King penguin population threatened by Southern Ocean warming

Abstract

Seabirds are sensitive indicators of changes in marine ecosystems and might integrate and/or amplify the effects of climate forcing on lower levels in food chains. Current knowledge on the impact of climate changes on penguins is primarily based on Antarctic birds identified by using flipper bands. Although flipper bands have helped to answer many questions about penguin biology, they were shown in some penguin species to have a detrimental effect. Here, we present for a Subantarctic species, king penguin ( Aptenodytes patagonicus ), reliable results on the effect of climate on survival and breeding based on unbanded birds but instead marked by subcutaneous electronic tags. We show that warm events negatively affect both breeding success and adult survival of this seabird. However, the observed effect is complex because it affects penguins at several spatio/temporal levels. Breeding reveals an immediate response to forcing during warm phases of El Niño Southern Oscillation affecting food availability close to the colony. Conversely, adult survival decreases with a remote sea-surface temperature forcing (i.e., a 2-year lag warming taking place at the northern boundary of pack ice, their winter foraging place). We suggest that this time lag may be explained by the delay between the recruitment and abundance of their prey, adjusted to the particular 1-year breeding cycle of the king penguin. The derived population dynamic model suggests a 9% decline in adult survival for a 0.26°C warming. Our findings suggest that king penguin populations are at heavy extinction risk under the current global warming predictions.

Demographic models and IPCC climate projections predict the decline of an emperor penguin population

“…Analyses that include only part of the life cycle (for example, see ref. 29) may reveal some aspects of population response, but cannot predict future trends and variability in a stochastic environment.…”

Climatic effects on breeding grounds are more important drivers of breeding phenology in migrant birds than carry-over effects from wintering grounds

“…Wintering ground precipitation may not affect clutch size if it does not strongly influence arrival phenology. Secondly, after unfavourable winters, individuals may prioritize investment in reproduction over self-maintenance, resulting in carry-over effects on survival [23], which were not examined. Thirdly, any increase in the survival of low-quality females during favourable winters may increase the proportion of small clutches laid, masking any potential carry-over benefit for fitter individuals [24].…”

Implications for seabirds off South Africa of a long-term change in the distribution of sardine

“…breeding success, survival) [e.g. Le Bohec et al 2008]. Seabird foraging movements and success are directly or indirectly susceptible to be affected by many factors, including: prey availability [e.g.…”