Advancing the Sea Ice Hypothesis: Trophic Interactions Among Breeding Pygoscelis Penguins With Divergent Population Trends Throughout the Western Antarctic Peninsula

• Main Authors: Gorman, Kristen B., Ruck, Kate E., Williams, Tony D., Fraser, William R.
• Format: Text
• Language: unknown
• Published: W&M ScholarWorks 2021
• Subjects: δ13 C and δ15 N stable isotopes; food web; Pygoscelis penguin; reproduction; sea ice; western Antarctica; Biological Sciences Peer-Reviewed Articles; Marine Biology; Antarctic; Antarctic Peninsula; Anvers; Anvers Island; Antarc*; Antarctica; antarcticus; Pygoscelis adeliae; Pygoscelis papua; Sea ice
• Online Access: https://scholarworks.wm.edu/vimsarticles/2214; https://doi.org/10.3389/fmars.2021.526092; https://scholarworks.wm.edu/context/vimsarticles/article/3215/viewcontent/fmars_08_526092.pdf; https://scholarworks.wm.edu/context/vimsarticles/article/3215/filename/0/type/additional/viewcontent/Data_Sheet_1_Advancing_the_Sea_Ice_Hypothesis_Trophic_Interactions_Among_Breeding_Pygoscelis_Penguins_With_Divergent_Population_Trends_Throughout_the.docx

We evaluated annual and regional variation in the dietary niche of Pygoscelis penguins including the sea ice-obligate Adélie penguin (Pygoscelis adeliae), and sea ice-intolerant chinstrap (Pygoscelis antarcticus) and gentoo (Pygoscelis papua) penguins, three species that nest throughout the western Antarctic Peninsula (AP) to test the sea ice trophic interaction hypothesis, which posits that penguin breeding populations with divergent trends, i.e., declining or increasing, are reliant on differing food webs. Our study relies on values of naturally occurring carbon (13C/12C, δ13C) and nitrogen (15N/14N, δ15N) stable isotopes as integrated proxies of penguin food webs measuredover three years at three different breeding colonies. At Anvers Island in the north, where reductions in sea ice and changes in breeding population trends among sympatric sea ice-obligate (Adélie) and sea ice-intolerant (chinstrap and gentoo) penguins have been most notable, our analyses show that all three species of Pygoscelis penguins became more similar isotopically over the reproductive period.