SOLS Podcasts

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Peggy Coulombe: Hi, this is Peggy Coulombe, School of Life Sciences at Arizona State University, and welcome to "Science Studio." According to the United Nations determinants and consequences of population trends, human populations have grown over time from an estimated five million worldwide, around the dawn of agriculture in 8,000 B.C., to 300 million in year one AD, to our present day, 6.5 billion. How many does that mean have lived on the planet since modern man first stepped onto the scene? One estimate found on the population reference bureau website was that more than 106 billion humans have lived at one time or another on earth's landscapes. So what kind of impact do all these people have on these landscapes? We talk about global climate change, for example, but what about what we see around us, out our windows, right here in the south west? Our guest today is John Briggs, and hopefully he'll shed some light on how ecological theory needs to incorporate human actions. John's research is proof that good things come through building long-term relationships. He's been working in LTERs, long-term ecological research projects, in both our southwestern deserts, and the grasslands of Kansas, looking at the impact of humans, their animals, and their plants on the environment over time. Welcome John.

John Briggs: Thank you.

Peggy: Can you tell us something about what an LTER is designed to do, and how a long-term project is different than most scientific research projects that are generally only funded for a couple of years?

John: Yes Peggy, I think you hit the nail right on the head when you said "most projects are funded for just a couple of years." They get funding for maybe two to three years. If you're real lucky, maybe four years. The LTER was set up after a set of workshops done in the '60s and '70s where they realized ecological phenomenon take a long time, and they needed to look at them over a long period of time. So these were set up. The first ones were funded in 1981, with the idea that they'll have a funding cycle of six years and with the hope that if progress was going on, and it was doing good research and good science, that it would continue for a longer period of time. For example, one of the sites I am has been funded since 1981 on a continuous basis. This allows you to set up experiments, and start monitoring things that you know take a long time to change. You can look at these things over a longer period of time that just aren't possible coupling together these two to three year research grants.

Peggy: Out of curiosity, given that man's been stomping around on the land since about 50,000 BC or so, is it really safe to think there's any area or region or surface on earth that hasn't been touched in one way or another by mankind?

John: I don't think so. When you say touched, you kind of get to a whether they put a footprint on it or something. There are probably some places where maybe some piece of one square centimeter hasn't been touched by a human footprint, but I think the actions of our activity, of our living here on earth, has impacted every possible square inch of the earth's atmosphere and its surface. Our footprint is just so large, particularly now in the past 250 years or so. There's just nothing on this earth that hasn't been touched by humankind.

Peggy: This would include things like carbon footprints, and nitrogen footprints, as well as physical footprints.

John: That's right. I think the excellent one that probably everyone is very familiar with is the ozone hole over Antarctica, which is one of the most isolated continents in the world, where very few humans live, and there's now this huge hold in the atmosphere that's impacting the animal and plant life in that very remote part of the world.

Peggy: There was a book we talked about previously, when we had an interview a little while ago. It was written by Charles Mann, entitled 1491. We talked about the concept that everyone wants to put the landscape back before 1492. How does one decide what the original landscape is, or was, or what it is we should be returning to?

John: Excellent book, and for those who haven't read it, I would encourage, if you're interested in that particular subject, that you read it. It is a very interesting thing, and for years and years I was caught into this, and I would write my papers, or when I was talking about the research that I'm doing. Particularly in what I would call more pristine environments, I would always say prior to European settlement. This idea of going back, at least in this part of the world, probably before the first cattle and things came in this area 150, maybe 200, years ago. Charles Mann, in his book, outlined very nicely and precisely, and he raises a lot of good points that humans were on this landscape long before Europeans were here, and they were impacting that environment in many ways. So this makes things very complicated, when you say you want to put things back to that. Arbitrarily, we have just set up this idea of before Europeans came on this, and had totally dismissed the role that Native Americans, and other individuals played in impacting the environment and the land that we're looking at.

Peggy: As I mentioned, John is involved in two LTERs. This fall, of 2007, will mark the 10th anniversary of the Central Arizona-Phoenix Long-Term Ecological Research Project -- CAP-LTER. It's a mouthful. This project is co-directed by the School of Life Sciences ecologist Nancy Grimm, and ASU anthropologist Charles Redman, and is administered out of the ASU Global Institute of Sustainability. It's one of 26 LTER sites funded by the National Science Foundation. CAP-LTER has a sister site in Baltimore, called the Baltimore Ecosystems Study. These two are unique among LTER sites in that their urban setting and perspectives, as most sites have been established in pristine wild land settings, and until recently, ecologists conducted little research on human dominated, or controlled landscapes. So tell me something about the Central Arizona-Phoenix Long-Term Ecological Research Study, also known as CAP-LTER.

