With decreasing populations in parts of rural Europe and marginal agricultural lands being abandoned, Europe is in a strong position to return land to wilderness. At the northern end of the border between Poland and Germany lies the Oder delta, where rewilding efforts on land and in water have contributed to a quick recovery of animal populations. The Oder delta is the second focus in our blog series about rewilding, which highlights areas where decreasing populations and land abandonment have given new hope for wild nature to regain a foothold in an otherwise human dominated landscape.

By Pernilla Hansson

Many parts of Europe are currently undergoing processes of rural depopulation,¹ something which is often seen as cause for concern. But a decreasing population results in less need for agricultural and residential lands, which can free up large areas for other species to live on and for humans to enjoy. While it is sometimes argued that traditional agriculture is important to maintaining a biodiverse rural landscape, an option that can be even more efficient in this regard is the process of rewilding. Rewilding aims to restore an area’s self-regulating abilities and ensure that the natural processes responsible for creating a dynamic wilderness are allowed to function. That may be achieved most fully in larger geographical areas, that are less sensitive to edge effects, infrastructure intrusions, and tourism.

The area of focus in this post is the Oder river delta. Located in northernmost Germany and Poland, the Oder river forms part of the countries’ border. The river ends in a large delta-region in the southern Baltic Sea, consisting of a mosaic of environments such as heaths, wetlands, forests, grasslands, and lagoons, most notably the large Stettin lagoon (also known as Szczecin lagoon). As many ecologically important species still reside in the area, efforts here are mainly focused on restoring degraded environments and habitats to strengthen the animal populations, as well as working with the residents in the area. Many rewilding measures, such as the restoration of numerous wetlands on the German side, have already been undertaken. In 2015, the organisation Rewilding Europe, which is involved in numerous ecological restoration projects throughout Europe, teamed up with local organisations that had already carried out big rewilding projects, to try to scale up efforts even further.² The protection of the Oder delta has been seen as a valuable endeavour by both countries during the last decades, and together they have ensured that two thirds of the delta region are protected and set aside for conservation and rewilding.³

Poland and Germany have maintained relatively stable human populations since the early 1990s and mid 1970s, respectively.⁴ While Germany’s urban population is currently growing, most cities in eastern Germany had ceased to grow by the 1980s due to decreasing birth rates and out-migration due to bad housing conditions in city centres. This urban shrinking of eastern cities continued into the 1990s, when the reunification of east and west Germany caused a large migration from east to west. Many small villages in the countryside became almost deserted.⁵ The state of Mecklenburg-Vorpommern, which surrounds the delta on the German side, was one of the regions where the most abandoned villages were recorded,⁶ and within the state, the district closest to the delta has shown a slight population decrease.⁷ The Mecklenburg-Vorpommern area is also subject to increased ageing due to the young generation moving to cities. While these demographic changes can be perceived as negative, the changes they are leading to illustrate a broader process of demographic development of many western societies.⁸ While agricultural abandonment is not a factor across the whole state of Mecklenburg-Vorpommern, there is still a considerable amount of abandoned farmland in north-eastern Germany closest to the delta.⁹

On the Polish side, depopulation is most prominent in the eastern part of the country⁶; however, the West Pomerania province, which covers the delta, has had decreasing populations⁷ and is projected to continue decreasing.¹⁰ Migration from rural to urban areas has occurred several times throughout Poland’s history. In the 1950s, the main reason for migration was the poor economic situation in the countryside, while later migration from rural areas was based on the possibility for better careers and greater access to education and other services.¹¹ After entry into the EU in 2004, many young people moved from Poland to other countries in Europe, as the Polish economy was doing poorly and unemployment was high.⁵ Currently, it is more common for people living in urban areas to move out to the countryside than vice-versa, a trend which started around the change of the millennium.¹² Within the province, the two subregions surrounding the Oder delta have experienced a natural decrease due to low fertility rates. However, the larger subregion of Szczecinski, which covers most of the delta on the Polish side, has seen a slight increase in inhabitants due to in-migration.¹⁰ Even with a slight increase in human population around the delta, the area still experiences agricultural land abandonment.¹³ In the province of West Pomerania, 6% of agricultural land was abandoned between 2000 and 2010. However, the majority of this abandoned land is not left for nature to reclaim, but is rather used for new buildings and infrastructure.¹⁴

While much of the land around the Oder is today set aside for nature, people in the region have long had great influence on the area, including the use of wetlands for agriculture. Wetlands play an important ecological role in regulating soil and water temperatures,¹⁵ cleaning pollutants out of the water, providing flood control, and other important services. Some wetlands also produce peat, which stores carbon.¹⁶ In this way, such wetlands help regulate greenhouse gases and climate. These lands were little used in earlier centuries in Germany, and a type of wetland called fens constituted 12% of the Mecklenburg-Vorpommern area. In the mid 18^th century, residents 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.^17,18 When peatlands, such as the fens, are drained, the stored carbon becomes exposed to the air and starts decomposing, emitting carbon dioxide into the atmosphere.

