Short Wave - To Save The Grizzly Bear, You Gotta Think Like One

Episode Date: August 12, 2024

Grizzly bears in the contiguous United States have been taken off — then put back on — the endangered species list twice since they were first labeled as threatened almost 50 years ago. Now, the issue is on the table again. Today, we get into the complicated science behind grizzly recovery, how humans have sliced up their habitat and what it will take to stitch that habitat back together again.Interested in more charismatic megafauna? Email [e-mail]. We've love to consider covering your favorite on a future episode! See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, Short Wavers, Regina Barber here with Science Queen and producer Burley McCoy. Hey, Burley. Hey, Gina. So I hear we're going to talk about grizzlies, and this is an animal that people have, let's just say, strong feelings about. They do. To a lot of people, they're what scientists call charismatic megafauna, which basically means a big animal lots of people love. People imagine grizzlies to be this giant soft teddy bear rolling around in pristine streams with mountains and wildflowers in the background.

I mean, yeah, I mean, there is the fat bear week, but honestly, they really scare me. And same, and same. Grizzlies are super dangerous, and we do have a lot of them up in my neck of the woods around Glacier National Park in northwest Montana, because they've rebounded from a pretty critical low point decades ago when they were reduced to less than two. of their historic range. They've rebounded? Like, I thought they were on the endangered species list. They are, but it's complicated.

Okay. Since they were first placed on the endangered species list in 1975 as a threatened species, the U.S. Fish and Wildlife Service has taken the grizzly population in and around Yellowstone National Park off the list twice, but both times it was reversed in court. Now the protected status of grizzlies is on the table again, but the service just announced they'll delay that decision until 2025. I'm getting the sense that this is like kind of a contentious issue. Like what is the debate here?

Well, on one side, you have people who say, look, grizzly bears in the lower 48 United States only live in a few separated pockets and their numbers and range aren't nowhere near what they were historically, which was tens of thousands of bears who lived from Canada to present-day Mexico from the west coast to the Midwest. Contrast that to today's around 2,000 bears who mostly live in 4,000.5,000 bears who mostly live in 4,000,000, populations in the northwest U.S. Wow, okay. And then you also have animal rights groups who want to protect the bears from being hunted, even in low numbers, which could happen if they come off the list.

And what's the other side? So on the other side, you've got people who say that two pockets of populations of grizzlies, the glacier area grizzlies and the Yellowstone area, grizzlies, they're doing so good that they don't need federal protection anymore. I talked to wildlife biologist Frank Van Manin. He's the team leader of the interagency grizzly bear study team. And he said the point of the Endangered Species Act is to get a species to recovery. It's fair to say that the Endangered Species Act was never designed to keep species on the list of endangered or threatened forever.

So today on the show, why to save a grizzly bear, you've got to think like a grizzly. Plus, how humans have fragmented their home and the difficulty in reconnecting it. You're listening to Shortwave, the science podcast from NN. And PR. Okay, Ranger Burley. Let's start by really zeroing in how grizzlies are doing, like, right now. You said that there are ones around you that have rebounded, but what's the, like, larger lay of the land here? Yeah, so the Yellowstone and the glacier area grizzlies are doing pretty good numbers-wise.

But there's actually another factor that's standing in the way of their long-term success as a species. And that's human development. Development has made it so these two pockets of bears plus two smaller, pockets are mostly isolated from each other. And Yellowstone Grizzlies have been isolated for 50 to 100 years. Wow. Yeah. And that means the bears aren't mating across populations. And that, Frank says, can potentially knock down their overall genetic diversity. In general, populations that have higher genetic diversity are better able to adapt to changing future conditions. And this is the thinking across most populations. Another scientist,

I talked to Sarah Cells echoed this idea. Her team at the University of Montana studies how wildlife managers could connect separated populations of grizzlies in order to increase that genetic diversity. Okay. Which is important because without connection to other populations, grizzlies like the ones in Yellowstone... They are reliant on the genetics that exist within their existing population and that can lead to things like genetic drift as the genetic diversity in the population declines. Yeah, explain to me what genetic drift is. So it's basically when the variation and certain traits change due to random mutations.

Okay. And this can be a bad thing of a population declines. So take, for example, the Florida Panther. That population reached critically low population numbers in the 90s. That led to genetic drift and inbreeding, which led to less genetic diversity. And ultimately, it resulted in all kinds of problems. like heart defects and poor sperm quality. So it's also important to note that populations with low genetic diversity don't always go downhill.

Like the Codiac brown bear population in Alaska is stable even though their genetic diversity is really low. So genetic diversity could be another complication for grizzlies that researchers could sidestep if they get the populations mingling. So is one of the big issues for grizzlies just like connecting the populations? so they're not physically or genetically isolated anymore? Exactly. And scientists have been studying this for a long time, but with human expansion everywhere and the notorious clashing between grizzlies and people,

reconnecting grizzly populations, right? And by doing so helping them recover, it can be a tall order. Okay, well, so, like, given all this, how are biologists thinking about, like, reconnecting these grizzlies? Like a bear would. Think about how they move across the landscape

and what's getting in its way. Okay. Okay, so there's a specific section of highway about 80 miles south of my house. And it's really, really deadly for bears. And I learned this for the first time when I was talking to Carrie Kingery. She's a manager of the Confederated Salish and Cootney Tribe's Wildlife Program. This 11-mile stretch of highway accounts for about a third of all highway mortalities of grizzly bears in the northern continental divide ecosystem. Geez, that's huge.

