Ardea
Official journal of the Netherlands Ornithologists' Union

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van Eerden M.R., Lenselink G. & Zijlstra M. (2010) Long-term changes in wetland area and composition in The Netherlands affecting the carrying capacity for wintering waterbirds. ARDEA 98 (3): 265-282
In The Netherlands, arising in geological time as the delta of the rivers Rhine, Meuse and Scheldt, a considerable change in landscape occurred during the Holocene period due to sea level rise. In more recent times this change was dramatically enforced by human actions. This started with the opening up of the large woods on higher soils, some 4500 years BP. It is estimated that the country was only populated then by a few thousand people. During the next 2000 years, the extensive forest clearing continued, and up to approximately 60% of the upland area changed into grazed woodland. Over-exploitation during the Middle Ages resulted in extended heathlands, which covered up to 40% of the total area of upland sands by 1500 AD. Today woodlands cover only 1 promille of the surface area it covered 7000 years ago. Wetlands remained undisturbed for a long period, but they have become seriously affected since the late Middle Ages; the con¬struction of dikes, embankments and drainage have caused the area of wetlands to shrink dramatically. Especially when in the 19th and 20th centu¬ries, as a result of the introduction of steam and later diesel and electric engines, large-scale pro¬jects could be reali¬sed. This led to the disappea¬rance of many freshwater lakes and the almost complete loss of the area of brac-kish water, the natural link be¬tween sea water and fresh¬water. Although the influen¬ce of Man upon the Dutch landscape commenced some 4500 years ago, it is only during the last 600 years that wetlands have been affected. Particularly the last 100 years have been crucial with respect to drainage and cultivation. By reconstructing ancient landscapes, an attempt has been made to describe the species compositi¬on and numerical abundance of water birds, starting 7000 years BP. Two species have become extinct in the territory, many others show changes in abundance. The start of agriculture has caused a major change in the food provisioning of many herbivorous waterbirds. Over the last 7000 years, a sevenfold increase of the number of herbivorous waterfowl is estimated. On the other hand the number of fish-eaters, benthos-eaters and planktivorous waterbirds has declined, their available habitat now having diminished by 45%, 36% and 55% respectively with respect to the Late Subatlantic period, c. 850–1350 AD.


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