Returning life in the Oder delta [Northern Europe]

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By Pernilla Hansson

Pernilla has a master’s degree in biology with a focus on conservation biology.

In the northernmost region of Germany and Poland, the Oder river forms part of the border between the countries, culminating in the large Oder delta. The delta consists of a mosaic of environments such as heaths, wetlands, forests, grasslands, and lagoons, most notably the large Stettin lagoon. Both Germany and Poland have recognised that protecting the delta is a valuable endeavour and together they have ensured that two-thirds of the delta region has been set aside for conservation and rewilding. As many ecologically important species still reside in the area, the efforts are mainly focused on restoring degraded habitats to strengthen the animal populations.

Wetlands make up a large part of the delta, and they hold many important functions: regulating soil and water temperatures; cleaning pollutants out of the water, providing flood control; and, in some cases, also playing an important role in regulating greenhouse gases by storing carbon through peat production. In the mid-18th century, residents of the German side began digging ditches to drain the wetlands, and when large-scale drainage became possible in the 1970s, many of the area’s wetlands were converted into intensively-used grasslands for dairy farming. Now, on both sides of the border, marginal agricultural lands around the delta have been abandoned. Although most of the abandoned land in Poland is used for new buildings and infrastructure, the abandoned farmland represents an opportunity to rewild the land and restore lost ecosystem functions.

An area that has already seen rewilding measures is Ueckermünde heath. The area was identified in a project to restore populations of the lesser spotted eagle, one of the rarest breeding birds in Germany. Through the relatively straightforward process of refilling old drainage ditches, Ueckermünde heath was restored to the open, wet areas in which the species prefers to hunt. To rewet other degraded lands, larger efforts may be needed, such as at Bergischow Polder. That rewetting process is ongoing and involves pumping, dam building, and dyke relocation.

The decision to reduce or seasonally stop fishing in the most important spawning and migration regions of the large Stettin lagoon has allowed the numbers of fish in the area to increase. Further efforts aim to rewild river banks, restore natural hydrodynamics, remove obstacles, and recreate spawning areas, for example gravel beds for salmonids. Seventeen such new gravel beds have already been created in tributaries of the river. With the observed increase in the fish population, piscivores such as the white-tailed eagles have also increased.

Stettin Lagoon in the Oder delta (cropped from a photo by Andreas Lippold; CC BY-SA 4.0)

Rewilding efforts have further looked at larger species such as the European bison. Once extinct in the wild, European bison survived in zoos and parks, but have in recent years been successfully reintroduced into the wild. One such area is the Polish side of the Oder delta region, where they act as a keystone species in keeping the landscapes open through their grazing.

The role of local people and organisations has been an important factor for the success of the rewilding efforts. Excluding people from the region is not feasible, as the area is still densely populated, so the development of sustainable, nature-based occupations is a vital piece of the rewilding puzzle. Hunters in the area have not only established no-take areas and adopted less disturbing hunting methods, but hunting associations are also taking an active role through the involvement in guiding wildlife tours.

The generation of a new source of income for people in the region through nature tourism has helped foster local support. This support has strengthened the rewilding efforts, and local people and organisations recently helped in preventing a project that would have dug new dykes in Poland and undone some of the restoration work already carried out. With strong efforts from local residents, conservation organsisations, and governments, one can see how rewilding is a viable option in many parts of Europe, especially with the continued farmland abandonment. The rewilding of the large Oder delta serves as a reminder of humanity’s ability to co-exist with wilderness, and the readiness of nature to recover.

Location of the Oder delta