Seabird diet indicates changing Arctic marine communities in eastern Canada

Abstract

Changing climatic conditions are affecting ecosystems worldwide, but polar ecosystems are experiencing the most rapid changes as the extent of summer sea ice has diminished over the last several decades. In the Canadian Arctic, thick-billed murres Uria lomvia can be used as samplers of the marine environment, and we examined changes in the diet of the birds between recent and historical studies from the 1970s and 1980s. In the low Arctic, the amount of Arctic cod, an ice-dependent species, declined in the murre diet; and capelin, a subarctic species, has now become the primary prey item. In the mid-Arctic, where summer sea ice is still present during the summer, Arctic cod persists as an important prey item, but capelin is now regularly observed, marking an apparent northward expansion of this species over the last 30 yr. In the high Arctic, summer sea ice continues to dominate the seascape in most years, and Arctic cod continues to dominate the diets of the murres. Changes in Arctic cod in the bird diet were found to be more related to sea ice conditions averaged over multiple years rather than single-year indices, indicating that long-term changes in sea ice do impact this prey species. The diversity of the prey sampled by the birds has decreased, signaling a potential change in the number of prey species available. Overall, the birds illustrate changes occurring in the marine environment in areas where little other information is available.KEY WORDS: Seabird · Arctic · Climate change · Diet shift · Fish community · Zooplankton · Thick-billed murre · Uria lomvia · Sea ice cover

Spatial and temporal variation of an ice-adapted predator’s feeding ecology in a changing Arctic marine ecosystem

“…In addition, Chambellant et al (2013) found that the importance of Arctic cod to ringed seal diet declined after 2000 in western Hudson Bay, while capelin and sand lance became more prevalent thereafter. Similarly, several sea bird populations in Hudson Bay have switched from an Arctic-cod-dominated diet to capelin since the late 1990s (Gaston et al 2003;Provencher et al 2012). Overall, ringed seals, as a species, employ dietary plasticity to changing resource availability and environmental conditions.…”

“…The physical factors affecting the Arctic climate are in extreme states, with no indication that a reversible shift will occur in the foreseeable future (Hinzman et al 2013;Polyakov et al 2013). These marine environmental changes are dramatically altering habitat (Laidre et al 2008) and causing a higher prevalence of subarctic species (Higdon and Ferguson 2009;Provencher et al 2012) and parasites/disease (Davidson et al 2011), which have together negatively impacted the abundances and distributions, decreased the growth and condition, and changed the behavior of numerous Arctic organisms, ranging from phytoplankton to polar bears (Wassmann et al 2011).…”

Seabirds and climate change: roadmap for the future

“…In this TS, Burthe et al (2012), Pro - Watanuki et al (2012), Grémil-let et al (2012), and Dorresteijn et al (2012) show how seabird food webs are changing in different regions. The changes in food webs, exemplified by changes in seabird diet, sometimes (Burthe et al 2012) but not always (Dorresteijn et al 2012, Grémil-let et al 2012, Provencher et al 2012, Watanuki & Ito 2012 reflect changes in diet quality; often the food web change is driven by species abundance or availability (Dorresteijn et al 2012). In some cases, these changes affect breeding success or other demographic attributes.…”

How Arctic Marine Birds Help Researchers Study a Changing North

“…Studies that have examined the diet of Thick-billed Murres have been ongoing in Canada since the 1970s, and recent work has shown that changing climatic conditions are affecting the forage fish species in the region (Gaston et al, 2003). Declining levels of summer sea ice are linked with a decline in ice-associated Arctic cod (Boreogadus saida) and an increase in the warmer water capelin (Mallotus villosus) in the diet of the murres in the low Arctic region, where summer sea ice has declined the most (Provencher et al, 2012).…”

“…Collaborative community research efforts and education opportunities related to marine bird research continue to provide insight and capacity building with our northern partners (Mallory et al, 2006a;Provencher et al, 2013). Marine birds also offer long-term data sets that are helping us to understand how changing conditions may be affecting wildlife throughout the region (Provencher et al, 2012;Iverson et al, 2014). Through my own PhD research and as a member of the northern marine bird research team, I strive to carry on this collaborative approach to northern research, always keeping in mind that those who study birds in the North are more than just bird biologists.…”