Large-scale climatic anomalies affect marine predator foraging behaviour and demography

Abstract

Determining the links between the behavioural and population responses of wild species to environmental variations is critical for understanding the impact of climate variability on ecosystems. Using long-term data sets, we show how large-scale climatic anomalies in the Southern Hemisphere affect the foraging behaviour and population dynamics of a key marine predator, the king penguin. When large-scale subtropical dipole events occur simultaneously in both subtropical Southern Indian and Atlantic Oceans, they generate tropical anomalies that shift the foraging zone southward. Consequently the distances that penguins foraged from the colony and their feeding depths increased and the population size decreased. This represents an example of a robust and fast impact of large-scale climatic anomalies affecting a marine predator through changes in its at-sea behaviour and demography, despite lack of information on prey availability. Our results highlight a possible behavioural mechanism through which climate variability may affect population processes.

How Elephant Seals (Mirounga leonina) Adjust Their Fine Scale Horizontal Movement and Diving Behaviour in Relation to Prey Encounter Rate

“…As the movements of free-ranging animals reflect how they interact with their physical and biological environment, spatial patterns in their trajectories provide a basis from which to understand foraging behaviour as well as gain insights on prey distribution and accessibility [6,7]. Recent technological advances in miniaturised electronic devices have enabled the detection of foraging events and the description of diving behaviour over very fine scales.…”

Key Questions in Marine Megafauna Movement Ecology

“…Migration patterns of marine megafauna will likely change to be more poleward with warming [48], although the complex effects of biotic interactions and habitat availability, for example, can lead to counter-intuitive re-distribution patterns in some taxa [49]. Some animals, including pinnipeds and penguins, might be particularly sensitive to large-scale environmental changes when they are tied to land-or ice-based breeding colonies and hence have limited ability to shift their foraging locations [50]. Similarly, the rapid loss of Arctic sea ice might affect the movement patterns of Arctic megafauna, restricting those of animals, such as the polar bear and the walrus using sea ice as a platform, and enhancing ones whose access to the Arctic had been precluded by sea ice.…”

Breeding success of a marine central place forager in the context of climate change: A modeling approach

“…e ., they commute between their breeding (central) colony on land and foraging at sea), are constrained by particular distribution ranges of prey. Therefore, during breeding when they are restricted to a central place foraging strategy, pinnipeds such as otariids and non-flying seabirds should be more impacted by changes in prey distribution [8, 11–16]. Consequently, it is necessary to consider possible alterations in the structure of the prey fields in these environments.…”

“…Consequently, it is necessary to consider possible alterations in the structure of the prey fields in these environments. For instance, within the Southern Oceans, climatic scenarios predict a southward shift of the highly productive Polar Front [17], which separates Subantarctic waters from cold waters of Antarctica, with direct consequences on the foraging and breeding performances of king penguins Aptenodytes patagonicus [8] and other marine top predators [18, 19]. How central place foragers should modify their provisioning/foraging behavior to accommodate changes in prey accessibility in relation to their colony?…”