Wildlife bridges and spatial planning are more effective than culling

Switzerland has 303 supra-regional wildlife corridors. Of these, 47 – around 16 percent – are now largely disrupted and no longer usable for wildlife. Over half of the remaining corridors are significantly to severely impaired in their functionality. Every year, nearly 21,000 medium to large wild animals die on Swiss roads and railways, including over 8,000 deer – statistically, one deer every hour. Over 100,000 amphibians are run over annually. More than 100 people are injured each year, and the property damage amounts to tens of millions of Swiss francs.

What the hobby hunting community makes of this is remarkable: they declare themselves the solution to the problem. Culling, they argue, reduces wildlife populations and thus wildlife collisions. Preventing damage to roads caused by wildlife is used as a justification for hobby hunting, especially where other justifications no longer hold water. However, science, practice, and experience from Switzerland and across Europe clearly show that the effective answers to habitat fragmentation and wildlife collisions are wildlife bridges, wildlife crossings, scent fences, wildlife warning systems, and consistent spatial planning – not culling.

This dossier shows why habitat fragmentation is a structural problem that requires structural solutions, why recreational hunting does not solve the problem but sometimes exacerbates it, and why Switzerland, despite a good legal foundation, is decades behind the demand.

You can find more background information on lobby arguments for recreational hunting in the dossier Hunting Myths: 12 claims you should critically examine .

What awaits you here

Habitat fragmentation: What it means and why it is the central wildlife problem of our time. How roads, settlements, and railway lines are cutting animal habitats into ever smaller islands, what this means for populations, genetics, and survival chances, and which species are particularly affected.
303 corridors, 47 interrupted: The state of Switzerland's wildlife corridors. What the FOEN inventory shows, where the biggest gaps lie, why national roads form the biggest barrier, and how far the restoration has progressed.
Wildlife bridges and wildlife crossings: What they can do – and what research says. Why green bridges are effective for all terrestrial animal groups, what 2,300 wild animals per bridge per year means, and which factors determine success or failure.
Wildlife collisions: 21,000 fatalities per year and the hidden figures. What the Swiss wildlife collision statistics reveal: which groups of people are harmed, what costs are incurred, and why the official figures are systematically understated.
The hunting argument: "Shooting animals prevents wildlife collisions." Why this claim doesn't hold up scientifically, how driven hunts and night hunting causally increase wildlife collisions, and what studies on population dynamics and road safety show.
Effective alternatives: scent fences, reflectors, wildlife warning systems, speed reductions : Studies show that non-lethal measures can reduce wildlife accidents by up to 80 percent, how technical wildlife warning systems work, and why a speed limit of 60 km/h on critical stretches of road saves lives.
Spatial planning as a solution: What consistent habitat networking means : how Pro Natura, BAFU and cantons secure corridors, what the Biodiversity Action Plan provides and why the restoration of Swiss wildlife corridors will take decades.
What would need to change : Concrete political demands: mandatory renovation with a deadline, mandatory wildlife warning systems, speed reductions, spatial planning reservation.
Argumentation : Answers to the most common justifications of the hobby hunting lobby.
Quick links : All relevant articles, studies and dossiers at a glance.

Habitat fragmentation: The central wildlife problem of our time

Wild animals need interconnected habitats. They migrate daily between feeding and resting places, seasonally between summer and winter habitats, and across generations so that young animals can disperse, populations can exchange information, and species can colonize new areas. What was once taken for granted is no longer possible for many species in Switzerland and Central Europe: roads, railway lines, settlements, canalized waterways, and intensively farmed land have fragmented the landscape into ever smaller islands.

The consequences are severe. Isolated populations lose genetic diversity because there is no longer any exchange with neighboring populations. Local events—a harsh winter, a disease, an extreme weather event—can wipe out entire populations if no immigration from neighboring areas is possible. Species that require large habitats or depend on seasonal migrations lose further options with every new road and every new settlement. Road traffic is now the most frequent cause of death for wild mammals in Switzerland, killing around half of those wild animals that do not die from recreational hunting.

This is not a niche issue in nature conservation. It is the fundamental structural problem of wildlife ecology in Switzerland, and it will not be solved by a single cull. Anyone who wants to seriously discuss wildlife protection, species conservation, and road safety must start here – not with hunting licenses.

