Eve Allen, serving as the Program Director for the Northeast Bioregion at the Ecological Health Network, recounts her visit to the Southern Grassland Biome and highlights the pioneering efforts of the Southeastern Grassland Institute to conserve and restore endangered grassland ecosystems in the U.S. Southeast.
In the United States Southeast, the knowledge and practice of natural history are essential for conserving and restoring imperiled grassland ecosystems. In 2021, I met with Dwayne Estes, the Co-Founder and Executive Director of the Southeastern Grasslands Institute. Together, we toured remnant and restored grasslands in Tennessee and Kentucky, which provided the backdrop for learning about the near erasure of the expansive grasslands that once covered the region and the work required to remember and restore these biologically and culturally significant ecosystems.
The Southern Grassland Biome
Spanning twenty-four states, the Southeastern region of the United States encompasses biogeographical, climatic, and geological diversity that gives rise to a wide array of ecosystems. The area includes low-lying coastal plains extending from the Atlantic Ocean to the Gulf of Mexico. As one travels inland and northward, the topography transitions into rolling hills known as the Piedmont Plateau and then rises to the rugged Appalachian Mountains. A few generations ago, the region had abundant prairies, savannas, woodlands, meadows, bogs, fens, and sparsely vegetated communities like barrens and glades. Researchers estimate that before European settlement, grasslands covered at least 40–49 million hectares (ha) (100–120 million acres) in the Southeast region [1]. Today, those grassland ecosystems have declined by more than 90 percent and, in some areas, have undergone almost complete eradication. This is because grasslands have been easy targets for land cover conversion because of the ease with which people can transform them into agricultural fields, rangelands, or suburban developments. Woody encroachment, species invasion, and altered fire and grazing regimes have also contributed to the degradation of the Southeast’s grasslands. Needless to say, the species-rich ‘grassy communities’ have suffered a major loss of species and genetic diversity.
Southeastern Grassland Institute’s 24-state focal region. Areas in yellowish-brown above show regions of the Southeast that historically supported large areas of grasslands and associated open, grassy woodlands. Image courtesy of SGI.
Painting of Calcareous Oak Savanna and Meadow in the Nashville Basin, This lost and largely forgotten landscape not seen since ca. 1790. Image courtesy of SGI, Painting attributed to Flavia F. Baretto.
However, the slivers of remaining remnant grassland ecosystems contain more species diversity than the Midwest and Great Plains combined. In 2012, E.O. Wilson characterized the region as the “Southern Grassland Biome,” which he described as “probably the richest terrestrial biome in all of North America” [2]. The Natural History of Ecological Restoration editorial team was unsure about the accuracy of Wilson’s statement. I followed up with Dwayne, who also connected us with Reed Noss, SGI’s Chief Science Advisor. They both explained that although the California Floristic Province is widely acknowledged as the most biodiverse temperate region in North America, the area includes a broad spectrum of ecosystems, including coastal rainforests and coniferous forests to grasslands, scrublands, and deserts. Therefore, it is not an apples-to-apples comparison. The Southern Grassland Biomes encompasses various grassland ecosystem types like prairies, savannas, and meadows. If one were to examine solely the plant diversity and endemism associated with the grassy ecosystems in the California Floristic Province and the Southern Grassland Biome, it’s highly probable that the latter would surpass California in terms of species richness and endemism. However, both Dwayne and Reed explained this is still just a hypothesis because, to their knowledge, no published paper has compared grassland-associated species between the two regions.
In 2015, the low-lying portion of the Southern Grassland Biome, the North American Coastal Plain (NACP), extending from the Gulf of Mexico to the Atlantic Ocean, was designated as the world’s 36th biodiversity hotspot [3]. To qualify as a global biodiversity hotspot, an area must have more than 1,500 endemic vascular plants and greater than 70 percent habitat loss [4]. The NACP, covering 1.13 million km2, contains at least 6,200 plant species, twenty-nine percent (1816) of which are endemic [5]. Nevertheless, Dwayne, Reed, and their colleagues consistently discover and record new species every year.
Atlantic Coastal Plain Hydric Savanna with Pitcher Plants (Sarracenia flava), Francis Marion National Forest, Berkeley County, North Carolina, Courtesy of SGI. Photo credit: Alan Cressler.
