Do penguins share? Evidence of foraging niche segregation between but not within two sympatric, central-place foragers

Marine Ecology Progress Series

M. J. Polito¹  N. G. Rosciano¹  A. Raya Rey¹ 

关键词: Eudyptes chrysocome chrysocome;    Spheniscus magellanicus;    Stable isotopes;    Niche partitioning;    Isla de los Estados;   

DOI  :  10.3354/meps11689

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: Niche theory predicts that sympatric species should differentiate ecologically in order to co-exist and conspecifics will also differentiate to reduce intra-specific competition. As central-place foragers, colonial breeding seabirds represent an ideal model system to test this theory and examine the mechanism of niche segregation. We used GPS-TDlog devices for tracking and diving data and stable isotope analysis to examine patterns of inter- and intra-specific niche segregation among southern rockhopper penguins Eudyptes chrysocome chrysocome and Magellanic penguins Spheniscus magellanicus breeding on Isla de los Estados, Argentina, across 3 consecutive breeding seasons. Tracking data indicated strong inter-specific spatial segregation of foraging locations and little overlap. Diving data also highlighted vertical foraging niche segregation as female rockhopper penguins dove deeper than male and female Magellanic penguins. δ¹³C values supported the general pattern of habitat segregation, with lower values for female rockhopper penguins that dove deeper and foraged off the shelf break. Female rockhopper penguins exhibited a lower relative trophic value (δ¹⁵N) than male and female Magellanic penguins, consistent with previous dietary studies of both species. These differences likely act to reduce competition between the 2 species during the breeding season, when they are constrained to exploit the resources around their colonies. In contrast, male and female Magellanic penguins shared a similar foraging niche as measured by areas used to forage, dive depths, relative habitat use and trophic values. The lack of sex-specific foraging niche segregation of Magellanic penguins at Isla de los Estados could be related to the availability of food in the area and/or the small population size.

【 授权许可】

Unknown