Trophic Interactions between Snow Goose and Brant Goose in the Breeding Time with Regard to Their Population Trends

This paper studies the differences in the trophic resource use in the breeding time between the snow goose Anser caerulescens that is the most abundant in the Arctic and the most widespread brant goose Branta bernicla under the conditions of the main part of the snow goose nesting range (Colville River Delta, Alaska). It was found that the diets of these species consist mainly of grasses and shrubs and to a lesser extent of mosses, sedges, horsetails and forbs, having almost no differences in the composition of resource items. It also was found that both species have the highest foraging costs in coastal habitats and the lowest ones have in marsh habitats. Without significant differentiation of trophic niches, the snow goose has significantly lower foraging costs than the brant goose. A probable transformation mechanism of communities including the species based on their trophic interactions was suggested.

Automated summary

In the Colville River Delta of Alaska, the snow goose and brant goose show little difference in trophic resource use during breeding time, but the snow goose has significantly lower foraging costs than the brant goose.