Nic R Mclellan, Glen J Parsons, Lucas Savoy
    Abstract:

    The American Common Eider Somateria mollissima dresseri is a sea duck of coastal mid-Atlantic North America, and breeding colonies in the southern part of its range have been in decline. To better understand threats faced by the subspecies, we used satellite telemetry to track 46 Eiders through their annual cycle in four years from three regions in the southern part of the range, to identify key locations and migratory corridors. Female Eiders exhibited highly variable movement phenology within and among colonies, but coastal Maine and Massachusetts were consistent, important moulting areas for males and females from all breeding colonies. Most birds wintered in coastal waters around Cape Cod and Nantucket Sound, meaning that threats in this region (industrial development, disease outbreak, harvest) could have deleterious effects on much of the population.

  • anti parasite treatment results in decreased estimated survival with increasing lead pb levels in the Common Eider somateria mollissima
    Proceedings of The Royal Society B: Biological Sciences, 2019
    Co-Authors: Andre Morrill, Mark L Mallory, Jennifer F Provencher, H G Gilchrist, Mark R. Forbes
    Abstract:

    Field experiments where parasites are removed through treatment and contaminant levels in host tissues are recorded can provide insight into the combined effects of parasitism and contaminants in w...

  • Nest usurpation by a Common Eider toward a long-tailed duck
    Norwegian Polar Institute, 2016
    Co-Authors: Isabeau Pratte, M. Maftei, Mark L Mallory
    Abstract:

    Intraspecific and non-obligate brood parasitism and nest takeover is well documented in Common Eiders (Somateria mollissima borealis) nesting in the Arctic. However, we report the takeover of a long-tailed duck (Clangula hyemalis) nest by a female Common Eider on Nasaruvaalik Island, Nunavut, Canada. The high nesting density due to limited habitat in the region may have contributed to this seemingly risky behaviour, which provides no clear benefits to the Eider

  • colonial marine birds influence island soil chemistry through biotransport of trace elements
    Water Air and Soil Pollution, 2015
    Co-Authors: Mark L Mallory, Lewis Mahon, Molly D Tomlik, Christopher D White, Randy G Milton, Ian Spooner
    Abstract:

    Marine birds are important vectors of nutrient and contaminant transfer from sea to land. In eastern Nova Scotia, Canada, colonial marine birds nest on specific nearshore islands within archipelagoes, and we predicted that soils on islands with bird colonies would have higher concentrations of selected trace elements (notably K, Ca, As, Cd, Cu, Pb, Se, Hg, and Zn) than soils on islands without colonies. In this study, Common Eider (Somateria mollissima), Leach’s storm petrel (Oceanodroma leucorhoa), black guillemot (Cepphus grylle), double-crested cormorant (Phalacrocorax auritus), great black-backed gull (Larus marinus), and herring gull (Larus argentatus) were considered to be the principal avian vectors for contaminant transfer. Results indicate that soils from islands with bird colonies had unique chemical compositions and Commonly displayed elevated concentrations of K, Ca, Cu, Se, and Zn when compared to islands without colonies. Thus, marine birds feeding in the nearby marine zone move pollutants and nutrients from the ocean to nesting islands, potentially influencing habitat quality for coastal terrestrial species.

  • Assessing regional populations of ground-nesting marine birds in the Canadian High Arctic
    Norwegian Polar Institute, 2015
    Co-Authors: M. Maftei, S. E. Davis, Mark L Mallory
    Abstract:

    The Queens Channel region of Nunavut is an ecologically distinct area within the Canadian High Arctic consisting of an extensive archipelago of small, low-lying gravel islands throughout which form several localized but highly productive polynyas. We used aerial survey and colony-monitoring data to assess regional- and colony-level fluctuations in the number of birds in this region between 2002 and 2013. Regional and colony-specific monitoring suggested that Common Eider (Somateria mollissima) numbers are increasing, while numbers of Arctic terns (Sterna paradisaea) may be in decline. Based on these data, we suggest that even infrequent comprehensive surveys are more useful than annual monitoring at specific sites in generating an accurate assessment of ground-nesting seabird populations at the regional level, and that dramatic fluctuations at individual colonies probably belie the overall stability of regional populations

Evan Richardson - One of the best experts on this subject based on the ideXlab platform.

