Podcast from Roan Mountain Radio about "Old-Growth Grasslands"

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Listen to Roan Mountain Radio's Ken Turner interview SGI Director, Dr. Dwayne Estes, about the Southeastern Grasslands Initiative.

Click here to listen: https://s3.amazonaws.com/…/RMR-079-Old-Growth-Grasslands-a-…

Dr. Estes will be joining several invited speakers at Roan Mountain State Park's Winter Naturalists' Rally, February 17, 2018.

For more information about the grasslands of Roan Mountain see the SGI website (https://www.segrasslands.org/southeastern-grasslands-1/) and to register for the Winter Naturalists' Rally go online go towww.friendsofroanmtn.org

 

#6 Southern Ridge and Valley Dolomite Seep

Southern Ridge and Valley Dolomite Seep, Campbell Co., TN. This community consists of a weird mix of species. On the margins one finds Northern White Cedar (Thuja occidentalis) and Interior Bushy St. Johnswort (Hypericum interior). But in the seep itself, which may have qualities of a barren, there are "prairie species" such as Prairie Dock (Silphium terebinthinaceum). Credit: Aaron Floden.

The term "grassland" is broadly used to refer to natural communities where the ground layer of vegetation is dominated by grasses, graminoids (grass-like plants), and forbs, though shrubs, tree saplings, scattered trees, mosses, lichens, and even bare rock or soil may be present to varying degrees. Everyone is familiar with the nearly treeless tallgrass prairies of the Midwestern U.S. but the southeastern U.S. is home to many atypical grasslands that many, if not most, people would walk by and dismiss as grasslands. Although many atypical grasslands may not look "prairie-like" or "savanna-like" one thing that connects them is the presence of sun-loving herbaceous species, many of which often grow in typical grasslands. In the Ridge and Valley ecoregion of southwestern Virginia, east Tennessee, northwestern Georgia, and northeast and central Alabama, dolomite and limestone seep communities represent one of these atypical grasslands.

These seeps occur on steep to moderate slopes and percolate out of cracks in the dolomite bedrock. Credit: Aaron Floden.

These tiny open wetlands occur on steep to moderately sloping seepage slopes in hilly, dissected landscapes. Springs bubble out of the sides of hill slopes through cracks in the underlying dolomite bedrock and flow over shallow gravelly or rocky slopes. Sometimes deeper sediments accumulate toward the bottom of seeps. Due to the shallow soils and constant seepage, trees are prevented from growing too large because these slopes are subjected to slumping or slope creep. However, just outside the seepage zone, where slope creep is not as prevalent, sediments may be moist or dry, but tend to accumulate to deeper depths. These deeper-soiled areas support forests or woodlands.

Trees can't grow to large sizes in these seeps, but a variety of small- to medium-sized shrubs, herbs, graminoids (=grasses, sedges, and rushes), and mosses are able to endure the shallow, saturated soils.

The term "fen" is often used for a wide variety of open, groundwater-fed wetlands. Traditionally it has been applied to wetlands underlain by calcareous/mafic bedrock with alkaline or circumneutral pH and mucky sediments. In recent decades there has been a growing realization that such communities are not always easy to separate from wetlands with acidic soils, some of which are called acid seeps or bogs. Due to this lack of a clear-cut difference based on soil/groundwater chemistry, some ecologists advocate calling the wide variety of groundwater-fed seepage wetlands fens. Those that are more on the alkaline end of the spectrum are called "rich fens" and tend to have a greater dominance by broadleaf herbs and grasses and usually lack Sphagnum (peat) moss. Those that are more acidic are often called "poor fens" and tend to have more coverage by sedges and ferns, and Sphagnum is often abundant or dominant. These wetlands of the Southern Ridge and Valley would tend to fit into the "rich fen" type.

Rich fens themselves vary tremendously across the eastern U.S. depending on such variables as topography, slope, depth to bedrock, substrate (muck soils, gravel), etc. Sometimes the term "fen" is reserved for those wetlands in level to gently sloping sites where sediments may become fairly deep. In these situations, sediments are rich in organic matter and become dark, often blackish, and are smooth (not gritty or fibrous) when rubbed between the fingers. Many 20th century ecologists describe fens such as this as occurring mostly in the northeastern U.S. in regions formerly covered by glaciers during the last ice age.

These deep-soiled rich fens do occur in unglaciated regions south of the glacial boundary, in parts of the Southeast and lower Midwest. Two exceptional examples include Grasshopper Hollow Fen in the Missouri Ozarks and Bluff Mountain Fen in the Blue Ridge Mountains of northwestern North Carolina. These deep-soiled calcareous or mafic fens will be described in more detail in future blog posts...stay tuned.

Above: Fens are considered by many ecologists to be groundwater-fed wetlands in basins, flats, and other topographic lows, that tend to have alkaline pH (due to calcareous or mafic bedrock), organic mucky soils, and dominated by graminoids, forbs and shrubs. The best known classic fens are in the glaciated regions of the northeastern U.S. and eastern Canada, but some large classic fens occur in the Southeastern Grasslands Initiative focal area such as Bluff Mountain Fen, Ashe Co., North Carolina (above left, credit, Alan Weakley) and Grasshopper Hollow Fen, Reynolds Co., Missouri (above right, credit, Jim Rathert, Missouri Dept. of Conservation).

In the meantime, the terms seep, seepage wetland, seepage glade, or seepage fen are used for similar wetlands that lack substantial organic soils due to shallow depth to bedrock or abundant bedrock exposures that tend to occur on slopes. These seeps when developed over limestone or dolomite, or mafic or ultramafic metamorphic rocks tend to be alkaline. Those over granite, gneiss, sandstone, and chert tend to be acidic. The Southern Ridge and Valley Dolomite Seep community described here would fit the alkaline type and is developed on shallower soils. Therefore, I advocate referring to these natural openings as seeps and reserve the term fen for the deeper soiled examples. Again, more on these later....

Strongly sloping groundwater-fed calcareous wetlands occur in scattered places across the Southeast, such as this one in Lewis Co., Tennessee. Such sites are sometimes called Seepage Fens or simply Seeps but differ in important ways from deeper-soil fens described above. Credit: Dwayne Estes.

Calcareous hillslope seep communities are found at just a few areas within the Southeastern Grasslands Initiative focal area, including parts of the Missouri and Arkansas Ozarks, the Outer Bluegrass of southern Ohio, the Interior Plateaus of central Tennessee, and the Ridge and Valley from western Virginia south to central Alabama.

No matter where they occur, they all tend to provide refuge for numerous rare plants (including a few that are endemic to these open seeps), rare insects (e.g. dragonflies) and a wide diversity of aquatic macroinvertebrates, salamanders, and aquatic snails. 

Aaron "Golden-Boy" Floden Discovers a Botanical Goldmine

In my last year of graduate school at the University of Tennessee-Knoxville in 2007, I received a phone call from Mark Mayfield, botanist at Kansas State University. Mark explained how one of his undergraduate students, Aaron Floden, was about to move to Knoxville and described him as one of the most talented botanists he had ever seen. I told Mark we would make room for him in the herbarium and looked forward to Aaron being a part of our Tennessee botany family.

Aaron Floden (right) works with staff of the University of Tennessee documenting flora of an incredible seep discovered by Aaron about 10 years ago. Credit: Ed E. Schilling.

When Aaron moved to Knoxville he made an immediate impact on Tennessee botany. It was about that same time that Google had just introduced Google's "Street View." In fact, it was Aaron who first showed Street View to me. While playing around with it, he began using Street View to explore Tennessee's backroads from the comfort of his office.

One of the first projects Aaron embarked upon after moving to Knoxville was attempting to rediscover the rare Needleleaf Beaksedge (Rhynchospora capillacea). This sedge had not been seen in Tennessee since the early 1930s when it was last collected about 40 miles north of Knoxville in an area that now mostly lies beneath Norris Lake, a large lake dammed as part of Franklin Roosevelt's New Deal projects. 

While "virtually-cruising" the backroads of Campbell County, Tennessee, Aaron was intrigued by one open area along the side of a rural backroad. Thinking about it now, it's kind of surprising to me that one of Google's cars would have even been on that dead-end road. He saw an area with an open canopy just a few feet off the road that looked like a seepage wetland.

