Sean Gerrity dreams of a Serengeti, a vast landscape of rolling grasslands where large mammals roam. But instead of elephants and hyenas, Gerrity's savannah would contain bison, elk, bighorn sheep, and wolves. They would graze, hunt, and rear their young on 5,000 square miles of northeastern Montana prairie.

For more than a decade, Gerrity has been working to turn his dream into reality. He is president of the American Prairie Reserve, which has been plugging away since 1999 at what he calls a "habitat assembly project," piecing together a vast grassland ecosystem in which 25,000 bison and multiple packs of wolves may one day live. Gerrity's organization hopes ultimately to own 500,000 acres of private land and through that to influence what happens on the adjacent 3 million acres of public land, much of it now home to grazing livestock. "I want to restart the golden age of conservation," says Gerrity, who estimates his project will cost $450 to $500 million.

But the Montana native and former Silicon Valley entrepreneur — Gerrity co-founded Catalyst Consulting, which has worked with firms such as eBay, Cisco Systems, and Netflix — faces a daunting challenge persuading skeptical ranchers and farmers that bison and wolves roaming in their backyard is a good thing. To date, American Prairie Reserve has assembled 250 genetically pure bison on about 60,000 acres of land.

In an interview with Yale Environment 360 contributor Hillary Rosner, Gerrity discusses his vision, the future of large-scale conservation in the U.S., and the rationale for restoring part of the prairie to a Lewis-and-Clark incarnation.

Yale Environment 360: How did you come up with this crazy idea, and how did you get it started?

Sean Gerrity: The idea to create a big, iconic reserve on the grasslands of North America has been around since the 1830s. But the grasslands were not seen as sexy at the time we were doing our really big ecological-scale conservation in this country, from 1870 to 1950.

So it's not an original idea — it has been reiterated lots of times by authors, conservation groups, an endless parade of people. The trick was, who the heck is going to do it? And you can't do it by government fiat anymore, so how is it going to get done? That's what was going on in 1999 when I first showed up, and there was a big discussion about it, led by WWF.

The big question was, somebody is going to have to quit their day job and do nothing but this for a very long time. That became appealing to me, not because I'm a martyr but because the idea was extraordinarily exciting. The pieces started to fall together for it to look like it could be done. It wasn't that expensive — half the price of a new NFL football stadium. There's a tremendous amount of public land, meaning you didn't have to buy it all, you only had to buy the glue and pull it together. Anybody coming from business, which I had been, coming from 20 years in Silicon Valley, is always looking for a way to finesse things rather than muscle things. And the idea of wildlife was something in my bones because I grew up in Montana and both my parents were naturalists.

e360: You say you only had to piece it together because so much is public land. How does that work? You just have to buy the private parcels and stitch it together?

Gerrity: Yes, and then change the use of the [public] lands. What's really great about the public lands is they're really malleable in terms of what they're used for. You can use them for commercial purposes like forestry, for livestock grazing. You can also, if you have a lot of public leases, use them for wildlife value as the number one priority. That was very exciting, that we could co-opt a lot of public land and change the use from livestock production to wildlife emphasis, for essentially no cost. That means putting together millions of acres of public land and converting it to our vision.

e360: What agency owns all that land?

Gerrity: There are four big players. The biggest is BLM [the U.S. Bureau of Land Management], with 2.5 million potential acres. Currently 99 percent of that is under cattle and sheep grazing. The second piece is about 700,000 acres of Montana state school trust land. These are also leased for agriculture. The third piece is the Upper Missouri River Breaks National Monument, which is about 370,000 acres, still primarily used for cattle grazing, but it does have monument status and as you buy property along that you can affect what's happening at the monument. The last big chunk is the Charles M. Russell Wildlife Refuge, at 1.1 million acres. It also has tens of thousands of head of cattle. But we can also affect it by how we interact with it when we become border neighbors and help the [U.S.] Fish and Wildlife Service [convert it to] all wildlife.

e360: So it sounds like there's a big political piece to this that involves convincing all these agencies to buy in?

