Unraveling Ecological Mysteries In a Vanishing American West

By Kevin Dennehy

It wasn’t the pull of grasslands that lured William Lauenroth into a career in drylands ecology. As a matter of fact, he says it was an accident that he ended up working in the Rocky Mountain West in the first place. 
bill lauenroth yale
But he arrived in the field at a good time. Scientists had just begun to understand the critical functions of these iconic natural systems. And over the next four decades Lauenroth himself would be among those who helped illustrate how these systems work — and how factors such as grazing and climate change are altering them.
Although he recently joined the faculty of the Yale School of Forestry & Environmental Studies (F&ES), Lauenroth still holds appointments at the University of Wyoming and Colorado State University and will continue to focus his research on drylands ecosystems. In an interview, Lauenroth discusses the challenges facing the western drylands, the changes he has observed during more than 40 years of research, and strategies that could help protect remnants of a vanishing U.S. West. 

“If you look at those nice pictures that show all the lights in the East and the West Coast and the darkness in the middle — well, it was even darker in those days,” Lauenroth says. “There was just nobody between the Sierra Nevadas and the Rockies. And now, we’re everywhere.”

You’ve spent most of your career in the Rocky Mountain West. What it is it about that region that drew you in, and has made you want to stay?

William Lauenroth: It’s gorgeous. And there’s a lot to it at the intersection of work and play. I accidently ended up in the Rocky Mountains, and decided that there were many interesting things to do. I went to school there and started a research program. And then I got a job teaching. It turned out to be exactly what I wanted to do, perhaps even before I even realized it.

You studied range management as an undergraduate. Is that something that you were exposed to as a young person?

Lauenroth: Not at all. Growing up in California, my childhood was all about getting out on the water and fishing and hunting. The closest I’d ever gotten to a cow was the distance between me and the plate. When I went to Humboldt State College, I was planning to be a wildlife manager. When I got there I went and talked to the fella in charge of the wildlife biology program, and he said, “Oh, that’s great. It’s such an interesting field and there are so many interesting things to do… But I hope you don’t want to get a job! If you think you want to get a job we should end this right now and you should go down the hall and talk to a gentleman who’s starting a range management program, because there are plenty of jobs with the BLM [Bureau of Land Management] and the Forest Service.” I took his advice. And it was pretty good advice, because there were thousands of bachelor’s level wildlife managers looking for jobs and very few bachelor’s-level range management professionals out there.
And as it turned out I was way more interested in plants and landscape than I realized.

What made you become interested in the science of the landscape?

Lauenroth: After graduation I moved to central Kansas and started working at a small school, and while I was there I worked with a graduate student who was just finishing up his thesis on grasslands. He was so excited about what he was doing, and so enthusiastic about showing me what he was doing, why he was doing it, how it was connected to the literature. He just talked me into it. I hadn’t expected that I was going to be so engaged, but I got terrifically enthusiastic about it. So when an opportunity came up in North Dakota, I said, “Put me in, coach.” It sounded like what I wanted to do. And it turned out that I had a great time learning about grasslands. At that point, I knew boats and ducks and marshes and San Francisco Bay. And all of a sudden I was in the grasslands. That was my transition from range management to ecology.

Was it the landscape itself or the underlying questions you found?

Lauenroth: It was solving the puzzles. I did come to love the grasslands, but at that point I think I could just as easily have loved forests, or marshes, or any other kind of ecological system.

What were some of the early puzzles that really grabbed you?

Lauenroth: The time I was a graduate student was just at the beginning of what would become ecosystem ecology. At the time we knew nothing about productivity of natural systems, other than how many pounds of beef you could produce or how many bushels of wheat you could grow if you plowed up a piece of land. There was no appreciation of what was going on with the native grasslands. The fact that they were capturing carbon, and that some of it was staying above ground and some of it was going underground was barely appreciated.

What did you make the focus of your research — and how has that evolved over your career?

Lauenroth: I started out with observational studies. But when I left North Dakota to work on my Ph.D. at Colorado State University I had a chance to work on my first experimental study. All of a sudden I was manipulating a grassland: adding water and nutrients, and asking questions about what would happen if we add more nitrogen, or more water… It just seemed that there was no way you could not stumble on an interesting question as we came to understand natural systems at the ecosystem scale. Sure, we knew a lot about individual species and we had a lot of information about natural history and animals were a big topic. But plants are the base of the food web, and primary production is where everything starts with carbon storage — and we really didn’t know anything about it!
Also at that time, the first big-money program in ecology — the International Biological Program [IBP] — was just starting. It was a worldwide program, and the theme was “the natural system basis of productivity for human benefits.” At the time Colorado State University was the headquarters of what was called the IBP Grassland Biome Project… So I was exposed to all of the people who were working anywhere on these grasslands issues. They’d come to Fort Collins for meetings and I’d get to hear them talk about their work, and hear them speculate about what we needed to know and what we didn’t know.
It was also the time when ecosystem-scale simulation modeling was being invented. And again, Colorado State University was an important center for that. There were mathematicians, and engineers, and business modelers coming together trying to figure out, “Can we really represent these natural systems in simulation models?”

