"Maximizing nutrient and biomass intake by herbivorous geese"
ved
Jens Nyeland Kristiansen
Department of Population Ecology, University of Copenhagen
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Abstract:
The selectivity of Greenland White-fronted Geese Anser albifrons flavirostris feeding on Phleum
pratense (Timothy grass) hayfields in Iceland during their spring staging was studied in three fields of
different shoot density (high: 36.50 shoots/100 cm2, medium: 16.31 shoots/100 cm2 and low: 9.94
shoots/100 cm2) and discussed in connection with optimal foraging. Biomass and protein contents of
the Phleum lamina (leaf) taken by the geese were analysed and correlated to lamina length. In all fields
the geese selected highly for the larger lamina avoiding the smaller. However, in the high density field
the mean size of the selected lamina was significantly smaller (16.20 mm + 0.598 SE) compared with
both the medium density field (21.28 mm + 1.227 SE) and the high density field (23.71 mm + 0.964
SE). Therefore, feeding on the sward of high density shoots must have a cost relative to feeding on
swards of lower density. Because the quality (protein content) of the lamina only decreased slightly
with increasing lamina length, the geese maximised their intake per peck by taking the largest lamina.
Hence, this study suggests that herbivorous geese are capable of optimal foraging on a fine grained
scale.
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Sted:
Torsdag d. 7-10-1999, kl. 15.00 (præcist)
Afdeling for Populationsøkologi
Jagtvejsfløjen, Kollokvierum1, 1.sal
Universitetsparken 15
2100 Kbh.Ø.