Historical seabird population dynamics and their effects on Arctic pond ecosystems: a multi-proxy paleolimnological study from Cape Vera, Devon Island, Arctic Canada

Abstract

Rapid environmental changes occurring in polar regions may pose a signifi cant threat to the ~10 mil- lion seabirds currently inhabiting the Canadian Arctic. However, a paucity of long-term data on seabird population dynamics makes effective management diffi cult. As top predators in the oceanic pelagic foodweb, seabirds provide marine-derived nutrients to freshwater habitats via their guano, causing trophic cascades that may be tracked using paleolimnological techniques. Diatoms (Bacillariophyceae) are the most commonly used bioindicators in paleolim- nological studies and, because they are known to respond sensitively to changes in trophic status, may be effective proxies for tracking changes in seabird population dynamics. Here, we present diatom data obtained from sediment cores in seabird-affected ponds near Cape Vera, Devon Island, High Arctic Canada. We also report on additional sedimentary proxies that can be used to track seabird infl uence, namely stable isotopes of nitrogen (δ 15 N) and