Teacher resources and professional development across the curriculum
Teacher professional development and classroom resources across the curriculum
Sam Fuhlendorf is a professor of rangeland ecology and management at Oklahoma State University. He was interviewed on location at the Tallgrass Prairie Preserve in Osage County, Oklahoma, where he studies grassland ecosystems.
Q: What sets the Tallgrass Prairie Preserve aside from other prairies?
Fuhlendorf: The Tallgrass Prairie Preserve sits at the southern end of the last piece of tallgrass prairie left in the world. The estimates are that there's no longer more than one percent of the original tallgrass prairie that occurred here historically at the time of European settlement, which started in the 1850s. The reason this area is still intact is because it has lots of rock that kept it from being cultivated by settlers. It's also some of the most productive prairie left in the world.
Q: How do you think a biologist might look at this prairie differently than a historian?
Fuhlendorf: The basic difference between a biologist's perspective and a historian's perspective is that some biologists try to remove humans from their studies. But this landscape is a very, very nice place to see that they're really linked. You can't understand all of biology without understanding some about history, so it's fairly typical for biologists to at least be partially interested in the history of the area. Historical accounts give me an idea of how certain ecological disturbances affected the landscape. It's amazing how many things were known historically by Native Americans or even by earlier settlers that we seem to be just recently discovering.
Q: Can you give us a timeline of human impact on this land?
Fuhlendorf: The Great Plains formed millions of years ago, and that led to a more arid area in the central part of the United States. That greater aridity led to increased fires. People arrived ten to fifteen thousand years ago, and immediately the fire frequency went up even more. We don't really know the first time that humans set fire to the prairie, although we do know that it's been burned for a long time. There are estimates that Native Americans used fire for as many as seventy different activities or needs, ranging from hunting all the way to entertainment, and the initial impact was an increase in fire frequency. When the white settlers arrived, they actually decreased the fire frequency in many areas; the exception is this Flint Hill region, where the Tallgrass Prairie Preserve is located. This area continued to burn throughout time, and that's one of the reasons it's still an intact prairie. But when the white settlers came in, they increased cultivation, and that's how most of the tallgrass prairie was initially lost. Now, some of it is being lost to woody plant increases and things like that. But in general, the initial impact was the introduction of agriculture and cultivation.
Q: What do you think the white settlers felt or thought when they saw Native Americans setting fires to the prairie?
Fuhlendorf: Most of the white settlers were very scared of fire: If you've seen the landscape out here and the amount of grass that can grow in a given year, and you see the wind—you can actually imagine why they might be nervous about that. We have a lot of documentation about the fear of fire. In fact, that fear lead to laws that prohibited burning parts of the Great Plains. In some places, it was a felony. There are early accounts where settlers have described their fear of fire; many of the people actually knew that the fire was good, but they still had fear.
Q: What types of written records describe what the prairie looked like at the time of white settlement?
Fuhlendorf: We use explorers' journals, early settlers' books, historical accounts, and descriptions from cattlemen or cowboys that moved through the area. We use aerial photography, which actually goes back to the early thirties in some cases. Most early explorations from the Lewis and Clark expedition and others included botanists and zoologists that could record what plants and animals they saw, and those are very good sources. There is a little-known exploration that went along the Red River between Texas and Oklahoma at about the time of the Lewis and Clark expedition. It left written records that described a lot of Native American settlements—really large settlements in really intensively managed landscapes. There are accounts of Native Americans along the Red River that actually were farming and actively managing the land.
Q: How do we know what we know about Native Americans using fire to manage the land?
Fuhlendorf: We have oral histories that have been passed down in different regions. They describe how Native Americans burned during different seasons, under different conditions. They knew the varied times that they needed to burn to make grasses that were better for basket-making, to help certain plants produce more berries, and all of those sorts of things. I've heard accounts of them setting up camps in areas that were fire protected; the frequent locations of their camps were on the sides of creeks that were less likely to burn with the prevailing southern winds. So they had a very specific, very practical understanding of how to use fire. And there are recent suggestions that they may have even been careless with fire. That's to say they understood that the prairie burned, so they didn't worry about putting out campfires or things like that. So, to a large extent, they became a very fire-driven society.
We also have some paleontology-based evidence such as charcoal data in lakes and vegetation data that tells us how vegetation changed and responded to different amounts of fire. Those sources in combination suggest that there was a lot of fire on the landscape.
Q: How do you know that these weren't naturally occurring fires?
Fuhlendorf: We know that there are some areas where there were probably frequent climate-driven, weather-event-driven fires. But based on climate data and ongoing records of lightning strikes, we've determined that there are areas where natural fires are much less frequent.
Q: What evidence helps you determine how long this land has been a prairie?
Fuhlendorf: The Tallgrass Prairie Preserve has been tallgrass prairie for the last fifteen thousand years; but when you get back into the glacial cycles, the vegetation could have been considerably different. There are pollen records within lakes that we can look at to determine what plant species dominated the area. We also have fossil remains that indicate prairie species such as bison were the dominant kinds of species here over the last ten thousand years. All of these findings suggest that the area was an open grassland, because that's the kind of habitat that these plants and animals prefer.
