March 2008

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English summaries

    • Management of salt marshes
    • Bakker, J.P.
    • The Chair Coastal Conservation Ecology in salt marshes searched for possibilities of generalisation and scaling up from a single site or experiment to a larger scale. A strong positive correlation was found between the thickness of the clay layer and the productivity of plants on sandy salt marshes. The control between plants and small herbivores such as hares and geese is bottom-up: the number of herbivores along the productivity gradient depends on quantity and quality of plant biomass. Also a top-down controle was found: hares can retard vegetation succession for a few decades, and thus facilitate for geese. When hares lose control larger herbivores such as cattle can set back the successional clock, and facilitate for both geese and hares. Long-term exclusion of livestock results in a decrease of plant species, plant communities, and spring staging geese. However, not all kinds of organisms behave in a similar way with respect to grazing regimes. Hence, setting ecological targets is important in the decision to establish a certain regime.
    • The contribution of ecological environmental management to the quality of nature areas
    • Eijsackers, H.J.P.
    • Nature management has an intimate relation with environmental management: by man-made ecosystems, by the influence of negative environmental conditions on nature and - recently - by the potentials of natural cleansing processes in nature areas. This article describes these three relations using as an example the soil and sediment problems in the Netherlands lowland peat area and the riverbanks. These areas have been contaminated with heavy metals and PAHs. In field, experimental and desk studies the risks of these contaminant are assessed. Moreover, the impact of bioturbation by earthworms on cleansing processes is investigated.
    • Nature and flowing water
    • Smits, A.J.M.
    • The endowed professorial chair ‘Nature conservation of stream corridors’ has been hosted by the Radboud University Nijmegen during the period 1998-2006.One of the focal points was the scientific elaboration and application of the ‘ecosystem based approach’ to river basin management. The ecosystem based approach recognizes the importance of dynamic fluvial processes for a sound river ecosystem. Hence, traditional water management strategies and land use patterns require specific adaptations to enable economic growth and maintain ecological integrity and hydrological resilient river basins.Two topics have received substantial attention: finding a solution for the ‘nature-safety’ dilemma in the floodplains of the large rivers and determining the role of bioturbators in replacements of polluted floodplain soil.An example of an international research project of the endowed professorial chair is the ‘Freude am Fluss’ project. This is a European funded cooperation project between various German, French and Netherlands organizations. The deliverables of the ‘Freude am Fluss’ project comprises the modification of some land use plans in France (Loire), Germany (Rhine) and The Netherlands (Waal river). All these modifications have in common that both nature as well as flood protection benefit from the suggested changes.Apart from the various research projects the endowed professorial chair also initiated with the University of Duisburg-Essen (Germany) a MSc Transnational Water Management. In October 2006 the endowed chair has been transformed into the fulltime professorial chair ‘Water Management’ at the Radboud University Nijmegen. Despite the fact that the name of the professorial chair has been altered the focus on nature conservation remains unchanged.
    • Restoration ecology: ecological and philosophical aspects
    • Schouten, M.G.C.
    • The paper describes the main research projects which have been and are being carried out in the context of the special chair of Restoration Ecology which was established at Wageningen University at the request of the National Forest Service of The Netherlands (Staatsbosbeheer) in 1999. On the one hand these projects have an ecological character and focus on raised bogs and coastal sand dunes. On the other hand they are more philosophical in character and are concerned with perception of nature. The implications of the results of the various studies for the management of nature reserves in The Netherlands are discussed.
    • Challenges for environmental education
    • Koppen, C.S.A. van & M. Margadant-van Arcken
    • While environmental education has been one of the aims of Dutch nature conservation advocates for a century, both the urgency and the scope of environmental education have increased over the last decades. In 1997 a special chair in environmental education was appointed by the ‘Stichting Bijzondere Leerstoelen Natuurbeheer’ (Foundation for Appointment of Special Chairs for Nature Management), with support from the Prince Bernhard Cultural Foundation. The article describes the activities of the chair in supporting education and research in the field of environmental education. A specialization for environmental education has been realized within the MSc Science Communication and Education at Utrecht University. The chair has engaged in several fields of research, such as development of standards for environmental education, development of conceptual frameworks and materials for e.g. education on pluralism in nature views, and evaluation of environmental education. Recent research themes include environmental education and civil society, and comparative research on environmental education curricula in Europe and China.
    • Discharge peaks and the presence of the caddis fly Agapetus fuscipes
    • Hoorn, M.W. van den, T.H. van den Hoek & R.C. Nijboer
    • The natural hydrological conditions of many areas are changed in the past century. Changed hydrology leads to non permanent situations in streams, often in combination with excessive high peaks of discharge in rainy periods. We investigated the relation between discharge dynamics, substrate stability and population size of the caddis fly Agapetus fuscipes CURTIS in six different streams during a period of two years. Discharge was measured every fifteen minutes. During a period of one and a half year the changes of gravel beds were followed. Small discharge peaks of more than twice the median discharge seemed not to occur under natural conditions in common years. Regular occurrence of discharge peaks of more then four times the base flow affected the population size negatively. The effect depended on the stage in the life cycle of the organisms. Discharge peaks of more than eight times the base flow strongly affected the population size and should therefore be avoided.