Self-Regulation of Wildlife Populations: Scientific Evidence from Geneva, the National Park, and International Comparisons

50 Years of Geneva, 110 Years of National Park: The Scientific Balance Sheet.

The question of whether wildlife populations can regulate themselves without hobby hunting is central to the legitimacy of Swiss hunting practices and highly politicized.

The hobby hunting lobby argues that without culling, the ecological balance would collapse. The opposing position, supported by long-term observations in the canton of Geneva, in the Swiss National Park, and by international research, tells a different story: wildlife populations are regulated primarily by food availability, predators, and habitat capacity — not by shooting quotas. This dossier brings together the scientific evidence and honestly examines where researchers genuinely disagree.

What to expect here

Canton of Geneva since 1974: 50 years of long-term experimentation in a densely populated canton with intact biodiversity and stable ungulate populations.
Swiss National Park since 1914: 110 years of hunting prohibition, scientifically documented biodiversity, and a nuanced reassessment of the deer problem of the 1980s.
Compensatory reproduction: why hobby hunting generates the very populations it claims to regulate. Evidence from wild boar, red deer, bear, puma, and jackal.
Where researchers disagree: browsing damage, predators as a substitute for hunting, and the scalability of the Geneva model.
International comparative findings: from Luxembourg to Yellowstone to the Słowiński National Park in Poland.
What must follow politically: concrete demands directed at the federal government, the cantons, and the research community.
Argumentarium: responses to the six most common objections to the self-regulation thesis.
Quick links: to related dossiers and study overviews.

Canton of Geneva since 1974: Europe's longest field experiment

The canton of Geneva is the world's unique long-term experiment in a hunting ban within a densely populated, intensively used economic area. On May 19, 1974, around two-thirds of Geneva's population voted to abolish the militia-based hunting system. Since then, twelve cantonal wildlife wardens of the «Police de la nature» have handled all necessary wildlife interventions.

What the data show after more than fifty years is remarkable. A cantonal long-term study documents a sharp increase in biodiversity since 1974. Despite its high population density, viticulture, and international airport, Geneva is today considered one of Switzerland's most biodiverse cantons. Lake Geneva and the Rhône have become waterfowl reserves of international significance. The number of overwintering waterfowl increased spectacularly after the hunting ban, with no comparable trend in neighboring cantons. The hare population density stands at 17.7 animals per 100 hectares, well above the Swiss average. Ungulate populations are also stable: around 100 red deer and 330 roe deer. Roe deer, red deer, and wild boar, which were considered nearly extinct in 1974, have reestablished themselves.

Public acceptance is overwhelming. In 2004, nearly 90 percent of Geneva's population voted against reintroducing hobby hunting. In 2009, the cantonal parliament rejected a corresponding motion by 71 votes to 5.

The Limits of the Geneva Model

Even critically minded researchers must acknowledge: the Geneva model is not a model without any regulation at all. As wildlife populations grew, significant forest damage caused by ungulates was documented, which necessitated the development of a forest-wildlife management plan in accordance with the FOEN implementation guidelines. As countermeasures, wildlife fencing was reinforced and targeted culls of roe deer were carried out, managed by professional game wardens.

The hunting-affiliated magazine «Tierwelt» notes that “so good that even the small canton cannot do without hunting,” and reports that the hare population had to be kept in check. In 2007, around 60 animals were relocated to Valais and France. In addition, growing wildlife populations increased the risk of wildlife-related accidents. Between 50 and 100 such incidents are reported per year.

The critical assessment is essential: the Geneva model refutes the claim that hunting-free systems lead to collapse. At the same time, it demonstrates that professional interventions remain necessary — but carried out by trained game wardens, not by armed hobby hunters. Fauna Inspector Gottlieb Dandliker states clearly that roe deer do not threaten the forest and that in the predominant oak forests, little damage is recorded.

More on this: Geneva and the Hunting Ban and Studies on the Impact of Hunting on Wildlife

Swiss National Park since 1914: the oldest experiment

Since its founding in 1914, the Swiss National Park has been legally protected as a reserve in which nature remains free from all human intervention, including hunting. It is thus the oldest and strictest hunting-free area in Switzerland.

Botanists in 1914 assumed that the former alpine pastures would quickly become overgrown. Research findings show the opposite. Species diversity rose from an average of 17 species per square meter in 1921 to 42 species per square meter in 2011. Female red deer keep grassland short through grazing, thereby promoting biodiversity. More recent studies show that the regeneration of young trees is less influenced by browsing and depends more on site-specific and climatic conditions. At current red deer densities, forest regeneration is by no means being prevented. A study published in 2025 in “Ecology and Evolution” also demonstrated how red deer contrrastingly adapt their habitat selection inside and outside the national park — evidence of complex behavioral adaptations in a hunting-free environment.

