The rivers Rhine and Meuse in The Netherlands: present state and signs of ecological recovery |
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Authors: | W Admiraal G van der Velde H Smit W G Cazemier |
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Institution: | (1) National Institute of Public Health and Environmental Protection, P.O. Box 1, 3720 Bilthoven, BA, The Netherlands;(2) Laboratory of Aquatic Ecology, Catholic University of Nijmegen, Toernooiveld, 6525 Nijmegen, ED, The Netherlands;(3) Institute for Inland Water Management and Waste Water Treatment, P.O. Box 17, 8200 Lelystad, AA, The Netherlands;(4) Netherlands Institute for Fisheries Research, P.O. Box 68, 1970 IJmuiden, AB, The Netherlands |
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Abstract: | The ecosystems of the rivers Rhine and Meuse have suffered drastic environmental changes, for example because of the regulation
of the stream bed and the construction of weirs and dams. Furthermore, discharges of industrial and municipal waste water
have caused the water quality of these rivers to deteriorate; this problem became acute in the sixties and seventies. Recently
some chemical parameters of water quality have improved in the Rhine, and as a consequence some aquatic communities are showing
signs of recovery after decades of severe degradation. This paper describes the present state of the aquatic communities in
the Dutch part of the rivers Rhine and Meuse, using published observations on plankton, macrophytes, invertebrates, and fish.
The sparse information on the food chain in these rivers is summarized. The main channels of the Rhine and Meuse are characterized
by a dense plankton that develops rapidly in the nutrient-rich river waters. The stream beds, now dominated by wave-exposed
sand and gravel, have a sparse fauna and flora. The river banks, mostly consolidated by blocks of stone, offer a substratum
for numerous benthic organisms, particularly now that the water quality has improved. The floodplain waters and old river
channels harbour a flora and fauna rich in species. The degree of water exchange with the river is crucial for the ecological
development of the river and its backwaters. Today the freshwater tidal reaches of the rivers occupy a very restricted area,
and only remnants of the previously abundant vegetation of rushes are found.
Losses in the numbers of animal and plant species, notably those specific to rivers, are evident, but over the last 15 years
several species have returned. Allochthonous species (exotics), including crustaceans and molluscs, have also settled in the
Rhine and Meuse. Fish species characteristic of these rivers, such as river lamprey, sea trout, barbel, and flounder, have
recently been observed in appreciable numbers.
The Rhine Action Programme provides a framework for the large-scale rehabilitation of the Rhine. Experiments on re-stocking
the Rhine with Atlantic salmon and on the ecological rehabilitation of floodplains are being carried out on the assumption
that there will be a further reduction of the pollution load. A similar programme is required for the Meuse. |
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Keywords: | River Rhine River Meuse river ecosystems ecological rehabilitation pollution abatement |
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