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Border security fencing and wildlife

13.9.2015, Carnivores.cz

Earlier this year, we have shared the statement of the International Union for the Conservation of Nature (IUCN) who has raised “serious concern about erection of the razor wire fence” at the border between Slovenia and Croatia, which “has already proven to harm the wildlife by exposing it to suffering”.

The fence construction is opposed by conservationists as well as local people who, according to the Guardian, also question its effectivity in stopping the flow of refugees while fearing a decline in regional tourism. However, according to the peer-reviewed paper published recently in the journal PLOS Biology, this appears to be part of a more general trend of border fence construction across Eurasia during the 21st century.

In their study, the international team of researchers attempted to provide an overview of the impacts of security fencing on wildlife across the Eurasia. To do so, they surveyed available literature, online media coverage, and other online resources, combining them with their own field experience and that of their colleagues working in affected countries.

Border security fencing represents barrier for wildlife

In 2015, as a reaction to the sudden influx of refugees fleeing conflicts in Syria, Iraq, Afganistan, and the Horn of Africa, hundreds of kilometres of border security fences were rapidly erected on both the external and internal borders of the EU with no environmental assessments concerning their design or placement. This is in conflict with the concept of transboundary cooperation which emerged as the major conservation paradigm for large carnivores and much other wildlife in Europe over the last decades.

The removal of many border fences after the fall of the Iron Curtain allowed the creation of transboundary protected areas. Restored habitat connectivity together with the harmonisation of legislation across borders resulted in a tremendous recovery of large carnivore populations in Europe. Given their extensive spatial requirements, large carnivores obviously benefited from their renewed access across the continent’s borders.

Similar processes have been ongoing in the Caucasus and Central Asia following the dramatic socioeconomic and political changes after the collapse of the Soviet Union. On the one hand, the importance of Central Asia as a hotspot for the conservation of large herbivore migrations is increasingly recognized; and so is the significant role of the transboundary wildlife conservation across the region. On the other hand, in response to recent regional security concerns, border fences have been reinforced, or newly erected, leading to increased mortality and fragmentation of wildlife.

For example, the almost entirely fenced 4,710-km Mongolian–Chinese border presents an absolute barrier for the Asiatic wild ass (Equus hemionus) known as khulan in Mongolian. Interestingly, the associated 10-km limited entry security zone on the Mongolian side seems to have become a winter pasture refuge for khulan in the southeastern Gobi, while their population status in the adjacent Chinese autonomous region of Inner Mongolia is uncertain with illegal hunting remaining a major problem.

In southwestern Mongolia, on the other hand, there are large populations of khulan on both sides of the fence (thanks to a tight control of firearms in the adjacent Chinese autonomous region of Xinjiang) and experts believe that implementing wildlife crossings would be greatly beneficial here.

[Fig 3: Extent of border security fencing along national borders in Europe and Central Asia]

Impact of habitat fragmentation on large carnivores in the Dinaric Mountains

In their paper, the authors claim that there is a huge amount of border fencing in the study area (about 30,000km), although it is difficult to assess its exact extent due to the national security considerations and often restricted access to border areas. It is clear, however, that particularly in Eastern Europe and Central Asia, the opportunities for wildlife to roam across borders decreased significantly. Migratory large herbivores and large carnivores are likely to be the most affected.

The highly controversial construction of razor-wire fence along the border between Slovenia and Croatia (mentioned at the beginning of this article) attracted the attention of media to the impacts of security fencing on wildlife. The fence cuts through some of the best-preserved nature areas in the Dinaric Mountain range, most of which are covered by the Natura 2000 network and are the home to many rare and endangered species including three of Europe’s large carnivores: the brown bear, the grey wolf, and the Eurasian lynx.

The Dinaric lynx population, reintroduced in 1973 and already threatened by its small size and a high degree of inbreeding, appears to be in the most imminent danger. The conservationists worry that “the fence construction could just mean the last push for the population to spiral down the extinction vortex”.

The viability of Slovenian wolf population also seems to depend on its connectivity with the core meta-population in the south. Five out of country’s 10 or 11 wolf packs have their home ranges on both sides of Slovenia–Croatia border.

The bear populations in Slovenia and Croatia seem to be large enough to persist in the short term. However, the scientists warn that both countries would have to adapt their hunting/culling regimes to prevent local over-harvest in the view of limited cross-boundary movement.

[Fig 1: A: A border security fence being constructed along the border between Slovenia (SLO) and Croatia (HR) separates all three large carnivore (LC) species in Slovenia from the core population areas in the Dinaric Mountains. B: The expected effect of the fence on brown bears. Points are individual bears, genetically sampled from bear mortalities between 2003 and 2013 (N = 1,414). Lines showing full siblings or parent–offspring relations between individuals demonstrate that the border between both countries, where the fence is now being constructed, had, up until now, no effect on movement and gene flow in this bear population). C,D: GPS telemetry tracks of lynx (C, N = 11) and wolves (D, N = 28) show that these animals had no problems crossing the border before construction of the fence, and even had home ranges that straddled the border.]

So far, most of the animals killed by the razor-wire have been roe and red deer. The images of animals dying after becoming entangled in the coils of wire soon made media headlines. Local people claim that the official numbers of killed animals are greatly underestimated. The Slovenian conservationists (some of them being among the authors of the PLOS Biology paper) fear that what was supposed to be a temporary measure could become a permanent feature.

Border fencing and international legislation on nature conservation

The Guardian has reported that the Slovenian government is currently seeking to exempt fence-related construction from “regulations governing environmental protection, nature conservation, and water”. The issue highlights the question of border fences compatibility with relevant international legislation in the field of wildlife conservation.

The construction of border fences may be violating some important wildlife treaties, most notably the UNESCO World Heritage Convention, the Convention on Migratory Species, the Convention on Biological Diversity, the Bern Convention, and the Habitats Directive. All of these stress the need to avoid and remedy fragmentation and ensure adequate connectivity of wildlife habitats. Under Article 6 of the Habitats Directive – which is binding for the EU member states including Slovenia – protected sites have been designated for key species as part of the Natura 2000 network. Any projects that may adversely affect such protected sites may only go ahead if a prior comprehensive assessment has conclusively ruled out such effects. It appears that in various European countries, which are home to wolves, brown bears, and Eurasian lynx, this provision has been violated.

Mitigating negative impacts of border fences

In their conclusion, the PLOS Biology paper’s authors stress the importance of conservation biologists increasing their presence in national and international debates surrounding the issue. Decisions must only be made based on a transparent assessment of the full range of costs including impacts on wildlife.

Border security fences need to be placed more thoughtfully based on animal tracking data and wildlife crossing structures should be incorporated as suitable. Effects of different fence designs on the habitat fragmentation also need to be studied more systematically. The authors expect that the latest generation of fencing (such as two-metre-high panel fences increasingly used in Slovenia) is likely to constitute an even greater barrier than the older models.

The current geopolitical situation could mean that conservationists will have to recognise the impacts of security fencing on habitat fragmentation and adapt population management accordingly. It will be necessary to improve our knowledge and understanding about border fences and their effect on wildlife. This would require close cooperation between wildlife biologists and researchers within the field of geopolitics, as well as effective communication between scientists and policy-makers, and cross-sectorial cooperation between different government agencies.



Linell, J. D. C. (2016). Border Security Fencing and Wildlife: The End of the Transboundary Paradigm in Eurasia? PLOS Biology | DOI:10.1371/journal.pbio.1002483.

Neslen, A. (2016). Balkan wildlife faces extinction threat from border fence to control migrants. Guardian.com

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