The deer problem of the 1980s: real crisis or political instrumentalization?

This is where the greatest scientific controversy lies. After the founding of the national park, red deer populations developed exponentially. In the 1980s, peak numbers of around 3,000 animals were reached. The causes were multiple: the national park lacks all natural predators, particularly wolves. Hunting outside the national park was, until the 1970s, primarily focused on stags — that is, trophy hunting — and was unable to curb population growth. Winter feeding outside the park additionally led to forest damage and winter mortality.

The high population levels led to repeated, massive winter die-offs, impairment of forest regeneration, and agricultural yield losses. This triggered political controversies between the 1950s and 1990s that shook the very foundations of the national park. The verdict of the national park's own research is, however, nuanced. The fears of an ecological catastrophe are, from today's perspective, considered to have been unfounded. Nevertheless, a hunting-based regulation of the red deer population was deemed appropriate. The solution was a two-stage hunt outside the protected area — a high hunt in September and a special hunt in late autumn — without violating the fundamental ban on hunting within the national park.

Interspecies competition: not just idyllic

Research findings from Val Trupchun show that at high red deer densities, chamois increasingly retreat to less food-rich scree slopes. The horn growth of chamois kids correlates negatively with red deer density. A higher deer population also negatively affects the population growth rate of ibex. A comparable pattern is shown by a Polish study from the hunting-free Słowiński National Park. There, high red deer densities significantly displaced the roe deer population through resource competition. Self-regulation therefore does not automatically mean harmony for all species simultaneously. It can be associated with dominant species that displace others.

More on this: The Chamois in Switzerland and The Red Deer in Switzerland

Compensatory reproduction: the strongest scientific counter-argument

A central biological principle supports the position of hunting critics: compensatory reproduction. Wildlife populations respond to losses from hunting with increased birth rates, earlier sexual maturity, and larger litters.

The evidence is international and crosses species boundaries. A French long-term study spanning 22 years demonstrated that hunting pressure significantly increases the reproduction rate of wild boar. Under normal circumstances, only the lead sow reproduces. When she is shot, all females in the group begin to reproduce. In Switzerland, red deer populations have risen from around 23,000 to over 40,000 animals between 2000 and 2024, even though the number of kills practically doubled during the same period. Hobby hunting preferentially targets males — and therefore trophies — which shifts the sex ratio in favor of fertile females.

International studies provide additional findings. Swedish researchers showed that female bears shorten the rearing period of their cubs in response to hunting pressure, in order to reproduce again more quickly. A study from Washington State refuted the "compensatory mortality hypothesis" for mountain lions. Heavy hunting correlated with increased immigration, lower juvenile survival rates, and a younger age structure — but not with the predicted population stabilization. In the case of the black-backed jackal, hunting led to a younger age structure and an expanding rather than stable population, as social regulation by older animals was eliminated.

These findings support the central argument of hunting critics: hobby hunting produces the very populations it claims to prevent.

More on this: Why hobby hunting fails as population control and Hunting myths: 12 claims critically examined

Where researchers actually disagree

Natural predators as a substitute for hobby hunting?

WSL researchers Andrea Kupferschmid and Kurt Bollmann show that wolves significantly alter the spatial behavior of ungulates and locally reduce browsing damage. However, this effect applies only to a limited degree, and the picture is more nuanced than simple causality. In the Calanda region, home to the first Swiss wolf pack, browsing damage to silver fir, maple, and rowan declined noticeably within the core territory. The influence of the lynx on roe deer browsing has also been documented, including through research conducted at BOKU Vienna in the canton of St. Gallen.

At the same time, forestry associations such as the Swiss Forestry Association have taken a clear position: “Large predators like lynx and wolf cannot solve the regeneration problem,” though they do influence the spatial distribution and behavior of ungulates. These associations therefore call for an intensification of hobby hunting. This is noteworthy because WSL data simultaneously show that forestry professionals rate wildlife impact as low or insignificant on around 68 percent of the assessed forest area.

Browsing damage: widespread and critical, or locally limited?

The 2025 Forest Report by BAFU and WSL confirms that excessively high wildlife populations in certain areas are impairing natural regeneration. At the same time, it identifies heat, drought, storms, and harmful organisms as greater stressors. According to WSL researcher Kupferschmid, forestry professionals rate wildlife impact as low or insignificant on 68 percent of the forest area. Only 5 percent is considered silviculturally intolerable. The browsing question cannot be answered with simple yes-or-no responses.

