Winter carry-over effects on spring body condition driven by agricultural subsidies to Lesser Snow Geese (Anser caersulscens caerulescens)

Avian Conservation and Ecology
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Abstract

Anthropogenic changes to landscapes associated with intensive agriculture often have deleterious effects on avian abundance. However, some species like the Lesser Snow Goose (Anser caerulescens caerulescens), can benefit from increases in agricultural crops on both wintering and migratory stopover sites. We investigated the influence of winter habitat use on spring body condition in Lesser Snow Goose, a species that has increased in population following expansion into agriculturally based winter habitats. We used stable isotope measurements of four elements (δ2H, δ13C, δ15N, and δ34S) to determine likely prior winter habitat use of snow geese collected during spring migration across Arkansas, Missouri, and Nebraska in 2016. We evaluated differences in body size, lipid, and protein reserves from individuals with isotope values that suggested winter habitat use in traditional coastal marsh and non-coastal /agriculture habitat. Inferred winter habitat influenced total body lipid levels in snow geese collected during spring migration. Adult and juvenile individuals inferred to have overwintered in coastal marsh (n = 60) had, on average, 33.4 g (95% Confidence Interval: 0.4 g, 66.4 g) less lipid than counterparts wintering in non-coastal / agricultural habitat (n = 77). Waterfowl foods found in marshes typically have low true metabolizable energy values as a consequence of their high fiber content, which likely increases daily consumption rates. Increased energy expenditure related to greater time spent foraging, paired with lower energetic rewards, may result in lower lipid reserves among geese using coastal marsh habitats compared to birds using agricultural landscapes. Consequently, carry-over effects based on winter habitat use could explain variation in lipid reserves among individuals during spring migration and may ultimately explain differential fitness rates or susceptibility to harvest. Our results have implications for the conservation and management of this species as historic wetland landscapes become more intensively converted and used for agricultural purposes.

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Publication type Article
Publication Subtype Journal Article
Title Winter carry-over effects on spring body condition driven by agricultural subsidies to Lesser Snow Geese (Anser caersulscens caerulescens)
Series title Avian Conservation and Ecology
DOI 10.5751/ACE-01743-150221
Volume 15
Issue 2
Year Published 2020
Language English
Publisher Resilience Alliance
Contributing office(s) Coop Res Unit Atlanta
Description 21, 11 p.
First page 1
Last page 11
Country United States
State Arkansas, Missouri, Nebraska
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