Savanna-like landscape and the Couchville Glades and Barrens State Natural Area, Davidson Co., TN. Drone credit: Eve Allen.
Grasslands, encompassing forty percent of Earth’s terrestrial ecosystems, exist in all climatic zones except the polar regions, hyper-arid deserts, and the highest mountain peaks [6]. According to Petermann and Buzhdygan (2022), grasslands provide habitat for an extraordinary number of plants, birds, insects, and other animals, and especially in temperate regions, may have higher species diversity levels than some tropical rainforests at meter-squared scale [7]. From an ecosystem services perspective, grasslands supply freshwater, control soil erosion, sequester and store carbon, provision forage, support pollinator health, and provide recreational and aesthetic value to human communities [8]. The well-being of billions of people worldwide is intricately connected to the health of grassland ecosystems. Yet, grasslands are among the most endangered ecosystems on Earth. As mentioned before, grasslands are low-hanging fruit for land cover conversion and also face numerous escalating contemporaneous threats, including wildly misguided afforestation schemes [9].
Charting a course for 21st-century conservation and restoration
Dwayne Estes, affectionately called the “Prairie Preacher,” is the Executive Director of the non-profit organization, the Southeastern Grasslands Institute (SGI), headquartered at Austin Peay State University in Clarksville, Tennessee. That’s a nickname he received for “spreading the gospel of grasslands” by giving over sixty-seven presentations across twenty states in one year [10]. The work of SGI focuses on the conservation, restoration, and management of native grassland ecosystems through science-based partnerships and community engagement. SGI occupies a leadership position by facilitating public, private, and non-profit collaboration to generate innovative solutions to halt and repair grassland loss. However, the organization is also building a social movement to bring back the native grasslands of the Southeast by giving them a seat at the conservation table. The lion’s share of conservation funding in the Southeast goes into protecting forests, wetlands, rivers, and the various coastal ecosystems. Traditionally, conservation dollars have been extremely scarce to protect the South’s endangered grassland ecosystems. SGI is changing that by attracting significant new funding support from philanthropic, corporate, and government sources. Dwayne explained, “Putting grasslands on the radar of conservationists has required waking people up from a collective amnesia by dispelling long-held ecological myths.”
Dwayne Estes, Executive Director of the Southeastern Grasslands Institute (SGI). Photo credit: Thomas DePauw.
Ecological forensics
I learned how much of the work to conserve and restore grasslands requires employing what Dwayne called ecological forensics since most of the Southeast’s grasslands vanished by the mid-1800s before the camera was invented. Many people, including botanists and ecologists, have long believed the Southeast was always forested. However, the dense forests that cover the region today are artifacts of fire suppression and abandoned agricultural fields. Reed Noss, SGI’s Chief Science Advisor, whom I introduced previously, is a pioneering conservation biologist and activist and one of the Southeast’s premier ecological detectives. In 2012, he published Forgotten Grasslands of the South, which helped to uproot many deeply entrenched ecological myths, including the “Myth of the Squirrel.” Legend has it that the North American continent was once densely forested, to the extent that a squirrel could traverse from the Atlantic Ocean to the Mississippi River without ever setting foot on the ground. Because the forests were so thick and continuous, the squirrel could simply hop from tree to tree, branch to branch, without needing to touch the forest floor. Nonetheless, this narrative is significantly flawed when we consider that certain researchers estimate that before European settlement, woodlands and savannas spanned more than 100 million hectares (250 million acres) throughout the eastern United States. [11]. Reed Noss’ influential work has encouraged the organization’s creation and inspired innumerable other organizations as well.
Blackland Prairie in southern Arkansas. Typical blackland prairie plants include little bluestem (Schizachyrium scoparium), Indian grass (Sorghastrum nutans), compass-plant (Silphium laciniatum), and purple prairie-clover (Dalea purpurea). Image courtesy SGI, Photo credit: Eric Hunt.
The Blackland Prairie in southern Arkansas supports Arkansas’ state butterfly, the Diana fritillary (Speyeria diana), male left and female center, and grassland birds like the Bachman’s Sparrow (Aimophila aestivalis). Photos courtesy of the Arkansas Natural Heritage Commission.
