Bringing Nature Back to Man-Made Spaces

11:46 minutes

Bison at the Rocky Mountain Arsenal National Wildlife Refuge in Commerce City, Colorado. Photo by Becky Fogel
Bison at the Rocky Mountain Arsenal National Wildlife Refuge in Commerce City, Colorado. Photo by Becky Fogel

The Rocky Mountain Arsenal National Wildlife Refuge previously housed a chemical weapons manufacturing center and a pesticide factory. Today, the 16,000 acres located 10 minutes outside of Denver is one of the nation’s largest urban wildlife refuges. Project leader David Lucas discusses how to bring nature back from contaminated land, and what wilderness means in an age of urban sprawl.

Segment Guests

David Lucas

David Lucas is a project leader at the Rocky Mountain Arsenal Wildlife Refuge Complex, part of the U.S. Fish and Wildlife Service, in Commerce City, Colorado.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow.

The Rocky Mountain Arsenal Wildlife Refuge Complex right outside of Denver is one of the largest wildlife sanctuaries in the country. But it didn’t start out that way. During World War II, the Army set up a chemical weapons factory on that spot. The plant was producing mustard gas, napalm, and arsenal of deadly chemicals. After the weapon plant was decommissioned, the site was converted into a pesticide factory.

It’s not the first place you’d nominate for a wildlife refuge. So how do you bring nature back to a place destroyed by humans? And what does wilderness mean in the age of urbanization? That’s what we’re going to be talking about.

Let me introduce my guest. David Lucas is the Project Manager for the Rocky Mountain Arsenal Wildlife Refuge Complex in Commerce City, Colorado. Welcome to Science Friday.

DAVID LUCAS: Thank you, Ira.

IRA FLATOW: Let’s talk about the cleanup for the refuge. It spanned over– what, over two decades ago? What was the process like?

DAVID LUCAS: Well, it’s really been a robust process. As you mentioned, the day after Pearl Harbor, they needed to create an arsenal in reaction to the World War II threat. And that led all the way up until 1987 when cleanup officially began of the Rocky Mountain Arsenal.

So as you mentioned, about 20 years, they were characterizing the site, looking and investigating, and then cleaning up.

IRA FLATOW: Well, cleaning up, is it literally digging things, plowing?

DAVID LUCAS: Exactly. With this site, most of the contamination was windblown. And they were scraping soils and putting those into large landfills and moving on so that the site could be restored. And that’s what we’ve been focused on, is the restoration.

IRA FLATOW: Now, I understand that the bald eagle helped you put the cleanup in motion.

DAVID LUCAS: That’s true. The bald eagle was an endangered species at that time. Thankfully, it’s not any longer. But bald eagles were found on the Rocky Mountain Arsenal, and the US Fish and Wildlife Service began working with the US Army in managing those eagles. And one of the bitter ironies of the site is that the persistent organochlorine pesticides that were produced there put the bald eagle on the endangered species list, and then those eagles found their way back and helped us to turn it into a national wildlife refuge.

IRA FLATOW: Does it have something to do with the eggs being fragile?


IRA FLATOW: In Silent Spring, they talked about that.

DAVID LUCAS: Exactly. Rachel Carson, who is a Fish and Wildlife Service employee, she was researching that. And the egg thinning from the DDTs and DDEs was one of the principal reasons that that species was endangered.

IRA FLATOW: Wow. What a full circle.

How do you manage this area differently from a refuge that doesn’t have a history of contamination?

DAVID LUCAS: Well, first and foremost, we’re urban, and we’re excited to be urban. Because we are part of the National Wildlife Refuge System– 560 refuges across the country, one in every state. But most of those are rural, and that’s where they’ve evolved. But this is an urban complex– 16,000 acres just outside of Metropolitan Denver.

And so how do we manage it different? I believe we try to manage it exactly the same as we manage our other national wildlife refuges. And that’s why it’s neat– because we have millions of people that have access to this refuge and can see the work that we’re doing there and then understand why we’re trying to conserve fish and wildlife in their habitat.