Google Earth street view image of the initial seep discovered by Aaron Floden in Campbell Co., Tennessee. He found this seep first by using Google Earth street view to do a "virtual backroad survey." Credit: Google Earth.

Not long after, Aaron jumped in the car and drove up to the site. What he found was incredible. Stepping about 20 feet off the roadside, he found an open dolomite seep. The seep was quite large and originated upslope about 100-200 feet and was about 30 feet wide. The portion higher on the slope was surrounded by forest but no trees were rooted in the seep itself. The lower half of the seep was beneath a small utility-line right-of-way.

Hypericum interior (Inland Bushy St. Johnswort) dominates the margins and interiors of some seeps. Credit: Aaron Floden.

Around the margins of the open seep, the dominant shrub was an exceptionally narrow-leaved form of what most people previously had called Bushy St. Johnswort (Hypericum densiflorum), but he realized it was likely a forgotten species long ago recognized by J.K. Small as Hypericum interior.

Aaron's discovery of this complex of previously unexplored seeps was initiated by his desire to rediscover the Needleleaf Beakrush (Rhynchospora capillacea) (above). He found it on his first day of looking for it in Campbell Co., TN and had not been seen in TN since the 1930s. Credit: Aaron Floden

In the middle of the seep, the vegetation was quite short and throughout were little hummocks. And there on the little mossy mats was the Needleleaf Beaksedge (Rhynchospora capillacea) that initially had inspired his search. And, it was there in abundance. Just like that, he rediscovered a lost species that no Tennessee botanist really thought would be rediscovered. Most of us had assumed the population last observed in the 1930s was submerged beneath Norris Lake.

But, Aaron's big day was just beginning. Growing there among the tussocks of the Needleleaf Beaksedge was a small white-flowered "lily" with narrow strap-like leaves and a sticky stem. He instantly recognized it as Sticky False Asphodel (Triantha glutinosa), a species not previously known from Tennessee. This find is what botanists call a "state record."  Interestingly, both the Sticky False Asphodel and the Needleleaf Beaksedge, are northern species that are near their southern range limit in North America in Tennessee. They are more common in the fens of the northeastern U.S. and eastern Canada.

One of the other cool plants Aaron found on that eventful day was this small white-flowered "lily"--the Sticky False Asphodel (Triantha glutinosa). This represented one of numerous state records found by Aaron in these dolomite seeps. Credit: Aaron Floden.

It takes a sharp botanist to be able to notice what Aaron observed next. Across the open seep are numerous graminoids. The term "graminoid" is just a catch-all term for a "grass-like" plant and includes grasses, sedges, and rushes. In Tennessee alone, there are more than 150 species of sedge in the genus Carex and it takes a honed eye to be able to identify many of them to species. But Aaron noticed that this seep was home to two really significant sedges that turned out to be new state records. These included the Interior Sedge (Carex interior) and Rigid Sedge (Carex tetanica).  

No doubt, Aaron must have been on a botanical high as he slowly worked his way upslope through the magnificent seep. I, myself, have been in similar situations and you have to almost catch your breath because cool stuff and new discoveries are coming at you from all sides. It can be hard to slow down and process it all. Throughout the seep one of the dominant plants was the Large-leaved Grass-of-Parnassus (Parnassia grandifolia). This gorgeous fall-blooming plant is stunning with its green-veined petals. It is rare in Tennessee and throughout most of the South, but was doing great at this seep.

Large-leaved Grass of Parnassus (Parnassia grandifolia) dominates some dolomite seeps. This is one of several rare species tracked by the Tennessee Division of Natural Areas. Credit: Aaron Floden.

Reaching the top of the seep, Aaron found a small straggling shrub that seemed unusual. After studying it for a bit he concluded that it was the rare Alderleaf Buckthorn (Rhamnus alnifolia), which had only been found in Tennessee a couple of other times at just a couple of other sites.

Alderleaf Buckthorn (Rhamnus alnifolia) is a rare shrub that prior to Aaron's discovery of numerous populations had been known only from a couple of old records. Credit: Aaron Floden

Having been to this seep myself later with Aaron, I remember vividly the view looking down from the top of the seep and being amazed at the incredible diversity and assortment of rare and disjunct plants. Looking back downslope, Aaron observed that the most dominant plant in the entire seep was actually the most significant find of all. 

Throughout the seep was a fairly robust herb with broad, stiff, tri-lobed leaves and a lean stem topped by rounded clusters of white flowers. He instantly recognized the plants to belong to a genus known as Trautvetteria (Tassel-Rue or Bugbane)In the eastern U.S. the Carolina Tassel-Rue (Trautvetteria caroliniensis) is occasional along streambanks, in seeps, and other wet habitats. Aaron realized these plants differed in having fewer leaf lobes and in their coarse texture and leaves held in a different position. He realized that he had just discovered a totally new species.

The most significant discovery Aaron made was the discovery of a completely new species to science (the leafy plant pictured above) that is known only from 4 counties in Tennessee north of Knoxville and nowhere else worldwide. Aaron Floden formally named this species in November 2017 and it is called Trautvetteria fonticalcarea. Left and center photos by Aaron Floden; right photo by Edward E. Schilling.

I remember being a little envious of Aaron's remarkable discovery. Certainly I was proud for him but I couldn't help but fantasize about being there myself. Aaron made such a big impact at the University of Tennessee Herbarium and in Tennessee botany in general that he easily won the favor of the herbarium director, Dr. Eugene Wofford. In fact, Dr. Wofford referred to him as "The Second Coming."  A few years before Aaron got to UT, my fellow PhD lab-mate, Joey Shaw, had enjoyed being the favorite of Dr. Wofford. Then, when I arrived in 2003, Joey kidded that I had replaced him as Dr. Wofford's favorite. But, when Aaron came in with a bang, he became the new favorite. Joey and I began to refer to him as the "Golden Boy." To those of us lucky enough to call Aaron a good friend, we like to refer to him as Aaron "Golden" Floden, or simple "Goldie."

The Tennessee Valley Authority has funded efforts by Aaron Floden and Adam Dattilo (TVA) to locate and study dolomite seeps of the Powell River Watershed. Credit: Aaron Floden.

After that discovery, Goldie went on to find dozens of other seeps across a four-county area (Anderson, Campbell, Claiborne, Union) of upper east Tennessee, including nearly two-dozen populations of the new Tassel-Rue. In fact, just about a month ago, Aaron and Dr. Ed E. Schilling (his PhD advisor at UT) formally named this new species after several years of research. It was named Trautvetteria fonticalcarea, reflecting the calcareous seeps to which it is endemic. This cool new species is only found in Tennessee and nowhere else worldwide. Prior to its discovery, it was part of a special club of about of 100 species of plants that botanists know about that are restricted to grasslands and grassland-related habitats. 

Recently, Aaron has been working with Tennessee Valley Authority botanist, Adam Dattilo, to search for and study more of these seeps within the Powell River watershed. They have found many populations of rare plants never before documented and have determined that this particular dolomite seep community represents a new community type, not previously described or recognized by community ecologists. Some of these seeps have prairie species, like Prairie Dock (Silphium terebinthinaceum), and other unexpected species. They have even found new populations of the extremely rare Showy Lady's Slipper Orchid (Cypripedium reginae). 

Showy Lady's Slipper Orchid (Cypripedium reginae) is one of the most spectacular species found in the Southern Ridge and Valley Dolomite Seeps. Aaron has found new populations of this Tennessee endangered species. Credit: Aaron Floden.

While looking for new seeps, they've had to explore a lot of non-seep habitat such as dry to moist calcareous forests and woodlands, which is the matrix habitat in which these seeps are found. In these woods they've found new populations of Northern White Cedar (Thuja occidentalis) and discovered three additional new state record species for Tennessee, White Rattlesnake Root (Nabalus albus), Wood's Sedge (Carex woodii), and Mountain Ricegrass (Patis racemosa).