On the second afternoon of my visit, I was following behind Dwayne’s pickup truck when he pulled over and parked on the side of a back country road close to the border between Tennessee and Kentucky. Dwayne jumped out of his truck and pointed to a large chinquapin oak tree (Quercus muehlenbergii) with evenly splayed-out branches. He then announced, “This tree is a storyteller species.” He explained how the tree provided a clue about what the landscape looked like 200 years ago, “If this agricultural field was once a dense forest, this tree’s form would be upright instead of beautifully open and spread out.”
Dwayne shared another story illustrating how researchers have gathered evidence to help reassemble information about lost grassland ecosystems. In the 1990s, the southern pine beetle (Dendroctonus frontalis) was ravaging shortleaf pine trees (Pinus echinata) across the forests of the South. The Tennessee Wildlife Resources Agency (TWRA), a state agency with the mission of managing the state’s fish and wildlife and their habitats, decided to conduct a salvage timber operation on the state-owned Catoosa Wildlife Management Area, part of the Cumberland Plateau, near Crossville, Tennessee. In 1999, the TWRA foresters and biologists started to selectively thin out shortleaf pine trees while leaving behind trees like white oak (Quercus alba) and post oak (Quercus stellata). The salvage operation continued for the next two and a half years, ultimately leading to the unintended formation of a sprawling savanna spanning nearly 2,000 acres. Clarence Coffey, a forester employed by the TWRA, was captivated by the early history of the Cumberland Plateau. His research revealed that savannas and meadows were prevalent across the plateau before the American Civil War. In the early 2000s, the adoption of prescribed fire in the Southeast was on the rise. Coffey, who Dwayne described as the “Savanna Preacher,” spearheaded an initiative to reintroduce controlled burns to the Catoosa Wildlife Management Area. What unfolded next left foresters and biologists astonished and ignited a rivalry among them. Grassland plants such as big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), broomsedge (Andropogon virginicus), Indiangrass (Sorghastrum nutans), and various forbs and wildflowers erupted from the forest floor. The robust growth of these native warm-season grasses was such an unexpected outcome, that some land managers accused the biologists of coming in and planting those species at night. Dwayne looked at me and said, “We all know how crazy of an idea that is, considering that it is still challenging to buy the seeds of most of those species!”
In the subsequent years, the TWRA continued its controlled burns, attracting the attention of researchers who began to visit the site for biodiversity studies. One PhD student from the University of Tennessee, Andrew Vander Yacht, led control studies of the closed canopy forest floor before and after thinning and burning. In 2020, Vander Yacht and his colleagues published their results in the wonderfully titled paper Litter to glitter: promoting herbaceous groundcover & diversity in mid-southern USA oak forests using canopy disturbance & fire in the Journal of Fire Ecology. The researchers found “thin-and-burn treatments increased graminoid groundcover 14-fold, forb groundcover 50-fold, herbaceous richness 9-fold, and herbaceous diversity 10-fold, relative to unmanaged stands.” Altogether, the plots subjected to thinning and burning yielded documentation of an additional 240 herbaceous species. Dwayne emphasized to me that the resurgence was not limited to just common weed species but also included rare and conservation-worthy plants, such as the white fringeless orchid (Platanthera integrilabia), which sprouted from the in situ soil-borne seed bank and rootstock bank. Moreover, it wasn’t solely about plants; biologists also witnessed the return of long-unseen insects and animals in the area, including grassland savanna birds and bats, the frosted elfin butterfly (Callophrys irus), and the golden mouse (Ochrotomys nuttalli). The thinning and controlled burns unintentionally kick-started the restoration of ecosystem structure, composition, and function. Despite these remarkable outcomes, Dwayne pointed out that many in the conservation community fail to fully recognize this as one of the most exceptional examples of savanna restoration in the Southeast.
Influence of oak woodland and savanna restoration on groundcover at Catoosa Wildlife Management Area near Crossville, Tennessee, USA. Panel A depicts pre-treatment conditions in 2008, and panel B depicts the response by 2016 after thinning to 7 m2 ha−1 residual basal area and burning in October three years (2011, 2013, and 2015). Caption and photo courtesy of Andrew Vander Yacht.