IRA FLATOW: Is there an indicator– the canary in the cave– that would be for an open prairie like that?

DAVID LUCAS: That’s a great question. Actually, during the super-fun cleanup, the Fish and Wildlife Service was responsible for biomonitoring, which they looked at the animals that were out living in the dirt– prairie dogs, various bird species, badgers, the fish that were in the lakes. And they were able to use those to detect where those chemicals were and when those chemicals were cleaned up. It was pretty neat.

IRA FLATOW: I understand the prairie dogs are a pretty good indicator.

DAVID LUCAS: They are. They did a lot of work with the prairie dogs, which leads us to a pretty exciting part of our site. We have a great deal of prairie dogs. And obviously, they reside down in their burrows, and they’re digging and moving around the site at all times. And we’re currently exploring reintroduction of black-footed ferrets, the most endangered mammal in North America, at this site.

IRA FLATOW: Because they feed on the prairie dogs?


IRA FLATOW: Wow. And I hate to say it this way– you kill two birds with one stone. Not the best way of putting it. But you’d be feeding the ferrets and–

DAVID LUCAS: Exactly. Well, the food chain is a big part of the business we do. And having top predators is one of the most important things that you can do to restore natural ecosystems.

IRA FLATOW: Now, speaking of that, I know you’re bringing the natural prairie plants and the animal’s back to the area, and this includes the bison. You took our producers on off-road hunt for a herd of bison, and this is what it sounded like.

DAVID LUCAS: We’re just leaving, and we are going to go out, actually, where the public can go on our tour route, and look for some bison. So I will have to hop out of the car and open the gate here.

You just entered the bison pasture. They hang out in a lot of different places, and they have very much a ritual. Bison spend a little bit of time once or twice a day getting water, and they’re on the move the rest of the time. So they’re on the move right now somewhere.

That was a bison wallow that we just drove through. It’s an area where they generally get water, roll, hoof around in an attempt to preserve water there in the future. So it looks like they’re further up, so we’re going to have to probably go down here and then take a right. No, there’s one– no, that’s a bush. Darn.

Oh, there is one. We’ve got one on the right. So we’ve got a yearling over here to our left rolling around and creating a dust storm. And to the right, we’ve got two males walking the other way. His head is probably about five feet across. He’s looking directly at us. He’s got the dark, mature head with the more tan, brown body. And there he’s going now. He’s going to start trying to catch up with the rest of his crew.

Oh, yeah. Look at what– we’re just coming over a hill, and there’s about 50 bison here. I can see dust from bison rolling. I can see calves running around the edges. So that male just pushed a female out of the way because she was blocking his view of us. But this big bull here is not as happy with us. He’s a little big. And I might move a little bit.

The reason we have bison here– there’s a couple reasons. Number one, we have them here to help us with our restoration program. So they are out here working every second eating grasses. The other reason we have them is they’re awesome. They’re superstars. They help us to connect with a lot of people.

When I started, it was all about protecting habitat. And i we protected enough habitat, wildlife would thrive, and everything would be OK. But we’ve learned now that if we can’t figure out how to get kids right now to care about the wildlife, conservation ends.

IRA FLATOW: Fascinating. And kids do show up to watch?

DAVID LUCAS: Yeah. Currently, we have about 30,000 kids a year that come through in formal programming. But we have 120,000 kids in schools just adjacent to the Rocky Mountain Arsenal National Wildlife Refuge. So there’s a lot more work to be done. But to me, that’s where it all starts. Basically, all science and everything that we all invest our careers in can be found in nature.

And if we can get kids to get excited and get outside and get disconnected from the various devices, I just think it’s– well, I think it’s an essential part of being a human. Obviously, we all as humans evolved over tens of thousands of years. And just in these last 30 to 40 years, we’ve become so disconnected from everything natural.

IRA FLATOW: That’s interesting. Yeah. We’re doing our electronic objects, right? But the kids will come out. Families do come out?

