According to new research, about 100 additional wolves died in Wisconsin during the winter due to the delisting grey wolves under Endangered Species Act. This was in addition to the 218 wolves that were killed by licensed hunters during Wisconsin’s first public wolf hunt.
Between April 2020 and April 2021, the state's total wolf population fell between 27% to 33%. Researchers believe that the majority of these uncounted deaths could be attributed to cryptic poaching. This is where poachers conceal evidence of illegal killings.
These are the first estimates of Wisconsin's Wolf population since February's public hunt, which was ended in the early hours of February after hunters exceeded their quota of only 119 wolves in a matter of days. These population estimates will help the Wisconsin Department of Natural Resources prepare for the next legally required wolf hunt in the fall.
These documents also serve as guidance for other states that plan wolf hunts after the end of federal protections, announced in November 2020. They are effective January 2021.
The research was performed by University of Wisconsin-Madison scientists Adrian Treves and Francisco Santiago-vila, who are environmental specialists at the University of Wisconsin. It was published in the journal PeerJ on July 5.
The researchers found that Wisconsin currently has between 695 to 751 wolves. This is a significant increase in population compared to the 1,034 wolves last season. Because they used optimistic assumptions about population growth, low poaching rates and wolf numbers in their models, this is likely to be the current maximum wolf population.
This is despite the 119 wolves hunting quota for non-native hunters. It was established with the goal to maintain the state's wolf population, but not decrease it. Ojibwe Tribes were allowed a quota for 81 wolves but did not hunt.
Treves, who is also a professor at the Nelson Institute for Environmental Studies, and director of UW-Madison's Carnivore Coexistence Lab, says that although the DNR aims for stable populations, they estimate that the population actually fell significantly.
According to the new study, about one-third is attributable to hidden deaths in the Wolf population due to loosening legal protections.
The Treves laboratory has previously shown that the wolf population grew in Wisconsin and Michigan after legal protections were relaxed. This was regardless of how many wolves had been legally killed. Santiago-vila was the one who conducted research that showed that Wisconsin's wolves and the closely monitored Mexican wolves in the American Southwest vanished at higher rates after lethal control methods were permitted.
The lab of attitudes towards wolves also found that governments that allow lethal management are more likely to permit poaching. This is because predators are perceived as less valuable.
These findings allowed Santiago-vila and Putrevu to model the uncounted Wisconsin deaths since November last year.
"During these periods we see an impact on poaching, both reported as well as cryptic. Santiago-vila, a postdoctoral researcher at the lab, says that wolves vanish and they are never found again. "Additional deaths can be caused by the policy signal and the wolf hunting adds to that."
Treves and his colleagues estimate that the population would recover within one to two years if it is not hunted. Wisconsin law allows wolves to be hunted between November and February, unless hunting is prohibited by federal protections.
The DNR originally planned to conduct the first hunt in October 2021 following the federal delisting and effective January 2021. After a lawsuit, however, the DNR implemented a wolf hunt immediately at the end February.
The research team hopes that Wisconsin DNR and other state natural resource agencies will use their methods to provide a better assessment of the impact of new policies on prey populations.
Putrevu, a doctoral candidate who studies tigers in the Russian Far East, says that these models and methods are readily available to them. They should use the best science available to achieve their goals.