John: Yes, I'd be happy too, and I could take a very long time, as it is a very complicated project. But I'll probably make it kind of short. As you mentioned, it was really a neat experiment that National Science Foundation, who funded this, decided to do. Because as you said, most LTER sites are in pristine sites. There are two in Antarctica, there's two in Alaska's wilderness. I worked on one back in Kansas in native grasslands, and they're more usually associated with what ecologists have traditionally done, working in pristine environments. The National Science Foundation has decided that if you're going to understand the environment, understand the ecology of what's going on, it's very critical to start putting humans into the project. In the past, we usually simply used humans as an external driver. They were the ones creating the fires, cutting down the trees. They were always seen as a disturbance on the environment. They were always external to it. So we always wanted to look at those areas where humans were not part of the environment. Basically, with the two urban sites -- the one in Baltimore and the one here in Phoenix -- what we're doing, we're actually putting humans as part of the system, not just externally. And we're doing that in a couple ways. Number one, by first looking at a city, which has a lot of people. But I think, most importantly, we're also branching out in ecology and that, for the first time, ecologists are working hand in hand with sociologists, economists, other types of individuals, who work with humans on a daily basis, because if we're going to understand how these cities operate, how the urban environment has changed or is modifying over past, we need to understand how humans are an integral part of that. And they're just not external, but they're also very much internal to it. They make decisions, they impact the environment, the environment impacts them, and then they modify the way they move, their decisions, etcetera, based upon what's happened in the past. And it's only by looking at an integrated process, like the CAP LTER and the one in Baltimore, that we hope to understand how humans operate in these types of environments.

Peggy: Why was Phoenix chosen as an urban representative site? What makes it of special interest?

John: Yes, it was chosen, first and foremost, like most of the LTER sites, basically, through a very highly competitive peer review process. And there was a large number of sites going in on this, and it was based upon the scientist, particularly the proposal that, as you mentioned, Dr. Grimm and Redman, put in. So that was, first and foremost, that it was very good science involved, asking neat questions. And I think, over time, people have also realized now that Phoenix is also a very interesting thing, because Phoenix, as you know, is a very fast-growing city, and it might represent what cities are going to be like in the future.

Peggy: What kinds of questions are being asked?

John: It's like a lot of the other LTER. We have some research to look at basic what we call ecological principles. How does the pattern of primary productivity change over time? What are their influences? What are the impacts of nutrients on the system? What are the populations that inhabit these environments--the birds, the bugs, the mammals? How do they change, how do they respond over time? And also, disturbance, droughts and other things that happen in natural systems, how do they impact the LTERS. And so the CAP LTER is looking at these similar type of functions, really putting humans into it. We have a whole variety of experiments set up to look at how people perceive the landscape, how they respond to changes in the landscape, and what, in turn, their planting of their various plants, their trees, how does that impact the plants and animals that use that environment. And then also, how does that affect the abiotic situation in which we all have to live in on a daily basis.

Peggy: How could such information be used to shape urban landscapes of the future?

John: Well, that's a really tough question...

Peggy: [laughs]

John: And a very interesting one. And we really do hope that the research that we're developing here will help managers, city planners, etcetera, start developing or start helping do what we call "smart growth." In that, instead of just simply putting up as many homes possible in a square area, maybe start developing homes and sub-developments that will make an environment more pleasant, not only for the individuals, but also for the native environment. Simple things. By planting native plants, for example, not bulldozing all the washes, looking at developing wildlife corridors. And all of this is very complicated, because there's a lot of factors involved. But we really do hope that, by the information we're gaining here, and also coupling that with the information gained from the Baltimore site--because people like to live in cities, this is the wave of the future--that our research can be used to help us direct what's going on and make these environments a more livable and enjoyable place for everyone.

