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Why Wolves Don_t Change Rivers(M4A_128K) · Luke's English Podcast

• 0:07
  Speaker 1: Hi, everyone.
• 0:08
  Speaker 2: Saima Khalid from Science of the Times.
• 0:10
  Speaker 1: And I'm Tim Colson. Welcome to another episode.
• 0:13
  Speaker 2: So, Tim, what can I see that you're wearing there?
• 0:17
  Speaker 2: Is that some Science of the Times merch?
• 0:19
  Speaker 1: We have a little bit more merch. Look at this. So,
• 0:22
  Speaker 1: it's a t-shirt made from very high quality cotton. Look
• 0:27
  Speaker 1: at that design. That's the design that you came up with, Saima.
• 0:31
  Speaker 1: Beautiful piece of artwork.
• 0:32
  Speaker 3: And.
• 0:33
  Speaker 1: it's uh yeah they'll be available on our shop shortly
• 0:38
  Speaker 1: when i get around to setting up the.
• 0:40
  Speaker 2: Shop it looks great yeah it's.
• 0:42
  Speaker 1: Really comfortable it's high quality cotton yeah Rapa Nui is
• 0:45
  Speaker 1: the uh is the makers of the t-shirts that we
• 0:47
  Speaker 1: get them.
• 0:48
  Speaker 2: Printed can't wait to get my hands on my one
• 0:50
  Speaker 2: i've got one here for you cool so for this
• 0:53
  Speaker 2: episode tim we have um one of your one of
• 0:55
  Speaker 2: your collaborators with us joining us can you tell us tell.
• 0:58
  Speaker 1: Us a bit about that yeah so his name's dan
• 1:00
  Speaker 1: dan mcnulty and he's Someone I met about 15 years
• 1:05
  Speaker 1: ago when I started working on the Wolf Project in Yellowstone.
• 1:09
  Speaker 1: And he has been with the Wolf Project in Yellowstone
• 1:15
  Speaker 1: since really near the beginning. So I think he joined
• 1:20
  Speaker 1: in the autumn of the year that the wolves had
• 1:24
  Speaker 1: been released and they had been released the previous summer.
• 1:26
  Speaker 1: So he's seen the whole effect of wolves you know
• 1:32
  Speaker 1: play out in Yellowstone and he happened to be in
• 1:34
  Speaker 1: Oxford visiting me doing some work and I said you
• 1:37
  Speaker 1: know what I I've got a hunch that our listeners
• 1:40
  Speaker 1: might be interested in learning a bit about the real
• 1:43
  Speaker 1: story of wolves in Yellowstone.
• 1:45
  Speaker 2: Absolutely nothing like hearing it from the well I was
• 1:48
  Speaker 2: going to say the horse's mouth but maybe the wolf's.
• 1:50
  Speaker 1: Mouth no and and it's interesting because a lot of
• 1:54
  Speaker 1: people think they know the Yellowstone story because of a
• 1:58
  Speaker 1: video is that something you've seen online that.
• 2:00
  Speaker 2: Video I have indeed. I have. So the impact on
• 2:04
  Speaker 2: rivers and such like?
• 2:05
  Speaker 1: Yeah. So that was a video that has accrued something
• 2:09
  Speaker 1: like 45 million hits. So it's been very good for,
• 2:13
  Speaker 1: in many ways, for explaining about Yellowstone and wolves are
• 2:17
  Speaker 1: good for the ecosystem. But to be honest, nearly everything
• 2:22
  Speaker 1: in that video has subsequently been shown to be wrong.
• 2:26
  Speaker 1: And in fact, we use it as a teaching tool
• 2:28
  Speaker 1: now in Oxford where we show it to the students,
• 2:31
  Speaker 1: we ask them to go away and identify, um, the
• 2:33
  Speaker 1: errors and they'll sort of shout, stop, stop, stop. And
• 2:36
  Speaker 1: I mean, it then takes the whole hour to go
• 2:38
  Speaker 1: through the video, but that's not to say that wolves
• 2:41
  Speaker 1: haven't had an effect on Yellowstone. They have, it's just
• 2:44
  Speaker 1: not the way it's described in that video.
• 2:45
  Speaker 2: Okay, great. So, uh, should we, should we, should we
• 2:50
  Speaker 2: get him in and let's hear, let's, let's, let's let
• 2:52
  Speaker 2: him tell us all about it.
• 2:54
  Speaker 1: Yeah, let's quiz him. And, um, um, you'll, you'll ask
• 2:56
  Speaker 1: the more pressing questions, I'm sure, because, uh, I'll treat
• 3:00
  Speaker 1: him easily.
• 3:01
  Speaker 2: That's very generous of you, Tim, to ask the naive questions.
• 3:07
  Speaker 1: Well, listeners, welcome to another episode of Science of the
• 3:10
  Speaker 1: Times podcast. And today we have Dan McNulty with us. Dan,
• 3:15
  Speaker 1: would you like to introduce yourself?
• 3:17
  Speaker 4: Hi, Tim.
• 3:18
  Speaker 5: My name is Dan McNulty.
• 3:19
  Speaker 4: I'm a professor at Utah State University in Logan, Utah.
• 3:23
  Speaker 1: Fantastic. Well, welcome and thanks very much for So Dan
• 3:26
  Speaker 1: and I have actually worked together a little bit over
• 3:29
  Speaker 1: the years in Yellowstone National Park. So it's a real
• 3:33
  Speaker 1: pleasure to have you on. But but Simon, you know,
• 3:36
  Speaker 1: knows a little bit less about the park than than
• 3:39
  Speaker 1: both of us. So I think just to ease our
• 3:41
  Speaker 1: listeners in, maybe you'll start with a few questions. Simon,
• 3:44
  Speaker 1: how's that sound? Absolutely fine.
• 3:46
  Speaker 2: So actually, obviously, I know significantly less than the two
• 3:50
  Speaker 2: of you. But so, yeah, Dan, I've been reading about
• 3:54
  Speaker 2: something that I just didn't know, didn't know anything about,
• 3:57
  Speaker 2: that wolves can have a profound effect on lots of
• 4:00
  Speaker 2: different things, even perhaps change the course of rivers. Is
• 4:03
  Speaker 2: that right?
• 4:05
  Speaker 4: Well, yes and no. It's a much more complicated question.
• 4:10
  Speaker 4: picture than that. And I think that's one of the
• 4:13
  Speaker 4: take home messages of the last 30 years of research
• 4:15
  Speaker 4: in Yellowstone is that it isn't just as simple as
• 4:18
  Speaker 4: dropping wolves in and then magical ecological change occurs. There's
• 4:23
  Speaker 4: actually a lot of other changes that were happening in
• 4:25
  Speaker 4: the system.
• 4:26
  Speaker 1: Perhaps we should just have a little bit of a
• 4:28
  Speaker 1: history from the park. Starting at what point? Well, the
• 4:32
  Speaker 1: park was what formed in 1880 something?
• 4:33
  Speaker 4: 1872.
• 4:33
  Speaker 1: 1872. And the wolves there then?
• 4:39
  Speaker 4: Yes, they were being eliminated from the time of park
• 4:43
  Speaker 4: establishment through to their final extirpation, which is around 1926.
• 4:50
  Speaker 4: And between 1926 and 1995, there were no wolves in
• 4:54
  Speaker 4: Yellowstone National Park.
• 4:56
  Speaker 1: Why did people go there then?
• 4:58
  Speaker 4: Why did they go to Yellowstone? To see the bears. Yeah,
• 5:04
  Speaker 4: people love the bears and bear numbers were reduced, but
• 5:07
  Speaker 4: they were never eliminated completely. Bears were seen as being more.
• 5:13
  Speaker 2: Positive.
• 5:14
  Speaker 4: Wolves were seen as predators that took things away from people.
• 5:17
  Speaker 4: They were seen as a threat to the big game,
• 5:19
  Speaker 4: the elk, the bison.
• 5:20
  Speaker 2: So Dan, just so I'm clear, so the wolves were
• 5:23
  Speaker 2: deliberately eliminated?
• 5:26
  Speaker 4: Yes. They were deliberately eliminated by the park service actually,
• 5:30
  Speaker 4: because they were seen as threats to the big game population,
• 5:33
  Speaker 4: which had been decimated previously by humans. in the late
• 5:37
  Speaker 4: 19th century. And so the park service was charged with
• 5:40
  Speaker 4: restoring the elk population along with other wildlife populations and
• 5:44
  Speaker 4: predators were seen as a threat to that interest, to
• 5:48
  Speaker 4: that project. And so that's why they were eliminated.
