Using Videography to Quantify Landscape-Level Availability of Habitat for Grazers: An Example with Emperor Geese in Western Alaska
ABSTRACT. We present a videography approach to estimating large-scale availability of grazing lawns, an important food resource used by broods of emperor geese (Chen canagica) on the Yukon-Kuskokwim Delta, Alaska. Sampling was conducted in 1999, 2003, and 2004 at six locations that encompassed ~40 %...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2005
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.494.7394 http://pubs.aina.ucalgary.ca/arctic/arctic59-3-252.pdf |
| Summary: | ABSTRACT. We present a videography approach to estimating large-scale availability of grazing lawns, an important food resource used by broods of emperor geese (Chen canagica) on the Yukon-Kuskokwim Delta, Alaska. Sampling was conducted in 1999, 2003, and 2004 at six locations that encompassed ~40 % of the North American population of breeding emperor geese. We conducted ground truthing in 2003 and 2004 to estimate how accurately grazing lawn was classified. Overall, classification accuracy for grazing lawn and non-grazing lawn habitat was greater than 91%. Availability of grazing lawns was stable among years, but varied both among and within locations. Some locations have up to three times as much available grazing lawn, which in combination with densities of geese, likely represents dramatic variation in per capita food availability. Our results suggest that videography is a useful way to sample quickly across a large region and accurately identify fine-scale habitats. We present its use for estimating the availability of a preferred food resource for emperor geese, but the method could be applied to many other cases. Key words: Alaska, Carex, emperor goose, Chen canagica, grazing lawn, Yukon-Kuskokwim Delta, videography RÉSUMÉ. Nous présentons une méthode vidéographique pour évaluer, à grande échelle, la disponibilité des pâturages, une importante ressource alimentaire pour les couvées d’oies empereurs (Chen canagica) du delta Yukon-Kuskokwim, en Alaska. Des échantillonnages ont été effectués en 1999, 2003 et 2004 à six emplacements visant environ 40 % de la population nord-américaine d’oies empereurs nicheuses. Nous avons réalisé des vérifications au sol en 2003 et en 2004 dans le but d’estimer dans quelle mesure les pâturages étaient bien classés. Dans l’ensemble, l’exactitude du classement des habitats destinés au pâturage et de ceux qui |
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