Peggy: Now, we've discussed how CAP LTER is unique, as it's situated in the desert, that it's being faced with rapidly changing urban growth and development, and that scientists have the opportunity to sort of see it as it happens, so to speak. But another of your projects, in collaboration with School of Life Sciences assistant professor Sharon Hall, centers on the impact of ancient peoples on the Southwest. Tell me, how do you evaluate the effects of past populations on landscapes and plant communities in this area?

John: Yes, what we're doing on this particular project is we're looking at the role of agriculture. And one of the main reasons we're doing that is because agricultures have been going on for a long time. And particularly in the Southwest, because there's no written records of these prehistoric people living on the environments, we have to rely on archaeological sites. For example, old terraces, canals, etcetera. And from that, and from the archaeological work, we know these particular areas were used for agriculture purposes. And then we can find adjacent areas that are very similar in soil properties, in the same general area but haven't been farmed. And then by sampling the plant, sampling the soil properties, we can then determine what has been their impact on this particular landscape.

Peggy: Where are you conducting your studies?

John: On this particular project, we're concentrating our studies on two general areas. One of these areas is the Cave Creek area, just north here of Phoenix, in almost an extension of the Hohokam people that were living here. Right along Cave Creek, we found some areas that have been surveyed quite extensively by archaeologists. There are some remnant canals. We know these areas were field, farmed, so we have some areas that are terraced by dry farming, and also areas that have brought in the water, so we call them the silk fields or irrigation fields. The other one, the more recent one that we're doing, is on the national monument, Agua Fria, which is literally almost kind of halfway between here and Flagstaff, right off I-17. And again, because of this extensive work by archaeologists, we know there's a large number of pueblos there, and we've been concentrating some efforts around the pueblos. And from these pueblos, we've surveyed the areas. We've found vast number of dry land terrace fields. And so this is where we're conducting our two studies, to compare and contrast these two general areas.

Peggy: What are you trying to understand about the utilization of land by these past populations?

John: Well, to me it was started kind of a curiosity thing. And I hate to say it, or maybe I should say that this was brought forward to me by my graduate student, Hoski Schaafsma, who has a long history in archeology, and first approached me with this idea. Everyone knows, or probably would guess, that the impacts of modern day agriculture--with the large tractors and plowing a same piece of land for a large amount of time, or even cutting of trees, like they did in the Northeast, to plant fields--has a large impact on today's modern vegetation. But it was very hard for me to believe that a population who were planting corn by terracing, by digging holes in the ground with sticks... And literally, at the Agua Fria, they were there for a very short amount of time. The estimates put them at one to maybe 300 years, max. That they would have an impact on that landscape that would be measured today might have some broad implications for ecological theory.

Peggy: So does it end up being a question of how much or how long, or what kind of contact leaves a mark or causes change?

John: Yes. It's like everything; it gets complicated. One can't say, "Well, if they're on the landscape for five years, they're going to leave a mark, or if they're there for 150 years, they're always going to leave a mark. The best I've gathered, in some of the review, is if they start changing the soil properties--something that takes a long time to develop--and by literally building these terraces, they're changing how the soil processes are being formed, over time, increasing the amount of silk coming in, etcetera. It seemed like, once you start changing the soil properties in a way that are radically different from the surrounding soil properties, that these things will then, in turn, change the vegetation. But it's also more complicated, because once you start changing the vegetation, the vegetation can also have an impact on other processes, too, and there's this feedback situation. To me, that's what makes it interesting, but also very complicated, because there's not just a simple formula one can apply and always find out exactly what's going on.

Peggy: The other LTER project that you've been working on--I guess nearly 25 years, as I understand--is situated in the grasslands of Kansas, and it's called KONZA. [laughs] Is that an acronym?

John: Konza Prairie Research Natural Area is owned by the Nature Conservancy, and the money given to purchase this site was given by Katherine Ordway, one of the descendants of the 3M company. And when she gave the money, one of the things she required was that the land that was purchased with her funds would be given an Indian name. And Konza is another spelling of the word "Kansas," and it just simply implies "people of the south wind."

Peggy: You said it was one of the first of the six original LTER sites, started in 1981. What kinds of things are you trying to understand there?

