Data from: Variable sea-ice conditions influence trophic dynamics in an Arctic community of marine top predators

Sea‐ice coverage is a key abiotic driver of annual environmental
conditions in Arctic marine ecosystems and could be a major factor
affecting seabird trophic dynamics. Using stable isotope ratios of carbon
(δ13C) and nitrogen (δ15N) in eggs of thick‐billed murres (Uria lomvia),
northern fulmars (Fulmarus glacialis), glaucous gulls (Larus hyperboreus),
and black‐legged kittiwakes (Rissa tridactyla), we investigated the
trophic ecology of prebreeding seabirds nesting at Prince Leopold Island,
Nunavut, and its relationship with sea‐ice conditions. The seabird
community of Prince Leopold Island had a broader isotopic niche during
lower sea‐ice conditions, thus having a more divergent diet, while the
opposite was observed during years with more extensive sea‐ice conditions.
Species' trophic position was influenced by sea ice; in years of
lower sea‐ice concentration, gulls and kittiwakes foraged at higher
trophic levels while the opposite was observed for murres and fulmars. For
murres and fulmars over a longer time series, there was no evidence of the
effect of sea‐ice concentration on species' isotopic niche. Results
suggest a high degree of adaptation in populations of high Arctic species
that cope with harsh and unpredictable conditions. Such different
responses of the community isotopic niche also show that the effect of
variable sea‐ice conditions, despite being subtle at the species level,
might have larger implications when considering the trophic ecology of the
larger seabird community. Species‐specific responses in foraging patterns,
in particular trophic position in relation to sea ice, are critical to
understanding effects of ecosystem change predicted for a changing
climate.