Sea ice predicts long‐term trends in Adélie penguin population growth, but not annual fluctuations: Results from a range‐wide multiscale analysis

Understanding the scales at which environmental variability affects populations is critical for projecting population dynamics and species distributions in rapidly changing environments. Here we used a multilevel Bayesian analysis of range‐wide survey data for Adélie penguins to characterize multide...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Global change biology 2020-07, Vol.26 (7), p.3788-3798
Hauptverfasser: Iles, David T., Lynch, Heather, Ji, Rubao, Barbraud, Christophe, Delord, Karine, Jenouvrier, Stephanie
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Understanding the scales at which environmental variability affects populations is critical for projecting population dynamics and species distributions in rapidly changing environments. Here we used a multilevel Bayesian analysis of range‐wide survey data for Adélie penguins to characterize multidecadal and annual effects of sea ice on population growth. We found that mean sea ice concentration at breeding colonies (i.e., “prevailing” environmental conditions) had robust nonlinear effects on multidecadal population trends and explained over 85% of the variance in mean population growth rates among sites. In contrast, despite considerable year‐to‐year fluctuations in abundance at most breeding colonies, annual sea ice fluctuations often explained less than 10% of the temporal variance in population growth rates. Our study provides an understanding of the spatially and temporally dynamic environmental factors that define the range limits of Adélie penguins, further establishing this iconic marine predator as a true sea ice obligate and providing a firm basis for projection under scenarios of future climate change. Yet, given the weak effects of annual sea ice relative to the large unexplained variance in year‐to‐year growth rates, the ability to generate useful short‐term forecasts of Adélie penguin breeding abundance will be extremely limited. Our approach provides a powerful framework for linking short‐ and longer term population processes to environmental conditions that can be applied to any species, facilitating a richer understanding of ecological predictability and sensitivity to global change. Temporal scales at which sea ice most strongly predicts population growth of ice‐obligate penguins is unresolved. Using Bayesian multilevel analysis, we found that multidecadal population trends of Adélie penguins are strongly predicted by long‐term sea ice concentration at colony locations. Our results are consistent with an intermediate sea ice optimum hypothesis. However, annual fluctuations in population abundance are not predicted by annual sea ice anomalies, potentially limiting the ability to produce useful short‐term forecasts.
ISSN:1354-1013
1365-2486
DOI:10.1111/gcb.15085