The importance of well-functioning wetlands was highlighted in Germany in the 1990s, and as animal production declined in the country and land was abandoned, this was seen as an opportunity to restore their functions.¹⁸ Such an opportunity presented itself at Bargischow Polder, an old farmland in Germany which, before drainage, had been a large peatland. The restoration process of rewetting is complex, with pumping, dam building, and dyke relocation, which will continue until 2023. A nature reserve of similar ecology nearby is a haven for animals such as the otter (Lutra lutra), Eurasian crane (Grus grus), and beaver (Castor fiber), showcasing how the area may look once nature has recolonized it.³

It is not only wetlands and terrestrial areas that are under consideration in the delta; open water habitats are equally important for conservation work. Fishing has been reduced or seasonally stopped in the most important spawning and migration areas of the Stettin lagoon. To help restore fish populations and migration in the lagoon and its associated rivers, the efforts aim to rewild the river banks, restore the natural hydrodynamics, remove obstacles, and recreate spawning areas for fish.³ Improving spawning areas has been a major focus in the Oder river system, where a total of 17 new gravel beds have been created in tributaries to the river.² Many salmonid species need these gravel beds to lay their eggs.¹⁹ The efforts have already seen an increase in fish numbers in the lagoon, and this has not only helped the fish populations, but also the white-tailed eagles (Haliaeetus albicilla), who feast on the strengthened fish populations.²

There are other noteworthy species found in the area. One of the rarest breeding birds in Germany, the lesser spotted eagle (Lophateus pomarina), lives in the delta region, and special efforts have been deployed to help it. Nest protection devices were installed in several nesting trees around the delta, and restoration of the Ueckermünde heath, through the refilling of old drainage ditches, was done with the lesser spotted eagle in mind,³ as this species prefer open, wet areas in which to hunt.²⁰

Another important species is the European bison (Bison bonasus), which has been reintroduced into the Oder delta region of Poland. The European bison was once extinct in the wild, with the only remaining populations residing in zoos and parks. But tireless efforts to save the species have resulted in the creation of new herds several European countries. By killing trees and by grazing, bison herds can help keep landscapes open, as they currently do in the Oder delta region.³ Such large grazers are an important ecological group that has been lost from the continent, so the reintroduction brings with it great opportunities to be less reliant on domesticated grazers to keep the lands open on less economically viable lands, especially as animal rearing is being abandoned in the region.¹⁸

While the focus may lie on the wilderness in the region, the involvement of the local community is important for successful conservation efforts. Since Europe is still a highly overcrowded continent, too strong limitation of human activity within the area is not feasible. Instead, the development of sustainable, nature-based occupations is a vital piece of the puzzle. Fishers have seasonally stopped or reduced fishing in some sensitive areas and hunters are also restricting their activities. There are established no-take areas, and new, less disturbing hunting methods have been adopted by hunting associations, who have also involved themselves in guiding wildlife tours.³ Generating new income for people in the region, through nature tourism, has helped create local support for the rewilding efforts. This is shown, for example, in more positive attitudes towards wolves. While this is a species historically feared and hated by many livestock owners, the existence of wolves is now celebrated in the region, and sightings are met with both pride and enthusiasm.³ Local people and organisations were also vital recently in preventing the digging of new dykes in Poland, which would have threatened hydrological processes and destroyed some of the ecosystems that had been laboriously restored.²

What has already been accomplished in the region is inspiring, but what will happen in the future? That will depend, in part, on human numbers. The fertility rates in Germany and Poland are currently low: in 2017 they were 1.57 and 1.45 respectively. ²¹ This opens up the possibility for smaller populations in the future and increased opportunities for rewilding across the landscape. But populations may also increase, depending on policies enacted at the national and EU levels.

In Poland, out-migration is the dominant movement of people. If migration and fertility levels remain at their current rates throughout this century, the population as a whole will decrease 44% by 2100, generating a comparable decrease in human population density (see projections below, and click to reach interactive TOP grapher).

In Germany on the other hand, increased migration in recent decades has counterbalanced low fertility rates, leading to a relatively stable population. Depending on fertility rates and migration policy, Germany’s population could increase or decrease substantially, with corresponding impacts on habitat availability for other species (see projections below, and click to reach interactive TOP grapher).

With strong efforts from local residents, conservation organisations, and governments, one can see how rewilding is a viable possibility in many parts of Europe. The rewilding of the large Oder delta serves as a reminder of humanity’s ability to co-exist with wilderness, and of the readiness of nature to recover. Central Europe is densely populated, but with fertility rates well below replacement level and the possibility to set policies that allow for population decrease, more land might be freed for wild nature to reclaim, allowing more species to thrive than just us.

TOP and Pernilla Hansson wish to thank Hannes Weber for valuable comments on the text. Hannes has published a German Book about population and demography: Weber, H. (2019): “Der demographische Wandel: Mythos – Illusion – Realität.” Stuttgart: Kohlhammer, 121 pp.

See the first instalment in this series, “Fewer people leads the way to rewilding in Portugal.”

References:

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