Shifting Effects of Ocean Conditions on Survival and Breeding Probability of a Long-Lived Seabird

PLoS One. 2015 Jul 13;10(7):e0132372. doi: 10.1371/journal.pone.0132372. eCollection 2015.

Abstract

With a rapidly changing climate, there is an increasing need to predict how species will respond to changes in the physical environment. One approach is to use historic data to estimate the past influence of environmental variation on important demographic parameters and then use these relationships to project the abundance of a population or species under future climate scenarios. However, as novel climate conditions emerge, novel species responses may also appear. In some systems, environmental conditions beyond the range of those observed during the course of most long-term ecological studies are already evident. Yet little attention has been given to how these novel conditions may be influencing previously established environment-species relationships. Here, we model the relationships between ocean conditions and the demography of a long-lived seabird, Brandt's cormorant (Phalacrocorax penicillatusI), in central California and show that these relationships have changed in recent years. Beginning in 2007/2008, the response of Brandt's cormorant, an upper trophic level predator, to ocean conditions shifted, resulting in lower than predicted survival and breeding probability. Survival was generally less variable than breeding probability and was initially best predicted by the basin-scale forcing of the El Niño Southern Oscillation rather than local ocean conditions. The shifting response of Brandt's cormorant to ocean conditions may be just a proximate indication of altered dynamics in the food web and that important forage fish are not responding to the physical ocean environment as expected. These changing relationships have important implications for our ability to project the effects of future climate change for species and communities.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Birds / physiology*
  • California
  • Climate Change
  • Demography
  • Pacific Ocean
  • Reproduction

Grants and funding

AES was supported by a National Science Foundation Graduate Research Fellowship (grant No. 1148897), a University of California, Davis, Graduate Group in Ecology fellowship, a Jastro Shields research fellowship, and a grant from the Selma Herr Fund for Ornithological Research. No other authors received specific funding for this work. The continued operation of Point Blue’s Farallon Research Program is supported by the Baker Trust, Marisla Foundation, Campini Foundation, Kimball Foundation, Mead Foundation, and individual donors. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.