Ecological determinants of avian distribution and abundance at Rankin Inlet, Nunavut in the Canadian Arctic

Large areas of the Arctic remain poorly surveyed, creating biological knowledge gaps as scientists and managers grapple with issues of increasing resource extraction and climate change. We modelled spatiotemporal patterns in abundance for avian species in the low Arctic ecosystem near the community of Rankin Inlet, Nunavut, from 2015 to 2017. We employed six habitat covariates, including terrain ruggedness and freshwater cover, and contrasted the influence of elevation with distance from coast, as well as the normalized difference vegetation index (NDVI; a proxy for vegetative productivity) with the normalized difference water index (NDWI; a proxy for vegetation water content). Our results most clearly show the importance of low elevation, large amounts of freshwater and high vegetative productivity for Arctic birds at relatively local scales (<1 km2). Although NDVI more consistently appeared in competitive models of abundance, NDWI was particularly important in predicting abundance for shorebirds, ducks, Tundra Swans (Cygnus columbianus) and Lapland Longspurs (Calcarius lapponicus), demonstrating that it may be a more influential habitat covariate than NDVI for species that frequent habitats with wet vegetation. We also documented apparent shifts in habitat between early and late summer for geese, which were more strongly associated with freshwater later in the season, likely due to the presence of flightless juveniles and moulting adults at that time. Our study illustrates a relatively easy to implement survey methodology for avian species, provides baseline information for an Arctic study area that had not previously been surveyed intensively, and includes species that are underrepresented in previous literature.