Citation: Layton-Matthews, K., K. E. Erikstad, H. Sandvik, M. Ballesteros, K. Hodges, M. d. S. Mesquita, T. K. Reiertsen, N. G. Yoccoz, and J. O. Bustnes (2024) Path analysis reveals combined winter climate and pollution effects on the survival of a marine top predator. Journal of Animal Ecology, 93, 1351–1364. https://doi.org/10.1111/1365-2656.14159
Key words: Adult survival, Bayesian inference, capture–mark–recapture, climate change, Larus marinus, persistent organic pollutants.
Abstract:
1. Marine ecosystems are experiencing growing pressure from multiple threats
caused by human activities, with far-reaching consequences for marine food webs.
Determining the effects of multiple stressors is complex, in part, as they can affect
different aspects of biological organisation (behaviour, individual traits and
demographic rates). Determining the combined effects of stressors, through different
biological pathways, is key to predict the consequences for the viability of populations
threatened by global change.
2. Due to their position in the food chain, top predators such as seabirds
are considered more sensitive to environmental changes. Climate change is affecting
the prey resources available for seabirds, through bottom-up effects, while organic pollutants
can bioaccumulate in food chains with the greatest impacts on top predators. However,
knowledge of their combined effects on population dynamics is scarce.
3. Using a path analysis, we quantify the effects of climate change and pollution
on the survival of adult great black-backed gulls, both directly and through effects of
individuals’ body mass.
4. Warmer ocean temperatures in gulls’ winter foraging areas in the North Sea
were correlated with higher survival, potentially explained by shifts in prey availability
associated with global climate change. We also found support for indirect negative effects
of organochlorines, highly toxic pollutants to seabirds, on survival, which acted, in part,
through a negative effect on body mass.
5. The results from this path analysis highlight how, even for such long-lived species
where variance in survival tends to be limited, two stressors still have had a marked influence
on adult survival and illustrate the potential of path models to improve predictions of
population variability under multiple stressors.
Full text: © 2024 the authors. If you accept (i) the conditions specified in the Creative Commons "Attribution-NonCommercial-NoDerivatives" 4.0 licence, and (ii) that printouts have to be made on recycled paper, you may download the article here (pdf, 4.8 MB).
Supplementary material: Supporting Information S1–S4 may be downloaded here (docx, 0.9 MB).