Three new state record species found by Aaron Floden during his survey of dolomite seeps in the Powell River Watershed. These are species found in adjacent rocky woods outside of the seeps. Left: White Rattlesnake Root (Nabalus albus); Center: Mountain Ricegrass (Patis racemosa);Right: Wood's Sedge (Carex woodii). Credit: Aaron Floden.

Aaron continues to work on studying this rare community, in spite of the fact that he has gone on to St. Louis to work for the Missouri Botanical Garden as Flora of Missouri Curator. But his work takes him well outside Missouri to most parts of the Southeast and he even frequently goes on expeditions to east Asia (China, north Vietnam) where has discovered several species, including a new genus. His incredible work highlights just how much continued baseline surveys are needed to better understand our natural world.

These open wetlands are mostly in private ownership. Their small size makes them very susceptible to invasion by invasive species or to degradation by any number of factors. Unfortunately, we will never know just how much of this community we have lost because there were certainly seeps that now are beneath Norris Lake and we may have lost populations of species that no longer occur in the state that are known from similar seep communities farther northeast in Virginia--we will never know.

This open gap in the forest was once home to a thriving seep but has been destroyed by bulldozing. The small size of these Southern Ridge and Valley Dolomite Seeps makes them susceptible to these activities and because they are so tiny it doesn't take much to wipe them out. Credit: Ed E. Schilling.

This open gap in the forest was once home to a thriving seep but has been destroyed by bulldozing. The small size of these Southern Ridge and Valley Dolomite Seeps makes them susceptible to these activities and because they are so tiny it doesn't take much to wipe them out. Credit: Ed E. Schilling.

Thanks to Aaron for making such a great contribution to conservation! I hope I have captured the essence of his discovery and I hope our readers are as inspired by his work as I am.

 

Contributed by: Dwayne Estes

 

 

 

 

#5 Interior Plateaus Limestone Riverscour Glade

Interior Plateaus Limestone Riverscour Glade, Rock Island State Park, White and Warren counties, Tennessee. Credit: Dwayne Estes.

Interior Plateaus Limestone Riverscour Glade, Rock Island State Park, White and Warren counties, Tennessee. Credit: Dwayne Estes.

In the previous blog post describing the Southeast's super diverse grassland communities, I described the sandstone cobble bars referred to by ecologists as Cumberland Plateau Riverscour. This blog post is dedicated to a related but entirely different community, Highland Rim Limestone Riverscour Glade. 

This photo shows the two factors that maintain this unusual grassland, soils thin to absent and high degree of flooding (note the driftwood).

This photo shows the two factors that maintain this unusual grassland, soils thin to absent and high degree of flooding (note the driftwood).

This community is a type of glade, which is a rocky grassland/shrubland community that is found along just a few rivers in the Interior Plateaus ecoregion of central and east-central portions of Tennessee and Kentucky, southern Indiana, southern Ohio (?), and historically northern Alabama. 

You may be wondering, "where is the grass?" Unlike most "typical" grasslands which have more grass cover, in this grassland type, the grasses and other herbaceous species characteristic of prairies, savannas, and barrens, are restricted to thin cracks in the limestone bedrock. This community also differs from most "typical" glades in that it occurs alongside rivers. Therefore, it is maintained by two factors. First, its extremely shallow soils and high exposure of bedrock makes it an edaphic grassland. Secondly, due to its position alongside streams it is also subjected to scouring effects of periodic floods.

The best example of Interior Plateaus Limestone Riverscour occurs at Rock Island State Park on the Caney Fork River in White and Warren counties, Tennessee. It may have been more common historically in small thin glade strips farther down the Caney Fork River but Center Hill Lake has impounded most of the lower portion of the river. Just a half-mile upstream from Rock Island is Great Falls Dam, so this natural gem is literally sandwiched between completely altered sections of river.

Google Earth image of the best Limestone Riverscour Glade complex probably in existence in the southeastern U.S. At lower right is Great Falls Dam. In upper left (out of scene) the river flows around a bend and then the impounded waters of Center Hill Lake are reached. This is a glimpse at what the original riverbed in this section looked like. The best glade is located at far left on the south side of the river. The northern half of the river is in White County and the southern half in Warren County, TN. Source: Google Earth.

Google Earth image of the best Limestone Riverscour Glade complex probably in existence in the southeastern U.S. At lower right is Great Falls Dam. In upper left (out of scene) the river flows around a bend and then the impounded waters of Center Hill Lake are reached. This is a glimpse at what the original riverbed in this section looked like. The best glade is located at far left on the south side of the river. The northern half of the river is in White County and the southern half in Warren County, TN. Source: Google Earth.

When I first visited Rock Island several years ago I was blown away not only by the biodiversity of this community, but also by the abundance of rare species. Not long after, I introduced one of my graduate students, Mason Brock, to the site and we decided he would begin to study the riverscour communities of the Caney Fork River. The Caney Fork originates on the Cumberland Plateau and drops about 1,000 feet in elevation and enters the Interior Plateaus ecoregion. Along its length, it features three distinct types of riverscour: sandstone cobble bar barrens, sandstone glades, and limestone glades.

Undescribed species, the Cumberland Leatherflower (Clematis sp. nov.), on limestone scour at Rock Island State Park, White Co., TN. Credit: Dwayne Estes.

Undescribed species, the Cumberland Leatherflower (Clematis sp. nov.), on limestone scour at Rock Island State Park, White Co., TN. Credit: Dwayne Estes.

Mason studied all three types and found that the limestone scour communities were very different floristically from the sandstone sites. However, a number of uncommon species were found on both sandstone and limestone scour. One of the more notable species that occurs on both the sandstone and limestone sites is an unnamed species that Austin Peay graduate and SGI research associate, Devin Rodgers, and I will be naming soon. It is to be called the Cumberland Leatherflower and is a type of Clematis. It is unique in the region for having long flower stalks and leafy bracts located near the base of the leafstalk.

The large flat glade at Rock Island is divided on its surface by numerous cracks, and the area between the cracks is largely devoid of plants. Within each of the cracks, a number of species compete for space, including such prairie indicators as big bluestem (Andropogon gerardii), Indian grass (Sorghastrum nutans), and little bluestem (Schizachyrium scoparium).

Limestone Riverscour Glade, Rock Island State Park, Warren Co., TN. The cracks in the bedrock are densely packed with a small form of big bluestem (Andropogon aff. gerardii) which is also dominant on sandstone cobble bars of the Cumberland Plateau. This big bluestem may be an undescribed species or variety unique to riverscour. Pringle's Aster is common in these cracks along with Little Bluestem (Schizachyrium scoparium), Bushy St. John's-wort (Hypericum interior), False Dragonhead (Physostegia virginiana var. praemorsa), Aromatic Aster (Symphyotrichum oblongifolium),  and Carolina Willow (Salix caroliniana). Credit: Dwayne Estes.

Limestone Riverscour Glade, Rock Island State Park, Warren Co., TN. The cracks in the bedrock are densely packed with a small form of big bluestem (Andropogon aff. gerardii) which is also dominant on sandstone cobble bars of the Cumberland Plateau. This big bluestem may be an undescribed species or variety unique to riverscour. Pringle's Aster is common in these cracks along with Little Bluestem (Schizachyrium scoparium), Bushy St. John's-wort (Hypericum interior), False Dragonhead (Physostegia virginiana var. praemorsa), Aromatic Aster (Symphyotrichum oblongifolium),  and Carolina Willow (Salix caroliniana). Credit: Dwayne Estes.

Pringle's Aster (Symphyotrichum pilosum var. pringlei is known only from this single site in Tennessee. Credit: Dwayne Estes.

Pringle's Aster (Symphyotrichum pilosum var. pringlei is known only from this single site in Tennessee. Credit: Dwayne Estes.

Numerous rare or uncommon species occur in the cracks, including white prairie clover (Dalea candida), Pringle's aster (Symphyotrichum pilosum var. pringlei), blue wild indigo (Baptisia australis), Shining Bluestar (Amsonia illustris), and stiff goldenrod (Solidago rigida). In fact the aster is the only place in all of Tennessee for what is mostly a northern/Midwestern aster.