• 5:51
  Speaker 1: And so elk, for our listeners, are sort of an
• 5:53
  Speaker 1: American red deer. And like many American things, they're bigger
• 5:57
  Speaker 1: than our red deer. But people also went to Yellowstone,
• 6:02
  Speaker 1: of course, to see the geysers. Well, right.
• 6:05
  Speaker 4: The geysers, right. The geology is really why the park
• 6:08
  Speaker 4: was established. The wildlife was sort of a secondary consideration.
• 6:13
  Speaker 5: And of course.
• 6:15
  Speaker 4: Yellowstone's known worldwide for the amazing geology, the geysers, the
• 6:19
  Speaker 4: hot springs, all of that.
• 6:21
  Speaker 5: Yeah.
• 6:21
  Speaker 1: And it's built on a cold area, isn't it?
• 6:23
  Speaker 4: On a giant volcano. Yes.
• 6:26
  Speaker 1: And that went off about 600,000 years ago.
• 6:28
  Speaker 5: Approximately.
• 6:29
  Speaker 1: Yeah. Some people say we drew another one. Yeah.
• 6:34
  Speaker 4: Well, and the place has only been ice-free for about 10,000, 12,000 years.
• 6:38
  Speaker 4: So it's a relatively new ecosystem, like a lot of
• 6:40
  Speaker 4: ecosystems here in the place. So we think about Yellowstone
• 6:43
  Speaker 4: as being this very ancient wilderness when we go visit it,
• 6:45
  Speaker 4: but it's actually fairly recent.
• 6:47
  Speaker 1: Simon, have you been?
• 6:49
  Speaker 2: No, no. I mean, obviously, like probably many of our listeners,
• 6:53
  Speaker 2: I've been watching the TV show Yellowstone and the two
• 6:57
  Speaker 2: prequel series to that. I'd love to go.
• 6:59
  Speaker 1: Well, next trip, you'll have to come. We have to
• 7:02
  Speaker 1: do a, podcast from on location.
• 7:06
  Speaker 4: I haven't watched a single episode of yellowstone i can't
• 7:09
  Speaker 4: bring myself to watch we.
• 7:10
  Speaker 1: Won't question i neither have i we won't question you
• 7:13
  Speaker 1: about that then so anyway the wolves were off the
• 7:15
  Speaker 1: landscape for 70 years bears had bears were still there
• 7:19
  Speaker 1: but perhaps a little bit reduced much reduced what about
• 7:21
  Speaker 1: other predators mountain lions coyotes.
• 7:23
  Speaker 4: Uh Mountain lions were also reduced significantly. The records show
• 7:29
  Speaker 4: that they were removing equal numbers of mountain lions as
• 7:31
  Speaker 4: they were wolves.
• 7:32
  Speaker 5: So lions were really.
• 7:33
  Speaker 4: Taking a hit and were largely absent from the landscape
• 7:37
  Speaker 4: up until maybe around the 1970s, 1980s or so. And
• 7:41
  Speaker 4: that's when they started sort of slowly coming back in numbers,
• 7:45
  Speaker 4: mainly because hunting outside of Yellowstone was reduced on mountain lions.
• 7:52
  Speaker 4: And then the few that remained slowly built their numbers up.
• 7:55
  Speaker 4: So when wolves were reintroduced in that 1995 to 1997 period,
• 8:02
  Speaker 4: cougars and grizzly bears were naturally recovering. And grizzly bears
• 8:06
  Speaker 4: were recovering because they were listed as a threatened species
• 8:09
  Speaker 4: under the Endangered Species Act.
• 8:11
  Speaker 1: So before we get back to the 90s, so what
• 8:13
  Speaker 1: happened in that 70 years then between the 1926 and...
• 8:21
  Speaker 1: And the wolf reintroduction, which we'll come to in a
• 8:23
  Speaker 1: little bit. Right.
• 8:23
  Speaker 4: So because the park service was interested in restoring and
• 8:28
  Speaker 4: rebuilding the elk population, they intensively managed them at first.
• 8:32
  Speaker 4: They began feeding them inside the park in places, not everywhere,
• 8:36
  Speaker 4: but in places today that we sort of associate with
• 8:40
  Speaker 4: being sort of wild and unmanaged.
• 8:41
  Speaker 5: Back then, they were actually feeding the elk.
• 8:44
  Speaker 4: They were irrigating the land, growing hay and that sort
• 8:47
  Speaker 4: of thing. And so elk were being concentrated, their numbers
• 8:50
  Speaker 4: were increasing. And when wolves were eliminated, elk numbers at
• 8:54
  Speaker 4: that time, there was concern that there were too many elk,
• 8:58
  Speaker 4: that they had sort of overshot the appropriate number of
• 9:02
  Speaker 4: elk to be in the northern range. And so they
• 9:03
  Speaker 4: actually started removing elk shortly after they had restored their
• 9:07
  Speaker 4: numbers to bring them back to some sort of balance.
• 9:11
  Speaker 4: And I use that word sort of reluctantly, but they
• 9:14
  Speaker 4: wanted to reduce the numbers in order to reduce the
• 9:17
  Speaker 4: effects on riparian vegetation was a big one. So effects
• 9:20
  Speaker 4: on things like willow plants, aspen vegetation. And so from
• 9:24
  Speaker 4: about around the time that wolves were eliminated, elk numbers
• 9:29
  Speaker 4: also started to decline. But that was because they were
• 9:32
  Speaker 4: either culling the elk, so shooting them, or they were
• 9:36
  Speaker 4: live trapping them, putting them on trains and trucks and
• 9:39
  Speaker 4: translocating them elsewhere in the United States to repopulate those
• 9:43
  Speaker 4: elk ranges. So elk in Utah, for example, where I live,
• 9:46
  Speaker 4: trace their ancestry to Yellowstone elk because the elk in Utah,
• 9:50
  Speaker 4: by and large, were hunted out during the 19th century.
• 9:55
  Speaker 2: Wow. So that's remarkable, right? So on the one hand,
• 9:57
  Speaker 2: you sort of do something to to protect the elk
• 10:01
  Speaker 2: and help them propagate. And then that sort of goes
• 10:04
  Speaker 2: slightly out of control. And then, so you have to
• 10:06
  Speaker 2: take a reverse kind of strategy to then sort of,
• 10:09
  Speaker 2: sort of cull that and control those. Is that, is
• 10:12
  Speaker 2: that what happened?
• 10:13
  Speaker 4: Absolutely. And that is a really common, um, outcome of management,
• 10:18
  Speaker 4: we're always playing catch up to what's already happened. We're
• 10:21
  Speaker 4: always five, 10 years behind and trying to compensate for
• 10:25
  Speaker 4: something that we had done that we thought was appropriate,
• 10:29
  Speaker 4: but we've missed our opportunity to sort of control that
• 10:33
  Speaker 4: action and so we're playing catch up.
• 10:35
  Speaker 5: So that often happens in conservation.
• 10:37
  Speaker 2: And so what sort of led to the decision to
• 10:40
  Speaker 2: reintroduce the wolves?
• 10:42
  Speaker 3: Right.
• 10:43
  Speaker 4: The decision to reintroduce the wolves was purely a legal
• 10:47
  Speaker 4: decision in order to satisfy the requirements of the Federal
• 10:51
  Speaker 4: Endangered Species Act. That was the main motivation. So wolves
• 10:56
  Speaker 4: were listed as endangered species in 1973. Their numbers in Minnesota,
• 11:01
  Speaker 4: which was the last remaining population, were sort of naturally increasing.
• 11:07
  Speaker 1: Last population in the lower 48 states.
• 11:09
  Speaker 4: In the lower 48 states, yeah.
• 11:11
  Speaker 5: There were wolves, of course, up in Alaska.
• 11:13
  Speaker 1: And over in... in Asia as well. Of course. Yeah.
• 11:17
  Speaker 4: And there were wolves in Isle Royale National Park as well.
• 11:19
  Speaker 4: So in the United States, back in the seventies, when
• 11:22
  Speaker 4: wolves were listed, we had wolves in Northern Minnesota and
• 11:24
  Speaker 4: Isle Royale in Alaska. And so the wolves that were
• 11:27
  Speaker 4: listed were the lower 48 United States wolves. Yep. Because
• 11:34
  Speaker 4: wolves were listed, a recovery plan was initiated in the
• 11:38
  Speaker 4: 1980s to restore them. And there was slowly wolves recolonizing
• 11:43
  Speaker 4: northwest Montana in the 1980s. And the decision was made
• 11:47
  Speaker 4: to fast track that natural recovery with additional reintroductions sort
• 11:52
  Speaker 4: of to augment that. And they reintroduced wolves in central
• 11:56
  Speaker 4: Idaho and then also in Yellowstone National Park. And the
• 11:59
  Speaker 4: motivation for that was to achieve population recovery. to remove
• 12:05
  Speaker 4: the wolves from the endangered species list and achieve population recovery.