Transferability of the Geneva model

The hunting lobby's most common counter-argument is that Geneva is too small and too urban, and that the model cannot be transferred elsewhere. The counter-argument is substantively strong. Geneva is densely populated, has intensive viticulture, an international airport, and direct cross-border traffic with the hunting-intensive areas of France and the canton of Vaud. If professional wildlife management works in this context, there is no structural argument against transferability to larger, less densely populated cantons. However, scalability is a genuine research question. Geneva covers 282 square kilometers, Graubünden 7,105 square kilometers. Twelve cantonal game wardens are sufficient for Geneva. How many would Graubünden need? Reliable model calculations are lacking in the literature.

More on this: The forest-wildlife conflict in Switzerland and Wolf in Switzerland: facts, politics, and the limits of hunting

Overview of international comparative findings

Canton of Geneva, since 1974: Biodiversity is increasing, ungulate populations are stable, the brown hare is at a Swiss record high. Caveat: professional interventions continue to be necessary.
Swiss National Park, since 1914: Species diversity has increased significantly, with no ecological catastrophe. Caveat: the deer problem of the 1980s required special measures outside the park.
Luxembourg, ban on fox hunting since 2015: No epidemics, no explosion of fox populations. Limitation: short time series.
Yellowstone, wolf reintroduction: Behavioral changes in red deer, vegetation regenerates. Limitation: complex trophic cascades, not directly transferable to Central Europe.
Słowiński National Park Poland, without hunting: Red deer displaces roe deer through resource competition. Shows side effects in the absence of predators.

More on this: The Fox in Switzerland and Hunting and Biodiversity: Does Hunting Protect Nature?

What Would Need to Change

Recognition of scientific evidence: The federal government and cantons must incorporate empirical findings from Geneva, the National Park, and international research as a basis for decision-making in revisions of the hunting law. Scientific evidence must not be overridden by lobbying interests.
Independently funded long-term monitoring: An independently funded long-term study must document wildlife populations in Geneva, in the National Park, and in comparable hunting-intensive cantons in parallel over at least twenty years. Only then will the question of transferability be empirically answerable.
Pilot cantons for hunting-free zones: Two to four Swiss cantons test the wildlife warden model on designated areas with transparent cost calculations and open performance monitoring. Model motion: Wildlife Wardens Instead of Hobby Hunters.
Disclosure of shooting statistics: The trend of growing populations despite rising kill numbers — such as red deer increasing from 23,000 to over 40,000 animals in 24 years — belongs in the public debate. Compensatory reproduction is not a peripheral issue, but a structural argument against the regulation narrative.
Dialogue between forestry and wildlife biology: The browsing damage question is currently dominated by forestry associations that simultaneously advocate for hobby hunting. A joint working group comprising wildlife biology, WSL, cantonal authorities, and animal welfare organizations should develop viable alternatives.

Argumentarium: Objections to the self-regulation thesis, and what holds up

“Without hunting, populations will explode and nature will collapse.” Geneva has refuted this claim for 50 years, the Swiss National Park for 110 years. In both systems, biodiversity has not collapsed — it has increased. The core thesis of the hobby hunting lobby is empirically disproven.

“The Geneva model is not transferable because Geneva is urban.” Geneva has an international airport, intensive viticulture, and direct cross-border traffic to regions with heavy hunting activity. If wildlife management works there, no structural argument exists against it working equally well in less densely populated cantons. The question of scalability is a research mandate, not a refutation.

«Hobby hunting is necessary to regulate populations.» Compensatory reproduction demonstrates the opposite. Swiss red deer populations rose from 23,000 to over 40,000 animals, even though the number of kills virtually doubled. Hobby hunting produces the very populations it claims to prevent.

«Without hunting, forests will collapse due to browsing damage.» WSL data show that forestry professionals rate wildlife impact as low or negligible on 68 percent of forest area. Only 5 percent is considered silviculturally unsustainable. The 2025 Forest Report identifies heat, drought, and storms as greater stressors than browsing damage.

«Predators alone cannot regulate populations.» That is correct, and no one claims otherwise. The hunting-critical position is this: professional wildlife rangers, supplemented by natural predators and sensible habitat management, are sufficient. Hobby hunting is not part of the solution here — it is part of the problem.

«The deer problem of the 1980s shows that hunting-free zones do not work.» The assessment of national park research itself is nuanced: fears of an ecological catastrophe were, in retrospect, unfounded. A hunting-based management approach outside the park may well have been warranted, but the hunting ban within the park itself never needed to be touched.

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Our Mission

Self-regulation is not a theory — it is a 50-year field experiment in Geneva and a 110-year experiment in the Swiss National Park. The data show: wildlife populations stabilize, biodiversity increases, the ecosystem does not collapse. Compensatory reproduction exposes hobby hunting as a structurally ineffective management tool. The real question is not whether balance is possible without hobby hunting. The question is why political Switzerland has been ignoring this balance for decades.

The IG Wild beim Wild compiles the scientific evidence because an honest public debate about hobby hunting must begin with facts, not myths. This dossier is continuously updated as new studies, figures, or political developments require it.

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