Doug Smith-Age Structure and Pack Composition of an Unexploited Wolf Population, Yellowstone
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Doug Smith-Age Structure and Pack Composition of an Unexploited Wolf Population, Yellowstone

October 18, 2019

– Okay, like Carrie, I
would like to recognize my co-authors, most everybody of which is on the Yellowstone Wolf Project. We all work together as a
team and I think we’re all proud of that and work
together quite well. But I’ve received scrutiny and criticism in the past for
exceeding time limits. So my plan is to finish my talk with a third to a quarter of my time left. So, I’m going to cover two major topics and I’m going to do so very brief… Actually three, but two
major points about wolves. And I’m going to try
and cover them briefly and finish and then the rest of the talk is details to support those conclusions in case you’re interested, but somebody will probably cut me off, and so I can just stop wherever I am. Although my last slide, I do like because it was from a horse trip a couple of weeks ago and I have a philosophical point with that slide. But, because this session seems to have a management empahsis,
I’d like to stress that our mission of restoration
and preservation of natural systems, the goal of my talk is to assess how well we’re achieving that Park Service mission of restoring and protecting natural systems. So I want to reflect on that. And because we’re talking about cross-boundary management,
I want to talk about the fact that our mission
is as close as you’ll get in the country to preservation. Which means no-use, but it’s not the pure definition of no-use. Many audience members have reminded me of that after my talks in the past. That the states… And we have representatives
from the states here today, their mission is
conservation which is wise-use. Both of those are worthy goals, and everything I’m going to talk about that we do in Yellowstone, doesn’t mean what the states do outside of Yellowstone is a less worthy goal. A very important statement. It’s just a difference in objectives determined by policy. So the main message of my talk, are what do wolf packs look like when they are not exploited by people? And there are actually very, only a handful of places in North America where wolves aren’t exploited by people. By far and away, the leading cause of mortality for wolves, is human caused. 80% in the Northern Rockies, and that’s not the case in Yellowstone. So we want to explore
what wolf packs look like in Yellowstone, in the
absences of human exploitation. And secondly, as a second objective, to look at what promotes
disbursal of wolves from Yellowstone and from
different recovery areas because this is an
important management metric that delisting depended on. And actually, we lost
a court case about it, that there was not adequate connectivity to the GYA and wolves were
relisted because of that. So, I want to explore what leads to greater connectivity or disbursal. So those are the two
objectives of my talk. But first, Oh, I got… Of what is natural and what should we be doing about it? Again, I’m not in-sync with my slides. Wildlife Division, manage
to help keep natural but should be primitive. The word primitive, primeval, baseline was used repeatedly
during these early times of George Wright and others, mostly from the University of California Berkley. The Absaroka conservation committee, it was the one, because this is when intensive elk management
started in the 30’s. Bison management, we started killing elk because we wanted to preserve the range. So this was intervention to restore kind of a balance of nature. And then the Leopold report. Management intervention was
stressed in that report. I find that interesting because in 1968 we went into a
period of natural regulation. But right out of that, preserve or restore natural biotic scheme. So we have been wrestling with this idea for natural for a long time. The 2012 version of the Leopold Report kind of eloquently written report, short on prescriptive recommendations but none-the-less they
kept saying throughout things like, “Preserve
ecological integrity.” They define that as self sustaining. “Strengthening resilience.” They define that as self regulating. I wrote down a quote to read from the latest version of the Leopold
Report, but you get the gist. And actually having
read that several times, you all should read that as well, it kind of opens the door for many different interpretations, which I think we got a dose of last night. For example, Monica Turner’s talk, I think many of us could
conclude two different things. Let it go, there’s nothing we can do. Yellowstone is going to burn more. Or, we should start putting out more fires so we can emulate the
historic fire frequency that Monica showed so much about. So we’re going to have different interpretations of the data. And what Monica talked about last night has already happened in
northwest territories. 100 miles south of
treeline, all the forest has burned in the last 25 years and coincidentally all the barren ground caribou herds have all declined. They have not established cause and effect in the publications, but certainly that’s key winter habitat to those caribou and all those lichen food resources that they need in the winter, which grow in old forests, have burned in the last 25 years. I think there’s lessons
for that in Yellowstone. So, back to wolves,
sorry for my digression and I’m sure I just burned valuable time. Parks will preserve the condition of resources that would
occur in the absence of human domination over the landscape. That’s straight from an
NPS policy statement, 2006. So what do wolf packs look like in the absences of human dominance? We don’t know. Typically, what we use to define natural is based on population status. Is the population increasing, decreasing, or is it stable? But wolves are, everybody knows and they’ve been studying
it for a long time, a very social species. They function better socially than they do independently, we know that. But it has not been often
