Factors driving Adélie penguin chick size, mass and condition at colonies of different sizes in the Southern Ross Sea

Marine Ecology Progress Series

David G. Ainley¹  Amy L. Whitehead¹  Katie M. Dugger¹  Kerry Barton¹  Amelie Lescro#xebl¹  Brian J. Karl¹  Grant Ballard¹  Phil O#x2019B. Lyver¹  Scott Jennings¹  Peter R. Wilson¹ 

关键词: Adélie penguin;    Chick growth;    Diet variability;    Provisioning efficiency;    Intraspecific competition;   

DOI  :  10.3354/meps11130

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Body size, mass and condition can affect an organism’s ability to cope with variation in resource availability or metabolic demand, particularly as juveniles reach independence. It follows that changes to parental provisioning efficiency (size and frequency of meals) through intraspecific competition or environmental conditions that affect prey availability may affect chick size, mass and condition and ultimately post-fledging survival. We examined how Adélie penguin chick size, mass and condition varied among colonies of different sizes on Ross Island during a 15 yr period of high environmental variability and varying intraspecific competition. Aiding the study was a natural experiment in which the presence of 2 giant icebergs midway through the study abnormally increased sea ice concentration (SIC), altering adults’ access to food. Concurrently, the colonies were rapidly increasing in size; based on previous work, this indicated increased trophic competition near colonies, a trend likely indicating a changing food web in the greater region. Results showed that increased amounts of sea ice, which reduced the ability of adults to access food, had a negative effect on the size and mass of chicks. However, a greater proportion of fish (vs. krill) in the diet had a positive effect on chick size. Moreover, in some cases, increased intraspecific competition may be a more important driver of provisioning rate and chick size than abiotic factors, with chicks showing the effects of reduced food delivery at larger colonies. Understanding these patterns will allow better understanding of how factors such as climate change and altered food webs may affect Adélie penguin populations.

【 授权许可】

Unknown