• 12:09
  Speaker 4: That was the primary motivation. It had nothing to do
• 12:12
  Speaker 4: really with ecological restoration. I mean, that was sort of
• 12:16
  Speaker 4: the broad outlines in the background, but the actual legal
• 12:21
  Speaker 4: mechanism that led to this effort and what motivated people
• 12:25
  Speaker 4: was that this was an endangered species in the lower
• 12:28
  Speaker 4: 48 United States, and that's why they did the reintroduction.
• 12:32
  Speaker 1: And there was some concern, I think, from one or
• 12:34
  Speaker 1: two senators that wolves might recolonize naturally. And is that right?
• 12:40
  Speaker 4: Absolutely. So there was concern from the senator from Idaho
• 12:43
  Speaker 4: that if wolves had naturally recolonized all of the Northern
• 12:46
  Speaker 4: Rockies from Montana, they would have retained their endangered status
• 12:51
  Speaker 4: as a listed species, which greatly restricts management intervention. If, say,
• 12:57
  Speaker 4: like those wolves were to kill a cow or managers
• 13:00
  Speaker 4: wouldn't be able to go in and move the wolves,
• 13:03
  Speaker 4: kill the wolves, deal with that conflict. They would just
• 13:06
  Speaker 4: continue to kill cows. But as a non-essential experimental population
• 13:14
  Speaker 4: under what's called the Section 10J rule, reintroduced wolves had
• 13:18
  Speaker 4: more management flexibility.
• 13:20
  Speaker 5: They were allowed to.
• 13:21
  Speaker 4: Be moved, to be relocated, And a lot of that
• 13:24
  Speaker 4: happened in the 1990s after they were reintroduced. Lots of
• 13:27
  Speaker 4: wolves coming and going. And it was heavy management and
• 13:30
  Speaker 4: still is for wolves outside the park.
• 13:34
  Speaker 2: So, I mean, I understand very little about the sort
• 13:38
  Speaker 2: of nuances about wolf populations. But so the wolves that
• 13:42
  Speaker 2: were reintroduced or came back, do we know about the
• 13:48
  Speaker 2: sort of genetic origin of all these? Can that be
• 13:51
  Speaker 2: traced back? Do we know where they came from?
• 13:53
  Speaker 5: Oh, absolutely.
• 13:54
  Speaker 4: So the wolves that were released in 1995, those came
• 13:57
  Speaker 4: from Alberta, Canada. And the wolves that were released in 1996,
• 14:02
  Speaker 4: those came from British Columbia. And then there was actually
• 14:05
  Speaker 4: a third release in 1997. Those wolves were actually wolves
• 14:11
  Speaker 4: that were from Northwest Montana. They came from a pack
• 14:15
  Speaker 4: that was called the Sawtooth Pack. Their parents, the parents
• 14:20
  Speaker 4: in that pack were killed because of livestock conflict. And
• 14:23
  Speaker 4: they didn't want to kill the pups. And so the
• 14:26
  Speaker 4: Park Service agreed to take those pups into Yellowstone and
• 14:31
  Speaker 4: release them subsequently from a holding facility in Yellowstone National
• 14:35
  Speaker 4: Park in 97.
• 14:36
  Speaker 1: So Simon, if someone asked you to go and catch
• 14:38
  Speaker 1: a wolf, what approach would you take? Have you thought, oh,
• 14:41
  Speaker 1: you probably never thought about trying to catch a wolf.
• 14:43
  Speaker 2: I think about this all the time, actually, like every
• 14:46
  Speaker 2: other sane person. So yeah, I mean, probably with a
• 14:49
  Speaker 2: slingshot or a poison dart. How do you think? What
• 14:52
  Speaker 2: do you think?
• 14:53
  Speaker 4: Well, so darts is the common practice, but when we
• 14:57
  Speaker 4: were relocating wolves from one pen to another in Yellowstone,
• 15:00
  Speaker 4: we were using giant salmon fishnets that we're actually throwing
• 15:04
  Speaker 4: over these wolves.
• 15:05
  Speaker 5: Really?
• 15:06
  Speaker 4: Yeah, because it was safer than using a dart gun.
• 15:08
  Speaker 5: I mean, that was the logic behind it.
• 15:10
  Speaker 1: But when you caught them in the wild, well, when
• 15:12
  Speaker 1: they were caught in the wild in Canada and BC,
• 15:15
  Speaker 1: was that with a big net as well?
• 15:16
  Speaker 5: No, darts.
• 15:17
  Speaker 1: Yeah. From a helicopter.
• 15:18
  Speaker 5: A dart gun with a helicopter, yeah.
• 15:20
  Speaker 1: So you should explain to our listeners, kind of, because it's,
• 15:22
  Speaker 1: I mean, it's astonishing actually to see it. Oh, yeah.
• 15:25
  Speaker 4: It's amazing that they can even pull this off.
• 15:28
  Speaker 5: Yeah.
• 15:29
  Speaker 4: So Carter Niemeyer was the one that did a lot
• 15:32
  Speaker 4: of the captures up in Canada for the Fish and
• 15:35
  Speaker 4: Wildlife Service back in the 90s. And it was extremely cold.
• 15:39
  Speaker 4: So you combine Arctic temperatures, you're in a harness, you're leaning.
• 15:44
  Speaker 5: Out of the helicopter.
• 15:45
  Speaker 1: The helicopter's low.
• 15:48
  Speaker 4: Extremely low. I mean, you can see, practically touch the treetops.
• 15:52
  Speaker 4: The ground is rushing below you. And you're trying to
• 15:54
  Speaker 4: keep your eye on this wolf that's trying its best
• 15:57
  Speaker 4: to dodge the helicopter. And, you know, trying to put
• 16:00
  Speaker 4: a dart into a moving animal while you're in a
• 16:02
  Speaker 4: moving helicopter. I mean, talk about like an impossible task,
• 16:05
  Speaker 4: but they do it.
• 16:07
  Speaker 5: Carter did it.
• 16:08
  Speaker 4: The biologists in Yellowstone National Park do it every year.
• 16:12
  Speaker 4: So it is doable, but it does seem superhuman to me.
• 16:15
  Speaker 1: And Simon, I thought it would be fun to have
• 16:17
  Speaker 1: a go, but they wouldn't let me. They said I'd
• 16:19
  Speaker 1: be more likely to hit the pilot with the dart
• 16:21
  Speaker 1: than the wolf.
• 16:23
  Speaker 5: You might fall out of the helicopter.
• 16:27
  Speaker 1: Anyway, so the wolves were taken down to Yellowstone. They
• 16:31
  Speaker 1: were released in June, was it?
• 16:34
  Speaker 2: No.
• 16:34
  Speaker 4: So they were brought down in January, the first bunch
• 16:37
  Speaker 4: in January of 1995, and then they were put into
• 16:43
  Speaker 4: chain link pens. These were sort of like half acre
• 16:46
  Speaker 4: pens to acclimate them to those sites in order to
• 16:51
  Speaker 4: keep them in those areas upon release.
• 16:54
  Speaker 1: Because otherwise they'd have just run back.
• 16:55
  Speaker 4: The concern was that if you just did a hard release,
• 16:58
  Speaker 4: so it was called a hard release, they would just
• 17:00
  Speaker 4: run back to Canada. And that's kind of what happened
• 17:03
  Speaker 4: with the wolves in Idaho. Because those wolves were hard release.
• 17:06
  Speaker 4: They didn't use the soft release method. And those wolves
• 17:10
  Speaker 4: ranged much further upon release. The other thing that was
• 17:13
  Speaker 4: different about the Yellowstone reintroduction is that They relocated whole
• 17:17
  Speaker 4: packs into these pens. So, for example, the Crystal Creek pack,
• 17:22
  Speaker 4: which was one of the first packs I started studying
• 17:24
  Speaker 4: 30 years ago, that pack came as one unit from Alberta, Canada,
• 17:29
  Speaker 4: and was placed in the Crystal Creek pen, acclimated for
• 17:32
  Speaker 4: about 10 weeks, and then in March of 1995, were released.
• 17:38
  Speaker 1: And you joined the project shortly afterwards.
• 17:40
  Speaker 5: In November of 1995.
