Body mass of prefledging Emperor Geese Chen canagica: Large-scale effects of interspecific densities and food availability

Ibis
By: , and 

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Abstract

We studied body mass of prefledging Emperor Geese Chen canagica at three locations across the Yukon–Kuskokwim Delta, Alaska, during 1990–2004 to investigate whether large‐scale variation in body mass was related to interspecific competition for food. From 1990 to 2004, densities of Cackling Geese Branta hutchinsii minima more than doubled and were c. 2–5× greater than densities of Emperor Geese, which were relatively constant over time. Body mass of prefledging Emperor Geese was strongly related (negatively) to interspecific densities of geese (combined density of Cackling and Emperor Geese) and positively related to measures of food availability (grazing lawn extent and net above‐ground primary productivity (NAPP)). Grazing by geese resulted in consumption of ≥ 90% of the NAPP that occurred in grazing lawns during the brood‐rearing period, suggesting that density‐dependent interspecific competition was from exploitation of common food resources. Efforts to increase the population size of Emperor Geese would benefit from considering competitive interactions among goose species and with forage plants.

Publication type Article
Publication Subtype Journal Article
Title Body mass of prefledging Emperor Geese Chen canagica: Large-scale effects of interspecific densities and food availability
Series title Ibis
DOI 10.1111/j.1474-919X.2008.00814.x
Volume 150
Issue 3
Year Published 2008
Language English
Publisher Wiley
Contributing office(s) Alaska Science Center
Description 14 p.
First page 527
Last page 540
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