ebook img

Netherlands-Wetlands: Proceedings of a Symposium held in Arnhem, The Netherlands, December 1989 PDF

326 Pages·1993·29.055 MB·English
Save to my drive
Quick download
Download
Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.

Preview Netherlands-Wetlands: Proceedings of a Symposium held in Arnhem, The Netherlands, December 1989

Netherlands-Wetlands Developments in Hydrobiology 88 Series editor H. J. Dumont Netherlands-Wetlands Proceedings of a Symposium held in Arnhem, The Netherlands, December 1989 Edited by E.P.H. Best& J.P. Bakker Reprinted from Hydrobiologia, vol. 265 (1993) Springer Science+Business Media, B.V. Library of Congress Cataloging-in-Publication Data A CLP. Catalogue record for this book is available from the Library of Congress. ISBN 978-94-010-4904-7 ISBN 978-94-011-2042-5 (eBook) DOI 10.1007/978-94-011-2042-5 Printed on acid-free paper All Rights Reserved © 1993 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 1993 Softcover reprint of the hardcover 1st edition 1993 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner. v Contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Vll INTRODUCTION Netherlands-Wetlands by W. J. Wolff .................... ... .. ........ .. ............ ... ............ . . CASE STUDIES Coastal systems Nutrient cycling and foodwebs in Dutch estuaries by P. H. Nienhuis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 The Dutch Wadden Sea: a changed ecosystem by V. N. de Jonge, K. Essink & R. Boddeke ....... .. .. ... ........ .. .......... .... 45 Salt marshes along the coast of The Netherlands by J. P. Bakker, J. de Leeuw, K. S. Dijkema, P. C. Leendertse, H. H. T. Prins & J. Rozema 73 Large river systems The rivers Rhine and Meuse in The Netherlands: present state and signs of ecological recovery by W. Admiraal, G. van der Velde, H. Smit & W. G. Cazemier . . . . . . . . . . . . . . . . . . . . . . 97 Base-rich freshwater systems An ecosystems approach to base-rich freshwater wetlands, with special reference to fenlands by G. van Wirdum ...................... ........... ........................... 129 The structure and function of fen lakes in relation to water table management in The Netherlands by H. de Haan, L. van Liere, Sj. P. Klapwijk & E. van Donk ... .................... 155 Wetlands of recent Dutch embankments by W. Joenje & B. Verhoeven ........ ........... ... ........ .......... ..... ..... 179 Nutrient-poor freshwater systems Nutrient-poor freshwater wetlands by L. W. G. Higler .. ...... ......... ... .... ....... ........ .... .. .. .. ... ..... .. . 195 The Bourtanger Moor: endurance and vulnerability of a raised bog system by W. A. Casparie ............................................................ 203 Hydrological differences between bogs and bog-relicts and consequences for bog restoration by J. M. Schouwenaars .................. ..................... ...... ....... .. .. 217 Ecology and management of moorland pools: balancing acidification and eutrophication by H. van Dam & R. F. M. Buskens .. ... ................... .. ....... ....... ... . 225 VI Stream valleys as wetlands by L. W. G. Higler & P. F. M. Verdonschot ....................................... 265 Wet dune slacks: decline and new opportunities by H. W. J. van Dijk & A. P. Grootjans .......................................... 281 ECOLOGY, CONSERVATION, MANAGEMENT, RESEARCH AND POLICY The ecology of The Netherlands wetlands: characteristics, threats, prospects and perspectives for ecological research by E. P. H. Best, J. T. A. Verhoeven & W. J. Wolff ................................ 305 Wetlands policy of the Dutch government: failure or success? by F. Colijn, R. Uyterlinde & H. W. Kroes ....................................... 321 Hydrobiologia 265: vii, 1993. E. P. H. Best & J. P. Bakker (eds), Netherlands-Wetlands. VB Preface The Netherlands is a country rich in water. The variety in water bodies is enormous taking the relatively small size of the country into consideration. Most land is situated below sea level, and would be inundated without the management measures required to keep it dry. Three large rivers, the rivers Rhine, Meuse and Scheidt, cross the country and form extensive estuaries in the coastal areas. Former sea arms have been closed partly or completely, with consequences for water quality and biotic communities. Because the country is so rich in water bodies it also hosts many wetlands. Scientific and public awareness has been growing during the last decade that the original wetland character of The Netherlands is unique. Therefore, the Netherlands Ecological Society (,Oecologische Kring') and the Netherlands Society for Aquatic Ecology ('Hydrobiologische Vereniging') jointly organ ized a symposium on 'The Netherlands Wetland', December 1989, in Arnhem (The Netherlands). The symposium was meant to (1) summarize the existing knowledge on structure and function of the wetland types characteristic for The Netherlands, (2) identify