What is some of your research that you are most proud of?

Lauenroth: Well, early in my master’s work I collected some of the first data on belowground biomass in grasslands. Nobody had looked before! And the numbers I was coming up with were incredible. I mean, no one suspected that there could be so much stuff down there. Whether they were all roots or not was unclear. But the plants were putting a lot of carbon in the soil. It was surprising to me and to a lot of the people I talked to.
One of the other big things I worked on, considerably later, was a series of theoretical and data analysis papers that tried to answer the question: Why is there such a variety of responses in grazing lands worldwide? In other words, why are there places where you can introduce cattle and it essentially completely destroys the system while there are other places where it doesn’t change so much?
At the time ecologists were just getting into Africa. They were looking at the Serengeti and Sam McNaughton’s work suggested that this was a system that had plenty of animals and yet it was not being destroyed. So with a couple of colleagues I started asking, why is that? And we came up with what turned out to be a pretty straightforward explanation: it comes down to the evolutionary history of these systems. Basically, has the system developed in the presence of a large generalist herbivore or not? That provides a lot of predictive ability for how it’s going to respond. Then, if you know where it falls on the productivity gradient, that can give you additional information.
So we published a theoretical paper, and then a heavily data-based paper. Those two papers are probably the most cited of any of my work. And this model is still the basis for a lot of thinking about how ecological systems respond to herbivory.
We also published a couple of papers that suggested that for certain grasslands removing herbivory was a disturbance. If you have a system that developed with fire or under a large generalist herbivore, and you take that away… in the West we’ve seen what can happen if you protect forests from fires. Well, we were suggesting the same thing for grasslands: if you protect them from this major selection pressure that has been a driving force for 10,000 years you should expect to see substantial changes.
It turned out that managers were using this information. The Nature Conservancy was able to figure out that when they buy a piece of property, taking the cattle off is not the answer everywhere. It might be the answer somewhere. And one of the ways you figure out if it is the answer is by thinking about the evolutionary history.

You were also getting into this field, and into western land issues, at a time when human development was starting to change the face of the Rocky Mountain West. How have those pressures changed the West — particularly the grasslands — since you started working there?

Lauenroth: Well, there’s not much grassland left. The pressure of food production has reduced the remaining area of grasslands in central North America to a very small area. And the part that’s left is the part that’s too dry, the soil is too thin, and the climate too variable to be worth investing in a crop-production system… In a course I’ll teach here at F&ES, I’ll talk about the Tall Grass Prairie, but for the most part there is no Tall Grass Prairie left. It’s this thing that we think we remember, but now it’s the corn and soybean belt.
The interesting thing is that in the places where there hasn’t been conversion to cropland, a wave of recreationists has just washed over the landscape. If we begin a timeline in the middle of the 20th century, the West was ranchers’ territory; they were the only ones who cared about the land. Some of them were good and some were bad. But if anybody was thinking about the land back then it was probably a cattle or sheep rancher — as well as a few big game hunters or some fishers. But that was it. It was really sparsely inhabited. Recently many areas are now dominated by recreationists.

There weren’t too many third homes back then... 

Lauenroth: Exactly. If you look at those nice pictures that show all the lights in the East and the West Coast and the darkness in the middle — well, it was even darker in those days. There was just nobody between the Sierra Nevadas and the Rockies. And now, we’re everywhere. And we’re out there trying to push the ranchers off the much of the West. Some of them probably deserve to be pushed off because they’ve done such a horrible job. We’ve trusted them with our land and they’ve just squandered it. And others are doing great. But we have this new wave of recreationists and second- and third-home owners and people who want to have a hobby ranch and buy a piece of the West, not to mention ski resorts and all those other things.
It’s quite clear now that even the bad ranchers were providing a sort of dam against all these other pressures. The only reason we still have big open spaces is because some of these people were so stubborn — no matter how much money you offered them they were going to stay… The strategy for the West should not be to get rid of them, but to try to get them to do a better job. Because otherwise we’re not going to have any large open spaces.

