MEPS 677:197-208 (2021) - DOI: https://doi.org/10.3354/meps13869
Feeding at the front line: interannual variation in the use of glacier fronts by foraging black-legged kittiwakes
Philip Bertrand1,2,*, Hallvard Strøm2, Joël Bêty1, Harald Steen2, Jack Kohler2, Mikko Vihtakari3, Ward van Pelt4, Nigel Gilles Yoccoz5, Haakon Hop2, Stephanie M. Harris6,7, Samantha C. Patrick7, Philipp Assmy2, Anette Wold2, Pedro Duarte2, Geir Moholdt2, Sébastien Descamps2
ABSTRACT: Tidewater glacier fronts can represent important foraging areas for Arctic predators. Their ecological importance is likely to change in a warmer Arctic. Their profitability and use by consumers are expected to vary in time, but the underlying mechanisms driving such variation remain poorly known. The subglacial plume, originating from meltwater discharge, is responsible for the entrainment and transport of zooplankton to the surface, making them more readily available for surface-feeding seabirds. Both discharge and zooplankton abundance are known to fluctuate in time and are thus expected to modulate the foraging profitability of glacier fronts. This study tested the predictions that annual use of glacier fronts by black-legged kittiwakes Rissa tridactyla is positively related to the average glacier discharge and prey biomass in the fjord. To do this, we combined a multiyear dataset of environmental drivers and GPS tracks of birds in Kongsfjorden, Svalbard. Our results confirmed the interannual variation in the use of glacier fronts by kittiwakes; however, contrary to our predictions, these variations were negatively correlated to both glacier discharge and zooplankton abundance. These apparent negative relationships likely reflect non-linear effects and complex interactions between local and regional environmental factors that affect the relative profitability of glacier fronts as foraging areas. Despite their high spatial predictability, glacier fronts may not offer consistent foraging opportunities for marine predators over time.
KEY WORDS: Tidewater glacier front · Habitat selection · Profitability · Discharge · Zooplankton biomass · Rissa tridactyla · Biologging
Full text in pdf format  Supplementary material | Cite this article as: Bertrand P, Strøm H, Bêty J, Steen H and others (2021) Feeding at the front line: interannual variation in the use of glacier fronts by foraging black-legged kittiwakes. Mar Ecol Prog Ser 677:197-208. https://doi.org/10.3354/meps13869
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