gaps in knowledge, and (3) indicate new avenues for ecological research. This book is a compilation of most of the seminars presented during the symposium. The introduction treats not only The Netherlands as wetland in a larger landscape but also the various wetland types within the country itself. The subsequent case studies concern representative wetland types. Introduction and case studies, both give an historical, hydrological, physico-chemical and biotic characterization of the wetland concerned, give a description of management measures in the past and in the present, summarizes the threats of the systems and indicate perspectives for the ecosystems given the present environmental conditions and the expectations for short- and long-term changes therein. In the introduction special attention is paid to the border-crossing biotic elements like birds. These sections are followed by a summary of the ecology of the Netherlands wetlands and indications for future ecological research. Finally, environmental policy and its consequences for management on a national, regional and local scale is discussed. Wageningen/Haren ELLY P. H. BEST J. P. BAKKER Hydrobiologia 265: 1-14, 1993. E. P. H. Best & J. P. Bakker (eds). Netherlands-Wetlands. 1 © 1993 Kluwer Academic Publishers. Netherlands-Wetlands W.J. Wolff DLO-Institute for Forestry and Nature Research, P.O. Box 46, 3956 ZR Leersum, The Netherlands and Dept. of Nature Conservation, Agricultural University, Wageningen, The Netherlands Key words: wetlands, The Netherlands, wetland history, wetland policy Abstract The Netherlands occupy 41,864 km2 of which about 6,600 km2 (16%) have been classified as interna tionally important wetlands. About 3000 km2 (7%) have been included in the Ramsar Convention list of internationally important wetlands. The situation of the wetlands in The Netherlands has seen large changes during the last 2000 years. Thousands ofkm2 of peatlands have disappeared; thousands ofkm2 of coastal salt marshes and a similar area of shallow lakes have been reclaimed for agriculture. The Dutch wetlands occupy a key position in the bird migration of the West-Palaearctic flyway. The hydrology of The Netherlands and of Dutch wetlands is dominated by the river Rhine. Hence, nutrients and contaminants imported by the Rhine and from other sources have a major impact on Dutch wetlands. Reduction of pollution and eutrophication is a major requirement for conservation of Dutch wetlands. Dutch politics appears to be moving in this direction. Introduction mulated in Ramsar, Iran, in 1971. It entered into force in 1975 when seven countries had acceded Literally translated Nederland (,The N ether the treaty. The Netherlands ratified this conven lands') means the Low Country. Hence, it is not tion in 1980 and it is in this period between 1971 astonishing that The Netherlands always have and 1980 that the word 'wetlands' became part of been and still are a very wet country. This is il the Dutch language, especially the jargon spoken lustrated by many topographical names, such as by conservationists and politicians. 'Waterland' (water land), 'Zeeland' (sea land), The Ramsar Convention aims at the conserva and the many toponyms containing the terms tion and wise use of wetlands and of the popu '-dam' or 'polder' (drained land). lations of waterbirds occurring in these wetlands. However, although every type of wetland in Although in the early years the Convention put The Netherlands can be named with a specific much emphasis on waterbirds, the Ramsar Con Dutch word, there is no general term in the Dutch vention is essentially not a bird treaty, but a wet language denoting wetlands. What is wetland lands treaty. Under this treaty the government of elsewhere, is land to the Dutch. The word 'wet The Netherlands has prepared an official list of land' was introduced into the Dutch language es wetlands of international importance (Rooth, pecially because of the participation of The Neth 1985, 1989). Of this Dutch list enumerating 103 erlands in the so-called Ramsar Convention. This wetlands with a total area of 6,600 km2 10 wet 'Convention on Wetlands of International Impor lands with a total area of about 3,000 km2 have tance especially as Waterfowl Habitat' was for- been designated for inclusion in the international 2 List of Wetlands of International Importance re should be considered to form part of these wet ferred to in Article 2 of the Convention (as per 1 lands. January 1990). This means that about 16% of Part of the Dutch wetlands qualify as such the territory of The Netherlands is considered to under all definitions. However, about half of The consist of internationally important wetlands and Netherlands consists of agricultural land lying that about 7% of its territory actually has been below sea level. Originally this land used to be registrated as an internationally important wet very wet, and hence wetland, but due to centuries land. However, The