More on this topic: Switzerland still hunts, but why? and Hunting and animal welfare: What the practice means for wild animals

303 corridors, 47 interrupted: The state of Swiss wildlife corridors

The Federal Office for the Environment (FOEN) has inventoried 303 supra-regional wildlife corridors in Switzerland. These corridors connect forest areas, bodies of water, and near-natural areas, forming the backbone of wildlife mobility in Switzerland. The results of the current inventory are sobering: only about 28 percent of the corridors function largely without restrictions. 47 corridors – 16 percent – are completely blocked and no longer usable by wildlife. More than half, namely 171 corridors, are significantly to severely impaired in their functionality.

The biggest barrier is the national highways. Since 2003, the Federal Roads Office (ASTRA), together with the Federal Office for the Environment (BAFU) and the cantons, has been working on the restoration of wildlife corridors that cross national highways – a total of 41 corridors of supra-regional importance. Progress is slow: in 2021, there were 44 wildlife bridges in Switzerland; the first were built in 1992 in the canton of Thurgau over the new A7 motorway. Further crossings, underpasses, and specialized small animal crossings are being added, but the restoration project will take decades, not years. In the canton of Zurich, the current restoration program encompasses 50 wildlife corridors and is designed in three phases over 24 years, from 2024 to 2044.

This situation was not caused by a wildlife population, and no culling will remedy it. It is the result of decades of spatial planning failures and requires spatial planning corrections.

More information: FOEN: Wildlife corridors and wildlife crossings and Pro Natura: Free passage for wild animals

Wildlife bridges and wildlife crossings: What they can do – and what research says

Wildlife bridges and wildlife crossings work. This isn't just the opinion of conservation groups, but the result of decades of research. A meta-analysis evaluating green bridges in Germany, the Netherlands, France, and Switzerland concludes that green bridges are suitable for all terrestrial animal groups to at least locally compensate for the fragmentation effects of transport infrastructure. They are most effective when they not only serve as narrow crossing corridors but are integrated into the home range of the respective species.

The figures are impressive: On a wildlife overpass over the A11 motorway in Brandenburg, almost 2,300 wild animals were recorded between May 2005 and April 2006. The crossing was used not only by larger wild animals, but also by invertebrates such as butterflies, spiders, and beetles. Monitoring by the Baden-Württemberg Forest Research Institute at 66 wildlife crossings – from large overpasses to small animal underpasses – documents that bridges are suitable as crossing aids and habitats for a wide variety of species and make a significant contribution to connectivity. For the European wildcat in Luxembourg, DNA analysis proved that at least nine different individuals used a single wildlife overpass as a migration corridor.

Crucial for success: width. The wider a bridge is, the better it is used. Narrow bridges without cover are avoided by shy species. A bridge at least 50 meters wide with natural vegetation achieves significantly higher usage rates than narrow, "budget" models. This has consequences for planning: those who cut corners on wildlife bridges compromise their effectiveness.

More information: Canton of Zurich: Wildlife corridors and FOEN functional monitoring of wildlife crossings (PDF)

Wildlife collisions: 21,000 deaths per year and the unreported cases

According to official statistics, nearly 21,000 medium to large wild animals die in road accidents in Switzerland every year – including over 8,000 deer, as well as foxes, badgers, hares, wild boar, and occasionally red deer. Over 100,000 amphibians – primarily frogs and toads – are run over annually. Around 90 percent of accidents occur on roads, the remainder on railways. In addition, over 100 people are injured each year, and the property damage from reported insurance claims alone amounts to tens of millions of Swiss francs: insurers such as AXA and Helvetia report thousands of claims annually.

These figures must be interpreted with a crucial caveat: they are underestimates. Only accidents reported to a game warden or authority are included. Smaller animals, nocturnal species, and accidents on secondary roads are often overlooked. In the canton of Zurich alone, around 2,800 wild animals died in road traffic in 2023 – and this only includes reported cases. The actual number is likely to be considerably higher across Switzerland than the official figure of 20,000. The Jura, Fribourg, and Graubünden regions, as well as the wine-growing region and the lakeside communities in Zurich, are particularly prone to such accidents.

What these figures also show is that the problem does not primarily concern wild animal populations as abstract numbers, but rather specific individual animals that die on a road at night – often after a long, agonizing process, far from any veterinarian, unnoticed by authorities and the public. Around half of the animals found on the road show bite wounds or other injuries sustained during hunting, suggesting that escape reactions caused by hunting pressure and driven hunts contribute causally to road deaths.

More on this topic: Dossier Hunting and Animal Welfare and Wild Animals, Fear of Death and Lack of Anesthesia

The hunting argument: "Shooting prevents wildlife accidents"

The argument is old and persistently repeated: Fewer wild animals mean fewer wildlife collisions. Therefore, culling is a means of road safety. At first glance, this sounds plausible. On closer inspection, however, it doesn't hold up empirically or ecologically.

