| 1. |
- Arzel, Céline, et al.
(author)
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Average mass of seeds encountered by foraging dabbling ducks in western Europe
- 2007
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In: Wildlife Biology. - 0909-6396 .- 1903-220X. - 0909-6396 ; 13:3, s. 328-336
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Journal article (peer-reviewed)abstract
- Many dabbling ducks Anas spp. are largely granivorous, consuming a variety of seeds chiefly from aquatic plants. To assess the relative value and carrying capacity of wetlands for dabbling ducks, species-specific information about seed mass is needed, but it is still largely missing or scattered in the literature. By combining weights of seeds collected in the field with a literature review, we provide a reference table for seed mass of 200 western European plant taxa frequently encountered by foraging dabbling ducks. Seeds collected in the field were sampled in microhabitats and at depths at which ducks were observed to forage, and study sites represent wintering, staging as well as breeding areas within a flyway in western Europe. When combined with calorimetric data, the present reference table will aid managers and scientists in assessing the importance of seed food resources at different sites and during different parts of the annual cycle.
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| 2. |
- Arzel, Céline, et al.
(author)
-
Average mass of seeds encountered by foraging dabbling ducks in western Europe
- 2007
-
In: Wildlife Biology. - : Nordic Council for Wildlife Research. - 0909-6396. ; 13:3, s. 328-336
-
Journal article (peer-reviewed)abstract
- Many dabbling ducks Anas spp. are largely granivorous, consuming a variety of seeds chiefly from aquatic plants. To assess the relative value and carrying capacity of wetlands for dabbling ducks, species-specific information about seed mass is needed, but it is still largely missing or scattered in the literature. By combining weights of seeds collected in the field with a literature review, we provide a reference table for seed mass of 200 western European plant taxa frequently encountered by foraging dabbling ducks. Seeds collected in the field were sampled in microhabitats and at depths at which ducks were observed to forage, and study sites represent wintering, staging as well as breeding areas within a flyway in western Europe. When combined with calorimetric data, the present reference table will aid managers and scientists in assessing the importance of seed food resources at different sites and during different parts of the annual cycle.
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| 3. |
- Nilsson, Leif, et al.
(author)
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France as a staging and wintering area for Greylag Geese Anser anser.
- 2013
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In: Wildfowl. - 0954-6324. ; 63, s. 24-39
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Journal article (peer-reviewed)abstract
- France is traditionally a staging area for Greylag Geese Anser anser migrating fromnorthwest Europe to wintering sites in Spain, though increasing numbers havewintered in France over the last three decades. This paper considers sightings withinFrance of neck-banded individuals marked elsewhere in Europe since the 1980s, todetermine the origin of Greylag Geese staging and now wintering in the country. The geese included in this study were all caught in summer during the annual moult, either as family groups or in non-breeding flocks. Most sightings of neck-banded geese were from western France, and most birds identified were from breeding areas in the Nordic countries or to a lesser extent in the Netherlands. The Lac du Der area in northeast France was found to be a wintering area for an introduced population of Greylags established southwest of Stockholm in Sweden, and the geese wintering on the Camargue in southern France were recruited mainly from central Europe. Numbers wintering in France have increased in line with the general increase in the European Greylag Goose population, whereas numbers on passage in France have not increased in the same way, possibly due to a northward shift in the winter distribution of Greylags across Europe. The numbers wintering in France are, however, still small compared to other areas along the flyway.
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| 4. |
- Ramo, Cristina, et al.
(author)
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Latitudinal-Related Variation in Wintering Population Trends of Greylag Geese (Anser Anser) along the Atlantic Flyway: A Response to Climate Change?
- 2015
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:10
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Journal article (peer-reviewed)abstract
- The unusually high quality of census data for large waterbirds in Europe facilitates the study of how population change varies across a broad geographical range and relates to global change. The wintering population of the greylag goose Anser anser in the Atlantic flyway spanning between Sweden and Spain has increased from 120 000 to 610 000 individuals over the past three decades, and expanded its wintering range northwards. Although population sizes recorded in January have increased in all seven countries in the wintering range, we found a pronounced northwards latitudinal effect in which the rate of increase is higher at greater latitudes, causing a constant shift in the centre of gravity for the spatial distribution of wintering geese. Local winter temperatures have a strong influence on goose numbers but in a manner that is also dependent on latitude, with the partial effect of temperature (while controlling for the increasing population trend between years) being negative at the south end and positive at the north end of the flyway. Contrary to assumptions in the literature, the expansion of crops exploited by greylag geese has made little contribution to the increases in population size. Only in one case (expansion of winter cereals in Denmark) did we find evidence of an effect of changing land use. The expanding and shifting greylag population is likely to have increasing impacts on habitats in northern Europe during the course of this century.
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