There is now ample evidence of the ecological impacts of recent climate change in marine ecosystems. Seabirds are good bio-indicator species of the ecological consequences of climate change on marine ecosystems.
In polar ecosystems, the sea ice environment is a critical habitat for many seabirds because it influences their foraging habitat and the entire food web. Climate model simulations developed in the last Intergovernmental Panel on Climate Change (IPCC) report project that Antarctic sea ice will shrink dramatically by the end of the century. Such changes will almost certainly affect sea-ice dependent species.
While previous work has provided insight into the role of climate change for some seabirds, considerable uncertainty remains due to limited understanding of some of the climate-species linkages.
The aim of this study is to include a more detailed representation of the processes by which sea ice affects the demography of an Antarctic seabird, the southern fulmar (Fulmarus glacialoides). We are particularly interested in the processes by which seabirds acquire resources (i.e. foraging behaviour) and allocate their energetic resources (i.e. food load) between chick growth/ breeding success, and adult mass gain/ survivorship. We will link these processes with a dynamic population model incorporating contrasting sea ice conditions.
Results/Conclusions
The foraging trips of 12 adult fulmars during incubation and chick rearing were studied in Pointe Geologie (66°40’S, 140°01’E), using the Argos satellite tracking system during two years of contrasted sea ice conditions.
Fulmars forage over open waters near the ice edge, North East of the colony, near the Mertz polynya (open water within sea ice), which is an area of high productivity. Birds foraged further in 2000 than in 2001 (390 km and 238 km respectively between colony and foraging zone) when sea ice edge was further.
The trip durations were in average greater in 2000, and adults delivered less food to the chick, lowering chick growth. There is a high variability in these results caused by inexperienced breeders and the overall breeding success is not related to foraging parameters. The adult mass gain between each trip does not differ between the two years, suggesting that adults don’t deteriorate their body condition to a level that may jeopardize their own survival.
Building on another study (see abstract by Guery et al.), and including effect of sea ice change on Fulmar foraging behaviours into a population model, we expect that future change in sea ice extent may impact its populations.