Seventy percent of king penguins - around 1.1 million breeding pairs - will abruptly relocate or disappear before the end of the century if greenhouse gas emissions continue at present rates, reports a study published online this week in Nature Climate Change.
While cold-loving species are usually expected to move pole-ward in response to climactic warming, the king penguin’s fragmented habitat - breeding exclusively on continuously ice-free parts of islands in the Southern Ocean - makes their displacement complicated. They can only shift breeding grounds in a stepping-stone manner, amongst available islands, while their feeding grounds move more continuously with changes in the location of the Antarctic Polar Front and associated ocean upwelling.
Modelling species response in these complex conditions is challenging, so authors Emiliano Trucchi, Celine Le Bohec, and colleagues used a biophysical ecological niche model validated by population genomics and past dynamics in order to simulate the king penguin’s past habitat shifts and identify future vulnerable areas. The authors found that 49% percent of the king penguin population (breeding on the Crozet and Prince Edward Islands) are projected to lose their habitat completely, while 21% (breeding on the Kerguelen, Falkland and Tierra del Fuego islands) will experience strongly altered habitats due to increasing foraging distances. Substantial losses, however, may be partly compensated by the colonisation of Bouvet Island, and by growth on Heard and South Georgia due to improved foraging conditions.
This modelling approach may also be useful for other species which occupy highly fragmented habitats.