• 17:40
  Speaker 2: Yep.
• 17:42
  Speaker 4: So I had graduated from the University of Colorado in
• 17:46
  Speaker 4: May of 95, and I walked the Continental Divide Trail
• 17:49
  Speaker 4: from approximately Boulder, Colorado, all the way down to Durango.
• 17:53
  Speaker 4: It was like a 500 mile trek over seven weeks.
• 17:55
  Speaker 1: Were you lost?
• 17:56
  Speaker 5: After I finished. I was not lost. We had maps,
• 17:59
  Speaker 5: no GPS.
• 18:01
  Speaker 4: After I finished, then I went up to Yellowstone and
• 18:05
  Speaker 4: participated in the post-release monitoring. So those initial packs had
• 18:09
  Speaker 4: been released. And our job as field technicians was to
• 18:12
  Speaker 4: follow these wolves around using radio telemetry to determine how
• 18:16
  Speaker 4: often they were killing, what they were killing, interactions between packs,
• 18:21
  Speaker 4: monitoring the movements and spatial distribution of the wolves, that
• 18:26
  Speaker 4: sort of thing.
• 18:27
  Speaker 5: I picked up a lot of dead elk.
• 18:30
  Speaker 2: So is it fair to say that all the wolves
• 18:34
  Speaker 2: that are currently in Yellowstone essentially came from three locations originally.
• 18:39
  Speaker 2: So the two in Canada you mentioned and then Western Montana?
• 18:43
  Speaker 1: Yes.
• 18:44
  Speaker 4: There's been surprisingly little immigration into the population from outside.
• 18:51
  Speaker 4: There's been a couple cases that have come into the
• 18:56
  Speaker 4: park itself. There's been more immigrants from elsewhere to areas
• 19:00
  Speaker 4: outside of the park in the public lands that surround
• 19:03
  Speaker 4: Yellowstone National Park. So You have to understand that Yellowstone
• 19:07
  Speaker 4: is sort of this postage stamp in Northwest Wyoming. Okay,
• 19:10
  Speaker 4: that's the boundary. And then around that is a collection
• 19:14
  Speaker 4: of national forest lands that also have some level of protection,
• 19:18
  Speaker 4: varying from very strict to allowing development, logging, that sort
• 19:23
  Speaker 4: of thing. And so wolves are inhabiting that area. And
• 19:26
  Speaker 4: a lot of the wolves in that area, not a lot,
• 19:27
  Speaker 4: but some came from elsewhere, from Idaho particularly.
• 19:32
  Speaker 1: And so these wolves were... released, they settled into the park,
• 19:38
  Speaker 1: and they've been studied ever since, along with many of
• 19:42
  Speaker 1: the other animals in the park, so the elk and
• 19:44
  Speaker 1: the bison.
• 19:45
  Speaker 4: Absolutely. So when I you know, when I started as
• 19:48
  Speaker 4: a technician, all I thought about every day was wolves.
• 19:52
  Speaker 4: That's all, you know, and what they ate. I was
• 19:55
  Speaker 4: looking at the world purely through the point of view
• 19:57
  Speaker 4: of a wolf's mouth, basically, because I was following what
• 19:59
  Speaker 4: they were killing. And, you know, we would go in, we'd, uh,
• 20:03
  Speaker 4: we'd crack open bones to look at bone marrow, that
• 20:05
  Speaker 4: sort of thing. And it, it wasn't until later that
• 20:08
  Speaker 4: that we began to appreciate really we being all of
• 20:11
  Speaker 4: us that were studying wolves, the importance of other components
• 20:14
  Speaker 4: of the ecosystem, um, in particular, uh, the other predators, um,
• 20:20
  Speaker 4: including human beings. That's a big part of the story
• 20:23
  Speaker 4: is that these elk that the wolves are eating migrate
• 20:26
  Speaker 4: outside the park.
• 20:28
  Speaker 5: Okay.
• 20:28
  Speaker 4: On a seasonal basis during the, during the winter time.
• 20:32
  Speaker 4: And when they do that, they expose themselves to hunting.
• 20:36
  Speaker 4: And so humans, at the same times that wolves were
• 20:38
  Speaker 4: being reintroduced and expanding their numbers, humans were killing large
• 20:42
  Speaker 4: numbers of elk. And that had an impact on the
• 20:45
  Speaker 4: elk population that to this day, many people don't really appreciate.
• 20:49
  Speaker 2: So the, so it's sort of, were we going back
• 20:52
  Speaker 2: to where we were sort of prior to 1926, when
• 20:56
  Speaker 2: the elk population was coming down, wolves then were disappeared
• 21:01
  Speaker 2: for 70 odd years. They come back and then now
• 21:03
  Speaker 2: wolves and humans together are combining and the elf population
• 21:06
  Speaker 2: is going down again. Is that right?
• 21:09
  Speaker 4: It's a huge stew really of different animals. And yeah, that's,
• 21:13
  Speaker 4: that's what's happening. And so the, the population at the
• 21:16
  Speaker 4: elk population was at a record number in 1994, 1993,
• 21:19
  Speaker 4: about 19,000. And it was that that's probably a minimum estimate.
• 21:22
  Speaker 4: And then, uh, The following winter in December of 1994,
• 21:33
  Speaker 4: their numbers started to decrease. We know that because a
• 21:37
  Speaker 4: count occurred using aircraft. And so now remember I said
• 21:42
  Speaker 4: December 1994, the elk population began to decrease. That was
• 21:46
  Speaker 4: before the wolves had even come through the gate in
• 21:49
  Speaker 4: January of 1995. And so the population was starting to
• 21:52
  Speaker 4: decrease prior to the wolf range reduction. So that's an
• 21:56
  Speaker 4: important point because when you look at the data, You
• 21:59
  Speaker 4: can see, oh, wolves were dropped in in 1995, and
• 22:02
  Speaker 4: that's when the population started to decrease. But actually, the
• 22:05
  Speaker 4: reintroduction happened after the elk decline started. So the wolves
• 22:09
  Speaker 4: didn't trigger the decline. They certainly contributed to it. But
• 22:13
  Speaker 4: other predators were involved in the decline, including humans, the bears,
• 22:17
  Speaker 4: and also the cougars.
• 22:18
  Speaker 1: So before we kind of move on to how the
• 22:22
  Speaker 1: rivers have changed, let's have a quick break as we
• 22:26
  Speaker 1: go to our sponsors. Hi, Tim.
• 22:28
  Speaker 2: You're looking particularly snazzy today. What are you wearing?
• 22:31
  Speaker 1: I'm wearing a piece from a company called Grace and Garbo.
• 22:36
  Speaker 1: And actually, you know a little bit more about them
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• 22:39
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• 22:40
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• 22:42
  Speaker 2: I'm also wearing a piece from Grayson Garbo. So this
• 22:45
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• 22:50
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• 23:01
  Speaker 2: with its beautiful purple flowers. And so they're big on
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• 23:08
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• 23:11
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• 23:13
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• 23:16
  Speaker 1: And thank you very much to them for supporting our podcast.
• 23:19
  Speaker 1: I hope their sales soar.
• 23:22
  Speaker 4: Thanks a lot, Grace and Garvo.
• 23:23
  Speaker 1: Well, welcome back. We are here with Dan McNulty. We've
• 23:26
  Speaker 1: been hearing a little bit about the early history of
• 23:28
  Speaker 1: the park. And then we're kind of up to November 95,
• 23:32
  Speaker 1: when Dan has walked half the length of America and has...
• 23:36
  Speaker 1: started on the project. And the, I mean, the wolf
• 23:40
  Speaker 1: story is kind of one of the great conservation success
• 23:44
  Speaker 1: stories in many ways. But I think the aim when
• 23:47
  Speaker 1: they released them was in the states of Idaho, Montana,
• 23:50
  Speaker 1: and Wyoming, there were going to be about 300 wolves.
• 23:53
  Speaker 1: I think it peaked at over 1500, didn't it?
• 23:56
  Speaker 5: Something around those.
• 23:57
  Speaker 3: Yeah.
• 23:58
  Speaker 1: So, but let's go back to the park and perhaps
• 24:01
  Speaker 1: you can tell us, maybe we should work through What's
• 24:04
  Speaker 1: happened to some of the species? You talked about elk.
• 24:08
  Speaker 1: They were starting to decline. The wolves came back, were reintroduced.
• 24:12
  Speaker 1: What's happened to the elk sort of since? Why don't
• 24:15
  Speaker 1: we work through sort of elk and bison and a
• 24:17
  Speaker 1: few other species? Sure.
