Wolf population in Wisconsin (Extended)
Department of Forest and Wildlife Ecology
UW-Madison College of Agricultural and Life Sciences
Phone (330) 465-8176
6:34 – Total Time
0:21 – Wolf population
0:40 – What kills wolves
1:12 – Wolf numbers
1:26 – What affects population
1:53 – Biological and social limits
2:27 – Population management
2:56 – Risks of pack reduction
3:36 – Surprises about the wolf population
4:24 – A wolf sink
5:04 – Different management in other states
5:44 – A sable wolf population
6:25 – Lead out
Sevie Kenyon: Jennifer welcome to our microphone. What is your investigation telling you about the wolf population here?
Jennifer Stenglein: What I look at are different causes of mortality across the state, how they vary in different regions; dealing with agriculture, road density, where there’s a lot of wolves, where there aren’t, and why they die from different causes basically in those different areas.
Sevie Kenyon: And can you tell us the kinds of things that kill a wolf?
Jennifer Stenglein: The main ones we keep track of are vehicle collisions, legal mortality; so those are when a wolf depredates or kills livestock and then Wildlife Services or DNR goes in and kills that animal, illegal killing, and also natural causes, which come in a suite of things like diseases, sometimes starvation, inter specied strifes—so when wolves kill other wolves over territory and things like that.
Sevie Kenyon: And what can you tell us about the population of wolves in the state?
Jennifer Stenglein: The winter population, so a low count, is around eight hundred, and they’re distributed in the northern part of the state in the forested areas and also the central part of the state.
Sevie Kenyon: Is there some optimal level where the wolf population would stabilize?
Jennifer Stenglein: So you could think of that biologically and then socially as well, and there is probably both a biological and a social carrying capacity and they’re probably not the same. So biologically we think the population may stabilize at a thousand or twelve hundred wolves, something like that, and socially we believe that level would be lower. And maybe even lower than the eight-hundred that we have right now
Sevie Kenyon: Can you explain the difference between the biological and the social?
Jennifer Stenglein: Yeah, the biological is what the land can support and what there is for prey. So wolves in Wisconsin are not prey limited, they have plenty of deer to eat, so they have prey resources, they have space resources, but when they start to get to the carrying capacity of one of those resources—in this case we think it’s space that [is] the biological limit of the population. The social is, in this case, we think lower than the biologically. So it’s what people, what humans, are willing to deal with on the landscape.
Sevie Kenyon: Can you tell us the objectives of population management?
Jennifer Stenglein: I think one of them would be to lessen some of the livestock depredation problems. To make sure that those aren’t happening, and then when they are happening to deal with them. I’d say that’s one, and it seems like most recently one of the goals of wolf management has been population reduction and to bring the population down to some level that I believe has yet to be determined.
Sevie Kenyon: Are there dangers in population reduction?
Jennifer Stenglein: There’s a lot of unknowns that have to do with population reduction, and one that I could talk about is the effect on the social structure of wolves. It’s again one of those unknowns we’re not real familiar with. We don’t have a lot of research yet to tell when we harvest how that effects the social structure, and how packs, which are typically made up of family units and Alfa or breeding male and female, and then multiple generations of pups that grow up, how those pack units are affected by hunting, and if they turn into something that isn’t as typical for a wolf population.
Sevie Kenyon: Jennifer what surprised you about the population dynamics of the wolf here in the state?
Jennifer Stenglein: One thing that really surprised me learning about this population is that, it’s not just the Wisconsin population we have to think about. There’s a big connection to the Upper Peninsula of Michigan and we ought to probably be thinking about this as one big population—Wisconsin, the UP of Michigan, and then probably even Minnesota, and the connection to Canada. So what we do in Wisconsin is in some ways, it depends on, and it affected by what Michigan and Minnesota decide to do. So right now these harvest rates, we’re probably not going to see as much of an affect of that as we could because Michigan and Minnesota right now are doing different things.
Sevie Kenyon: Can you give me an example of what you mean?
Jennifer Stenglein: If Wisconsin decides to harvest at high harvest rates, and Michigan decides not to, then Wisconsin becomes what we think of as a sink. Wisconsin becomes a sink— so population would actually decrease here, but a really strong healthy population in the Upper Peninsular of Michigan would then support this sink coming into Wisconsin so there’s the buffering effect that occurs because we aren’t just an island population, so the dynamics we see in Wisconsin are completely related to what our neighboring states were deciding to do for management as well.
Sevie Kenyon: What are they doing differently in the neighboring states?
Jennifer Stenglein: They’re harvesting at lower rates and Michigan has proposed a plan for harvest that effectively harvests about seven percent of the population, and in comparison to something like thirty percent which Wisconsin’s harvesting, and they’re also harvesting in Michigan based on where there’s a lot of depredation occurring. They’re trying to use harvest to target these problem areas, which is different. Minnesota is harvesting at about fourteen percent or so per year so that again is a little bit lower.
Sevie Kenyon: Jennifer can you perhaps describe for us what the wolf population as doing prior to the hunting?
Jennifer Stenglein: Looks like the growth of the population was slowing down and we have some more evidence of that because territory sizes were shrinking, so packs were looking like they were kind of getting closer together and using less area for filling up the space; the good available space. And we have seen some differences in causes of mortality recently too that may be more human influence causes of mortality. So as the wolf population has kind of been moving into more agricultural areas they are dying from different things, and potentially more rapidly because it’s not the prime habitat.
Sevie Kenyon: We’ve been visiting today with Jennifer Stenglein, University of Wisconsin, in the College of Agricultural and Life Sciences, Madison, Wisconsin, and I am Sevie Kenyon.