To Dwayne, this story also communicates the potential of the in situ soil-borne seed and rootstock bank to aid in conserving and restoring the region’s savanna grasslands and open grassy woodlands. However, activating this potential would require reintroducing controlled fire and selective canopy thinning to the landscape, necessitating cooperation from land managers, some of whom have traditionally resisted such measures. It’s no accident that SGI’s tagline is “25 years will be too late,” which the organization has used to invoke a sense of utmost urgency. Knowledgeable botanists and restoration ecologists estimate that the incredible biodiversity of grassland species laying dormant in the seed- and rootstock bank under artificially dense forests has a shelf life that is running out of time to recover. They fear that the loss of these underground biodiversity reserves could spell one of the greatest hidden collapses in biodiversity of our era, and that most people are completely unaware.
SGI and its collaborating partners dedicate a substantial portion of their efforts to identifying and safeguarding above-ground grassland remnants that face the immediate threat of extinction. Roadsides, powerlines, railroad corridors, and fencerows have provided grasslands a refuge from agricultural intensification and associated pesticide use, sprawling development, and the expansion of woody plants. The direct and indirect management of these land parcels, including periodic burns caused by sparks originating from power lines or train tracks or frequent mowing replicating the impacts of ruminant grazing, has enabled these remnants to persist. From these ecologically valuable scraps, including some of substantial size, SGI is confident they can reassemble historically informed reference ecosystems to restore a considerable portion of what has been lost.
Developing a Bioregional Vision
Dwayne has the remarkable ability to relay in grim detail the consequences of extensive ecological loss while instilling optimism. We stood side by side in the Baker Prairie Natural Area in Russellville, Kentucky, a municipal park housing a 66-acre remnant prairie—one of few remaining traces of a once 220-mile-long crescent-shaped plain. “200 years of American Progress has almost totally erased this ecosystem,” Dwayne said. “We are only now starting to grasp how vast our grasslands used to be. However, what gives me hope is how hungry people are for this message of grassland restoration. What started as a local effort to restore a prairie for the kids in our community has now developed into a social movement involving thousands of people across a twenty-four state region.” To date, SGI has played a role in conserving and restoring hundreds of acres of grasslands. However, their vision encompasses expanding their impact to millions of acres across the Southeast Bioregion in the upcoming decades.
66-acre remnant prairie at Baker Prairie Natural Area in Russellville, Kentucky. Drone credit: Eve Allen
SGI’s first volunteer workday at Dunbar Cave State Park, TN, Image courtesy SGI, Photo credit: Amanda Blount.
Southeastern Grasslands Initiative led an effort to restore a 15-acre hayfield to a tallgrass prairie, representative of what historically would have been there, at Dunbar Cave State Park in Clarksville, Tennessee. Volunteers are vital to the ongoing restoration and management activities at Dunbar Cave Grassland. Drone credit: Eve Allen
Earlier this year, I caught up with Dwayne to learn about the growth of SGI since my visit in 2021. I was pleased to hear that in 2023 alone, SGI has received major funding from several federal grants. The funding will help support mapping efforts across the 24-state region where they work, new grassland restoration projects on National Park Service land in the Eastern US, and the salaries of three Tribal Liaisons and ten to fifteen Interns. On this last point, Dwayne proudly shared, “We are particularly thrilled about securing funding for the recruitment of Tribal staff at SGI. The Tribal Liaisons are not only facilitating vital discussions with Southeastern Tribes concerning the cultural heritage of grasslands but also establishing Indigenous-led strike forces composed of professionals, volunteers, or experts mobilized to achieve specific objectives. These objectives encompass restoring areas affected by natural disasters, combating the proliferation of invasive species like common reed (Phragmites australis), kudzu (Pueraria montana), Japanese knotweed (Polygonum cuspidatum), and mile-a-minute weed (Persicaria perfoliata), and carrying out interventions like prescribed burns. These teams will provide invaluable support to communities, enabling them to engage in essential caretaking activities required to restore and maintain grasslands on Tribal lands in the Southeast.
References
[5] Same as #3 above.
[10] Segrasslands. (2022, October 6). Getting to Know Us: Dwayne Estes. Segrasslands Blog. https://www.segrasslands.org/blog/2022/10/6/getting-to-know-us-dwayne-estes (Accessed September 1, 2023).
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