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Climate influences on female survival in a declining population of southern elephant seals (Mirounga leonina)


Volzke, S and McMahon, CR and Hindell, MA and Burton, HR and Wotherspoon, SJ, Climate influences on female survival in a declining population of southern elephant seals (Mirounga leonina), Ecology and Evolution, 11, (16) pp. 11333-11344. ISSN 2045-7758 (2021) [Refereed Article]

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Copyright Statement

© 2021 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, ( which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

DOI: doi:10.1002/ece3.7919


The Southern Ocean has been disproportionately affected by climate change and is therefore an ideal place to study the influence of changing environmental conditions on ecosystems. Changes in the demography of predator populations are indicators of broader shifts in food web structure, but long-term data are required to study these effects. Southern elephant seals (Mirounga leonina) from Macquarie Island have consistently decreased in population size while all other major populations across the Southern Ocean have recently stabilized or are increasing. Two long-term mark-recapture studies (1956–1967 and 1993–2009) have monitored this population, which provides an opportunity to investigate demographic performance over a range of climatic conditions. Using a 9-state matrix population model, we estimated climate influences on female survival by incorporating two major climatic indices into our model: The Southern Annular Mode (SAM) and the Southern Oscillation Index (SOI). Our best model included a 1 year lagged effect of SAM and an unlagged SOI as covariates. A positive relationship with SAM1 (lagged) related the previous year's SAM with juvenile survival, potentially due to changes in local prey availability surrounding Macquarie Island. The unlagged SOI had a negative effect on both juvenile and adult seals, indicating that sea ice dynamics and access to foraging grounds on the East Antarctic continental shelf could explain the different contributions of ENSO events on the survival of females in this population.

Item Details

Item Type:Refereed Article
Keywords:ecology, demographic modelling, climate influence, southern elephant seal, female survival, Southern Annular Mode, Southern Oscillation Index, capture-mark- recapture studies, demographics, ecological modeling, El Niño Southern Oscillation
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Population ecology
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Biodiversity in Antarctic and Southern Ocean environments
UTAS Author:Volzke, S (Miss Sophia Volzke)
UTAS Author:McMahon, CR (Dr Clive McMahon)
UTAS Author:Hindell, MA (Professor Mark Hindell)
UTAS Author:Wotherspoon, SJ (Dr Simon Wotherspoon)
ID Code:145661
Year Published:2021
Web of Science® Times Cited:2
Deposited By:Directorate
Deposited On:2021-07-29
Last Modified:2021-11-22
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