First, population ecology studies show that intensive hunting can decimate wildlife populations in the short term, but not reduce them permanently, because losses are compensated for by increased reproduction rates. This is especially true for deer and wild boar: the population regulates itself through the resource capacity of the habitat, not through hunting quotas. Those who hunt create space for young animals in the short term – and thus increase the reproduction rate. Second, research shows that driven hunts and battues actively flush out wild animals and cause them to panic. Hunted animals cross roads in mortal fear that they would otherwise avoid. PETA states: "Hunters are partly responsible for many wildlife collisions. During hunts, especially large driven hunts, the animals are flushed out. They flee and run in mortal fear across roads and into settlements."

Thirdly, the argument against hunting is most clearly refuted in the canton of Geneva, which has managed without any recreational hunting since 1974: The number of wildlife-vehicle collisions in Geneva is no higher than in cantons where hunting is permitted. What makes the difference are structural measures: speed reductions, wildlife warning systems, and habitat planning. This demonstrates that road safety and wildlife protection are planning tasks, not hunting tasks.

Effective alternatives: scent fences, reflectors, warning systems, speed reductions

Between the extreme poles of "doing nothing" and "shooting wild animals" lies a broad spectrum of scientifically proven, non-lethal measures for reducing wildlife accidents, which are far more efficient in their overall effect than shooting.

Scent fences and wildlife reflectors, as demonstrated in a long-term study conducted jointly by the ADAC (German Automobile Club) and the German Hunting Association, reduced wildlife collisions by up to 80 percent on well-secured test sections. While their effectiveness is focused on specific road types and animal species and requires regular maintenance, the effect is measurable and reproducible. Acoustic wildlife warning systems that react to vehicle movements and emit ultrasonic signals have proven effective at critical hotspots. In the canton of Zurich, an improved warning system is being tested along Lake Zurich, specifically targeting the most accident-prone sections of road.

Speed limits on critical road sections – especially 60 km/h at night on known crossing points – are easy to implement and significantly reduce both the probability and severity of collisions: A 20-kilogram deer has an impact force of approximately one ton at 100 km/h. While wildlife fences along national highways prevent crossings, they simultaneously exacerbate habitat fragmentation – therefore, they are only ever effective in combination with wildlife crossings, never as a standalone measure. Acoustic deterrent methods, such as the "wild boar deterrent" tested by the Zurich University of Applied Sciences (ZHAW), show promising results in agriculture and could sustainably influence wildlife behavior near roads without harming a single animal.

More on this topic: Alternatives to hunting: What really helps without killing animals, and an initiative calls for "game wardens instead of hunters"

Spatial planning as a solution: What consistent habitat networking means

Wildlife corridors are enshrined in Swiss law: the network of corridors is a legal mandate, and their restoration is part of the federal government's action plan for the biodiversity strategy. The Federal Office for the Environment (FOEN), the Federal Roads Office (ASTRA), and the cantons are working together. The foundations are sound.

The problem is the pace. The restoration of the 51 interrupted corridors along national highways has been underway since 2003 – for over 20 years – and is still not complete. In the Canton of Zurich, the restoration program for 50 corridors is designed to last 24 years. Pro Natura has been demanding for years that impaired or interrupted corridors be made passable again and that the movement needs of wildlife be taken into account from the outset in the planning of new infrastructure. The Federal Office for the Environment is accelerating the restoration programs within the framework of the Biodiversity Strategy – a step in the right direction, but one that should not obscure the fact that new fragmentations are created for every restored section as long as spatial planning and building regulations do not enshrine a consistent corridor protection principle.

What a truly consistent approach would entail: a legally binding corridor reservation for all spatially impactful projects under federal law, an accelerated renovation program with clear deadlines instead of decade-long plans, a requirement for wildlife warning systems on all statistically accident-prone stretches of road, and the consistent strengthening of near-natural land use in corridor zones to ensure the continuity of hiking trails even between bridges and passages.

