Projected poleward shift of king penguins' ( Aptenodytes patagonicus ) foraging range at the Crozet Islands, southern Indian Ocean

Abstract

Seabird populations of the Southern Ocean have been responding to climate change for the last three decades and demographic models suggest that projected warming will cause dramatic population changes over the next century. Shift in species distribution is likely to be one of the major possible adaptations to changing environmental conditions. Habitat models based on a unique long-term tracking dataset of king penguin ( Aptenodytes patagonicus ) breeding on the Crozet Islands (southern Indian Ocean) revealed that despite a significant influence of primary productivity and mesoscale activity, sea surface temperature consistently drove penguins' foraging distribution. According to climate models of the Intergovernmental Panel on Climate Change (IPCC), the projected warming of surface waters would lead to a gradual southward shift of the more profitable foraging zones, ranging from 25 km per decade for the B1 IPCC scenario to 40 km per decade for the A1B and A2 scenarios. As a consequence, distances travelled by incubating and brooding birds to reach optimal foraging zones associated with the polar front would double by 2100. Such a shift is far beyond the usual foraging range of king penguins breeding and would negatively affect the Crozet population on the long term, unless penguins develop alternative foraging strategies.

King penguin demography since the last glaciation inferred from genome-wide data

“…Indeed, an abrupt increase in sea surface temperature (SST) has been demonstrated to be detrimental to king penguin survival and reproductive rates in populations breeding in the Crozet archipelago in the southern Indian Ocean [14,16]. This is caused by the longer distance the individuals have to swim to get to their main foraging ground (the Antarctic Polar Front during the summer season) whose latitudinal location is influenced by SST (the higher the SST, the higher the latitude [17]). However, when SST was lower, and food resources probably closer, the Crozet Islands were probably not suitable for the king penguin to complete their breeding cycle as this species needs year-round ice-free grounds for reproduction.…”

Frontal zones, temperature gradient and depth characterize the foraging habitat of king penguins at South Georgia

“…This means that penguins breeding in these locations may depend to a higher degree on the PF. Predicted declines of king penguins due to environmental variability (Barbraud et al 2008, Le Bohec et al 2008, Péron et al 2012 and in case of shifts in the PF may, therefore, only relate to areas where the animals are highly dependent on the PF due to the lack of alternative foraging areas. Such predictions might be of lesser value for king penguins breeding at South Georgia.…”

“…Identifying such features and their association with different oceanographic areas may increase our understanding of how horizontal habitat use by diving predators is related to their exploration of the water column. This may be of importance in the context of environmental change, and any future potential effects on king penguin populations (Le Bohec et al 2008, Forcada & Trathan 2009, Péron et al 2012.…”

Plasticity in the foraging behavior of male Southern Rockhopper Penguins (Eudyptes chrysocome) during incubation in the Falkland/Malvinas Islands

“…For example, in King Penguins Aptenodytes patagonicus climate change was predicted to result in increasing distances to the preferred foraging grounds at the Antarctic Polar Frontal Zone (APFZ), which in turn will have negative consequences on breeding success and recruitment (Péron et al 2012). …”