• 24:19
  Speaker 4: So the elk population continued to decrease until, I want
• 24:24
  Speaker 4: to say like around 2015, 2016, somewhere around there, sort
• 24:29
  Speaker 4: of their low point. And since then, their numbers have
• 24:32
  Speaker 4: slowly began to recover. And so this last April, they
• 24:38
  Speaker 4: counted approximately 7,300 elk, which is, we haven't had that
• 24:44
  Speaker 4: number for maybe about 10 years or so. So that's
• 24:48
  Speaker 4: a pretty substantial jump from where it's been in the past,
• 24:53
  Speaker 4: in the recent past. So they are recovering their numbers. Now,
• 24:59
  Speaker 4: at the same time that that was happening, as elk
• 25:01
  Speaker 4: numbers were going down, bison numbers were increasing in Northern Yellowstone.
• 25:06
  Speaker 4: So we talk a lot about Northern Yellowstone National Park
• 25:10
  Speaker 4: and we talk about it as if it's its own,
• 25:13
  Speaker 4: you know, park in some respects. And the reason why
• 25:16
  Speaker 4: we focus so much on it is because that's the
• 25:18
  Speaker 4: part of Yellowstone National Park where a lot of wildlife
• 25:21
  Speaker 4: spend the winter time because the conditions there in the
• 25:24
  Speaker 4: winter are fairly benign relative to the interior of the park,
• 25:27
  Speaker 4: which is at a much higher elevation.
• 25:29
  Speaker 1: They're not combined. They're not benign compared to, uh, Oxford Simon.
• 25:33
  Speaker 1: It's a pretty cold out there and you need, yeah,
• 25:35
  Speaker 1: it can get down to minus 30.
• 25:37
  Speaker 4: And, and so, and that's where we would see the
• 25:39
  Speaker 4: wolves interacting with the elk. And that's why the, the
• 25:42
  Speaker 4: wolves are reintroduced there in the first place. Cause it
• 25:44
  Speaker 4: was great wolf habitat because it's winter range for elk essentially.
• 25:48
  Speaker 4: And when I was there at 30 years ago, uh,
• 25:50
  Speaker 4: as a technician, elk were the dominant ungulate. Yeah. Occasionally
• 25:54
  Speaker 4: we saw bighorn sheep and there were some bison, there
• 25:57
  Speaker 4: were about 500 bison.
• 25:58
  Speaker 5: There were mule deer, occasionally moose.
• 26:00
  Speaker 4: But elk were by far the most abundant animal out
• 26:05
  Speaker 4: there in the landscape. I mean, it was amazing how
• 26:07
  Speaker 4: many elk there were.
• 26:09
  Speaker 5: Now, 30 years later.
• 26:10
  Speaker 4: The dominant ungulate in Northern Yellowstone is the bison or buffalo.
• 26:16
  Speaker 4: And now we have approximately 4,000 bison in Northern Yellowstone
• 26:22
  Speaker 4: National Park. So we went from 500 to 4,000. When
• 26:26
  Speaker 4: I started 30 years ago, most of the bison in
• 26:29
  Speaker 4: the park were in the interior.
• 26:31
  Speaker 1: Down in Pelican Valley.
• 26:33
  Speaker 2: The wolves don't eat the bison?
• 26:36
  Speaker 4: They do. But eating a bison and attacking a bison,
• 26:40
  Speaker 4: killing a bison is something as difficult as maybe you
• 26:44
  Speaker 4: trying to stop a bulldozer with your teeth. I mean,
• 26:47
  Speaker 4: these bison are huge. They're very hard to grab onto.
• 26:52
  Speaker 4: And so, yes, wolves attack and kill them. but not
• 26:56
  Speaker 4: nearly as frequently as they attack and kill elk, simply
• 26:59
  Speaker 4: because they're so big and dangerous. And wolves are really
• 27:03
  Speaker 4: sensitive to the risk of injury.
• 27:05
  Speaker 5: They're very cautious.
• 27:06
  Speaker 4: I mean, you know, your dog, Wolfla, he's quite cautious,
• 27:09
  Speaker 4: even around the most, you know, dangerous animals. And wolves
• 27:14
  Speaker 4: are the same way. So they'll go for the elk,
• 27:16
  Speaker 4: even when now bison are more abundant, they prefer.
• 27:21
  Speaker 1: To eat elk.
• 27:21
  Speaker 4: Elk makes up the lion's share of what wolves are killing.
• 27:25
  Speaker 4: That's not to say that wolves aren't eating any bison.
• 27:28
  Speaker 4: They are, but they're eating the bison that die from
• 27:30
  Speaker 4: other causes. So they're scavenging a lot on bison that
• 27:35
  Speaker 4: die because of exposure to winter conditions, competition during mating,
• 27:40
  Speaker 4: the bulls are rutting, that sort of thing. There's mortality
• 27:43
  Speaker 4: associated with that, and wolves are scavenging on those animals.
• 27:46
  Speaker 1: And there's about 100 wolves in the park at the moment.
• 27:50
  Speaker 4: Yes, 108, I think, is the number.
• 27:52
  Speaker 1: And sometimes it goes down to about 80 or 90,
• 27:54
  Speaker 1: and then it kind of goes. So yeah, it, it,
• 27:56
  Speaker 1: it kind of jumps around. One thing that the listeners
• 27:59
  Speaker 1: might be amazed about the bison story. So they went
• 28:02
  Speaker 1: down to 26, 26 bison globe. That was the global
• 28:06
  Speaker 1: population of bison. And, um, they've now, you know, recovered
• 28:11
  Speaker 1: in the park. They're also farmed a lot now as well,
• 28:14
  Speaker 1: aren't they?
• 28:14
  Speaker 4: And a lot of those farmed bison are mixtures of
• 28:18
  Speaker 4: cattle with bison, um, And yeah, 100 years ago, 1923,
• 28:22
  Speaker 4: I think, so a little over 100 years ago, was
• 28:26
  Speaker 4: that low point of 26 bison.
• 28:28
  Speaker 5: And that was in the interior of Yellowstone.
• 28:31
  Speaker 4: Well, so in Yellowstone National Park, that was the remnant herd.
• 28:37
  Speaker 4: There were some captive bison in Texas, up in Northwest Montana,
• 28:43
  Speaker 4: that were brought into Yellowstone to help augment the population.
• 28:48
  Speaker 5: And so... There was a few more than those 26,
• 28:51
  Speaker 5: but not a lot more.
• 28:53
  Speaker 1: And so elk came down and then have kind of
• 28:56
  Speaker 1: stabilized going up a little bit now. Bison have gone
• 29:00
  Speaker 1: up and are now, as you say, the kind of
• 29:01
  Speaker 1: dominant animal. What about some of the other herbivores, things like,
• 29:05
  Speaker 1: you know, what's the story about moose and things like
• 29:07
  Speaker 1: mule deer and pronghorn antelopes?
• 29:10
  Speaker 4: So pronghorn are a great kind of a recovery story
• 29:14
  Speaker 4: themselves because when I arrived, there was concern that pronghorn
• 29:17
  Speaker 4: in Yellowstone could potentially, become extirpated because their migratory pathways
• 29:22
  Speaker 4: had been interrupted in places like Paradise Valley north of
• 29:25
  Speaker 4: the park. And they also suffered a lot from predation
• 29:28
  Speaker 4: from coyotes on their fawns. Since then, since the reintroduction
• 29:33
  Speaker 4: and the elk numbers have gone down, pronghorn numbers have
• 29:36
  Speaker 4: actually increased significantly. And one of the reasons they attribute
• 29:39
  Speaker 4: to that is less coyote predation on the pronghorn fawns
• 29:42
  Speaker 4: as a result of wolves pushing coyotes around.
• 29:46
  Speaker 1: Coyotes are smaller than wolves, quite a lot smaller.
• 29:48
  Speaker 4: Substantially smaller, yeah. And then moose numbers have also increased.
• 29:54
  Speaker 4: There's evidence for that. And That's associated or correlated at
• 29:58
  Speaker 4: least with increases in some places of the vegetation that
• 30:02
  Speaker 4: moose eat. So things like willow and Aspen. So moose
• 30:06
  Speaker 4: are primarily browsers. They eat the shrubs and they have
• 30:11
  Speaker 4: to have those plants in order to survive. And with
• 30:14
  Speaker 4: those plants coming back in places like Blacktail Creek, Crystal Creek,
• 30:18
  Speaker 4: you do find lots of evidence of moose in those areas.
