Wolves endangered by illegal hunt
Poaching is the biggest threat to wolves in Norway and Sweden and can account for half of their deaths.
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An estimated one in every two wolves in Norway and Sweden is illegally killed by hunters, say researchers in a new study. In more professional terminology, about 50 percent of their mortality is attributed to the illegal hunt.
This means poaching has as much impact as all other factors combined – natural deaths, legal hunting and traffic accidents.
Scandinavian researchers presented similar figures in a report in 2006, but the new numbers cover an entire decade ending in 2009. In addition to data from wolves fitted with radio collars, probable results have been ascertained from all available data such as annual counts, DNA-charting and tracks in snow.
The results have been published in an article in the scientific journal Proceedings of the Royal Society B, which is already receiving international attention.
“The illegal hunt is as everybody knows a worldwide problem but its scope has been poorly documented for most stocks,” says one of the researchers, Petter Wabakken at Hedmark University College.
The data has been retrieved from Skandulv, the Scandinavian Wolf Project.
Wabakken says this article is special because researchers have succeeded in using several independent sets of data to define and numerically calculate the scope of illegal kills, which of course are undisclosed by the poachers themselves.
From 1998 to 2009, Norwegian and Swedish scientists radio-collared 104 wolves. This amounts to 10-15 percent of the wolf population.
Among these wolves with transmitters, 21 died of natural causes, road accidents or legal hunting, whereas five were confirmed kills by poachers.
When a radio-collared wolf is shot, the hunters often destroy the transmitter and hide the carcass. So the wolf disappears without a trace.
Researchers estimate that 18 radio-collared wolves vanished in this way as a result of the illegal hunt or other forms of poaching from 1998 to 2009.
As calculations of the undocumented hunt cannot be fully confirmed, the figures are controversial in Norway.
Minister of Justice in Norway, Knut Storberget, has said efforts will be stepped up to curtail poaching, but other officials have expressed their doubts about its magnitude.
In the new scientific article, the researchers from Norway, Sweden and the USA present figures indicating that the estimates based on radio-collared wolves are probably valid for the entire population.
According to these calculations the wolf population would be quadruple its current number had it not been for the illegal hunt.
It concludes that the stock could otherwise have been 990 animals in 2009.
Instead the estimated population of wolves in Norway and Sweden was 263 in 2008-2009. The Norwegian wolf population is so well monitored that researchers rule out the existence of many wolves in the forest that are unknown to them.
The illegal wolf hunt hasn’t stopped a gradual increase in the wolf population of the neighbouring countries, but it has affected the speed by which the population has propagated in Norway and Sweden combined.
Most of the Scandinavian wolves are found in Sweden.
“Although the population has continued to mount, the rate reduction caused by illegal hunting has had other negative consequences,” the researchers write in their article.
They assert that the illegal hunt has hindered the authorities from being more flexible about issuing hunting permits. As a result the conflicts between the wolf and farm animals in rural societies have escalated.
They also think that the genetic situation for the Scandinavian wolf population due to inbreeding has become more acute than it would have otherwise.
The unregistered elimination of individual animals poses a serious research problem for biologists. This is true whether conducting research on poaching of Siberian tigers in Russia or pirate fishing of cod in the Barents Sea.
Mortality – the share of the stock that dies annually – is a key factor when advising authorities about management.
The uncertainty and hidden statistics stemming from poaching make it even more difficult to resolve conflicts regarding predators such as wolves.
Researchers have stringent criteria for determining the wolves that can be noted as illegally killed when other documentation is lacking.
They are given this status when the radio signal is suddenly or unexpectedly cut off, when at least two aerial searches are made with radio searching equipment across large areas and when the wolf is not found by tracking or genetic analyses.
In addition, evidence that the wolf had recently been in the area must have been confirmed from tracks and genetic analyses.
An exception was made from these criteria in two cases when the radio contact was inexplicably broken and special circumstances made the cause evident – police has reported poaching in the area.
Increasing in Norway
“As regards the illegal hunt, our numbers are more likely to be an underestimate than an overestimate,” says Petter Wabakken at Hedmark University College.
He adds that no comparable study has been made with other predators based on such extensive data.
Wabakken says the data from the past two or three years seems to indicate that poaching is increasing more in Norway than in Sweden. The Swedes, who have a much larger stock than Norway, started issuing licences for wolf hunting last year.
If it not were for poachers the situation would be totally different and it is conceivable that Norwegian politicians would also have allowed a regulated and licensed hunt.
Calculations are based on the fact that the wolf population is not being naturally culled by limits in their growth such as access to territory or prey – primarily moose.
“The background here is that we have such large stocks of animals in the deer family yet the wolf population is so low. We are nowhere near the ceiling,” says another of the researchers behind the article, Hans Christian Pedersen at the Norwegian Institute for Nature Research (NINA).
He explains that the situation in North America is completely different. If a comparable study were conducted there, scientists would have to take into account that wolf populations in many areas have been so well replenished that they are now decreasing by natural causes.
Read this article in Norwegian at forskning.no - Norwegian online newspaper about science
Translated by: Glenn Ostling
- Olof Liberg et al: Shoot, shovel and shut up: cryptic poaching slows restoration of a large carnivore in Europe, Proceedings of the Royal Society B: Biological Sciences, 17. august 2011. Abstract