Water from both rain and floods often pools on the flat limestone bedrock creating small ephemeral wetlands. Many typical species of marshes and open wetlands are found in the cracks that are adjacent to these wet pools, including many sedges, rushes, and even a couple of beakrushes (Rhynchospora glomerata), the last of which is uncommon in calcareous habitats. Small-headed rush (Juncus brachycephalus) has been reported from these wet limestone glades in the past but has not been seen in more than 40 years. Other rarities include shining ladies-tresses (Spiranthes lucida). Widow's cross (Sedum pulchellum) grows in abundance in the spring when moisture is abundant.

Pools of water on the open Riverscour Glade add another dimension which provides habitat for dozens of species of wetland plants. The back edge of this glade also provides habitat for calcareous shrub wetlands. Credit: Dwayne Estes.

Pools of water on the open Riverscour Glade add another dimension which provides habitat for dozens of species of wetland plants. The back edge of this glade also provides habitat for calcareous shrub wetlands. Credit: Dwayne Estes.

Maidenbush (Phyllanthopsis phyllanthoides) grows in limestone riverscour habitats in central TN. Photo credit: Ketona Dolomite Barrens, Bibb Co., AL by Eric Hunt.

Maidenbush (Phyllanthopsis phyllanthoides) grows in limestone riverscour habitats in central TN. Photo credit: Ketona Dolomite Barrens, Bibb Co., AL by Eric Hunt.

Closer to the river where the rocks have been broken and form a bouldery bank along the water, several other rarities were found. Most notable perhaps is the Maidenbush (Phyallanthopsis phyllanthoides). This rare shrub of the spurge family is most common west of the Mississippi River in the glades of the Ozarks and Ouachita Mountains of Arkansas, Missouri, and Oklahoma. Prior to finding it on the Caney Fork River, it had only been documented to occur in three other areas east of the Mississippi River: on dolomite barrens along the Little Cahaba River (Bibb Co., AL) and on sandstone cobble bars of the Locust Fork and Mulberry Fork of the Warrior River (two different rivers in Blount Co., AL).

Map showing the distribution of Maidenbush (Phyllanthopsis phyllanthoides). Source: http://bonap.net/MapGallery/County/Phyllanthopsis%20phyllanthoides.png.

Map showing the distribution of Maidenbush (Phyllanthopsis phyllanthoides). Source: http://bonap.net/MapGallery/County/Phyllanthopsis%20phyllanthoides.png.

 

The day I first stumbled across the Maidenbush was a day full of discoveries. Growing nearby on the bouldery riverbank was the endangered rock grape (Vitis rupestris), a species with a very similar distribution as Maidenbush that previously had not been seen in Tennessee since the 1880s except for a population found just a couple of years earlier near Clarksville, Tennessee along the Cumberland River by Sunny Fleming, Tianita Duke, and myself.

Limestone Riverscour Glade along shore of Cumberland River below King and Queen's Bluff in Clarksville, Tennessee. This glade is home to numerous rare species including the endangered rock grape (Vitis rupestris) and prairie grasses such as big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), and eastern gamagrass (Tripsacum dactyloides) line the upper edge of the glade. Credit: Mason Brock. Some of the species found here are known in Tennessee otherwise only from Rock Island State Park about 100 miles to the east, including rock grape and Midwestern Silky Dogwood (Cornus obliqua).

Limestone Riverscour Glade along shore of Cumberland River below King and Queen's Bluff in Clarksville, Tennessee. This glade is home to numerous rare species including the endangered rock grape (Vitis rupestris) and prairie grasses such as big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), and eastern gamagrass (Tripsacum dactyloides) line the upper edge of the glade. Credit: Mason Brock. Some of the species found here are known in Tennessee otherwise only from Rock Island State Park about 100 miles to the east, including rock grape and Midwestern Silky Dogwood (Cornus obliqua).

Limestone scour glades are one of the rarest plant communities in eastern North America. This is due in part to the fact that over the past two centuries damming of rivers or dynamiting of riverbeds to improve navigation has eliminated some of the best sites. 

Specimen of Orbexilum stipulatum in the Ravenel Collection, University of South Carolina Herbarium. Credit: University of South Carolina Herbarium.

Specimen of Orbexilum stipulatum in the Ravenel Collection, University of South Carolina Herbarium. Credit: University of South Carolina Herbarium.

The Falls of the Ohio River, long known as a navigational hazard and as a major landmark to Native American tribes and the earliest French and English explorers, was an area of extensive limestone scour near present-day Louisville, Kentucky. It was considered to be an important crossing place for buffalo and Native Americans. Orbexilum stipulatum, one of the relatively few extinct plant species known from eastern North America according to expert Wes Knapp (North Carolina Natural Heritage Program), was discovered at the Falls of the Ohio presumably in limestone scour glades by Dr. Charles W. Short in the 1830s. He made several herbarium collections from the site which he deposited at numerous institutions where they are still preserved to this day. Unfortunately, the species has not been seen since the days of Dr. Short.

Another species at the Falls of the Ohio that is only found at a few other sites worldwide is Short's Goldenrod, named for Dr. Short who was the first person to collect it. Dr. Reed Noss, SGI's Chief Science Advisor and Professor Emeritus of the University of Central Florida, discussed this species in his recent book Forgotten Grasslands of the South. He noted how this species is associated with dry rocky glade-like habitats associated with former buffalo traces. Outside of the Falls of the Ohio, it occurs at the Blue Licks in the Kentucky Bluegrass and on limestone riverscour grasslands along the Blue River in Harrison Co., Indiana.

Falls of the Ohio State Park, Louisville, Kentucky, used to be an important crossing place over the wide Ohio River. Buffalo traces from the Midwest crossed here leading south into the Bluegrass and Pennyroyal Plain of Kentucky. This is the site from which Charles W. Short collected the now extinct Orbexilum stipulatum (Source: http://www.arrowssentforth.com/2011/03/falls-of-ohio-state-park.html).

Falls of the Ohio State Park, Louisville, Kentucky, used to be an important crossing place over the wide Ohio River. Buffalo traces from the Midwest crossed here leading south into the Bluegrass and Pennyroyal Plain of Kentucky. This is the site from which Charles W. Short collected the now extinct Orbexilum stipulatum (Source: http://www.arrowssentforth.com/2011/03/falls-of-ohio-state-park.html).

One of the most notable areas of former limestone scour was the Mussel Shoals (often incorrectly spelled Muscle Shoals) along the Tennessee River in north Alabama. The Shoals were formed by a very hard layer of rock known as the Fort Payne Chert. The Mussel Shoals were also an important crossing point on this major river, in fact, it was here that General Andrew Jackson crossed on his way southward to battle the Creek Indians in the Battle of Horseshoe Bend. The Shoals were a major navigational hazard where the river fell over 100 feet over a distance of more than 15 miles. This important landmark was drawn on some of the earliest maps of the southeastern U.S., apparently first appearing on French maps drawn about 1720. Perhaps it was in this riverscour habitat that the single record of Virginia Spiraea (Spiraea virginiana) ever reported from Alabama was collected. The Shoals were inundated following construction of Wilson Dam in 1918.

The red oval highlights the section of the Tennessee River (then referred to by the French as the Cusatees River or the Thegalegos River) on this 1720 French Map. Note within the red oval the river splits and a couple of islands are drawn within it. The shape resembles an eye. This is the Muscle Shoals (or Mussel Shoals). Note just south of the Tennessee River there is the inscription "All Level and Good Ground." This area evidently contained a large grassland immediately south of the river that is gone today.

The red oval highlights the section of the Tennessee River (then referred to by the French as the Cusatees River or the Thegalegos River) on this 1720 French Map. Note within the red oval the river splits and a couple of islands are drawn within it. The shape resembles an eye. This is the Muscle Shoals (or Mussel Shoals). Note just south of the Tennessee River there is the inscription "All Level and Good Ground." This area evidently contained a large grassland immediately south of the river that is gone today.

In coming years, SGI will continue to lead efforts to document what's left of these rare riverside limestone glades and their unique flora. We are planning expeditions to the Little South Fork of the Cumberland River and Buck Creek in Kentucky and to a few other streams in the Mid-South. If you know of similar sites elsewhere across the Southeast we'd love to learn about them. 

