Monday, December 31, 2012

DNR analyzing impact of wolf hunt


With Wisconsin’s first modern-day wolf hunt now history, biologists with the state Department of Natural Resources are already looking at the numbers, analyzing the impact of not only the 117 wolves killed during the season but also the 123 animals that died so far in 2012 in other ways.
Adrian Wydeven, a DNR ecologist who has overseen wolf recovery and studies the animals, said biologists have begun winter howling and tracking surveys that will allow them to determine the impact on the overall population of wolves as well as on individual packs. He said the data will also allow the agency to set population numbers and calculate whether the hunting season met the agency’s goal of reducing the statewide spring population — which is expected to be well over 1,000 wolves in the wake of breeding season — by about 10 percent.

Wydeven said he believes that goal was reached and that, even with the hunting season, the state’s wolf population remains at a healthy, sustainable level — a long way from the statewide population goal in the management plan of 350 wolves.

“The zones all achieved their quotas,” Wydeven said. “What the actual impact will be on the population, we won’t know until we finish our surveys in March . . . We know we still have lots of healthy packs out there.”

The final numbers show hunters and trappers killed 117 wolves statewide, one more than the DNR’s quota of 116.

Wydeven said that besides the 117 wolves killed legally during the hunting season, 123 additional wolves were also killed — hit by vehicles, killed by government agents as part of depredation control, killed illegally by hunters and trappers, or found dead from unknown causes.

By far the largest number of these additional dead wolves were killed under the depredation control program, which became legal after the wolf was removed this year from the endangered species list. Numbers from the DNR show that, under the new depredation policy, 19 wolves have been killed by landowners and 57 by agents with the U.S. Department of Agriculture.

In addition, the DNR reports that 19 wolves were killed illegally this year, compared to 25 last year. And 21 wolves were killed by vehicles.

Wydeven said the model used by the DNR to set quotas and arrive at the 10 percent statewide reduction in population took into account the mortality outside the hunting season.

The real story of the hunt, however, will be told when the DNR scientists begin drilling down to see what impact the hunt had on populations in each of the six hunting zones and on the individual packs within those zones.

Hunt quota too high?

Peter David, a biologist with the Great Lakes Indian Fish and Wildlife Commission, a group that represents the state’s Chippewa bands on hunting, fishing and conservation issues, said he fears that the DNR did not adequately consider the impact of all human-caused wolf mortality as it set quotas and managed the season in the individual zones. The commission and the state’s tribes opposed the wolf hunt on cultural grounds and refused to kill any of the 85 wolves allotted them under the quota system.

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But David said that, while the agency may have considered the additional dead wolves statewide, it was less precise in taking the added mortality into account in individual zones.

For example, David said, the estimated spring population in Zone 3, one of the areas in North Central Wisconsin designated as “secondary” range or moderately suitable for wolf habitat, was 93 animals. The state, after taking into consideration the tribal quota, set a quota in the zone of 18 wolves. Before the season, David said, 29 animals had been removed through depredation control. Hunters and trappers ended up killing 19 wolves, one more than the quota.

That means, David said, that 48 wolves out of the estimated population of 93 were killed this year, more than half of the total. In a report to the Natural Resources Board prior to the hunt, Wydeven said research has shown that wolves can tolerate up to about 29 percent to 35 percent human-caused mortality rates before populations decline.

“The wolf population in this zone, which is considered to be suitable wolf habitat in the state is getting hit very hard,” David said. “But the state seems OK with that since the statewide population is still likely to be over 350.”

Zone system worked

Wydeven, however, said the zone system did what was intended and spread the number of wolves killed more broadly across the state, protecting populations in core habitat and reducing numbers in areas not suitable for wolves.

Certainly, especially in southern and most of the central Wisconsin — part of a large Zone 6 that is considered unsuitable for wolves because of the proximity to farms and urban areas — wolves will likely be seen less frequently. Total population in these areas was pegged at 35 to 40 wolves prior to the season. Hunters and trappers killed 19 wolves during the season and eight wolves were killed through depredation control. The agency had no breakdown on wolves killed illegally or by vehicles in the zone. Even so, it would appear that the population in the area has been nearly eliminated.

Coming months will see more study and debate, Wydeven said, not only about how to set future quotas but also whether the current population goal of 350 wolves needs adjusting. Because hunters will be required to show wardens where they killed a wolf, the agency will be able to determine the impact of the hunt on specific packs, Wydeven added, an important consideration when quotas are set next year.

“How we’re going to set quotas next year is still a whole open area,” Wydeven said.