• 30:21
  Speaker 3: So I guess something I'm confused about again, perhaps naively,
• 30:26
  Speaker 3: is that the elk population has stabilized and is also
• 30:32
  Speaker 3: perhaps on the rise.
• 30:34
  Speaker 2: The bison have also, numbers have increased. We've got more,
• 30:41
  Speaker 2: you know, it seems that everything is, we're getting more
• 30:43
  Speaker 2: of everything, including the wolves. How does that work out?
• 30:49
  Speaker 5: Work out in what way? What do you mean?
• 30:51
  Speaker 2: There's more predators, but the number of the prey is
• 30:54
  Speaker 2: not going down, it's going up.
• 30:57
  Speaker 1: But the elk did come down from a high. Yeah.
• 31:00
  Speaker 4: They came down from a high of about 19,000 to
• 31:03
  Speaker 4: a low of say, like in 2016 or so, their
• 31:06
  Speaker 4: low was probably 3000 or so.
• 31:08
  Speaker 2: So this is a recovery. Yeah.
• 31:11
  Speaker 4: Now the elk numbers have increased since then to about 7,300.
• 31:15
  Speaker 4: And that's a minimum count. There's probably more like 8,000
• 31:20
  Speaker 4: total in the Northern Yellowstone elk population. Because I'm going
• 31:23
  Speaker 4: to confuse you even more by pointing out that there's
• 31:26
  Speaker 4: more than one elk population because Yellowstone.
• 31:29
  Speaker 5: Is this plateau.
• 31:30
  Speaker 4: And I mentioned to you all this National Forest Service
• 31:33
  Speaker 4: land that surrounds it. Well, there are elk populations that
• 31:36
  Speaker 4: winter on those Forest Service lands and they come and
• 31:39
  Speaker 4: they spend summer and they intermingle with the Northern Yellowstone
• 31:43
  Speaker 4: herd in summer. And so wolves are eating not only
• 31:46
  Speaker 4: the Northern Yellowstone elk, but they're also eating elk from
• 31:51
  Speaker 4: some of those other herds during the summertime. when they're
• 31:53
  Speaker 4: all co-mingled on the summer range.
• 31:56
  Speaker 1: But so kind of what I think one way of
• 31:58
  Speaker 1: thinking a little bit about what's happened, Simon, is the
• 32:02
  Speaker 1: kind of return of the wolves and the mountain lions and,
• 32:05
  Speaker 1: you know, perhaps to some extent the bears have essentially turned,
• 32:09
  Speaker 1: you know, you can think of that turning elk biomass,
• 32:11
  Speaker 1: so the mass of elk, into kind of a more
• 32:13
  Speaker 1: diverse range of herbivore species.
• 32:16
  Speaker 5: Yes, exactly.
• 32:17
  Speaker 1: Yep. So, you know, you've got more pronghorns, you've got
• 32:20
  Speaker 1: more bison, you've got more moose. I think there's a
• 32:22
  Speaker 1: few more deer.
• 32:23
  Speaker 5: More mule deer we're seeing.
• 32:25
  Speaker 4: And there's two species of deer. There's the mule deer
• 32:28
  Speaker 4: and the white-tailed deer. And I'm seeing more of those
• 32:31
  Speaker 4: as well.
• 32:32
  Speaker 1: And what about the vegetation? So that's the kind of
• 32:35
  Speaker 1: story that Simon was talking about at the beginning, this
• 32:38
  Speaker 1: forest recovering, you know, you know, it's obviously I know.
• 32:43
  Speaker 1: what it looks like over there now. But I mean,
• 32:45
  Speaker 1: what's your take on the kind of vegetation changes? Because
• 32:48
  Speaker 1: you've actually spent quite a bit of time working on aspen.
• 32:50
  Speaker 5: Yes, I have.
• 32:51
  Speaker 4: So my students and I have shown that there's a
• 32:54
  Speaker 4: link between aspen regeneration or recruitment. When I use the
• 32:59
  Speaker 4: word recruitment, I mean small aspen saplings turning into tall
• 33:03
  Speaker 4: aspen saplings that can escape herbivory from elk. And so
• 33:07
  Speaker 4: that's the key. That's been the key metric is how
• 33:09
  Speaker 4: tall these aspen are. Because elk basically browse... saplings as
• 33:14
  Speaker 4: high as maybe three meters. Once they get past three meters,
• 33:17
  Speaker 4: they've sort of survived and they've become mature trees. And
• 33:21
  Speaker 4: so there's a link between the rate at which saplings recruit,
• 33:25
  Speaker 4: join the overstory, and elk density. And so as elk
• 33:28
  Speaker 4: densities decreased from that high of 19,000 prior to the
• 33:32
  Speaker 4: wolf reintroduction, as those densities decreased, recruitment started to increase
• 33:36
  Speaker 4: because there was less browsing pressure on those saplings. And
• 33:40
  Speaker 4: so in some places, we do have the regeneration of
• 33:44
  Speaker 4: aspen stands that were sort of just hanging on and
• 33:48
  Speaker 4: actually disappearing at the time that I started in 1995.
• 33:53
  Speaker 4: But that isn't the whole story. That's only some aspen
• 33:56
  Speaker 4: stands in some places, and it's actually the minority of
• 34:00
  Speaker 4: aspen stands. The remarkable and somewhat disheartening thing is that
• 34:05
  Speaker 4: most of the aspen stands, according to the analyses that
• 34:08
  Speaker 4: we've done, have actually continued to decline since the wolf
• 34:13
  Speaker 4: reintroduction and despite the reduction in elk density. And we're
• 34:17
  Speaker 4: still trying to work out why that is, but we
• 34:19
  Speaker 4: think a lot of it has to do with the
• 34:21
  Speaker 4: fact that throughout this last 30 year period, conditions for
• 34:26
  Speaker 4: plants overall have become, it's become drier. There's basically more
• 34:30
  Speaker 4: water stress on plants and aspen are a deciduous tree.
• 34:33
  Speaker 4: They require a lot of moisture. They tend to live
• 34:37
  Speaker 4: in sort of wetter sites. And so we think this
• 34:40
  Speaker 4: increased water stress might be contributing to the decline overall,
• 34:43
  Speaker 4: the net decrease in Aspen stand area.
• 34:47
  Speaker 1: So why don't we bring beavers back into the park?
• 34:49
  Speaker 1: Cause they, you know, we know they make dams that
• 34:52
  Speaker 1: builds up water. Wouldn't you get them more Aspen coming back?
• 34:56
  Speaker 1: As a result of the beaver?
• 34:58
  Speaker 5: As a result of the beaver? Yeah.
• 35:00
  Speaker 4: No. So I think the causal relationship's the other way around.
• 35:02
  Speaker 1: So, yeah.
• 35:03
  Speaker 4: So the, you know, Tim's teasing me, I think, um, Yeah.
• 35:07
  Speaker 4: So the beaver eat the aspen, they eat the willow.
• 35:09
  Speaker 4: They need those things to build their dams and their lodges.
• 35:11
  Speaker 4: And in places like Crystal Creek and in Blacktail Creek,
• 35:14
  Speaker 4: where we've had substantial regeneration of aspen and crystal and
• 35:18
  Speaker 4: willow and blacktail, we do have beaver recolonizing those sites.
• 35:23
  Speaker 4: Those beaver were not there when I started 30 years ago,
• 35:27
  Speaker 4: nor were their lodges or dams because there was no
• 35:29
  Speaker 4: aspen or willow or very little. But now 30 years later,
• 35:32
  Speaker 4: it's there. I mean, I was out tramping around in
• 35:36
  Speaker 4: Blacktail Creek and Crystal Creek just a few weeks ago.
• 35:39
  Speaker 4: And some of these dams are actually quite large. But
• 35:41
  Speaker 4: what I also found, in addition to actually seeing a beaver,
• 35:45
  Speaker 4: is I also found evidence of predation on beavers. So
• 35:50
  Speaker 4: beaver are oftentimes referred to as sort of, you know,
• 35:53
  Speaker 4: tasty snacks, sort of meat packages for predators.
• 35:55
  Speaker 5: They're very slow.
• 35:57
  Speaker 4: They've got, you know, there's lots of meat there and
• 36:00
  Speaker 4: they will be picked.
• 36:02
  Speaker 5: Off by predators.
