By Patrícia Dérer

Thirty countries around the world have declining human populations. With the exception of Japan, these are European countries that, along with the rest of Europe, have successfully undergone the “demographic transition”. Impressive achievements in health care, education and economic development have resulted in lower child mortality and longer life expectancy, leading to voluntary fertility decline. Lower fertility rates have enabled families to avoid becoming impoverished from numerous dependents, and enhanced democracy through the participation of women in social, economic and political realms. This success, among other factors, is already contributing to the trend of rural depopulation, i.e., decreasing population in rural Europe.

Since 1960, the rural population in Europe has declined by 20%¹, and the population of predominantly rural regions is projected to fall another 7.9 million by 2050². Rural depopulation and aging contributes to the trend of farmland abandonment³. Within the past two decades, up to 7.6 million hectares of agricultural land have been abandoned in Eastern Europe, southern Scandinavia and Europe’s mountainous regions, as well as 10-20 % of the agricultural land in the Baltic states⁴. Although some of this farmland became (mainly coniferous) tree plantations, as of 2015, 15.8 % of total EU land area was considered abandoned⁵. This proportion is projected to grow: according to the Institute for European Environmental Policy, an additional 3–4% of total EU land will be abandoned by 2030, with other estimates ranging from 0.6 to 6.7 %. These areas will be primarily concentrated in the Alps, Apennines and Iberian mountains, but also in the semiarid plains in southern Europe, in Central Europe and Northwestern France^6,7.

Demographic trends, such as aging farmers and rural depopulation (due to emigration and low fertility), were identified as drivers of recent land abandonment in the Mediterranean region and Eastern Europe⁴; however, other socio-economic, ecological and political factors also contribute to this phenomenon. These include imports of agricultural products and concentration of farming on the most productive lands, geography, topography and soil properties as well as policy obstacles⁹. Despite the many underlying factors influencing land abandonment, we can logically assume that if population decline continues, or starts where it has not started yet, continued rural depopulation will lead to even more agricultural land released from human use.

Environmentally concerned people may assume that this land, free from ploughing and grazing and now available for the return of natural vegetation, is a reason to celebrate. On the contrary, abandonment is generally seen as a major socio-economic problem that should be fixed with incentives to continue agricultural activity on all lands where it formerly has been practiced⁸.

Indeed, farmland abandonment can have negative consequences under certain circumstances. Unmanaged recolonization of shrubs and forest regrowth can increase the risk of fires due to increased biomass, and can lead to a more uniform landscape, as is the case in many places in the Mediterranean region. In drier places, soil erosion and desertification can follow abandonment. In many places, land abandonment is associated with the loss of cultural and aesthetic values, as the traditional rural landscape becomes abandoned and revegetated⁹.

The biodiversity impacts of farmland abandonment are highly debated and depend on geography and landscape. Biodiversity changes consist of species declining in abundance (loser species) and other species increasing (winners). The agrobiodiversity associated with farmlands having high natural value (HNV farmlands) is in the loser category. The semi-opened habitats and the human activity which this agrobiodiversity depends on, decline or disappear with revegetation. The HNV farmlands are typically semi-natural pastures, mosaic habitats, and low-productive lands with high risk of abandonment, since traditional agricultural systems (as extensive farming) are less profitable. The uncontrolled shrub and forest development that occurs after the abandonment of these HNV farmlands is seen as undesirable and reported as a negative biodiversity effect by most European studies^3,6.

In such cases, there may be justification for the fears of negative consequences of abandonment of diverse semi-open landscapes. Yet it is important to note that the man-made agricultural landscape is not the natural state of these landscapes, even if it is more biodiverse than the abandoned, afforested landscape in the short term. Management may try to preserve the human-associated biodiversity of the traditional agricultural landscape through continued farming, but alternatively, the landscape can be rewilded. Rewilding means assisting natural regeneration of large areas of forests and other natural habitats, through passive management approaches, with the goal of restoring natural ecosystem processes that existed before agricultural activity. The aim is to reduce human control of landscapes and create self-sustaining wild areas. Although rewilding emphasizes no management or low levels of management, intervention, such as (re)introduction of species may be required in the early restoration stages⁶.

How could European landscapes become wild again?

Millennia of human activities have progressively replaced natural disturbances, such as herbivory, top predators, and fire, as shapers of the European landscapes. Restoring natural ecological processes may often involve restoration of these natural disturbances. Reintroduction or assisted recolonization of large herbivores (such as the European bison, or wild horse) and prescribed burnings can fill the role of natural disturbances. As a result, the habitat may be kept (partially) open, helping to manage fire regimes and secure habitat for species dependent on earlier stages of succession.

Some European species of large herbivores have had substantial increases in their populations since the 1960s, thanks to areas with lower human pressures that function as sources of natural recolonization⁸. Though legislation and conservation measures contributed the most to this success, rural depopulation and the associated reduced human pressure, both direct (e.g. less hunting) and indirect (e.g. more land available), have also furthered this comeback⁸. Continued depopulation and release of land from agriculture will further contribute to this success in the future.

In many regions of Europe, the transition from abandoned to semi-natural land takes less than 15 years, followed by another 15-30 years before reforestation, if the area relies only on passive decolonization of nature⁶. Natural regeneration is particularly slow in a dry environment such as the Mediterranean, or when the soils have been modified by past agriculture, or when the availability and quality of the native seed bank is bad⁶. Yet several good examples exist in Europe, where natural succession has led to habitats with high natural value. The spontaneous return of riverine forests after land abandonment has been observed in many regions of Europe, for example along the middle Loire in France¹⁰. Natural forest succession can lead to openness through self-thinning and windthrow, which produces deadwood and increases the population of threatened species dependent on this resource.

