PUB - Publikationen an der Universität Bielefeld

1. Anthropogenic changes in the marine environment and global climate change have led to population declines inseveral seabird species worldwide. Rockhopper penguins (Eudyptes chrysocomeandEudyptes moseleyi)haveexperienced a dramatic population decline, potentially linked to increasing sea surface temperatures (SST). AmongSouthern Ocean diving seabirds, rockhopper penguins typically occupy a low trophic level, and might therefore beexpected to mirror climate-driven bottom-up changes to the food web sensitively and on a short time scale.2. Using passive integrated transponders, survival rates of adults in a colony of southern rockhopper penguins(E. chrysocome) on the Falkland Islands were monitored overfive consecutive years. Mean annual survival rateswere in the range 84 to 96%.3. These values are high compared with other crested penguin species and reflect the generally good conditionsduring the study period, when low SST prevailed. However, survival rates were lower in 2010, corresponding tovery cold conditions. Curvefits showed a best-fit quadratic relationship between average SST anomaly and survivalrates for the present data, as well as for a data set including two additional years from a different study at Staten Island.4. Results of this study suggest that rockhopper penguins survive best at SSTs that are lower than the average ofthe last four decades. In accordance with previously observed rockhopper penguin population declines, the presentdata suggest that rockhopper penguins are highly sensitive to changes in SST and their effects on the food web, aworrying perspective in times of global climate change. It seems likely that these changes could, in the long term,also affect population trends of other seabird species with similar ecological preferences.5. The most promising conservation approach should aim at enhancing ecosystem resilience, mainly by reducingindustrialfishing and oil exploitation. This would allow the currently over-exploitedfish and squid stocks torecover, offering larger food resources to seabirds and other vertebrate species.