• 36:02
  Speaker 4: And that's what we found evidence for. So there is
• 36:05
  Speaker 4: sort of this push and pull. On one hand, the
• 36:07
  Speaker 4: predators have contributed to beaver recovery by indirectly increasing aspen
• 36:13
  Speaker 4: and willow in some areas. And so beaver have come back,
• 36:15
  Speaker 4: but then all of a sudden those beaver are exposed
• 36:18
  Speaker 4: to predation and they're getting picked off. And so there's
• 36:21
  Speaker 4: sort of this dynamic and we're still waiting to see
• 36:23
  Speaker 4: how it all works out. We would assume that these
• 36:26
  Speaker 4: beaver dams that have lost beaver as a result of
• 36:29
  Speaker 4: predation will continue to be maintained by other beavers that
• 36:32
  Speaker 4: come and take their place. Um, but it's, it's kind
• 36:36
  Speaker 4: of part of the story that's still unfolding.
• 36:39
  Speaker 2: So Dan for just thinking about all the different things
• 36:43
  Speaker 2: we've talked about, we've talked about lots of different species,
• 36:46
  Speaker 2: both in terms of sort of flora and fauna. And
• 36:50
  Speaker 2: do they have differences in their recovery and times and
• 36:55
  Speaker 2: their response times? So for example, you introduce, reintroduce the wolves,
• 37:00
  Speaker 2: stuff happens to elks, stuff happens to bison, stuff happens
• 37:04
  Speaker 2: to Aspen. Is that on a similar timescale or do
• 37:08
  Speaker 2: different things happen to different things on different timescales, if
• 37:11
  Speaker 2: that makes sense?
• 37:15
  Speaker 4: In terms of like recovery?
• 37:16
  Speaker 1: Yeah.
• 37:16
  Speaker 2: So in terms of a seeing the impact and then
• 37:20
  Speaker 2: for it to recover.
• 37:20
  Speaker 3: Yeah.
• 37:22
  Speaker 1: Yeah.
• 37:23
  Speaker 4: And I think the problem is even more basic than that.
• 37:26
  Speaker 4: I mean, what defines recovery? When people talk about Aspen recovery,
• 37:31
  Speaker 4: I always scratch my head and wonder exactly what they mean,
• 37:34
  Speaker 4: because that's a term that my graduate student, Lainey Bryson,
• 37:37
  Speaker 4: I struggled with a lot because you see it in
• 37:39
  Speaker 4: the literature. And so we have to figure out, well,
• 37:41
  Speaker 4: how do you define recovery? And then you have to
• 37:45
  Speaker 4: assess the extent to which the degree to different things
• 37:48
  Speaker 4: reach that you know, threshold varies over time and varies
• 37:52
  Speaker 4: between different species. And I don't think I have a
• 37:55
  Speaker 4: very good answer for you, to be honest with you,
• 37:58
  Speaker 4: because I think this system is still unfolding in terms
• 38:02
  Speaker 4: of what it is going to look like. And nobody
• 38:06
  Speaker 4: really predicted the current state of the system as we
• 38:11
  Speaker 4: see it today with all these bison and even all
• 38:15
  Speaker 4: the aspen and willow. I mean, there were some people
• 38:17
  Speaker 4: that were probably expecting some regeneration of Aspen and Willow
• 38:22
  Speaker 4: before the wolf reintroduction. But that wasn't part of any
• 38:26
  Speaker 4: of the predictions that were being made formally in the literature.
• 38:28
  Speaker 4: It was all about the impact of wolves on the
• 38:30
  Speaker 4: ungulate numbers and that sort of thing, hunter opportunities outside
• 38:33
  Speaker 4: the park. The vegetation wasn't on anybody's radar. And we
• 38:39
  Speaker 4: don't really know what's going to happen next because we
• 38:41
  Speaker 4: do have climate warming. And so That's one of the
• 38:45
  Speaker 4: questions we're working on now is to what extent are
• 38:47
  Speaker 4: these sort of effects, these cascading effects of predators, including wolves,
• 38:53
  Speaker 4: are those going to be muted or offset by opposing
• 38:58
  Speaker 4: effects of climate warming and water stress on plants?
• 39:01
  Speaker 1: So when you go to Yellowstone these days, Simon, when
• 39:05
  Speaker 1: you drive along the area that Dan's talking about, you'll
• 39:08
  Speaker 1: come up to some of these streams and you'll see
• 39:10
  Speaker 1: little bits of kind of forest coming back and some
• 39:13
  Speaker 1: of it, you know, some pretty big trees in some areas,
• 39:15
  Speaker 1: but actually most of it, what you see is kind
• 39:17
  Speaker 1: of sagebrush, isn't it?
• 39:18
  Speaker 5: Sagebrushing grassland.
• 39:19
  Speaker 1: Yeah. So it hasn't, this kind of idea that the
• 39:22
  Speaker 1: forests have come back throughout the Northern range and that's
• 39:26
  Speaker 1: kind of led to the rivers changing isn't isn't really
• 39:29
  Speaker 1: quite it's patchy isn't it it's kind of it's a
• 39:31
  Speaker 1: heterogeneous landscape with all sorts of different things going on.
• 39:34
  Speaker 4: I mean if that's a massive exaggeration this cartoonish you
• 39:38
  Speaker 4: know story that we've heard over and over again for
• 39:41
  Speaker 4: years it's just not true yes you can find examples
• 39:45
  Speaker 4: of it but they're quite limited you know In the,
• 39:49
  Speaker 4: in the Aspen stands that we've studied, which we track
• 39:52
  Speaker 4: the fates of 80 different Aspen stands from 1954 to 2022.
• 39:57
  Speaker 4: And 90% of those stands continue to decline. Despite the
• 40:03
  Speaker 4: Wolfrey introduction, only 10% of them have increased, including the
• 40:06
  Speaker 4: largest one. That is sort of the famous crystal Creek
• 40:08
  Speaker 4: Aspen stand that everybody sees when they drive to Yellowstone
• 40:11
  Speaker 4: because they drive rates right by it. So it's very visible,
• 40:14
  Speaker 4: but that's actually a real exception. Most Aspen stands are
• 40:18
  Speaker 4: substantially smaller and we've had Aspen stands disappear since Wolfrey introduction.
• 40:25
  Speaker 1: So it's a really complicated system, Simon, actually.
• 40:27
  Speaker 2: It seems to be, despite, I guess, in a way
• 40:30
  Speaker 2: it being a kind of self-contained model system as well.
• 40:34
  Speaker 2: It's the complexity is kind of mind boggling, but it
• 40:37
  Speaker 2: sort of leads me on to what next for you, Dan?
• 40:40
  Speaker 2: What are you sort of interested in now? What are
• 40:42
  Speaker 2: you keenly observing and what's, you know... What next is
• 40:46
  Speaker 2: the big thing?
• 40:49
  Speaker 4: For me, it's continuing this journey of incorporating into my
• 40:54
  Speaker 4: thinking all these other species in the food web and
• 40:57
  Speaker 4: really thinking about Northern Yellowstone, not as a system dominated
• 41:01
  Speaker 4: by wolves, but really as a food web that's dominated
• 41:05
  Speaker 4: by a lot of different species, you know, bison, moose,
• 41:10
  Speaker 4: the other carnivores. I mean, I think that's one of
• 41:12
  Speaker 4: the big things that has changed in the last 30
• 41:14
  Speaker 4: years amongst the researchers that focus on this system is
• 41:18
  Speaker 4: we're not thinking about it solely in terms of wolves
• 41:21
  Speaker 4: and elk, which is how I've thought about it for years.
• 41:24
  Speaker 4: We're thinking about it more as a community of predators
• 41:27
  Speaker 4: interacting with the community of herbivores. And then we're also
• 41:32
  Speaker 4: trying to get beyond the aspen and the willow. We're
• 41:35
  Speaker 4: trying to think more broadly about the grass that actually
• 41:38
  Speaker 4: is the primary food for these herbivores, the elk and
• 41:42
  Speaker 4: the bison in particular. So elk, you know, eat mainly
• 41:45
  Speaker 4: the grass. And the fate of the grasslands is a
• 41:49
  Speaker 4: legitimate question in and of itself, particularly in the case
• 41:52
  Speaker 4: of warming, because we deal with invasive grass species in
• 41:56
  Speaker 4: Yellowstone National Park that are favored by warming. And these species,
• 42:01
  Speaker 4: things like cheatgrass, they've begun to colonize the lower elevations
• 42:04
  Speaker 4: that are hospitable to them because it's warm enough. But
• 42:07
  Speaker 4: as warming starts to continue to accelerate, those species could
• 42:11
  Speaker 4: potentially colonize further up into the higher elevations with potentially
• 42:17
  Speaker 4: negative consequences on the herbivore community that relies primarily on
• 42:20
  Speaker 4: the grasses. So expanding our scope of inquiry is really
• 42:25
  Speaker 4: kind of, I think, the future for Yellowstone research and
• 42:28
  Speaker 4: getting away from just this wolf-centric, research program.
