Ecological developments in the Wadden Sea until 1990
Wolff, W.J. (1992). Ecological developments in the Wadden Sea until 1990, in: Dankers, N.M.J.A. et al. Present and future conservation of the Wadden Sea: Proceedings of the 7th International Wadden Sea Symposium, Ameland 1990. Publication Series. Netherlands Institute for Sea Research (NIOZ), 20: pp. 23-32
In: Dankers, N.M.J.A.; Smit, C.J.; Scholl, M. (Ed.) (1992). Present and future conservation of the Wadden Sea: Proceedings of the 7th International Wadden Sea Symposium, Ameland 1990. Publication Series. Netherlands Institute for Sea Research (NIOZ), 20. Netherlands Institute for Sea Research (NIOZ): Texel. VIII, 301 pp., meer
In: Publication Series. Netherlands Institute for Sea Research (NIOZ). NIOZ: Den Burg. ISSN 0923-330X, meer
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Documenttype: Congresbijdrage
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| Abstract |
The Wadden Sea along the coasts of the Netherlands, Germany, and Denmark has been subject to natural and man-induced changes. The major natural processes are considered to be: 1) coastal development resulting from sea-level rise on the one hand and filling in of the tidal basins by sedimentation on the other hand, and: 2) biogeographical processes resulting in the establishment and extinction of species. The most important change in the Wadden Sea landscape has been the embankment and reclamation of the coastal marshes and peat moors along this shallow estuarine area. This process was started in the Middle Ages and has continued to the present day. It has resulted in profound geomorphological, physical, chemical and biotic changes. Biotic changes have resulted from the exploitation of living resources, changes in habitat, the introduction of new species, and pollution. Several species of large mammals, birds and fish have decreased in number or become extinct due to exploitation. The introduction of new species mainly involves algae and invertebrates. Habitat change, for instance the creation of artificial rocky shores along the dike slopes, resulted in the colonisation of these habitats by several species originating from neighbouring regions. Pollution has had profound effects on the population size of a number of marine mammals and coastal birds. It also affects the condition of fish. Conservation measures have been quite successful when local reserves succeeded in counteracting the effects of exploitation and disturbance, for instance in the case of breeding colonies of sea birds. The present preservation of nearly the entire Wadden Sea has not shown any clearcut positive results so far, although it may have inhibited further degradation. The main reason appears to be that, at present, the threats to the Wadden Sea ecosystem are no longer of a local nature but reflect environmental degradation on a European or even a worldwide scale. |
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