Contributed by: Dwayne Estes

#4 Cumberland Plateau Sandstone Riverscour Barrens

High-quality riverscour barren on bank of Daddy's Creek, Catoosa Wildlife Management Area, Cumberland Count, TN. Photo credit: Dwayne Estes.

High-quality riverscour barren on bank of Daddy's Creek, Catoosa Wildlife Management Area, Cumberland Count, TN. Photo credit: Dwayne Estes.

Most natural grasslands of the world are maintained by fire, grazing or climatic factors (e.g. lack of rainfall, persistent cold/freezing in tundra), but in the depths of some of the deepest river gorges of Southern Appalachia are poorly known flood-maintained grasslands known to community ecologists as riverscours.

Old picture of Daddy's Creek Gorge, Morgan Co., TN (Catoosa Wildlife Management Area) in the 1950s. Riverscour grasslands occur in the depths of the gorge along the boulder-strewn riverbanks. Note the presence of open pine-oak savanna on top of the cliff at right.

Old picture of Daddy's Creek Gorge, Morgan Co., TN (Catoosa Wildlife Management Area) in the 1950s. Riverscour grasslands occur in the depths of the gorge along the boulder-strewn riverbanks. Note the presence of open pine-oak savanna on top of the cliff at right.

Riverscour communities occur on some of the larger streams of the Cumberland Plateau along high-gradient sections that have cut down deeply into the plateau surface. These streams are often popular for whitewater kayaking and often have Class I-IV rapids. 

In Alabama, riverscour is associated with the Locust Fork of the Black Warrior River, the Little Cahaba River, and Little River, which has formed one of the deepest canyons in the eastern U.S.  Given that the Plateau makes up such a small portion of Georgia, it is not surprising that riverscour grasslands are not well represented. One tiny patch occurs along Rock Creek downstream of Lula Falls just outside Chattanooga. In Kentucky, riverscour is found on the Big and Little South Forks of the Cumberland River as well as the Rockcastle River. Historically "scours" were also found on other Kentucky streams that have now been flooded by reservoirs. Tennessee is home to the largest and most diverse riverscour grasslands. The best developed ones are on the Big South Fork of the Cumberland River (the lower portion of which is in KY) and its tributaries, the New River and Clear Fork, as well as the Obed and Emory rivers (including their tributaries), and the Caney Fork River. 

Outside of the Cumberland Plateau, riverscour communities can be found in a few other isolated places, such as the Ouachita Mountains of Arkansas and Oklahoma, the Allegheny Plateau of West Virginia and Pennsylvania, a few rivers in the Blue Ridge (e.g. Ocoee, Hiwasee) and Piedmont (Yadkin, Potomac), and the "shut-ins" of the Missouri Ozarks. 

Riverscour grassland also occurs in areas outside the Cumberland Plateau. This beautiful example is from the bank of the South Fourche La Fave River in the Ouachita Mountains of Perry Co., Arkansas. Photo credit: Dwayne Estes.

Riverscour grassland also occurs in areas outside the Cumberland Plateau. This beautiful example is from the bank of the South Fourche La Fave River in the Ouachita Mountains of Perry Co., Arkansas. Photo credit: Dwayne Estes.

Riverscour vegetation varies greatly within the flood zone of a given stream. Imagine standing in the middle of the river in knee-deep water. Often one can find submerged aquatic species such as pondweeds (Potamogeton spp.) and riverweed (Podostemum ceratophyllum). Walking closer to shore in shallow water a few inches deep water-willow (Justicia americana) and golden-club (Orontium aquaticum) often occur, sometimes along with sedges. On the shore itself is a thin sandy shoreline only a couple of feet wide. Here one finds small annual herbs and grasses adapted to fluctuating water levels and moisture content of the sand, but sometimes this zone supports species more at home in the longleaf pine savannas of the Deep South and somewhat unexpected in mountainous terrain: dwarf sundew (Drosera brevifolia), yellow-eyed grasses (Xyris spp.), and bladderwort (Utricularia subulata). 

Now, I know what you're thinking..."Dude, this ain't no stinking grassland!"  Of course, you're right, but just be patient and let the intense richness and diversity of the narrow stream corridor blow your mind.

Stepping across the narrow sand shore and up onto the adjacent bank, you begin to encounter a variety of shrubs intermixed with a showy array of robust herbs. The variation is impressive and somewhat unusual in its mixture. Growing beside typical wetland shrubs like buttonbush (Cephalanthus occidentalis), indigo bush (Amorpha fruticosa), Virgina sweet-spires (Itea virginica), and hazel alder (Alnus serrulata), are species more typical of dry upland woodlands and glades such as ninebark (Physocarpus opulifolius), hawthorns (Crataegus), and shrubby St. Johnswort (Hypericum prolificum). Growing amongst these are cutleaf coneflower (Rudbeckia laciniata), cardinal flower (Lobelia cardinalis), wingstem (Verbesina alternifolia), ironweed (Vernonia gigantea), and other species typical of moist to occasionally wet soils. Again, not a grassland...I know.

The grassland along this riverbank can't be seen in this photo. Just to the left of Chris Mausert-Mooney the riverbank rises just a few feet. Beyond the border of shrubs and stunted trees at left is where we find the riverscour grassland. Photo credit: Dwayne Estes.

The grassland along this riverbank can't be seen in this photo. Just to the left of Chris Mausert-Mooney the riverbank rises just a few feet. Beyond the border of shrubs and stunted trees at left is where we find the riverscour grassland. Photo credit: Dwayne Estes.

The bank that you begin to ascend just two to three feet higher than the nearby stream is built on a deposit of sandstone boulders and cobblestones, with a healthy dose of sand filling the interstices. These cobble bars or boulder bars have been documented to be surprisingly stable over long periods of time, so once formed they are there for a while unlike gravel and sand bars which often shift after major floods events. Within this zone, the sand is kept moist much of the year and sometimes a few small trees might manage to grow up to 10 or 15 ft tall. They often have contorted trunks or in some cases may be bent over at the ground at a right angle but still remain alive. In most years the shrub and trees have old leaves, twigs, and other debris hanging from their branches from the season's floods as this lowest level nearest the stream regularly floods. Still, not a grassland...I get it.

Austin Peay State University graduate student, Chris Mausert-Mooney, squatting beside an ancient flood-beaten but still living eastern redcedar (Juniperus virginiana) growing appressed to the ground amid a highly diverse riverscour grassland along the Big South Fork of the Cumberland River, Scott Co., TN. Photo credit: Dwayne Estes.

Austin Peay State University graduate student, Chris Mausert-Mooney, squatting beside an ancient flood-beaten but still living eastern redcedar (Juniperus virginiana) growing appressed to the ground amid a highly diverse riverscour grassland along the Big South Fork of the Cumberland River, Scott Co., TN. Photo credit: Dwayne Estes.

At this point, turn around and look back at the stream. It's only about 6-20 feet behind you. Now, continue walking as you were.  The elevation of the cobble bar increases a bit more as you walk farther from the centerline of the creek. One thing to notice as you walk is that the largest stones are found immediately in and on the bank of the stream. Some of them may be the size of automobiles. But as you walk farther away the stream center the rock sizes get smaller, grading from large boulder to small cobblestones. At the highest elevation on the bar, which may be anywhere from 5-15 or so feet above normal low water, is where the rock sizes are smallest. As flood waters spread out during floods, smaller particles as sand or gravel are carried farther away from midstream so it is at these highest elevations within the flood zones where we find prominent deposits of sand. Sometimes they occur in nearly pure beds and are reminiscent of sandhill communities or dunes near the coast. 

The soils of these elevated sandy zones drain very rapidly, which means that plants growing in this zone need to be drought adapted. Just beneath the surface of the sand is also a jumbled mass of cobble and boulder which makes it difficult for bulky-rooted plants to survive. These factors along with the intense periodic flash floods that strike multiple times per year (some of which have been documented as having flows of up to 150,000 cubic feet per second) combine to make this zone particularly well-suited for perennial bunchgrasses, herbs, and small shrubs. Finally, this is where we find our grasslands!!!