Netherlands are wetter than of civil engineering (Van Veen, 1962) the water that! table is now more or less fixed below the surface of the soil. In clayey and sandy arable areas this water table may occur down to 1-2 metres, but Definitions of wetlands in peaty grassland areas the water table may be only 10-20 cm below the surface. The latter type In general terms, wetlands are areas where satu of agricultural areas still may be considered as ration with water is the dominant factor deter wetlands, because of the high water table and the mining the nature of soil development and the organisms occurring. Figure 1 shows the distri types of plants and animals living in the soil or on bution of the different types of wetlands in The its surface. Wetlands are transitional systems be Netherlands at present. tween land and water where the water table is Some Dutch words denoting specific types of usually at or near the surface or the land is cov wetlands have become incorporated in the inter ered by shallow water. According to Cowardin national scientific literature. Such words are: et al. (1979) wetlands have one or more of the - wad (singular, plural: wadden) denoting unveg following attributes: (1) at least periodically, the etated tidal flats in the northern (Friesland, bottom supports predominantly hydrophytes Groningen) part of The Netherlands; the plu (water plants); (2) the substrate is predominantly ral form is well known in the international undrained hydric soil and/or (3) the substrate is scientific literature on coastal areas; nons oil and is saturated with water or covered by - slik denoting unvegetated (muddy) tidal flats in shallow water at some time during the growing the southern (Zeeland) part of The Nether season of each year. lands and the NW (Flanders) part of Belgium; The 'Convention on Wetlands of International due to Belgian scientific studies 'slikke' is now Importance as Waterfowl Habitat' defines wet widely used in the French scientific literature; lands as 'areas of marsh, fen, peatland or water, - schor meaning salt marsh in the southern part whether natural or artificial, permanent or tem of the country; again due to Belgian studies porary, with water that is static or flowing, fresh, 'schorre' is often used in French scientific pub brackish or salt, including areas of marine water lications. the depth of which at low tide does not exceed six metres'. Another Dutch word which has acquired some Several authors (e.g. Shaw & Fredine, 1956; status outside The Netherlands is polder, origi Miller, 1976; Cowardin et al., 1979 and Frayer nating from the SW-Netherlands and NW etal., 1983), however, set the lower limit of wet Belgium (Dekker, 1971) and originally denoting lands at the extreme low water of spring tides or, an embanked and reclaimed salt marsh. Along in non-tidal waters, at a depth of 2 or 3 metres, the Wadden Sea, especially in Germany and because this is the maximum depth at which Denmark, the Frisian word koog has obtained the emergent plants normally grow. same meaning; it is still used in Germany ('Koog') According to the Ramsar Convention islands and Denmark ('kog'). Nowadays 'polder' in The situated within wetlands and channels deeper Netherlands also denotes an area with an inde than six meters situated within coastal wetlands pendent hydrology regulated by man. 3 12'/\1 dunes _ salt marshes D saline lakes _ freshwater lakes [:::::;::;::;:::3 fen mires o 50 km Fig. 1. Present distribution of wetlands in The Netherlands. Geological and historical development of The geological development may be summa wetlands in The Netherlands rized as follows (Zagwijn, 1986). After the last Ice Age sea level in the North Sea rose rapidly. When Geology the rate of sea level rise declined at about 6000 B.P. a system of barrier beaches and islands de Quaternary geology has prospered in The Neth veloped, situated approximately along the present erlands during the last decades and has resulted western and northern coastlines. With a sufficient in several palaeographic reconstructions of the supply of sediment the tidal basins behind the topography of the country (e.g. Pons & Wiggers, barrier coast filled in until the tidal inlets could be 1959,1960; Pons & Van Oosten, 1974; Van Staal closed by wave action, especially in the areas with duinen et al., 1979). Zagwijn (1986) summarizes smaller tidal amplitudes. In the former tidal ba all available evidence in an interesting series of sins marsh vegetation developed which gradually maps. Figures 2 and 3 are derived from his maps changed into ombrotrophic raised bogs. At larger and show the distribution of wetlands in The tidal amplitudes and/or in areas with a shorter Netherlands at about 100 A.D., i.e. during the supply of sediment, viz. the Wadden Sea area and Roman occupation, and around 1200. the south-western part of The Netherlands, the

See more

The list of books you might like

Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.