Plasticity in foraging behaviour and diet buffers effects of inter-annual environmental differences on chick growth and survival in southern rockhopper penguins Eudyptes chrysocome chrysocome

Dehnhard, N., Ludynia, K., Masello, J. F., Voigt, C. C., McGill, R. A.R. and Quillfeldt, P. (2016) Plasticity in foraging behaviour and diet buffers effects of inter-annual environmental differences on chick growth and survival in southern rockhopper penguins Eudyptes chrysocome chrysocome. Polar Biology, 39(9), pp. 1627-1641. (doi: 10.1007/s00300-015-1887-5)

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Abstract

In marine ecosystems, primary productivity and consequently food availability for higher trophic levels are often strongly affected by the water temperature. Thus, differences in sea surface temperatures (SST) may lead to differences in the diet composition of predators, but this link is still unknown in many species. By combining GPS tracking and dive analyses on chick-rearing southern rockhopper penguins (Eudyptes chrysocome chrysocome) with stable isotope analyses and monitoring of chick growth rates and chick survival, we here attempted a comprehensive assessment of the effects of inter-annual environmental variability as indicated by SST and chlorophyll a (reflecting primary productivity) data. Inter-annual differences in environmental variables around our study colony on New Island, Falkland/Malvinas Islands, contradicted the general expectation, with higher chlorophyll a concentrations coinciding with higher spring SST in 2010/2011 compared to 2009/2010. Penguins foraged further away from the colony during guard and crèche in 2010/2011 compared to 2009/2010, while performing deeper dives in 2009/2010. Stable isotope mixing models suggested a crustacean-dominated chick diet in 2009/2010, compared to a mixture of squid and fish in 2010/2011. These differences in foraging behaviour and diet, however, had no consequences for chick growth rates or chick survival and thus had no apparent effect on population trajectories. Potentially, environmental conditions in both years could still be seen as favourable compared to other years and breeding sites, enabling the parental birds to buffer the environmental differences by plastic foraging behaviour.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McGill, Dr Rona
Authors: Dehnhard, N., Ludynia, K., Masello, J. F., Voigt, C. C., McGill, R. A.R., and Quillfeldt, P.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Polar Biology
Publisher:Springer
ISSN:0722-4060
ISSN (Online):1432-2056
Published Online:18 January 2016
Copyright Holders:Copyright © 2016 Springer-Verlag Berlin Heidelberg
First Published:First published in Polar Biology 39(9):1627-1641
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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