But before we discuss this unique riparian grassland community, what lies just beyond if you were to keep walking away from stream center? The grasslands tend to occupy narrow zones but can be anywhere from 10-100ft or more wide. Once you cross this narrow swath, two things generally are to be expected. First, you might continue increasing elevation slightly (could vary from several inches to a few feet) until you reach a fairly dense shrub/stunted tree zone that then grades into the forested mountain slope above the river. In other cases, the grassland might occur in the center of a large cobble bar that has a small channel on its back side or on an island where you are again met with alder, buttonbush, indigo bush, river birch, etc.

Tell us more about this so-called riverbank grassland... 

The combination of flooding and rocky, shallow, excessively-drained soils in full sun, makes this zone perfect for grassland vegetation. Anyone who has spent time in prairies of the Midwest would have little trouble in identifying many of the plants in these little riverside prairies. Unlike the vast Midwestern grasslands, however, the largest known riverscour grassland is about one-quarter the size of a football field and most are smaller than the footprint of the average house.

Take one look around and right away many of the familiar prairie grasses are present: big bluestem (Andropogon gerardii), Indian grass (Sorghastrum nutans), little bluestem (Schizachyrium scoparium), switchgrass (Panicum virgatum), and even gamagrass (Tripsacum dactyloides). Dropseed (Sporobolus spp.), numerous species of rosette panic grass (Dichanthelium spp.), muhly grass (Muhlenbergia sylvatica), and river oats (Chasmanthium latifolium) are frequent. Even prairie cordgrass (Spartina pectinata) occurs on some. Additionally, other expected "prairie" species are here, such as blazingstars (Liatris spp.), asters (Symphyotrichum and Eurybia), goldenrods (Solidago), goat's rue (Tephrosia virginiana), and phloxes (Phlox spp.). My favorite herb, not unexpected to my friends I'm sure, is Sundrops (Oenothera fruticosa).  Like many grasslands around the world, these often contain a diverse mixture of shrubs and stunted trees, and even a few species of woody vines, but the grasses form the dominant groundcover.

Species Found Nowhere Else in the World

Black Warrior River Goldenrod (Solidago arenicola) named by Drs. Brian Keener and Robert Kral was originally discovered in riverscour in northern AL along the Black Warrior River. Several years later, it was found more than 150 miles to the north in the Obed River Watershed in Tennessee and along Rock Creek in northwest Georgia. Photo credit: Dwayne Estes.

Black Warrior River Goldenrod (Solidago arenicola) named by Drs. Brian Keener and Robert Kral was originally discovered in riverscour in northern AL along the Black Warrior River. Several years later, it was found more than 150 miles to the north in the Obed River Watershed in Tennessee and along Rock Creek in northwest Georgia. Photo credit: Dwayne Estes.

Several of the plants in riverscour look "different" from non-riparian populations. In the late 1990s, Dr. Brian Keener, then a graduate student at the University of Alabama and now a professor at the University of West Alabama, co-discovered a new species of goldenrod in riverscour habitat along the Locust Fork of the Black Warrior River north of Birmingham. This goldenrod, which he named Solidago arenicola [meaning inhabiting sand in Latin], at first glance resembles the common slender goldenrod (Solidago erecta) which is common in dry woodlands and savannas of the uplands of the Southeast, but differs in certain technical features.

There are numerous other species in riverscour that researchers have realized are different and represent previously undescribed species. For example, the dominant grass in most of the riverscours of Tennessee and Kentucky is a type of big bluestem. Whether it is a new species, a new variety, or merely an ecotype remains to be determined but these riparian plants are unquestionably "different" from non-riparian populations. They are smaller, often topping out at 4-5 ft, have consistently narrower leaves and sheaths that are smooth, have generally fewer spikes in the inflorescence, and the parts of the spikelet (the glumes, lemmas, etc.) have different patterns of venation and hairiness. This riparian big bluestem could be more attractive as a landscape plant due its shorter stature which is not as rank and "floppy" as material in cultivation currently and is probably much more suitable to cultivation in an urban setting, where it is usually avoided. This highlights how there is still much to be offered by studying and exploring wild habitats in the South, particularly grasslands, and how some of these discoveries are relevant to real-world issues.

Right now, researchers are aware of numerous undescribed species in the riverscours of the Cumberland Plateau. On the scourse, they are often very common. For example, a new white-flowered aster similar to the bushy aster (Symphyotrichum dumosum) is abundant on many sites. Canadian licorice-root (Ligusticum canadense) is a member of the carrot family common in eastern woodlands and forests but on the cobble bars there is a clearly different type with strikingly different leaves that represents a new species. It has been observed for decades but is still waiting to be named.

While the new aster and licorice root are common on a few different rivers of Tennessee and Kentucky, other new species are highly localized. A putative new species of flowering spurge (Euphorbia) occurs along the Obed River and its tributary, Daddy's Creek, but is not found outside this watershed.

Cumberland Rosemary (Conradina verticillata) is a narrowly endemic species known from just four counties in Tennessee and one county in Kentucky where it is restricted to Cumberland Plateau Sandstone Riverscour Barrens. Photo credit: Dwayne Estes.

Cumberland Rosemary (Conradina verticillata) is a narrowly endemic species known from just four counties in Tennessee and one county in Kentucky where it is restricted to Cumberland Plateau Sandstone Riverscour Barrens. Photo credit: Dwayne Estes.

One of the most remarkable endemic species in riverscour is a small shrub about a foot tall of the mint family known as the Cumberland Rosemary (Conradina verticillata). This shrub occurs in clonal patches in the sandiest zones. Oddly enough, all other members of the genus Conradina occur hundreds of miles to the south in the sandhills and dunes along the Gulf Coast, especially in Florida. This is the only mountain species in the genus. It begs the question of just how the Cumberland Rosemary evolved?

Out of Place

Within 100 meters of a given riverscour grassland, one can sometimes find species that are far removed from their main range.  For example, in the depths of the Obed River Gorge in Morgan Co., Tennessee, one can find red elderberry (Sambucus pubens), white pine (Pinus strobus), and eastern hemlock (Tsuga canadensis)--all species characteristic of the Northeast and southeastern Canada--growing within close proximity to Deep South species such as Pineland Dropseed (Sporobolus junceus) and Southern Jointweed (Polygonum americanum) which are disjunct by at least 100 miles from their nearest occurrence in north Alabama.

Cumberland Sandgrass (Calamovilfa arcuata) was discovered as a new species in the late 1960s on the Tennessee portion of the plateau. This riverscour endemic, which can be mistaken for switchgrass (Panicum virgatum), has since been found in highly isolated occurrences far removed from its original site of discovery, including southeast Kentucky, north-central Alabama, extreme northwestern Georgia, and then of all places, west-central Arkansas and southeastern Oklahoma.

Refugia for Rare Species

Riverscour grasslands provide refuge for many rare plant species. In the collage below, pictured from left to right, then top to bottom are: Cumberland Rosemary (Conradina verticillata), Rockcastle Aster (Eurybia saxicastellii), Cumberland Sandgrass (Calamovilfa arcuata), Witch Alder (Fothergilla major), Black Warrior Goldenrod (Solidago arenicola), Large-flowered Barbara's Buttons (Marshallia grandiflora), Rock Grape (Viitis rupestris), Old-pasture Bluegrass (Poa saltuensis), Southern Jointweed (Polygonum americanum), Coastal Fetterbush (Euobotrys racemosa), Sweetfern (Comptonia peregrina), Pineland Dropseed (Sporobolus junceus),  Virginia Spiraea (Spiraea virginiana), and Shortleaf Sneezeweed (Helenium brevifolium). These are just a few of the rare species known from riverscour grasslands in Tennessee and Kentucky.

Collage showing a few of the rare species of Tennessee Cumberland Plateau Riverscour Barrens.

Collage showing a few of the rare species of Tennessee Cumberland Plateau Riverscour Barrens.

Green pitcher plant (Sarracenia oreophila) is an example of one of the many rare species that can occur in Cumberland Plateau Sandstone Riverscour habitats. Photo credit: Alan Cressler.

Green pitcher plant (Sarracenia oreophila) is an example of one of the many rare species that can occur in Cumberland Plateau Sandstone Riverscour habitats. Photo credit: Alan Cressler.

