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

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journal contribution
posted on 2023-05-21, 01:15 authored by Sophia VolzkeSophia Volzke, Clive McMahonClive McMahon, Mark HindellMark Hindell, Burton, HR, Wotherspoon, SJ

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.

History

Publication title

Ecology and Evolution

Volume

11

Issue

16

Pagination

11333-11344

ISSN

2045-7758

Department/School

Institute for Marine and Antarctic Studies

Publisher

John Wiley & Sons Ltd

Place of publication

United Kingdom

Rights 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, (https://creativecommons.org/licenses/by/4.0/) which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Repository Status

  • Open

Socio-economic Objectives

Assessment and management of Antarctic and Southern Ocean ecosystems; Biodiversity in Antarctic and Southern Ocean environments; Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)