Researchers target areas where
wolves are most likely to attack livestock
By Susanne Quick
Milwaukee Journal Sentinel
If you knew you were more than twice as likely to get
roughed up in front of doorways that were painted blue
rather than red or green, you'd probably avoid those stoops
altogether, or at least get your police to patrol them.
In a way, identifying such danger zones is what a team
of Wisconsin, Minnesota and New York scientists have tried
to do - except, instead of targeting high-crime doorsteps,
the scientists have mapped areas where wolves are most
likely to attack livestock in the upper Great Lakes region.
And they hope this research will enable state and federal
wildlife agencies to focus their energy on potential hot
spots - allowing them to prevent and respond more quickly
to livestock killings, said Adrian Treves, lead author
and researcher at the Wildlife Conservation Society in
the Bronx, N.Y.
Their work appears in the most recent edition of the
journal Conservation Biology.
The loss of livestock to wolves in Wisconsin and Minnesota
has caused a lot of grief, anger and frustration among
livestock farmers who live in established wolf ranges.
According to the Wisconsin Department of Natural Resources,
wolves killed 20 cattle and 24 sheep on more than a dozen
farms in the state last year. They also killed one game
farm deer and six hunting dogs in the same period.
In Minnesota, where the wolf population is about seven
times larger than in Wisconsin, wolf numbers, trappings
and depredations were down last year - the result of the
nasty skin disease mange that has swept through the population.
Minnesota has nearly 2,500 wolves, and Wisconsin has about
But the livestock situation is likely to get worse, particularly
in Wisconsin, where the wolf population is increasing
and its range is spreading.
It is this fear, with a splash of anger over lost farm
animals, that has livestock farmers calling for wolf numbers
to be decreased.
And it is the acknowledgment that things will likely
get worse that has wildlife experts and conservationists
looking for ways to prevent, or at least soften, the inevitable
increase in domestic animals killed.
In search of a solution
According to Treves' and his colleagues' work, wolf management
is difficult. Outright killing of wolves is something
they hesitate to recommend, believing it can undermine
endangered-species protections and incite criticism from
groups other than livestock farmers.
But, they know doing nothing is not a solution, either.
Indeed, a recent study by Treves and his wife, Lisa Naughton-Treves,
a professor of geography at the University of Wisconsin-Madison,
showed that 36.5% of northern Wisconsin residents wanted
the state's wolf population maintained and 13% wanted
it expanded, while a similar percentage wanted the population
reduced (33.1%) or eliminated (17.4%).
These numbers leave management agencies in a predicament:
Anything they do is going to make somebody unhappy.
So Treves, Naughton-Treves, Adrian Wydeven, a wolf biologist
with the DNR, and others searched for a more efficient
method of management, one that would help state and federal
agencies anticipate and pinpoint future wolf attacks on
Currently, most of the wolf management zone in Wisconsin
is in the northern third of the state. Minnesota has two
zones - one with wolves and one without.
These vast expanses of land make it difficult for state
and federal agencies to monitor wolves, which can make
management ineffective, expensive and diluted.
By narrowing the zones to towns, Treves and his colleagues
believe they will enable agencies to manage the wolf problem
So, to create a new, focused system, the researchers
scrounged up data on wolf attacks on livestock and reviewed
the locations. Looking at 975 verified sites of livestock
killings by wolves in Wisconsin and Minnesota between
1976 and 2000, they analyzed each site.
They asked a series of questions: Was it in a prairie?
If so, how big? Was it in a crop field? Near conifer woodlands?
Open water? Wetlands? In a town?
Based on the localities of each of these incidents -
and the commonalities, if any - they tried to predict
where farmers would find future fatalities.
They discovered that wolf attacks tend to take place
in towns composed of lots of pasture with dense deer populations
but also have low proportions of cropland, coniferous
forest, herbaceous wetlands and open water.
The number of roads also seemed to be a factor: Fewer
wolf problems were reported in areas with lots of roads.
Entering this data into statewide maps, they were able
to pinpoint areas that are at high risk. Some of these
areas don't have settled populations of wolves anywhere
near them, but, if wolf populations continue to spread,
those areas could see some trouble.
Farm country prime target
One such place includes the livestock farms of southwestern
Wisconsin. The geography in this region could make them
prime targets for killings by wolves, if they were to
But this area may be a bit insulated because most of
the cattle are dairy, Treves said.
That's because dairy cows are generally kept close to
human-inhabited areas such as farmhouses.
The cattle most at risk, said Wydeven, are those that
stray from frequent human supervision.
"The best method for preventing wolf depredations"
is to have a person watching the herd 24 hours a day,
Other methods to keep wolves at bay - such as fences
and guard dogs - are not as effective, Wydeven said.
Fences can work, said Eric Koens, a livestock farmer
in Bruce and a director with the Wisconsin Cattlemen's
Association, though they have to be at least 8 feet highand
buried at least 2 feet in the ground to keep the wolves
from digging through.
And the maintenance would be formidable, he said.
David Mech, a senior research scientist with the U.S.
Geological Survey and a renowned wolf biologist, agrees.
"We just don't know of anything that would work
as a panacea" to prevent wolf depredations, said
Mech, who was not involved with the research.
"Where there are wolf and livestock, living side
by side, there's a good chance that at some point, they'll
prey on livestock," he said.
Treves and Wydeven disagree. They say there are good
packs and bad packs. Most wolf packs can live by cattle
or sheep farms for years and never attack. But there are
a few that do.
Although Wisconsin DNR officials have shown interest
in the map, they'd like to know if its powers of prediction
hold true before they start using it, Treves said.
The researchers will collect data on killings since 2000
and see how it fits with the map's predictions.
If the map predicted accurately, Koens and his fellow
farmers will, at the very least, be able to take preventive
measures if they are unfortunate enough to be in one of
the hot spots.