Greenhouse gases released into the atmosphere continue to drive up temperatures worldwide. While the effects of climate change vary across the globe, its reduction of sea ice levels could significantly impact the Arctic ecosystem.
Françoise Amélineau, a PhD student from the Université de Montpellier, recently investigated the impact of sea ice loss on North Atlantic seabirds known as little auks.
Amélineau and her colleagues compared little auks’ foraging habits during two breeding seasons on the east coast of Greenland. Whether sea ice was present or absent, they found, little auks foraged in the same areas, targeting the continental shelf and its edge for prey. When sea ice was absent, the birds targeted smaller species that were plentiful at the shelf break. Importantly, the change in diet did not affect the body condition of adult little auks or the growth of their chicks.
These unexpected findings, published in PLOS ONE, suggest little auks may be flexible as the Arctic warms, and identify underwater terrain as a potential key factor for foraging. To learn more about the study and the significance of its results, I interviewed Amélineau via email.
When did you become interested in studying the potential effects of climate change on Arctic seabirds?
FA: Upon the start of my PhD, 3 years ago, when I joined my PhD advisors’ research project ADACLIM. The project started in 2005 and is funded by the French Polar Institute (IPEV). One of its aims is the study of climate change effects on little auks.
Why did you choose to study little auks, specifically?
FA: Little auks are the most abundant seabird species in the North Atlantic with an estimated population of 40-80 million individuals. They breed in the High Arctic, where warming is twice as fast as in the rest of the world. In addition, these little birds are part of a simple food chain as they feed on zooplankton. They are therefore good sentinels of the changes occurring in the Arctic.
You found that a change in diet as a result of sea ice loss had no impact on the auks’ body condition or the growth of their chicks. Could the birds eating the smaller prey have other implications for that environment?
FA: One consequence of eating smaller prey is that birds have to gather more prey items in order to gain enough energy for their maintenance and their chicks, and their diving behavior may thus be modified. In our study, although the difference was not significant, dives were longer when birds ate smaller prey, possibly reflecting the need to gather more items. An increase in the foraging effort may have consequences on adult survival or breeding success in the long term.
Could other species potentially be flexible in the face of sea ice loss? Are there other consequences of climate change that significantly impact Arctic wildlife?
FA: The sea ice loss is opening new habitats northwards to boreal species that are not associated to the ice. The consequences are more harmful for species using the sea ice as a substrate to live such as the seals that breed on the ice and polar bears feeding on them, and also the ice algae that are fixed under the ice. Ice algae are the basis of the marine food web in the Arctic and changes in their dynamic will impact the whole Arctic marine ecosystem.
There are many other consequences of climate changes in the Arctic. For example, some species are expanding northwards and become new competitors, new predators, or bring new parasites to Arctic species.
Did you find that there were other effects on little auks as a result of less sea ice? What about other effects potentially linked to climate change in general?
FA: Please wait for my PhD thesis to learn more about that!
What are your next steps for this research?
FA: The next step is to look at little auk ecology in the long term. Many factors influence the biology of a species; therefore, it is important to collect long term data to monitor the effects of climate change.
Research Article: Amélineau F, Grémillet D, Bonnet D, Le Bot T, Fort J (2016) Where to Forage in the Absence of Sea Ice? Bathymetry As a Key Factor for an Arctic Seabird. PLoS ONE 11(7): e0157764. doi:10.1371/journal.pone.0157764
Image Credit: Samuel Perret, Françoise Amélineau