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The influence of diet on foraging habitat models: a case study using nursing Antarctic fur seals

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Casper, RM and Sumner, MD and Hindell, MA and Gales, NJ and Staniland, IJ and Goldsworthy, SD (2010) The influence of diet on foraging habitat models: a case study using nursing Antarctic fur seals. Ecography, 33. pp. 748-759.

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Abstract

Predictable sources of food underpin lifetime reproductive output in long lived animals. The most important foraging
areas of top marine predators are therefore likely to be related to environmental features that enhance productivity in
predictable spatial and temporal patterns. Even so, although productive areas within the marine environment are
distributed patchily in space and time, most studies assess the relationships between feeding activity and proximate, not
long term, environmental characteristics. In addition, individuals within a population may exploit different prey types,
and these are often associated with different hydrographic features. Until now, models attempting to associate core
foraging areas (CFAs) of marine predators with the environmental characteristics of those areas have not considered the
diet of individual animals, despite the influence this could have on these relationships. We used bathymetry and multiyear
(n24) mean sea surface temperature and variability as predictors of CFAs of lactating Antarctic fur seals
Arctocephalus gazella at Heard Island. The effect of prey types on the predictability of these models was explored by
matching diet and foraging trip data of individual seals (n40 seals, n1 trip each). Differences in diet between seals
were mirrored by their spatial behaviour. Foraging strategies differed both between and within groups of seals consuming
different diets. Long-term environmental parameters were useful for predicting the foraging activity of seals that
consumed a single prey type with relatively specific habitat preferences, but not for those that consumed single or
multiple prey types associated with more varied habitats. Ignoring individual variation in predator diet probably
contributes to the poor performance of foraging habitat models. These findings highlight the importance of incorporating
individual specialization in foraging behaviour into ecological models and management of predator populations.

Item Type: Article
Journal or Publication Title: Ecography
Page Range: pp. 748-759
Identification Number - DOI: 10.1111/j.1600-0587.2009.06155.x
Additional Information:

The definitive published version is available online at: http://onlinelibrary.wiley.com/

Date Deposited: 29 Feb 2012 00:55
Last Modified: 18 Nov 2014 04:23
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