Bakker, J.P., D. Bos, R.H. Drent & M.J.J.E. Loonen, 2003, Rotganzen tussen polder en kwelder., in: De Levende Natuur, 104, 1
- Author : Bakker, J.P., D. Bos, R.H. Drent & M.J.J.E. Loonen
- Year : 2003
- Title English : Geese between polder and salt marsh
- Journal/Series : De Levende Natuur
- Volume Number (ANNUAL: Counting Volumes of the Year shown above) : 1
- Volume Number (CONSECUTIVE: Counting all Volumes of this Journal ever published) : 104
- Pages : 24-29
- Abstract in English : Dark-bellied Brent geese Brenta bernicla bernicla breed in the Arctic. During winter and spring they stay in NW Europe before they leave for the breeding area in the second half of May. Initially they forage on fertilized pastures in polder areas, and stay when livestock grazing takes already place in early spring. When livestock grazing starts in May, the geese switch to adjacent salt marshes. With increasing levels of standing biomass due to primary production, the nutrient intake increases but declines again when levels of biomass become too high. This happens within a season due to declining forage quality caused by maturation, and to changes in sward structure: tillers become too long to be handled by the geese. Over the years, the geese are confronted with a decrease of palatable species due to ongoing succession on the salt marshes. Repeated removal of biomass by herbivores or farmers maintain the sward in a suitable stage, both within a season and over the years. By virtue to this facilitation Brent geese are enabled to utilize highly productive pastures until the end of their spring staging period and livestock-grazed salt marshes in spite of old marsh age. Disturbance of the geese strongly affects habitat use, especially because it allows the vegetation to 'escape' the grazing cycle and prevent it from losing its high quality. We hypothesize that the numbers of Brent geese in the entire Wadden Sea in May can be a factor four higher when all salt marshes are grazed by livestock, than in the absence of grazing.
- Comments/Notes : Further reading: the references contain 6 English titles