Is wolf culling necessary?

The 2012 killing of two she-wolves, Tonka and Tia, has fuelled a lively discussion in the media and among the general public about wolf culling in Slovenia. Is the cull too large, too small or necessary at all? Also, signatures are being collected for a complete ban on culling. The response to such subjects is frequently sentimental and thus varies from person to person. But what does scientific research say about culling?

The wolf is certainly among the best-studied animal species on the planet. For a long time, Slovenia remained behind other countries, but much has changed in the last few years with regard to research into wolves. This is largely due the 4-year SloWolf project, mainly financed by the EU. The project helped us acquire new knowledge on the wolves living in Slovene forests. For example, we learned that the average population is between 32 and 43 wolves (before and after the hunting season, respectively), which are spread among 10 to 12 territorial packs, with 4 to 5 territories extending into Croatia.

Over the past few centuries, wolves were ruthlessly hunted – until 1973 the country even offered rewards to those who killed wolves. By that time the Slovene wolf population was almost completely wiped out, but it was an initiative from hunters to protect wolves that saved them from complete extinction. Today the wolf is protected by several national and international regulations, conventions and directives; however, in some cases culling is still permitted. These exceptions have been in effect in Slovenia since 1999, when wolves once again began to be shot. For a long time, hunters kept reducing the wolf population under the pretence of protecting livestock and “population control”. However, after 10 years of such interventions, the newly-acquired data indicates that culling does not solve the problem. Why?

To answer this question, we must first understand how the wolf population functions. Unlike other Slovene carnivores (e.g. the Eurasian lynx and the brown bear), wolves live in groups. They have a complex social system based on their basic social unit – the pack. It usually consists of a family led by a dominant alpha pair, the alpha male and alpha female, while the other members are their pups from different litters. The young ones usually remain in the pack with their parents for a few years before setting out to find their own territory and a mate. The alpha pair stays together for the rest of their lives, which can in natural conditions amount to 10 years or more. This is very important for the functioning of the pack, since strong social bonds develop over the years, making the pack an efficient team. Hunting large herbivores, such as the red deer, roe deer, and wild boar, is very demanding and requires good coordination between the key members of the pack. The cohesion of the pack is also essential for successful protection of their territory.

Since wolves have no natural predator limiting their population, a self-regulatory system has developed through the course of evolution. This prevents overpopulation of the species, which would wipe out their prey and inevitably lead to the wolves’ starvation. The system is based on territorial behaviour. Every pack aggressively defends its territory and chases off or even kills any wolf that is not part of the pack. This has been shown in many studies that used telemetric collars to monitor wolves from different packs. A Slovene study has also shown that neighbouring territories are strictly separated or may overlap only slightly. This ensures that the pack is the only one hunting on its territory, which retains the sustainability of their prey. The size of their territory (around 40,000 ha in Slovenia) depends on the population density of the prey – the greater the game population, the smaller the territory. It is therefore not surprising that game is not wiped out and that there is no overpopulation of wolves even in areas where there is no human intervention. They are limited by the available space and their own internal population control.

Even the size of the pack is regulated – when it becomes too large, the oldest cubs must leave. The size of the pack depends on the size of the main prey. In Slovenia, this is the red deer, which means that packs usually consist of 2-10 wolves. However, in areas where the main prey is moose or buffalo, the pack can be up to three times larger. After youngsters leave the pack, their survival depends on whether or not they are able to find an unoccupied territory. Since most are occupied, only a small percentage of young wolves survive, while the rest are usually killed by other territorial packs that are protecting their areas from intruders. However, increased human intervention leads to instability in packs and many vacant territories for young wolves to occupy. This is why culling does not affect the size of their population (unless, of course, it is completely wiped out). However, it may interfere with the functioning of the packs. If one of the alpha wolves is killed, the structure of the pack collapses and it often breaks up. The first genetic studies of Slovene wolves have shown that our packs are highly unstable. Because of extensive culling (recently amounting to about a quarter of the wolf population per year), the natural structure of packs frequently collapses. This is why packs, as well as the entire population, no longer function naturally, despite the unchanged size of the wolf population.

When we understand how the wolf population functions, it becomes clear why extensive culling cannot prevent attacks on livestock. The size of the pack does not affect their hunting frequency. In fact, research has shown that a pack becomes less efficient in hunting game after one of its members is killed off. This is why the surviving members usually begin hunting easier targets, such as unsupervised livestock. This results in an apparent paradox: despite extensive culling, the number of attacks on domestic animals does not decrease – for a short time it can even increase. The same goes for cases where an entire pack is killed off. Unoccupied territories are quickly taken over by young wolves that are less experienced and therefore hunt livestock, which is a much easier target.

Research has shown that wolf culling has negative consequences as far as limiting damage to livestock and restricting the population are concerned. However, there might be some positive effects. These mostly relate to people. A complete ban on legal hunting usually leads to an increased level of poaching. A legalised cull also partly satisfies those who are against wolves. In recent years, opinion polls have shown that people who live in wolf areas have a positive attitude towards them and are in favour of their protection. Nevertheless, as with most things, we shall probably have to compromise. Though the culling of wolves for the sake of damage control and establishing balance in the territory is senseless and unnecessary, in the current social climate it is probably reasonable to permit a minimal cull as long as thus does not destroy their social structure. In the end, the future of wolves lies in our hands and depends on our ability to make compromises.

 

Author: Miha Krofel, biologist.

 

Translated by: Ernest Alilović.

 

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