Q: How do you interpret objective data, such as tree rings or fossil records, versus what might be biased data, such as a historical account?
Fuhlendorf: As a scientist, the highly quantitative data that contradicts the historical accounts always jump out to me as the kinds of things that I'm most interested in. I would be troubled if those data did not agree with the historical account. But in our situation, those kinds of data usually do agree with each other, and so they actually help you understand culturally what was going on as well as biologically.
Q: Can you explain how this piece of prairie would change if humans were no longer a factor?
Fuhlendorf: If humans were no longer a factor here, there would most likely be a decrease in fire frequency. That would cause an increase in woody plants that are fire sensitive, such as eastern red cedar. Essentially, the prairie would turn into an eastern red cedar woodland; the prairie species would disappear; and the potential to use that land for agricultural production would drop. We have simulation models that show how a tallgrass prairie with no trees on it could be replaced in as little as forty-five years and turn into a tree-dominated woodland.
Q: Explain how the landscape would change over the course of forty-five years. What would it look like if we took a snapshot every ten years?
Fuhlendorf: Initially, you would have an invasion of trees: primarily these highly productive, fast-growing eastern red cedars. You would have a lot of small trees grow in the first ten years. And in reality it would still look like a prairie. But those trees would grow really fast, and they would start to produce berries that then would germinate and establish, and then --within about twenty-five years—it would just explode and become a forest.
Q: Why are fire and bison so important to the prairie?
Fuhlendorf: Fire limits plant species that can expand. Basically, you cannot have a prairie—or at least it's very, very rare—to have a prairie without fire. When a fire occurs, the re-growth of the vegetation attracts the bison. The bison tend to graze very heavily on those areas, and they avoid the areas that haven't been burned. When another fire occurs, the bison shift to the new area; the originally burned area actually grows up, recovers, accumulates fuel, and increases its likelihood that it will burn again. So you actually have this cycle where everything's being burned periodically, and the bison are following the burn around.
Q: How does the study of birds inform your understanding of the prairie's history?
Fuhlendorf: When I first came to the Tallgrass Prairie Preserve, there were lots of people interested in conserving grassland bird habitat. But one of the challenges is that when you start, you get a list of birds, and you find that they all have different habitat requirements. So if you were to come up with one prescription that would be applied to the entire landscape, you would cause a decline in some species and an increase in others. There's a branch of biology often referred to as “biotic history” or “natural history” where you look at how an organism lives in its environment: the argument is that if that organism has been in that environment for a while, then you can understand that that environment must have not changed much in a while. So these species can tell us the way the landscape was historically by understanding their habitat requirements today. The take-home message is that the world needs to be highly variable. You need to have patchwork of things out there that can provide habitat. Studying birds can actually be a really good indicator of the condition of the grassland, but it can also be a good indicator telling you whether or not you have a good idea of the way the prairie was historically. So if you create habitat—basically by restoring fire and the bison grazing that we think historically occurred—and if we see the bird species responding to that, then we know we may be restoring some of the historical patterns that may have occurred. Essentially, if the species respond to the habitat that we think we're restoring, and the species were native to the area, then we must be restoring that habitat.
Q: What is an anthropogenic ecosystem?
Fuhlendorf: An anthropogenic ecosystem is an ecosystem that's maintained by humans. In reality, there are not ecosystems that are anthropogenic and those that are not anthropogenic. A better way to view it is as a gradient where some ecosystems are largely influenced by humans, and some are less influenced by humans. For example, many people think that Yellowstone is not a highly influenced landscape, but in reality it is. Most landscapes now are managed by humans, and many of the landscapes that we saw historically—in the 1800s, for example—were actually already being managed by humans, in some cases very intensively.
Q: For most people, preservation means you don't touch it: Let it be whatever it wants to be. The approach to preserving the tallgrass prairie goes against that, though.
Fuhlendorf: It's true that we think of the rain forest, for example, and when we preserve that, typically what we try to do is remove human influence from the area. But when you start understanding that humans are a part of the ecosystem, and they have been for a long time, you start to recognize that just protecting an area by building a fence around it and not doing anything can lead to greater degradation than some of the existing management. The reason the tallgrass prairie is still in the Flint Hills of Oklahoma and Kansas is that the local ranchers understood that this landscape needed burning, and they've been burning it for the last one hundred and fifty years or so. A lot of people think of fragmented forests where you take a chunk of trees out, but in the case of the tallgrass prairie, adding a chunk of trees is another way of fragmenting.
Q: Why is it important to restore habitat?
Fuhlendorf: That's the million-dollar question. One reason is that habitats are very productive. By maintaining them, we can actually restore agricultural productivity. But the primary reason is to maintain biodiversity. To me, the Tallgrass Prairie Preserve is a place where you can actually see a reflection of the historical landscape that may have occurred several hundred years ago. Most of us don't want to cause living things to become extinct, and we see a value in maintaining biodiversity that we may not entirely understand at this point.