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Decadal changes in habitat characteristics influence population trajectories of southern elephant seals


Hindell, MA and Sumner, M and Bestley, S and Wotherspoon, S and Harcourt, RG and Lea, MA and Alderman, R and McMahon, CR, Decadal changes in habitat characteristics influence population trajectories of southern elephant seals, Global Change Biology, 23, (12) pp. 5136-5150. ISSN 1354-1013 (2017) [Refereed Article]

Copyright Statement

Copyright 2017 John Wiley & Sons Ltd.

DOI: doi:10.1111/gcb.13776


Understanding divergent biological responses to climate change is important for predicting ecosystem level consequences. We use species habitat models to predict the winter foraging habitats of female southern elephant seals and investigate how changes in environmental variables within these habitats may be related to observed decreases in the Macquarie Island population. There were three main groups of seals that specialized in different ocean realms (the sub-Antarctic, the Ross Sea and the Victoria Land Coast). The physical and climate attributes (e.g. wind strength, sea surface height, ocean current strength) varied amongst the realms and also displayed different temporal trends over the last two to four decades. Most notably, sea ice extent increased on average in the Victoria Land realm while it decreased overall in the Ross Sea realm. Using a species distribution model relating mean residence times (time spent in each 50 x 50 km grid cell) to 9 climate and physical co-variates, we developed spatial predictions of residence time to identify the core regions used by the seals across the Southern Ocean from 120E to 120W. Population size at Macquarie Island was negatively correlated with ice concentration within the core habitat of seals using the Victoria Land Coast and the Ross Sea. Sea ice extent and concentration is predicted to continue to change in the Southern Ocean, having unknown consequences for the biota of the region. The proportion of Macquarie Island females (40%) utilizing the relatively stable sub-Antarctic region, may buffer this population against longer-term regional changes in habitat quality, but the Macquarie Island population has persistently decreased (-1.45% per annum) over seven decades indicating that environmental changes in the Antarctic are acting on the remaining 60% of the population to impose a long-term population decline in a top Southern Ocean predator.

Item Details

Item Type:Refereed Article
Keywords:bio-telemetry, climate change, environmental variability, integrated marine observing system, Macquarie Island, population trends, species distribution models
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Biodiversity in Antarctic and Southern Ocean environments
UTAS Author:Hindell, MA (Professor Mark Hindell)
UTAS Author:Sumner, M (Mr Michael Sumner)
UTAS Author:Bestley, S (Dr Sophie Bestley)
UTAS Author:Wotherspoon, S (Dr Simon Wotherspoon)
UTAS Author:Lea, MA (Professor Mary-Anne Lea)
UTAS Author:McMahon, CR (Dr Clive McMahon)
ID Code:120051
Year Published:2017
Web of Science® Times Cited:28
Deposited By:Ecology and Biodiversity
Deposited On:2017-08-09
Last Modified:2022-07-01

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