  • increasing nest predation will be insufficient to maintain polar bear body condition in the face of sea ice loss
    Global Change Biology, 2017
    Co-Authors: Evan Richardson, David Mcgeachy, Samuel A Iverson, Hugh G Gilchrist, Christina A D Semeniuk
    Abstract:

    Climate change can influence interspecific interactions by differentially affecting species-specific phenology. In seasonal ice environments, there is evidence that polar bear predation of Arctic bird eggs is increasing because of earlier sea ice break-up, which forces polar bears into near-shore terrestrial environments where Arctic birds are nesting. Because polar bears can consume a large number of nests before becoming satiated, and because they can swim between island colonies, they could have dramatic influences on seabird and seaduck reproductive success. However, it is unclear whether nest foraging can provide an energetic benefit to polar bear populations, especially given the capacity of bird populations to redistribute in response to increasing predation pressure. In this study, we develop a spatially explicit agent-based model of the predator-prey relationship between polar bears and Common Eiders, a Common and culturally important bird species for northern peoples. Our model is composed of two types of agents (polar bear agents, and Common Eider hen agents) whose movements and decision heuristics are based on species-specific bioenergetic and behavioral ecological principles, and are influenced by historical and extrapolated sea ice conditions. Our model reproduces empirical findings that polar bear predation of bird nests is increasing, and predicts an accelerating relationship between advancing ice break-up dates and the number of nests depredated. Despite increases in nest predation, our model predicts that polar bear body condition during the ice-free period will continue to decline. Finally, our model predicts that Common Eider nests will become more dispersed and will move closer to the mainland in response to increasing predation, possibly increasing their exposure to land-based predators, and influencing the livelihood of local people that collect Eider eggs and down. These results show that predator-prey interactions can have non-linear responses to changes in climate, and provides important predictions of ecology change in Arctic ecosystems. This article is protected by copyright. All rights reserved.

Mark R. Forbes - One of the best experts on this subject based on the ideXlab platform.

Gregory J Robertson - One of the best experts on this subject based on the ideXlab platform.

  • Common Eider and large gull nesting associations in coastal Labrador
    'Canadian Science Publishing', 2017
    Co-Authors: Gregory J Robertson, Keith G. Chaulk
    Abstract:

    Apparent nesting associations between avian egg predators and their prey have received much interest, with gulls and waterfowl receiving considerable attention. We examined the co-occurrence of breeding large gulls (Herring Gull (Larus argentatus Pontoppidan, 1763) and Great Black-backed Gull (Larus marinus L., 1758)) and Common Eiders (Somateria mollissima L., 1758) along the coast of Labrador from 1998 to 2003. Nest counts for large gulls and Eiders were undertaken by ground crews on 45–109 islands each year, counting 79–283 and 721–3424 nests annually, respectively. Gulls were more likely to nest on an island with nesting Eiders (69.4%) than without nesting Eiders (38.4%), and the probability and numbers of gulls nesting on an island increased as Eider colony size increased. Large gulls were 1.76 times more likely to occupy islands that had nesting Eiders in the previous year, while Eiders were equally likely to colonize islands that did or did not have nesting gulls in the previous year. Eiders were no more likely to abandon islands that had nesting gulls in the previous year. In subarctic coastal landscapes, large gulls appear to preferentially nest in association with nesting Eiders, while Eiders appear not to avoid nesting islands based on the previous presence of large gulls

  • factors affecting nest site selection and nesting success in the Common Eider somateria mollissima
    Ibis, 2008
    Co-Authors: Gregory J Robertson
    Abstract:

    Nesting site selection and nesting success in Common Eiders Somateria mollissima were studied over a 3-year period (1991–1993) in the Mast River delta (58o24'N, 94o24'W), 40 km east of Churchill, Manitoba, Canada. Eiders preferentially nested on islands that had incubating Lesser Snow Geese Anser caerulescens caerulescens on them; this effect was also seen between years on the same islands. Eiders which nested on islands with geese had a reduced chance of having eggs taken by predators during egg-laying and had a greater chance of hatching once incubation had begun, independent of the number of other Eiders nesting on the island. The distance to a goose nest was less in nests which did not lose eggs prior to incubation than in those which did, but there was no difference in the distance to a goose nest in Eider clutches which did or did not hatch. Artificial Eider eggs placed closer to goose nests had a lower probability of being predated than those placed farther away. Nests on islands farther up the river and farther from the mainland had higher nesting success, presumably because these nesting islands were inaccessible to Arctic Foxes Alopex lagopus.