Eventually, when ecosystem functions are restored, the rewilded area will become self-functioning without any further human intervention. Although the impacts of rewilding on biodiversity are mixed, there are several clear benefits. Rewilding often enhances a variety of ecosystem services, including increased freshwater supply, reduced soil erosion, flood prevention, and the removal of air pollutants^10,11. Where rewilding increases woody plant cover, as is typically the case in Europe, carbon sequestration will also increase. Moreover, if large areas are rewilded, the combination of connectivity and species diversity may enhance resilience to climate change¹².

Unfortunately, these potential benefits of rewilding and habitat regeneration on abandoned farmland tend to be neglected by European policy makers. Several measures have been implemented to limit depopulation and abandonment of marginal farmland. As part of the European Common Agriculture Policy, “Less Favored Areas”, (areas with “natural handicaps” where agricultural use is difficult, less profitable) were designated mainly to prevent rural abandonment and maintain cultural landscapes. The largest amounts of funding for biodiversity conservation are available through agri-environmental schemes aimed at preserving traditional farming systems and reversing abandonment trends⁸. Rewilding as a management option is disregarded despite the fact that it is likely to be cheaper to establish and maintain than efforts to preserve traditional high-diversity biocultural landscapes^11,6. A combination of support for traditional agriculture (e.g. semi-natural pastures, coppice) and rewilding of larger land areas may be ideal for conservation work, but remains to be implemented.

However, some scientists, environmentalists and organizations see the opportunities of land abandonment rather than just its negative aspects. They acknowledge that less human influence means more natural processes that can improve the natural environment and restore wild nature. The most prominent European organization working to rewild European landscapes is Rewilding Europe. They acknowledge the role of depopulation and associated land abandonment in rewilding, and they take advantage of it. This initiative aims to create vast wild landscapes in at least 10 different regions of Europe. One example is in the Côa Valley of Portugal, a region with one of the highest land abandonment levels in Europe. The reintroduction of wild horses and tauros saved this area from frequent, severe fires associated with the spontaneous shrubby vegetation that followed farmland abandonment. Restored herbivory led to a biodiverse mosaic landscape that boosted populations of rabbit, red-legged partridge, Iberian lynx and Bonelli’s eagle, and led to the return of griffon vultures.

Other ongoing rewilding activities include rewilding the forests in the Velebit mountains (Croatia), restoring fish populations in the Oder delta (Germany and Poland), boosting biodiversity through mosaic landscape creation in the Rhodope mountains (Greece), restoring a whole spectrum of biodiverse habitats in the Danube delta (Romania) and many more.

These good examples show us that there is a way to think differently about rural depopulation and land abandonment. In a world wounded by biodiversity loss, farmland abandonment should be seen as an opportunity to give nature back what initially belonged to it. With short term human management to aid the restoration process, these lands in many cases can again become independent, self-functioning wilderness. In order to achieve this, societies should embrace population decline and stabilization, and de-growth in general.

References:

1. “World Bank staff estimates based on the United Nations Population Division’s World Urbanization Prospects: 2014 Revision.” [Online].
2. ESPON Policy Brief, “Shrinking rural regions in Europe Towards smart and innovative approaches to regional development challenges in depopulating rural regions Inspire Policy Making with Territorial Evidence.”
3. C. Queiroz, R. Beilin, C. Folke, and R. Lindborg, “Farmland abandonment: Threat or opportunity for biodiversity conservation? A global review,” Frontiers in Ecology and the Environment, vol. 12, no. 5. Wiley-Blackwell, pp. 288–296, 01-Jun-2014.
4. W. Leal Filho, M. Mandel, A. Q. Al-Amin, A. Feher, and C. J. Chiappetta Jabbour, “An assessment of the causes and consequences of agricultural land abandonment in Europe,” Int. J. Sustain. Dev. World Ecol., vol. 24, no. 6, pp. 554–560, Nov. 2017.
5. E. Lindquist, “Land Cover and Land Use :,” no. May, pp. 10–13, 2015.
6. L. M. Navarro and H. M. Pereira, “Rewilding abandoned landscapes in Europe,” in Rewilding European Landscapes, Cham: Springer International Publishing, 2015, pp. 3–23.
7. R. T. Corlett, “Restoration, Reintroduction, and Rewilding in a Changing World,” Trends in Ecology and Evolution, vol. 31, no. 6. pp. 453–462, Jun-2016.
8. L. M. Navarro and H. M. Pereira, “Towards a European policy for rewilding,” in Rewilding European Landscapes, Cham: Springer International Publishing, 2015, pp. 205–223.
9. J. Rey Benayas, “Abandonment of agricultural land: an overview of drivers and consequences.,” CAB Rev. Perspect. Agric. Vet. Sci. Nutr. Nat. Resour., vol. 2, no. 57, 2007.
10. A. Schnitzler, “Towards a new European wilderness: Embracing unmanaged forest growth and the decolonisation of nature,” Landsc. Urban Plan., vol. 126, pp. 74–80, 2014.
11. Y. Cerqueira, L. M. Navarro, J. Maes, C. Marta-Pedroso, J. Pradinho Honrado, and H. M. Pereira, “Ecosystem Services: The Opportunities of Rewilding in Europe,” in Rewilding European Landscapes, Cham: Springer International Publishing, 2015, pp. 47–64.
12. R. T. Corlett, “The Role of Rewilding in Landscape Design for Conservation,” Curr. Landsc. Ecol. Reports, vol. 1, no. 3, pp. 127–133, Sep. 2016.