Habitat utilization of a mesopredator linked to lower sea-surface temperatures & prey abundance in a region of rapid warming

Rhian Evans*, Mark Hindell, Akiko Kato, Lachlan R. Phillips, Yan Ropert-Coudert, Simon Wotherspoon, Mary-Anne Lea

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Central place foragers rely on areas within a small range of their breeding grounds for chick provisioning. Therefore there exists a tight coupling between their breeding success and local bio-physical conditions. The effects of fine-scale variability in environmental parameters and resource distribution on the foraging behaviour of marine predators is studied in a region of rapid environmental change. Here we use little penguin habitat preference during two years of varying environmental conditions, to investigate the interactions between environmental variables, resource distribution and penguin habitat preference. Penguins were tagged with GPS devices during a marine heatwave event in 2016 and again in 2018 during comparatively cooler conditions. We found the distribution of penguins to be highly correlated with a fine-scale horizontal SST gradient feature, which appeared on the shelf in 2016 as a result of tropical water from the East Australian Current (EAC) interacting with cooler temperate water from southern Tasmania. Spatially, warmer SST anomalies corresponded to a lower probability of little penguins utilizing an area in both years. This was despite the much more uniform SSTs which were present during 2018. By modelling little penguin habitat preferences using two biological predictors, zooplankton community abundance as an indication of general resource distribution, and krill abundance - a prey species of little penguins - we show habitat preference to be only slightly more strongly driven by prey type, than by general resource distribution. The correlation between little penguin habitat preference and both zooplankton and krill abundance could indicate a plasticity in foraging behaviour which might be beneficial if lower-trophic level structure continues to change due to warming. In light of the continued warming predicted for this region, and the preference shown for cooler SSTs, this plasticity might be important under future resource climates.

Original languageEnglish
Article number104634
Pages (from-to)1-11
Number of pages11
JournalDeep-Sea Research Part II: Topical Studies in Oceanography
Volume175
DOIs
Publication statusPublished - May 2020

Keywords

  • Climate change
  • Marine predators
  • Prey-field dynamics
  • Species distribution models
  • Telemetry

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