INVESTIGADORES
RAYA REY Andrea Nelida
artículos
Título:
Do penguins share? Evidence of foraging niche segregation between but not within two sympatric, central-place foragers
Autor/es:
N ROSCIANO; M POLITO; A RAYA REY
Revista:
MARINE ECOLOGY PROGRESS SERIES
Editorial:
INTER-RESEARCH
Referencias:
Lugar: Oldendorf/Luhe; Año: 2016 p. 249 - 262
ISSN:
0171-8630
Resumen:
Niche theory predicts that sympatric species should differentiate ecologically inorder to co-exist and conspecifics will also differentiate to reduce intra-specific competition. Ascentral-place foragers, colonial breeding seabirds represent an ideal model system to test this theoryand examine the mechanism of niche segregation. We used GPS-TDlog devices for trackingand diving data and stable isotope analysis to examine patterns of inter- and intra-specific nichesegregation among southern rockhopper penguins Eudyptes chrysocome chrysocome and Magellanicpenguins Spheniscus magellanicus breeding on Isla de los Estados, Argentina, across 3 consecutivebreeding seasons. Tracking data indicated strong inter-specific spatial segregation of foraginglocations and little overlap. Diving data also highlighted vertical foraging niche segregationas female rockhopper penguins dove deeper than male and female Magellanic penguins. δ13Cvalues supported the general pattern of habitat segregation, with lower values for female rockhopperpenguins that dove deeper and foraged off the shelf break. Female rockhopper penguinsexhibited 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 reducecompetition between the 2 species during the breeding season, when they are constrained toexploit the resources around their colonies. In contrast, male and female Magellanic penguinsshared a similar foraging niche as measured by areas used to forage, dive depths, relative habitatuse and trophic values. The lack of sex-specific foraging niche segregation of Magellanicpenguins at Isla de los Estados could be related to the availability of food in the area and/or thesmall population size.
