The first five islands of the Marker Wadden have been developed. An example of a nature restoration project in which both the ecosystem services for humans and the ecological integrity of a natural area are improved, according to a team of researchers from Radboud University, the Netherlands Institute of Ecology (NIOO-KNAW) and the University of Groningen working in collaboration with the Dutch Society for Nature Conservation (Natuurmonumenten). In their publication in Ecological Solutions and Evidence, the team describes the ecological background and scientific findings of the first four years of this unique and innovative project. Plants, birds and fish quickly established in the new area. Economic developments often take place at the expense of natural processes in ecosystems. This is certainly true for freshwater ecosystems that are designed for water safety, drinking water supply, commercial fishing or recreation. Measures that might improve the functionality of a river or lake for people often come at the expense of biodiversity and space for nature. “That was also the case in lake Markermeer”, says researcher Casper van Leeuwen (Radboud University). “The Markermeer is an artificial lake that was created in the larger lake IJsselmeer in preparation for land reclamation. However, the Markermeer started to function as drinking water supply, recreational area and had natural values, and the reclamation never proceeded. In recent decades, however, the natural values of the Markermeer have been declining. This is probably because the human-created freshwater lake lacks all kinds of elements that are present in naturally formed freshwater lakes.” Outlook Classical restoration (i.e., returning to the situation before human intervention) is not possible in the case of the Markermeer, as this would mean removing the dikes around the lake. “Classical forms of ecosystem restoration targeted at only improving the ecology often face great societal resistance”, says professor Han Olff (University of Groningen). “It is time for a new way of thinking.” That is why an innovative form of nature restoration was started in 2016: the construction of a five-island archipelago, called Marker Wadden, built from local soft sediments. The islands aim to stimulate the ecological integrity of the Markermeer by adding characteristic elements of natural lakes, such as gradual land-water transitions, variation in water depths and sheltered areas among the islands where fine sediments can settle to improve water transparency. So far, the approach seems successful: birds and fish colonised the new area immediately, while the ecosystem functions for humans (recreation, fisheries, water supply) have been retained. “The unique feature of Marker Wadden is that we are looking ahead”, says Liesbeth Bakker, researcher at NIOO-KNAW and professor at Wageningen University. “Within four years the project is demonstrating how natural development can be stimulated using a rewilding approach.” According to the researchers, this project can serve as an example of a new form of ecosystem restoration. “New forms of ecosystem restoration are urgently needed to reverse the current global decline of ecosystems.” Image: Schematic overview of the changes in the last century at the location of the Marker Wadden. a) Before 1930 there was an estuary (Zuiderzee), b) 1975, creation of the Markermeer by dam construction, c) 2016-2020, construction of Marker Wadden. The main island seen from the tower. At the front the development of reed fields, in the back patches of swamp ragwort in shallow waters. Photographer: Casper van Leeuwen Pioneer vegetation in the form of swamp ragwort. In May and June a large part of the new islands is yellow. Photographer: Casper van Leeuwen