Farther south in Alabama, riverscour habitats support some of the same rare species listed above but have a more pronounced influence of species or groups often associated with pine savannas. The Green Pitcher Plant (Sarracenia oreophila), one of the few "mountain-lovers" in the genus Sarracenia, would seem to most people to be out of place in a rocky mountain gorge given that most of the species in the genus are found in the Deep South pinelands. But in Little River Canyon National Preserve in northeast Alabama, Green Pitcher Plant can be found growing directly in riverscour habitats in the depths of the gorge in and among saturated sands and cobblestones. Here it grows with other plants out of place such as sundews (Drosera spp.), five species of yellow-eyed grass (Xyris spp.), pipwort (Eriocaulon), and whitehead bogbutton (Lachnocaulon anceps). 

The South's Last Frontier

Riverscour habitats represent one of the last frontiers of the eastern American botany. Just getting to them and studying them has proven to be very challenging. There are many dangers in surveying Appalachia's understudied canyons. In one hike along a 3-mile stretch of the Obed River Gorge in 2007, 11 copperheads were observed. The countless rocks, logs, and steep slopes present an constant risk of breaking bones but fortunately we've always gotten out unscathed. It took us quite a while to master how to get down gorges safely. Riverscours never cease to surprise us. One particularly deep pool in the Obed River that we knew was deep turned out to be 64 feet deep. Currents and flash floods are always a concern given the remoteness of these gorges and the fact that once you are in the depths of a gorge if something goes wrong it can be very difficult to get out quickly. Planning is definitely something we've gotten good at. 

It is no wonder that the grasslands of these remote river canyons are among the least understood in eastern North America. My students have found that every Cumberland Plateau river with rivescour vegetation is really quite unique. Grasslands on different rivers separated by just a few miles are often very different floristically and structurally. One thing they all share in common though is that they are packed with species. A single 10 x 10 meter plot of open grassland can have more than 50 species of flowering plants. Adjacent flood-scoured shrublands and woodlands with open grassy and herb-rich ground layers can harbor as many as 80 species in the same area. 

Recently my graduate students and I have wrapped up surveys of four rivers: Big South Fork River of KY and TN (Chris Mausert-Mooney), Daddy's Creek of TN (Devin Rodgers), Caney Fork River of TN (Mason Brock), and the Locust Fork of the Warrior River of AL (Kelly Anderson). Recently, my student Zach Irick has begun surveying Little River in northeast AL and in 2018 we will be surveying the Clear Fork of the Big South Fork of the Cumberland River, helping to add to the already excellent work carried out by Claude Bailey Jr. several years ago.

Stay tuned for more highlights from riverscour grasslands...

Riverscour grassland along the Caney Fork River, White Co., TN showing transition from open water and exposed boulders at left to shrubby zones on the bank to grassland farther away from the river. Photo credit: Dwayne Estes.

Riverscour grassland along the Caney Fork River, White Co., TN showing transition from open water and exposed boulders at left to shrubby zones on the bank to grassland farther away from the river. Photo credit: Dwayne Estes.

Contributed by: Dwayne Estes

#3 Nashville Basin Limestone Savanna

Savanna-like landscape, Inner Nashville Basin, Couchville Glades and Barrens State Natural Area, Davidson Co., TN. Photo credit: Will McClatchey.

Savanna-like landscape, Inner Nashville Basin, Couchville Glades and Barrens State Natural Area, Davidson Co., TN. Photo credit: Will McClatchey.

"Glades don't burn..."

"Glades don't burn," said one of my undergraduate professors at Middle Tennessee State University in 2002, in response to my question about whether fire would be an appropriate management tool in the limestone glade ecosystem of central Tennessee's Nashville Basin.

Not being educated enough at that point in my career to articulate a response, I accepted the answer and then went about my way repeating the same mantra to others for the next several years. But then, in autumn 2008, my perspective changed.

Theo Witsell, botanist for the Arkansas Natural Heritage Commission and now also Director of Research for SGI, came to Nashville for the 2008 Natural Areas Conference. While in town, he visited the limestone glades southeast of Nashville during one of the conference field trips. I wasn't along on the same trip as he but afterward he asked, "what's going on with your glades?"

"What do you mean?" I asked.

He said, "there is an impenetrable thicket around each glade. In Arkansas, we are managing glade complexes with prescribed fire. There should be grassy savanna and open woodland around the edges of glades rather than an abrupt wall of redcedar and impenetrable shrub thickets."

My reply? "No way man. Glades don't burn. Fire is not important in these communities. Glades are edaphically maintained."

As you can see, I was repeating what I had been told a few years earlier.  By this point, I was in a much better position to argue my point after having read extensively the papers of renowned cedar glade ecologists, Jerry and Carol Baskin (Univ. of KY), and their mentor, Dr. Elsie Quarterman (Vanderbilt Univ.), none of whom considered fire important in the ecology of limestone glades. 

Typical limestone "cedar" glade, Flatrock Glades & Barrens State Natural Area, Rutherford Co., TN. Note how the open rocky grassland--the glade proper--is surrounded by nearly impenetrable thickets of eastern redcedar and shrubs (glade privet, fragrant sumac, Chinese privet). In the foreground, the glade is dominated by one of numerous endemic species, in this case the Nashville Breadroot (Pediomelum subacaule). The closest relative of this species, Pediomelum esculentum, is found mostly in the Great Plains. Photo credit: Alan Cressler.

Typical limestone "cedar" glade, Flatrock Glades & Barrens State Natural Area, Rutherford Co., TN. Note how the open rocky grassland--the glade proper--is surrounded by nearly impenetrable thickets of eastern redcedar and shrubs (glade privet, fragrant sumac, Chinese privet). In the foreground, the glade is dominated by one of numerous endemic species, in this case the Nashville Breadroot (Pediomelum subacaule). The closest relative of this species, Pediomelum esculentum, is found mostly in the Great Plains. Photo credit: Alan Cressler.

Theo explained that in Arkansas and Missouri, they manage glades of various types (shale, sandstone, igneous, dolomite, limestone) with fire. He acknowledged that while the glade proper may not burn due to high abundance of rock and paucity of fuels, that they routinely manage the surrounding habitats with fire, with much success.

He pulled out his computer and showed me a couple of PowerPoint presentations that showed dense thickets around glades that were thinned heavily leaving only a few scattered hardwoods (particularly post, blackjack and chinkapin oaks) and then burned. The before and after photos were dramatic and conservative grassland species rebounded quickly where previously there was very little herbaceous diversity.  The resulting structure was a complex of glades embedded in open grassy savannas or very open woodlands, characterized by scattered twisted and gnarled old oaks, with a nearly continuous and rich graminoid/herb layer, punctuated throughout with scattered shrub thickets.

Gattinger's Prairie Clover (Dalea gattingeri) is endemic to the most open and exposed parts of limestone glades and is capable of growing in cracks among limestone pavement or gravel glades. Photo credit: Sunny Fleming.

Gattinger's Prairie Clover (Dalea gattingeri) is endemic to the most open and exposed parts of limestone glades and is capable of growing in cracks among limestone pavement or gravel glades. Photo credit: Sunny Fleming.

Meanwhile, I began to contemplate my own experiences in the limestone glades of central Tennessee. Much of the focus in limestone glades of central Tennessee (and for that matter in other limestone glades of the Southeast such as the Moulton Valley of north AL, the Ridge and Valley of e. TN, sw. VA, and nw. GA, and the Pennyroyal Plain of sc. KY) has always been on the open glades proper, characterized by high exposures of bedrock or broken gravel/flagstone. It was in these situations where the majority of the endemic glade species occur. Species such as Nashville Breadroot (Pediomelum subacaule), Gattinger's Prairie Clover (Dalea gattingeri), and Limestone Fameflower (Phemeranthus calcaricus) are just three of more than two dozen endemics. While these species are geographically restricted they are often not rare in the glades and may in fact be dominant. This is true of many of the other glade endemics.

Wavy-leaved Purple Coneflower (Echinacea simulata) is a species that prefers glade margins and deeper soiled areas. Photo credit: Dwayne Estes.