Gerrity: Absolutely. But the interesting thing is that was one of the things that doubters, back around 2001 and 2002, were saying would be our toughest challenge. We're delighted to report it's been one of the easiest things. The reason why is that as we sat down and looked at the long-term strategic plans of the Fish & Wildlife Service, BLM, etc., and buried in their plans is a strong desire to be more wildlife habitat oriented. So we found that in fact many of their goals are very similar to where we want to end up. So instead of having to cajole people, our presence coming onto the landscape as a catalyst enables them to accelerate their own plans.

e360: How far along are you in your grand plan?

Gerrity: I'd say we're coming up to the end of our first trimester. That is because we have about 270,000 acres, between private property, BLM, and the state. But also the land in the [Russell reserve] is about 500,000 acres that's not grazed. So we're at about 800,000 of our end goal of 3 million acres. We don't own and ultimately control that, but again we're trying to be a catalyst. We own and control about 60,000 deeded acres. But those leverage about 210,000 acres of public land. And that ratio will stay about the same as we go along.

e360: Let's talk a bit about the wildlife you're hoping to reintroduce or to see move in on its own.

Gerrity: There are three aspects to our plan. It takes a great amount of sustainable grassland habitat to create a biome that was there. Scientists have modeled it in different ways, and they keep coming up with 5,000 square miles, or around 3.2 million acres. The reason for that is if you have catastrophic things that happen on grasslands, huge fires or icing over, wildlife needs to be able to move to new areas.

The second thing is that the public is able to access the land in a way that doesn't damage habitat or interfere with nature. We think of it as what it's like to visit the Great Barrier Reef. Lots of people can visit it, but they don't necessarily impact it because of its size and the way it's managed.

The third thing is wildlife. This is a very long-haul project. Getting the wildlife and the right species and populations will take some time, probably beyond my lifetime. Grassland birds, bighorn sheep, elk, cougars, and on and on — each one used to be there in populations that are nowhere close to that today. So there's a slow process of changing the neighborhood for the enjoyment and desire for wildlife, as opposed to seeing it as a threat to livestock operations. That's the biggest piece. The actual physical biology of bringing the animals back is very easy.

e360: Recently you did move a bunch of bison to this landscape, and there were some surprises with that. Where did the bison come from, and what happened?

Gerrity: Bison were one of those animals, like swift fox and a few others, that were [nearly] eradicated around 1870 and had not been reinstated. Elk and bighorn sheep had been reinstated. But we brought in 16 bison originally from Wind Cave National Park in South Dakota. Three years in a row we continued to supplement from Wind Cave, 20 to 25 animals at a time. And of course they had babies. The trick with the genetics was that from 2005 to 2008 Wind Cave was thought of as the gold standard for bison sourcing in all of North America. They had what was thought of as Yellowstone genetics — no cattle DNA — but better than Yellowstone because they had no brucellosis [disease].

About four years ago a relatively well-known test that had never been used on bison, called SNPs, single nucleotide polymorhphisms, became the order of the day. We went back and retested all of our bison, and found that between 35 to 40 percent of our bison had cattle genes. So we took those animals and shipped them out to people who were more interested in the bison for different reasons, the Bronx Zoo and different places, and we switched over to a new source, Elk Island Provincial Park in Canada. Now we test the animals on their way out of Elk Island and don't put them in the truck until they are tested. Every animal has tested 100 percent fine.

At this point, the American Prairie herd, which numbers about 250 animals, is to our knowledge the only conservation herd anywhere in North America where every single animal has been tested using the latest technology for cattle introgression and has come up clean. That includes Yellowstone park. Yellowstone animals have never been tested with SNPs.

e360: Why does the genetic purity matter for your purposes?

Gerrity: One answer is science, and one is politics. The science is simply being a little over-careful, a hedge. Even though these are very small trace amounts of introgression, bison and cattle are different metabolically. In the winter, bison metabolism slows by as much as 25 to 30 percent. That's why they can handle being out at 35 below zero for weeks on end and survive on little scraps of grass. Cows, their metabolism doesn't slow at all. They have an extraordinarily tough time being out where we are. The amount of introgression is enough to affect things like metabolism.