• 42:32
  Speaker 1: If only we had an early career postdoc who was
• 42:35
  Speaker 1: building models of Yellowstone called Willem Bonnefeu. This is why
• 42:42
  Speaker 1: Dan's over in Oxford, because we're working with this wonderful postdoc, Willem,
• 42:48
  Speaker 1: who's actually building these complicated models that will hopefully provide
• 42:51
  Speaker 1: some novel insights.
• 42:52
  Speaker 4: Absolutely, because that's part of the reason why we haven't
• 42:55
  Speaker 4: been able to really tackle these issues empirically is we
• 42:58
  Speaker 4: haven't had the quantitative tools to do so. And so
• 43:01
  Speaker 4: that's what Willem is developing. And that's what's really so
• 43:03
  Speaker 4: exciting is like for the first time, we'll have sort
• 43:06
  Speaker 4: of an integrated model for bringing together all these different
• 43:10
  Speaker 4: components that are really mechanistic way to understand these relationships.
• 43:13
  Speaker 2: How do you talk my language? Mechanistic understanding. That I get.
• 43:18
  Speaker 5: All right.
• 43:18
  Speaker 1: You know, this is where we collide, Simon, with our
• 43:21
  Speaker 1: methods and what have you. But I think, I mean,
• 43:23
  Speaker 1: thanks very much, Dan, for coming on. Oh, absolutely. It's fascinating.
• 43:27
  Speaker 1: And the Yellowstone story just continues, I think, because when
• 43:31
  Speaker 1: that video came out, I mean, in fairness to George Monbiot,
• 43:34
  Speaker 1: who made it, I mean, that's kind of what the
• 43:35
  Speaker 1: science is pointing at. The whole point, it's a journey,
• 43:38
  Speaker 1: isn't it?
• 43:39
  Speaker 4: There were a series of papers that led people to
• 43:42
  Speaker 4: believe that that was what was going on, but those
• 43:44
  Speaker 4: were all very preliminary results.
• 43:46
  Speaker 1: Yeah, I think that's right.
• 43:47
  Speaker 2: Yeah.
• 43:48
  Speaker 1: And so I think it will continue. The park will
• 43:49
  Speaker 1: continue to change. I have no doubt about it. We'll
• 43:51
  Speaker 1: have this conversation in 10 years and we'll say, no
• 43:54
  Speaker 1: one predicted that moose were going to become super. Well,
• 43:57
  Speaker 1: and then Dan will say, no, well, actually I did
• 43:58
  Speaker 1: just go back. Anyway, perhaps on that note, it's time
• 44:01
  Speaker 1: to finish. So thanks so much, Dan. Thank you for
• 44:03
  Speaker 1: coming along and spending the time talking to us.
• 44:06
  Speaker 2: Yeah.
• 44:06
  Speaker 3: Yeah.
• 44:07
  Speaker 1: Okay. Well, that was interesting. Simon, what did you make
• 44:09
  Speaker 1: of that? I mean, you're the, you're, you know, I know,
• 44:11
  Speaker 1: known quite a lot of that, that story. It was
• 44:13
  Speaker 1: still fascinating to hear it, of course, but what's your take?
• 44:17
  Speaker 2: I was a bit blown away to be honest, so
• 44:19
  Speaker 2: much to, so much to take away. Um, first, just
• 44:23
  Speaker 2: the incredible story of, of, you know, the wolves sort
• 44:26
  Speaker 2: of being taken away from the, just the historical aspects
• 44:30
  Speaker 2: being taken away, um, from Yellowstone reintroduce the impact on
• 44:34
  Speaker 2: the Elks. And I think, you know, the elk numbers
• 44:38
  Speaker 2: going down, going up and then sort of down and
• 44:40
  Speaker 2: then stabilizing. And I think, um, And the fact that,
• 44:45
  Speaker 2: you know, it's being looked beyond sort of looking at
• 44:48
  Speaker 2: things beyond wolves and Elks now onto the, you know,
• 44:51
  Speaker 2: the flora as well. I think there's, it's actually quite
• 44:54
  Speaker 2: a lot to sort of process.
• 44:56
  Speaker 1: No, and it's true. It's an iconic study, the Yellowstone study, particularly,
• 45:01
  Speaker 1: I mean, the wolf study, this is, you know, the
• 45:03
  Speaker 1: longest and most in depth study of, of, of, of
• 45:06
  Speaker 1: recognizable wolves that have got collars on that that's ever
• 45:09
  Speaker 1: been undertaken. And the fact that there's all these other
• 45:12
  Speaker 1: bits of research on the elk and the bison and
• 45:14
  Speaker 1: the moose and the Aspen and the willow, the beavers
• 45:17
  Speaker 1: and all sorts of, and the mountain lions, makes it
• 45:20
  Speaker 1: really unusual and makes it a special study. And wolves
• 45:23
  Speaker 1: have had an effect, but it's really interesting that it's
• 45:25
  Speaker 1: not the clear wolves change rivers that we'd all come to.
• 45:30
  Speaker 1: But I don't want to knock that video too much
• 45:32
  Speaker 1: because it has made people aware of how important predators
• 45:35
  Speaker 1: can be on landscapes.
• 45:37
  Speaker 2: I think for me also the resolution of the information
• 45:40
  Speaker 2: You know, at one point you sort of said, you know,
• 45:42
  Speaker 2: there's 100 wolves and the answer came out, there's 108.
• 45:46
  Speaker 2: And it was that level of detail, I think, which
• 45:51
  Speaker 2: for me was astonishing. I hadn't realised it was at
• 45:53
  Speaker 2: quite that level.
• 45:55
  Speaker 1: No, it really is. My pack wolf has just gone
• 45:57
  Speaker 1: rushing out, barking in the background. It's been picked up.
• 46:01
  Speaker 1: But no, I mean, things are studied in great detail.
• 46:05
  Speaker 1: Each pack will have two wolves with radio collars on,
• 46:08
  Speaker 1: so we can find each pack. you know, on a
• 46:10
  Speaker 1: regular every few days to work out where they are.
• 46:13
  Speaker 1: And then we can see which other wolves are in
• 46:15
  Speaker 1: the pack, whether there's been any, you know, any young born,
• 46:19
  Speaker 1: whether they've then come out of the burrow. So no,
• 46:21
  Speaker 1: it's a huge, astonishing amount of data. And I mean,
• 46:26
  Speaker 1: it's somewhere that having listened to that, do you think you'll,
• 46:29
  Speaker 1: next time you're in the US, would you swing by
• 46:31
  Speaker 1: Yellowstone and have a look round?
• 46:32
  Speaker 2: I'd love to, honestly. And, you know, I was just
• 46:35
  Speaker 2: sort of playing back in my mind some of these
• 46:37
  Speaker 2: images of people sort of out of helicopters firing darts and,
• 46:41
  Speaker 2: you know, the salmon fishing nets. It's just such a
• 46:47
  Speaker 2: different scale of science to what I do. It's just different.
• 46:52
  Speaker 2: And it's, yeah, I think it really, I'm really struck
• 46:54
  Speaker 2: by it, to be honest.
• 46:56
  Speaker 1: No, it was good. I'm glad you enjoyed it. And
• 46:57
  Speaker 1: of course, we're both using maths to model systems, right?
• 47:01
  Speaker 1: Whether they're at the very small scale of individual molecules
• 47:04
  Speaker 1: that you're looking at, or at the whole ecosystem scale. So,
• 47:07
  Speaker 1: But no, it was great to have Dan on. I
• 47:08
  Speaker 1: really enjoyed chatting to him.
• 47:09
  Speaker 2: Yeah, what a great guest.
• 47:10
  Speaker 1: Yeah, fantastic. We'll have a good week. And then next
• 47:14
  Speaker 1: week in our podcast, our football skills are going to
• 47:17
  Speaker 1: be put to the test.
• 47:18
  Speaker 2: Yeah, I might have to get a bit of practice
• 47:20
  Speaker 2: in over the weekend.
• 47:21
  Speaker 1: Have you got a football? I do, actually. Thank God
• 47:24
  Speaker 1: for that, because I haven't. I think I might buy one. Okay, excellent. Well,
• 47:29
  Speaker 1: good chatting to you, Simon. And have a good week
• 47:33
  Speaker 1: and I'll talk to you soon.
• 47:34
  Speaker 2: Cool, take care, Tim.
• 47:35
  Speaker 1: Yeah, bye.