DAVID LUCAS: Yeah. We get a lot of families. Obviously, one of our goals right now is to increase visitation and the accessibility of that. We had just 23,000 visitors in 2012. And last year, we had over 300,000.


DAVID LUCAS: And we’re expecting to have over a million visitors a year.

IRA FLATOW: And what are they coming out to see? What’s the attraction, do you think?

DAVID LUCAS: I think a lot of things. One, proximity– being an urban national wildlife refuge, they can get there. But I think families do recognize that they need to get their kids outside, and it needs to be someplace that they feel comfortable and they can do that, these baby steps of moving into nature. And so they come out, and they look at the bison, they look at the eagles, they look at the raptors, they look at the song birds, they look at the grasses, they look at the fish, the frogs, anything.

IRA FLATOW: That’s amazing. Because here you are in Colorado, surrounded by– you have Rocky Mountains, you have all this wildlife out there. And yet they’re still coming to see your place.

DAVID LUCAS: Yeah. And I love that, because I think the prairie ecosystem and the grassland ecosystems are far more exciting than those big mountains to our west. But those big mountains to our west are what draw people to Denver, and that’s why Denver is probably one of the largest-growing cities in the nation.

IRA FLATOW: So what would you like to do next? What kind of changes, improvements, whatever would you like to see?

DAVID LUCAS: Wow. That’s a huge question.

IRA FLATOW: I’m going to give you–

DAVID LUCAS: You’re giving me the blank check, too.

IRA FLATOW: I’m giving you the blank check. Because I don’t have it. I can give it.

DAVID LUCAS: You can give it. To me, I really would love for us to continue to build our partnerships with the schools and with all of the conservation organizations. This is one thing we’re lined up on, and we’re not always lined up. But everybody is lined up right now and agrees that what we have to do right now together is figure out how to bring kids out, get them excited about the outdoors, and get them excited about nature– not only for their own health, just up and moving, but also that those kids will be the future conservation leaders. So anything that we can do with that blank check to get more kids, the ability to get out and have positive experiences– I think that would be awesome.

IRA FLATOW: And any modifications or improvements to the refuge at all would you like to see?

DAVID LUCAS: Well, in planning for those million visitors a year, we are doing a lot of planning. And so there’s a lot of infrastructure that goes into that and protecting the main resources that are there that people want to enjoy. And that’s a big part of our job, is making sure we have that balance.

IRA FLATOW: So you don’t have too many people trampling the wilderness?

DAVID LUCAS: Yeah. So I think through planning, we can get people to the right spots, and we can allow people to come in and enjoy while also protecting the National Wildlife Refuge and its resources.

IRA FLATOW: How big a herd of bison do you think you have now?

DAVID LUCAS: Right now, we have 84.

IRA FLATOW: 84. Aiming for?

DAVID LUCAS: Eventually, 220 is our maximum capacity.

IRA FLATOW: And could they turn into bison meals for people if they get too many?

DAVID LUCAS: That’s a good question. Yeah. We have to do population management. They will continue to breed. When we have 220 animals, there will be 40 to 50 calves per year. And the Fish and Wildlife Service can access those animals. And most of them are going into other conservation herds.

IRA FLATOW: Oh, is that right? You move them around?


IRA FLATOW: Don’t confuse a bison with a buffalo.


IRA FLATOW: The nickel is not around anymore to show people what a bison really looks like.

DAVID LUCAS: But it is the centerpiece of the Department of Interior’s logo. It is the iconic prairie species. And like I always say, they deserve a spot somewhere in the United States.

IRA FLATOW: And you’ve given them a spot at the Rocky Mountain Arsenal Wildlife Refuge Complex. I’m talking with David Lucas, who’s the project leader. Thank you for taking time out of this holiday.

DAVID LUCAS: Thank you.

Meet the Producer

About Alexa Lim

Alexa Lim was a senior producer for Science Friday. Her favorite stories involve space, sound, and strange animal discoveries.