Using body mass dynamics to examine long-term habitat shifts of arctic-molting geese: Evidence for ecological change

Polar Biology
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Abstract

From 1976 onward, molting brant geese (Branta bernicla) within the Teshekpuk Lake Special Area, Alaska, shifted from inland, freshwater lakes toward coastal wetlands. Two hypotheses explained this redistribution: (1) ecological change: redistribution of molting brant reflects improvements in coastal foraging habitats, which have undergone a succession toward salt-tolerant plants due to increased coastal erosion and saltwater intrusion as induced by climate change or (2) interspecific competition: greater white-fronted geese (Anser albifrons) populations increased 12-fold at inland lakes, limiting food availability and forcing brant into coastal habitats. Both hypotheses presume that brant redistributions were driven by food availability; thus, body mass dynamics may provide insight into the relevance of these hypotheses. We compared body mass dynamics of molting brant across decades (1978, 1987–1992, 2005–2007) and, during 2005–2007, across habitats (coastal vs. inland). Brant lost body mass during molt in all three decades. At inland habitats, rates of mass loss progressively decreased by decade despite the increased number of greater white-fronted geese. These results do not support an interspecific competition hypothesis, instead suggesting that ecological change enhanced foraging habitats for brant. During 2005–2007, rates of mass loss did not vary by habitat. Thus, while habitats have improved from earlier decades, our results cannot distinguish between ecological changes at inland versus coastal habitats. However, we speculate that coastal forage quality has improved beyond that of inland habitats and that the body mass benefits of these higher quality foods are offset by the disproportionate number of brant now molting coastally.
Publication type Article
Publication Subtype Journal Article
Title Using body mass dynamics to examine long-term habitat shifts of arctic-molting geese: Evidence for ecological change
Series title Polar Biology
DOI 10.1007/s00300-011-1025-y
Volume 34
Issue 11
Year Published 2011
Language English
Publisher Springer
Publisher location Amsterdam, Netherlands
Contributing office(s) Alaska Science Center
Description 12 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Polar Biology
First page 1751
Last page 1762
Country United States
State Alaska
Other Geospatial Teshekpuk Lake Special Area
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