title: Forage digestibility and intake by lesser snow geese: effects of dominance and resource heterogeneity.
abstract: We measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted lesser snow geese (Chen caerulescens caerulescens) as they consumed underground stembases of tall cotton-grass (Eriophorum angustifolium) on an arctic staging area in northeastern Alaska. Geese fed in small patches ([Formula: see text]=21.5 m2) of forage that made up ≤3% of the study area and consisted of high-quality "aquatic graminoid" and intermediate-quality "wet sedge" vegetation types. Dominant geese spent more time feeding in aquatic graminoid areas (r=0.61), but less total time feeding and more time resting than subdominant geese. Subdominant geese were displaced to areas of wet sedge where cotton-grass was a smaller proportion of underground biomass. Geese metabolized an average of 48% of the organic matter in stembases and there was a positive correlation between dominance and organic matter metabolizability (r=0.61). Total mean retention time of forage was 1.37 h and dry matter intake was 14.3 g/h. Snow geese that stage on the coastal plain of the Beaufort Sea likely use an extensive area because they consume a large mass of forage and exploit habitats that are patchily distributed and make up a small percentage of the landscape. Individual variation in nutrient absorption may result from agonistic interactions in an environment where resources are heterogeneously distributed.
authors.affiliation: Alaska Science Center, National Biological Service, 1011 E. Tudor Road, 99503, Anchorage, AK, USA.
authors.forename: Jerry W
authors.initials: JW
authors.lastname: Hupp
authors.affiliation: Institute of Arctic Biology, University of Alaska Fairbanks, 99775, Fairbanks, AK, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: White
authors.affiliation: Institute of Arctic Biology, University of Alaska Fairbanks, 99775, Fairbanks, AK, USA.
authors.forename: James S
authors.initials: JS
authors.lastname: Sedinger
authors.affiliation: Alaska Science Center, National Biological Service, 1011 E. Tudor Road, 99503, Anchorage, AK, USA.
authors.forename: Donna G
authors.initials: DG
authors.lastname: Robertson
keywords: Alaska; Arctic ecosystems; Chen caerulescens caerulescens; Dominance; Forage intake