A couple of weeks ago I was able to attend the Mid-South Prairie Symposium at Austin Peay State University (APSU) in Clarksville, Tennessee. The symposium was organized by Dwayne Estes, professor of APSU’s Center of Excellence for Field Biology at APSU and botanical explorer for the Botanical Research Institute of Texas (BRIT). Dr. Estes’ research interests include biogeography, threatened and endangered species, and plant communities of Tennessee and neighboring states. Dr. Estes opened the conference by referring to an adage from his elementary-school days that, upon the arrival of the first Europeans in North America, the eastern half of the continent was almost entirely forested, such that a squirrel could travel from the Atlantic Ocean to Texas without ever touching the ground. This vision of the landscape reflects the notion that natural succession from cleared field, to weedy pioneer species, to shrubs and vines, to pine forest, to mixed pine-hardwood, and ultimately to a “climax” condition of dense, closed canopy hardwood forest, a pattern observed extensively on the eastern seaboard, applied everywhere that the climate supports forest. In reality, early European explorers noted extensive open grasslands across much of what is now the Southeastern United States including observations of horses legs being stained red from the juice of thousands of fruiting strawberries, and wildfires that burned for miles and days, a pattern that changed with shifts in wind direction. That squirrel would have to have taken a very circuitous route indeed to avoid touching the ground, which in many places was covered in grass. Today, those grasslands, and the ecological processes that supported them, are almost entirely gone from the scene.
Dr. Estes organized an impressive assemblage of leading researchers in natural grasslands conservation in the Eastern United States, including horticulturalists and nurserymen actively installing landscapes composed of regional ecotypes all across the region (and in some places on rooftops!), research professors studying everything from management of cattle to replicate the effects of bison grazing to the mysterious reproductive cycle of native bamboo (hint, it is semelparous, meaning that it blooms but once and then dies. Also, it explodes when it burns). Keynote speaker and renowned biologist Reed Noss placed prairie research in the larger context of natural history, a broad-based approach to the study of nature that is disappearing from the national consciousness almost as rapidly as the treasured landscapes themselves as researchers become increasingly specialized in their fields.
The theme of the symposium was “If we rebuild it, will they come?” This refers to the challenges of restoring these dynamic and complex ecosystems which, once destroyed, do not come back on their own. Dr. Estes prompted invited presenters to speculate on the process of taking forests that were once savannas and cornfields that were once prairie and rebuilding them as grasslands modeled on the few remaining natural examples, and then to speculate on the likelihood of whether doing so will cause the conservative plants and animals come back. University of Tennessee scientist Patrick Keyser re-phrased the question as, “if you have all the pieces of a 1967 Chevy Chevelle dumped in your driveway, do you have a 1967 Chevy Chevelle?” Functioning ecosystems require more than the presence of a set of representative species identified by scientists. Resilience, or the capacity for persistence in the landscape despite detrimental factors, requires certain ecological processes, such as fire and grazing, in addition to an assemblage of parts. Everyone involved in prairie conservation understands the importance of fire: there are no “fire skeptics” left. The more interesting (and controversial) research happening today examines the importance of grazers (historically bison) and browsers (historically deer and elk) in abating the successional processes that cause grasslands to transition to forests, and the feasibility of using domestic livestock, in addition to fire, in efforts to mimic the historic disturbance regime. Dr. Keyser and colleagues have been writing about the use of native warm season grasses as livestock forage for years; his talk at the symposium reviewed recent scientific investigations into the possibility of rotating cattle and fire intensively (a technique known as patch-burn grazing) as a native grassland ecosystem management tool.
Another theme that ran through the day-and-a-half of presentations was the diversity of types of prairies, grasslands, and savannas and the extraordinary rates of endemism (species unique to a particular geographic location) and the presence of threatened, endangered, and recently-described species at these locations. Natural grasslands occur on a continuum of soil depths (from deep soil prairies to thin soil glades on shallow bedrock) and tree densities (from treeless prairies to savannas to woodlands) and moisture (from dry prairies and barrens to montane bogs, fens, depression ponds, and riverscour, flood-maintained grasslands associated with riparian cobble and boulders in rugged Appalachian streams). Attendees were given a beautiful booklet describing all of these grassland types and more. A presentation by Theo Witsell, botanist with the Arkansas Natural Commission with experience in landscapes all across the Eastern United States, tallied high rates of endemic and recently-described species in grassland patches, many quite small, scattered widely across the region. His presentation culminated with dramatic aerial images of how these small patches, some of which at one time covered thousands of acres, are shrinking or disappearing altogether due to urbanization. Many of these patches were never surveyed botanically, and we’ll never know what was lost.
The Thursday field trip brought the attendees to the Fort Campbell Army installation on the Tennessee-Kentucky border a few miles north of Clarksville. The site was selected by the War Department in 1941 specifically for airborne training due to the extensive grasslands already in existence. There we were treated with a sight rarely seen in the Southeastern United States: a stand of tall grass, both native and exotic species, with trees present only in the drainages, as far as the eye can see. We were not allowed to take photographs of this or any other landscape at Fort Campbell, and we were also prevented from walking through these extensive fields, as they comprise the impact zone for ordinance training, kept virtually treeless due to the frequent burns associated with artillery and bombing exercises, similar to the way they were described 200 years ago. We were able to tour a smaller patch used as a drop zone for the 101st Airborne Division, where we observed a healthy mix of warm season native grasses and forbs interspersed with copses of mature oaks. It was a very fine day.
On behalf of the GCPO LCC, I would like to express my sincere gratitude to Dr. Dwayne Estes and to all those who attended the symposium, for their talent and dedication to the conservation of this important and sometimes overlooked system. Mike Black, director of the Shortleaf Pine Initiative, noted that, for the first time in recent memory, a net gain in landscape coverage by longleaf pine has recently been reported, due to efforts of groups such as The Longleaf Alliance and America's Longleaf. Similar good news for shortleaf pine is probably years away, for native grasslands, maybe decades. However, interest is building, coalitions and initiatives are forming, and the GCPO LCC, along with our neighbor LCCs, are excited about our potential contribution to efforts to collaborate across states, agencies, and organizations in this important work.
As I state above, photography was forbidden at Fort Campbell. However I am able to provide a few pictures of a beautiful pocket garden designed and planted by Dr Estes and his colleagues and students, comprised entirely of native plants, in the courtyard of the Sundquist Science Complex, where the conference was held.