Are you hopeful that at least this new land use — this influx of wealthy owners and recreational uses — could also help protect large swaths of land?

Lauenroth: I think the real hope is that we can provide education for more people. It’s a great opportunity for natural resource educators. A lot of Wall Street and Silicon Valley folks with pockets full of money — those people who someone told, “You know, you ought to have a ranch. You ought to have something with a river through it!” — they have no idea. And they have some of the most valuable and interesting land in the West. But if we can convince them to do a responsible job managing it, that is going to be a big step. For a place like F&ES, a program in private land management — such as the [Ucross High Plains Stewardship Initiative], which is getting a foot into that — is really important.

Are there any innovations or partnership possibilities that give you optimism that this region can retain some of that essence and that ecological integrity?

Lauenroth: Yes. But the problem is that the function that connects the degradation with enhancement is still probably eating up land faster than we’re enhancing it. But I think there has been widespread recognition that we need to do something. The state of Wyoming decided that if it doesn’t do something about declining sage-grouse populations things are going to get pretty bad. So in its own self-interest — and that’s the only thing that’s ever going to work — the state came up with a strategy to try to save areas that are most important to sage-grouse.
In Colorado they have a similar program for prairie dogs; they have a large program called “Ranching for Wildlife,” where they created a partnership between the Division of Wildlife and ranchers to increase their understanding of management of elk. Colorado has twice as many elk as would be ideal. In fact, the place is overrun by elk, in large part because of large areas of private land where the owners think their job should be to protect the wildlife from the rapacious hunter. Well, it turns out the hunters are not terribly rapacious, and that hunting was the key tool that the Division of Wildlife had to manage wild elk populations. And now the elk are the ones who are rapacious: They’re eating up parts of the West.
These days, when the first shot is fired all the elk and deer run onto private lands where the hunters can’t get to them. So now there are programs where they’ll give ranchers 10 tags that they can sell for $10,000 each for trophy elk, if you’ll let 20 average hunters onto the land to shoot a cow elk. Wildlife management is complicated. But being able to get to those people, helping them to understand the issues and allowing them to profit from their wildlife if they allow hunters, is critical.

How is climate change affecting the Rocky Mountain West?

Lauenroth: Anecdotally, Fort Collins, Colorado is warmer than it used to be. The winters are shorter. Twenty or 30 years ago, relatively long periods of temperature on the negative part of the Fahrenheit scale were common. When I moved to Fort Collins, the issue of an air conditioner was out of the question. Now I would say a large fraction of the people of Fort Collins would say they don’t even want to think about life without an air conditioner.
One of the bits of biological evidence that seems to support this trend is the bark beetle epidemic, which has swept the West and devastated much of the Colorado lodgepole and ponderosa pine forests in the last decade. What the beetle biologists tell us is that the frequency and duration of sufficiently cold periods to knock the populations back to small numbers is just not high enough anymore, and they’re building up. The beetles are not dying off over the winter.

What about water? Are the drylands getting dryer?

Lauenroth: It’s not so clear that the drylands have gotten drier. Because there is the complicating factor that as the atmosphere warms it can hold more water. And because the Intermountain West is so complex topographically, it turns out to be very complex meteorologically and climatologically. So it’s hard to reach that conclusion. But if you ask this question to someone in the Southwest, a longterm resident of Tucson or Phoenix, they might have a different answer. And I do think the data show pretty clearly that the Southwest is definitely drying.
In the low-elevation drylands of the Intermountain West, a lot of areas are going to get wetter. But I don’t think that’s going to be a big deal for sagebrush. Maybe the southern edge of the sagebrush is likely to contract. But as for the northern edge, the Canadians better be ready for more sagebrush. It’s likely that that’s the direction a lot of these plants and animal populations are going to go.

Which speaks to the importance of addressing when and how climate change will affect different regions.

Lauenroth: There’s a lot of hand waving: “It’s going to get warmer,” or “It’s going to get wetter or drier.” But when someone asks, “What’s going to happen here?” Who knows? Part of the reason we don’t have a better understanding, I guess, is we can point our fingers back at meteorological models. Why can’t they provide us with more specific information? And they’ll point back at the computer folks and say, “Where are those quantum computers that would allow us to start modeling these processes at a scale that you want?”

It’s complicated... 

Lauenroth: We love to say that. But we can offer more and we’re going to need to. We have made a lot of progress in the past 20 years, but it’s a little disappointing that we haven’t made more.