More information: FOEN: Wildlife corridors and Canton of Lucerne: Wildlife corridors and wildlife crossings

What would need to change

Federally binding corridor reservation for infrastructure projects : Currently, wildlife corridors must be considered in new road, rail, and settlement projects – but the binding nature of this requirement is incomplete. A clear legal framework is needed that fundamentally prevents the fragmentation of existing or planned corridors and ties exceptions to strict compensation obligations.
Accelerated rehabilitation program with deadlines : The ongoing rehabilitation of the 51 interrupted national corridor sections must be given binding completion deadlines. A 24-year plan is not a rehabilitation program, but rather a postponement. At the current pace, interrupted corridors will be restored decades too late.
Mandatory wildlife warning systems on accident-prone stretches of road : The cantons maintain wildlife accident statistics. This data must be systematically analyzed and used as a basis for mandatory wildlife warning systems, scent barriers, or speed reductions on accident-prone stretches of road. A wildlife accident hotspot left untreated is an avoidable decision.
Speed reductions on wildlife crossings : On road sections that intersect known wildlife crossings, especially during dusk and nighttime hours, a speed limit of 60 km/h must be the standard. Reducing the impact weight decreases the severity of accidents for both animals and humans.
Integrated wildlife management instead of culling quotas : Cantonal hunting authorities and spatial planning authorities must work more closely together. Wildlife management must no longer mean setting culling quotas. It must mean connecting habitats, creating buffer zones, and systematically prioritizing non-lethal conflict resolution.
Publicly accessible, complete wildlife accident statistics : Not all cantons publish comparable wildlife accident figures. A standardized, publicly accessible monitoring system with mandatory reporting requirements creates the data basis needed for evidence-based measures.
Sample proposals: Sample texts for proposals critical of hunting and protecting forests from recreational hunting

Argumentation

"Less game due to culling means fewer wildlife collisions." This is true in the short term and locally in certain situations. In the long term, wildlife populations compensate for losses through increased reproduction rates; the population recovers quickly. Furthermore, driven hunts and battues show a causal link to increased wildlife collision rates: Startled animals cross roads in mortal fear that they would otherwise avoid. The Canton of Geneva has had no recreational hunting since 1974 and has not experienced a comparatively higher number of wildlife collisions. This is the clearest empirical refutation of the argument.

"Wildlife bridges are too expensive – hunting is much cheaper." A wildlife bridge costs several million Swiss francs, depending on its width and location. But it lasts for decades, improves biodiversity, permanently reduces accidents, and doesn't create new problems. Culling is periodic, generates follow-up costs through increased reproduction, and doesn't solve the underlying problem – habitat fragmentation – at all. Anyone who calls wildlife bridges too expensive must ask themselves why they don't compare the cost of hunting, the tens of millions of francs in wildlife-vehicle damage, and the long-term loss of biodiversity.

"Wildlife corridors are useless if the animals don't use them." Research shows the opposite: Wildlife bridges are used by all terrestrial animal groups, from large mammals to invertebrates. Crucial factors are width, vegetation, and connection to near-natural areas on both sides of the passage. Narrow or poorly designed bridges do indeed function less effectively – this is an argument for better planning, not against wildlife bridges per se.

“Hunting regulates wildlife populations that would otherwise get out of control.” No wildlife population “gets out of control” without humans having altered its habitat, its predators, or its food sources. Where wildlife populations actually cause problems, non-lethal measures—scent fences, deterrent systems, habitat modifications—are often more effective and lasting than culling, which doesn't address the underlying problem.

"Pro Natura and other nature conservation organizations support hunting as a tool." Pro Natura consistently advocates for wildlife corridors, green bridges, and spatial planning. Where nature conservation organizations do not fundamentally reject individual hunting measures, this is not support for recreational hunting, but rather the result of pragmatic compromises within a system that offers no better alternative. As soon as non-lethal alternatives exist, the argument for hunting loses its validity in nature conservation.

"Switzerland has one of the best wildlife corridor systems in the world." Switzerland has a good inventory and a sound legal framework. However, 47 completely severely disrupted and 171 severely impaired corridors out of 303 supraregional connections are not a success. The restoration program has been running since 2003 and is designed to last for decades. It needs more speed, more funding, and more political will – not self-congratulation. bafu.admin+1

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Our claim

Wildlife corridors, wildlife bridges, and consistent spatial planning are not romantic conservation ideas – they are the only solutions that truly address the fundamental problem of habitat fragmentation. Culling does not solve this problem. At best, it masks it temporarily and creates new problems: increased reproduction rates, stress-induced abnormal behavior, panicked escapes across roads, and – as the Canton of Geneva has demonstrated since 1974 – no measurable advantages compared to a hunting-free, spatially rigorous alternative.

A wildlife policy that takes biodiversity and road safety seriously invests in wildlife bridges, accelerates the restoration of disrupted corridors, mandates wildlife warning systems at accident hotspots, and stops offering culling as a panacea for problems that require structural solutions. Switzerland has the legal foundation and the scientific knowledge to do so. What is lacking is the political will and the necessary speed. This dossier is continuously updated as new studies, planning reports, or political decisions necessitate it.

More on the topic of hobby hunting: In our dossier on hunting, we compile fact checks, analyses and background reports.