John: Yes, what we're trying to do there... As I mentioned earlier, that is a native grassland, and what that means is that it hasn't been plowed. And it simply hasn't been plowed because it's in that part of Kansas, which, if you believe it or not, is very rocky and very hilly. And so the grasslands there is a tall grass prairie. They've never been plowed. And we know, through past evidence, that fire, grazing, and climate are very important, because a tall grass prairie is at that part of the continent of North America where there's enough rainfall falling each year that trees can grow in normal times. And it's these fires that have been set, or started naturally, go through the landscape and remove the trees from the landscape. Then, in addition, at one time, there was a large number of native grazers, American bison. And so we know the combination of the fire, the grazing, and the occasional drought, really shapes these prairies. And so, the Konza prairie, we've set up this large experiment. It's around 8,000 acres. And some areas, we burn annually. Some we burn every four years or every 10 years. Some we call unburned, which means they get burned on a 20-year fire frequency. And then we also have areas that are grazed, and also that are ungrazed. And the grazing, right now, is being done by the American bison, so we've reintroduced these bison into this area.

Peggy: so what kinds of things have you found, through this long-term study, that might've been missed otherwise?

John: Well, one of the big things, when we first started, was this concept of fire. One could find that, some years, if you burnt a prairie, you got reduced production. Some years, if you burnt a prairie, other studies show that you increased productivity. Other studies show that there's no change, there's no difference whatsoever. So it's only through this long-term perspective. And we now have 20-plus years of data looking at the productivity, that we know the complications of fire and the climate on the tall grass prairies. That, in normal years, with adequate rainfall, you can get an increase in productivity, through the fire. But if you happen to burn in a year that there's not much rainfall, the burning can actually decrease your productivity. And so, again, it's only through this long-term perspective that one's able to look at these kind of consequences, as it goes on.

Peggy: How big were the original grasslands?

John: Well, the grasslands themselves, they're divided into various types--the tall grass prairie where I worked, the short grass prairie, and in-between, the mid-grass prairie. It literally follows the precipitation gradient across North America. Coupled with that are the California grasslands, and then the desert grasslands here in the Southwest. Of course, no one really knows the extent of them, but most people will say that it was the second largest biome in North America, only exceeded by forest lands.

Peggy: I understand, too, that the buffalo played an integral part in how the grasslands survived and grew. And I heard once that there were so many buffalo that, when they sweat, they would create a fog that they called "buffalo fog."

John: Yes, and there's a lot of readings like that. There's no doubt that they were very large in number. But the other thing to remember, too, is that the bison weren't widespread. They were mostly concentrated in the central part, and most people don't realize that they did not make it down here to the Southwest. And so this is why these grasslands here in the Southwest aren't as suitable to grazing as those in other parts of the country, because in the evolutionary history, the tall grass, short grass, and mid-grass prairie survived, or co-evolved, with these large number of grazers. And as you mentioned, those large number of grazing animals, those bison, had a tremendous impact on how these grasslands developed over time.

Peggy: We've been talking a lot about how your research is focused on long-term study. But I've also heard you take your long-term perspective onto the road and run marathons, including the Boston Marathon. When did you start running, and when did you start running long-distance?

John: I've been running. I've been keeping track, and believe it or not, I keep logs. I'm a scientist, and so I write down every little running that I've done. And I've been keeping track of my running since 1984, and I ran my first marathon in '91.

Peggy: And so how many marathons does that translate into?

John: Well, right now, I've gotten 12 underneath my belt.

Peggy: [laughing] Oh my goodness. I ran one, and that was enough for me. Which one left the biggest impact on you?

John: Every one of them is very unique. And probably the most important one that I remember--other than running Boston, because that's like the Super Bowl of marathons; everybody wants to go to that one--was when I did the Rock 'n' Roll Marathon here and I qualified for Boston. So that was the one I really remember. And there's nothing like going across the finish line and realizing that you've qualified, because the year before, I was like 30 seconds too slow to qualify. So that year when I did qualify, I still remember that feeling, coming across the finish line.

Peggy: [laughs] I bet. Thank you for joining us today, John. This is Peggy Coulombe, and you've been listening to the School of Life Sciences podcast, "Science Studio." You may have noticed that we've finally acquired theme music. Our music comes from the website Magnatune, and was composed by Yongen from the collection "Moonrise." The School of Life Sciences is in the College of Liberal Arts and Sciences on the Tempe campus at Arizona State University. [music]

Human Impact: Ancient Man and Urban Environments

Transcript - [Printable PDF format]

SOLS Podcasts 2007