Yeah, it's a big proportion of mortalities. And also, so the northern continental divide ecosystem is basically a long name for the bear recovery area in and around Glacier National Park. And she said like a third of the grizzly highway deaths happen in this one particular spot. Yeah. And she said it's because of the landscape where this highway runs through. So on either side of the highway, you just have these really pristine habitats. of prairie pothole wetlands, which is a really good habitat for grizzly bears and other wildlife. So this stretch of highway is at the very edge of this ecosystem and for bears moving out of the

recovery area and potentially into another recovery area, they have this huge impediment, the highway. And what do those reconnection efforts look like in this case? Yeah, so in this case, Carrie and her team are building a highway overpass based on where bears cross the most. Okay. And then going back to Sarah's work, she and her team are also working to connect bear populations. That's involved predicting how a grizzly bear would travel if it were moving between recovery zones.

And they did this by tracking how actual bears move within their habitat and then using that movement data to train a computer model. Oh. So then they could go in, ask the model, okay, so if a bear in glacier was going to move to the Yellowstone area, which as of 2020 is actually only like 60 kilometers away, or 35-ish miles. Wow. How would it do it? Right. So this is basically like Google Maps for Grizzlies.

100% Gina. Exactly that. If bears had computers and opposable thumbs. Then they would rule the world. I know. That would be scary. Okay. What did they find?

Okay. So Sarah's team found that there were pathways available between populations of grizzlies. And the exciting part was that some of these pathways did actually lead to Yellowstone, these like super isolated bears. Okay, so this is like doable. What are they going to do then with these like paths that they found? Like what do biologists need to do to get the grizzlies to go along these paths? Well, bears are moving outward.

They're spreading. But outside of these big national parks and wilderness areas, there are barriers like roads and people who have things like livestock and pet food and garbage, all sorts of things that get bears into trouble. Which is why Sarah and her team made these maps, which can help by, indicating where things like conservation easements could go, for example. And those are these areas of land that are often donated by private landowners that are protected from development. Or the maps could indicate where a certain crossing structure should be built. Like those highway crossings you had mentioned earlier. Exactly.

Okay. So it seems like there are solutions, right? It's just like a matter of like how much humans are willing to invest in these like solutions. So are scientists worried if this kind of connectivity doesn't happen? Yes and no. I mean, the scientists I talked to didn't seem like they thought the isolated grizzly bears were in, like, immediate danger, that this was a long-term concern and that connectivity is something to work toward, like to tie all the previous conservation work of boosting numbers together. But in terms of taking them off the endangered species list, like if that happens, which seems like it's a strong possibility, connectivity efforts would continue. And in fact, a couple of weeks ago, the Montana and Wyoming state agencies partnered up to translocate two bears from the glacier area down to the Yellowstone area.

So they physically moved these bears to help with this population. I mean, that's one way to help. Yeah. But it sounds like a lot of work. Yeah. And really the best case scenario would be if the bears moved on their own because it would be a sign of like this self-sustained recovery. Right. But this is another way agencies can make sure genetic diversity increases.

And Gina, they can use it to reintroduce Grizzlies to areas that they used to live, like the North Cascades in Washington State. Ooh, that's, you know, that's Northwest Washington. I used to live around there. I've actually been to the North Cascades. So it sounds like there's so much going on with Grizzlies and their recovery efforts. So like with all of your reporting, do you get a sense that they have fully recovered? You know, after talking to these scientists, it seems like it really depends on how you define recovery. Clearly, some people think some of the bear populations have recovered enough to delist them.

Others aren't sure they're ready. I did ask Carrie about recovery in the context of delisting Yellowstone and Glacier Area Grizzlies. The numbers look pretty good. And based on that alone, some people might say they're recovered. So what do you think about that and why? I feel like you don't have true recovery until, you know, all the recovery zones are linked genetically through the landscape. Culturally for the tribes, it's that genetic connectivity on the landscape, allowing the animals to naturally recolonize and have gene flow between these different populations.

And that means allowing them to persist outside of these population islands within the recovery zones. And it'll take more human interventions. intervention to get here. Grizzly bears would be fine without humans. We are the challenge for grizzly bears on the landscape. So it will take humans being ready to coexist with this large carnivore that can present challenges for coexistence. And so what's striking to me as a kind of note to go out on is that the tail of

grizzlies is also a window into human ingenuity and our capacity for coexistence. Thank you, Burley, for bringing us the story from your neck of the woods. You're welcome. This episode was produced by Rachel Carlson, edited by our showrunner Rebecca Ramirez and fact-checked by Burley McCoy. The audio engineer was Maggie Luthor. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. And I'm Burley McCoy. Thank you for listening to Shorewave from NPR. If you're in Grizzly Country, please take bear spray. Please.

Yeah. Please don't mess around with bears. Don't hug them. Don't leave your food out. Don't do that.