considered in their ecology. We know this for example… Again, I’ve got to pick up the pace here because I’m not going to
keep true to my intent. But this is Yellowstone park, Wyoming, Montana, Idaho, Grand Teton,
Glacier National Park. These are pack sizes. In general, larger pack
sizes in protected areas. Glacier probably isn’t
registering larger packs. A lot of those packs are
in and out of the park. So the first thing we
see, and this pattern has held up in other analysis, is larger packs in size
in protected areas. These slides are slightly different than I had thought they were. (audience laughing) But we also see, these are
all unexploited populations. We see more older animals
in these protected areas. Wolves greater than five years of age. Average age of death inside Yellowstone for a wolf is five, five
and a half, possibly six. They are surely dying at younger ages outside of parks, so we’re getting these older animals in
there and we’re seeing that mean age increases through time from re-introduction
through the late 2000’s and the number of three-year-olds
increases through time. So packs grow in size, they
gain more older animals. So, conclusions from this, I’m missing a slide or two here, I
don’t know what happened, the transcripts are in here… Unexploited packs are usually larger with more older individuals
in multiple age classes. And the Leopold Lessons
are: Continued value in monitoring sociality. Impacts of removals and emphasize communication with other agencies. So we’re working really hard on it. In other words, removing one type of wolf might be different than
removing a different type. The idea of high social rank. And then ecological integrity should include social factors. We have many examples of what I’m talking about in Yellowstone. Dan Stahler’s PhD work
talked about the value of pack size, female
size, population density, things of those… In terms of pups born and pups survival We’ve worked with Dan McNulty,
he was a student here, now he’s at Utah State, on the importance of pack size for killing elk. Average number, Kira Cassidy
mentioned this yesterday, average number of wolves
that are most efficient at killing elk is four, but
bison it’s much greater. This is Molly’s pack killing a bison and it’s probably over 10 or 11 wolves. So more group size effects. Emily Omberg yesterday talked about the importance of pack
size in terms of mange. You have a higher
probability of recovering if you have mange and
you live in a large pack. And then Kira Cassidy’s
presentation yesterday talking about the importance of pack size and composition in terms
of territorial defense. All of these things address what I’ve been talking about. About the importance of wolf sociality and again, to emphasize it, this has been lightly to not considered as part of wolf management in protected areas. So the next idea I want to talk about. What promotes connectivity, what promotes disbursal, how do we
get wolves moving around to meet the metrics of delisting? There are two competing
theories about this and there’s not enough data to conclude which is more correct. Theory one is that pack stability produces pups each year, those pups born in the pack causes upward pressure on the older animals in
the pack and they disburse. The other theory is that
harvesting intensively creates social openings
for other wolves to move in and so that causes wolves to move around and enhances genetic connectivity. At the moment there’s not enough data to distinguish between
these two hypotheses. So, we can address one of those. What does social stability
do for disbursal? We find here that more pups lead to less likely probability,
pointer doesn’t work, y axis: probability of disbursal, your probability of disbursal goes down. If you lose the female, a
lot of people hypothesize that the female is single most… The alpha female is the single most important wolf in the pack. You lose her, the probability of disbursal actually goes up. So this is reflecting on the idea of losing wolves of
different social position. But if she’s retained, probability of of disbursal goes down. And then this is an analysis that Mike Jimenez of the Fish
and Wildlife Service has been working on some
time and this just plots the timing of disbursal in
Montana, Wyoming and Yellowstone. What’s interesting about this, is there’s no pattern to Wyoming and Montana. Yet there’s a distinct pattern of, kind of winter time disbursal for wolves in the park, a protected population. And very much less disbursal
in the summer period. So there’s a different pattern for a protected area versus areas where there’s livestock control and hunting. So I have to go quickly
through the rest of my talk. And some of these slides I thought were going to show up earlier. So these are age structures of other unexploited wolf populations, I don’t have time to explain them. (audience laughs) But they’re all young! They’re young, so I don’t have time to make this point about the importance of older animals. But I do want to make the point about coming back full circle
about this struggle of what is natural, the
climate change effects that we’re undergoing, the intervention to keep it natural, and as importantly, the pride previous park
service people, staff and managers have taken in taking care of this place and keeping it a baseline, primeval, primitive. All of us in this room have known some of the generations
that have preceeded us in taking care of this
place, and there has been a great deal of pride
and cultural identity about keeping this as natural as it can and it’s more pressing
than ever, right now, given all of the things
that are occurring outside. This is truly a cherished place, we’ve struggled with that for a long time, we need to keep struggling with it. So, at that, I will leave. I’m sure I’m over the
question and answer period. Thank you very much.
(audience applauds)

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