The politics is that our long-term hope is that at some point bison will eventually be classified as free-roaming wildlife in Montana. Now, when they come out of Yellowstone, they're rounded up for slaughter or shot or hazed back into the park. They can't roam where they want, but we believe it's a historic inevitability. Bison is the only species not allowed to roam, and we think it will happen. When that occurs, we will go to Montana Fish, Wildlife & Parks and say, "We would like to give you our herd, let them join the wildlife of the people of Montana." That's the end result we're hoping for. That might happen in 30 years, 50 years, 100 years. For that handoff to occur and not hit any politics, these bison need to be as good as or better than any bison on the planet. They can't be seen as substandard. That reason is probably more important than the science.

e360: Who exactly are the project's opponents? Is it individual ranchers or organized groups? And what are they opposed to — fear of brucellosis, depletion of grasslands, the prospect of wolves at some future date?

Gerrity: Opposition comes from individuals, not organized groups, and I believe is generally a reaction to sociological change. APR gets lumped in with actions by the federal government to change aspects of the Farm Bill, state government wanting to increase wildlife numbers in the region, and the U.S. Fish and Wildlife Service making it more difficult to graze cattle in the Charles M. Russell Wildlife Refuge. Some local individuals see all of this and the goals of APR as unwelcome changes to the lifestyle they once knew.

e360: Is this opposition impinging on the grand plan at all?

Gerrity: The opposition is not hindering our progress toward our vision in any way. Over the past 10 years, people have become desensitized to the newness of our plans and some see it as a potential benefit, economically and otherwise. The concerns from the earlier days — that we would lock up all APR lands to outsiders, that bison would cause damage to neighboring property, that we would not contribute economically or act as good neighbors — have largely subsided for most people. Generally, as people learn more about our project and our organization, they become much more at ease with having us be a part of society out there. Most people now know that we pay the same taxes as anyone else, we contribute a great deal to the local economy, our bison in fact have created no problems for neighbors in the past seven years, and we welcome the public on our lands for hiking, bird watching, and camping.

e360: We can't turn back the clock on human influence. You can take down fences, bring back bison as they were, link landscapes together — but climate change marches on. Do you have a strategy for coping with that? Is the idea simply to make the landscape resilient enough that it can cope on its own?

Gerrity: We're looking at nearly 10,000 years of [human-animal co-existence] that was completely wiped out in 40 years, from 1860 to 1900. It's not about people, because people coexisted with those animals for 10,000 years, but this group of people came with barbed wire, set it up, said this land is going to be surface agriculture with farming and livestock. And all the wildlife was completely gone in 40 years — we wrecked 10,000 years of history in 40 years. That can easily be put back. It's not turning back the clock, it's continuing on with something that's very capable of being there.

About 5,800 to 3,800 years ago, there was an extreme drought, far hotter and drier than there is now. That area survived far beyond what any projections for climate change are now. And then it started to cool again and it also got more moist, about 2,800 years ago, and the animals came back in bigger numbers, and there were more people on the landscape. So I don't have any concerns about any temperature rise like what we're talking about now.

There's still a place for [large-scale conservation]. We quit about 60 years ago with Grand Teton National Park in 1950, and we should get it going again. There's plenty of money out there to do it, and there is plenty of land. It just takes looking at it and saying, "How do we make it happen?" Someone just has to go after it for about 20 years.

e360: What's the next step for the American Prairie Reserve?

Gerrity: The next phase is simply to keep going. We have numerous properties in the pipeline right now, so it's simply raise funds, buy properties, go on to the next one. Ever-increasing effort to get people out there to enjoy it. We have a campground where you can stay for $10, and we'll open more of those, and we're opening a high-end safari lodge like they have in Africa. We want to make it a world-class reserve like people have never seen in North America.