Wavy-leaved Purple Coneflower (Echinacea simulata) is a species that prefers glade margins and deeper soiled areas. Photo credit: Dwayne Estes.

But a second class of species often considered rare within the limestone glades are species that are often much more widespread geographically but their populations in the glades are either at the edge of the main range or they are disjunct-far removed-from the main set of populations of that species. Species such as White Four O'Clock (Mirabilis albida), Prairie Gentian (Gentiana puberulenta), Gattingeri's Goldenrod (Solidago gattingeri), Purple Prairie Clover (Dalea purpurea), Prairie Dropseed (Sporobolus heterolepis), and Wavy-leaved Purple Coneflower (Echinacea simulata) are each very rare in the limestone glades of central Tennessee. The main geographic distributions of these species is to northwest or west of central Tennessee, in the Midwestern tallgrass prairies or Ozark barrens and glades.

Prairie Dropseed (Sporobolus heterolepis), growing in deeper-soiled margin of limestone glade, Flatrock Glades and Barrens State Natural Area, Rutherford Co., TN. Photo credit: Dwayne Estes.

Prairie Dropseed (Sporobolus heterolepis), growing in deeper-soiled margin of limestone glade, Flatrock Glades and Barrens State Natural Area, Rutherford Co., TN. Photo credit: Dwayne Estes.

Unlike the endemic species that require the open shallow-soiled habitats, these species tend to occupy deeper-soils (but still shallow and rocky by comparison with richer soils in the region) of sloping limestone barrens or glade edges, sites dominated by perennial grasses and shrubs versus the annual grass dominated open glade habitats. For a definition of glades vs. barrens adopted by SGI see https://www.segrasslands.org/guide-to-the-grasslands-of-the-midsouth/

Tennessee Coneflower (Echinacea tennesseensis), like most other species of coneflowers, prefers deeper soils than most of the open glades afford. The presence of this narrowly endemic species in the Nashville Basin suggests a long history of the presence of open savannas.

Tennessee Coneflower (Echinacea tennesseensis), like most other species of coneflowers, prefers deeper soils than most of the open glades afford. The presence of this narrowly endemic species in the Nashville Basin suggests a long history of the presence of open savannas.

It is this second class of species, not the majority of the limestone glade endemics, that are on the brink of disappearing entirely from the Basin. There are a few notable exceptions to this. The former federally-threatened Tennessee Coneflower (Echinacea tennesseensis), the federally-endangered Pyne's Groundplum (Astragalus bibullatus) and Limestone Clover (Trifolium calcaricum) are exceptions. They are all very narrow endemics and the clover and groundplum are each known from only a handful of populations and are both struggling to survive. 

Limestone Clover (Trifolium calcaricum) occurs in just four counties worldwide, with three confined to the Nashville Basin where it is known from about five populations. This species inhabits cedar thickets and shrub thickets and edges of glades. It has declined drastically from a century ago when it was described as common. Photo credit: Dennis Horn.

Limestone Clover (Trifolium calcaricum) occurs in just four counties worldwide, with three confined to the Nashville Basin where it is known from about five populations. This species inhabits cedar thickets and shrub thickets and edges of glades. It has declined drastically from a century ago when it was described as common. Photo credit: Dennis Horn.

What is presumably the Limestone Clover was described by Augustine Gattinger in 1901 as "very common in the glades of middle Tennessee." Today, however, it is known from just three counties in Tennessee from five or fewer populations. Pyne's Groundplum is known today from a single county from about five populations. 

Recent work by the Matthew Albrecht and Quinn Long of the Missouri Botanical Garden showed that Pyne's Groundplum, which often occurs near glade edges, benefits from manual removal of shrub and woody plant cover. Similar work needs to be done for the clover, for at least a couple of the populations I've observed are extremely suppressed with limited flowering and a high incidence of vegetative growth, presumably because they aren't getting enough light. In both species, reproduction seems very limited.

Pyne's Groundplum (Astragalus bibullatus), originally described by Edwin Bridges and Rupert Barneby in 1989, is a federally-endangered species known from just a handful of populations all in the vicinity of Murfreesboro, Rutherford Co., TN and nowhere else in the world. Recent research shows this species prefers glade margins but benefits from removal of woody plants. Photo credit: Dwayne Estes.

Pyne's Groundplum (Astragalus bibullatus), originally described by Edwin Bridges and Rupert Barneby in 1989, is a federally-endangered species known from just a handful of populations all in the vicinity of Murfreesboro, Rutherford Co., TN and nowhere else in the world. Recent research shows this species prefers glade margins but benefits from removal of woody plants. Photo credit: Dwayne Estes.

Albrecht and Long dug a little deeper into the history of the limestone glades of Rutherford County, Tennessee (literally the epicenter of limestone glades) to search for extra clues to explain their results. They examined witness tree records in the local archives from the late 1700s. What they found is that redcedar accounted for just 2 percent of the reported trees in those early land surveys. Oaks were most common, followed by "stakes." In those days, many of the land grants in the region were being awarded to Revolutionary War soldiers from North Carolina. Surveyors would mark off the boundaries of a given property and would note the tree species (witness trees) on the property boundary. When surveyors were delineating property boundaries, if they encountered open areas with no trees they would use a wooden "stake" to mark the boundary. In rocky areas, like the glades, they also frequently used "stacks" of rocks in similar fashion. Therefore, the relative abundance of stakes or stacks in early land surveys can be used to infer openness of the historical landscape. 

Recently, a team of three historians from the Nashville area, published an incredible body of work. They spent decades studying and mapping tens of thousands of land survey records in the State Archives in Nashville for most of Middle Tennessee and published their work in four separate books and supplements. Check their website for more details (http://www.cumberlandpioneers.com/). Their work covers the period from 1789-1804 and spans properties from the Kentucky line in the north to the Alabama line in the south and includes all of the Nashville Basin. SGI is working to have these survey records entered into ArcGIS so we can see patterns of concentrations of stakes, etc. These records support the findings of Albrecht and Long and preliminary assessment of the relative abundance of stakes and stacks and oaks (particularly post oaks) indicates that major portions of the Nashville Basin were open at the time of first settlement of the region. 

Example of Revolutionary War land survey from near Nashville published recently by Drake et al. (http://www.cumberlandpioneers.com/). For each record they provide a copy of the original hand-drawn survey map. Many of the topographic features such as streams or salt licks were first named by these surveyors. They also transcribed the original hand-written notes. This survey is of a property in what is now Davidson Co., TN (Nashville area) but at the time of the survey in 1786 it was part of the state of North Carolina. 

Example of Revolutionary War land survey from near Nashville published recently by Drake et al. (http://www.cumberlandpioneers.com/). For each record they provide a copy of the original hand-drawn survey map. Many of the topographic features such as streams or salt licks were first named by these surveyors. They also transcribed the original hand-written notes. This survey is of a property in what is now Davidson Co., TN (Nashville area) but at the time of the survey in 1786 it was part of the state of North Carolina. 

These open landscapes weren't restricted to areas around limestone glades. Surprisingly, the land survey data suggests other areas traditionally thought to be heavily forested were also open. For example, a large section of southwestern Rutherford County was recorded as open in these early land surveys and it remains one of the few areas in the state with Mollisol soils (Caitlin Elam, TN Division of Water Resources, pers. comm.), soils that are characteristic of Midwestern grasslands. Even some portions of the Outer Nashville Basin, areas with deep, phosphate-rich soils, may have been open or partially open. The upscale community of Belle Meade (=beautiful meadow) is one such Outer Basin opening. Numerous significant Paleoindian archaeological sites, Woodland Era Sites, and Mississippian Culture sites are located in these richer sections of the Outer Basin.

Open areas associated with glades were likely maintained by a combination of lightning fires in the region. The vegetation is often parched and drought stressed while those of stream valleys in deeper, richer soil were probably maintained by Native American burning. Fire compartment sizes in the Basin are relatively large and fires once started could have burned sizable portions of land. The combination of these factors, combined with the abundance of bison that congregated around the hundreds of natural salt licks, probably kept the Basin in a much more open state.

Recently, Edwin Bridges, a phenomenal botanist with experience throughout the Southeast and formally employed by the Tennessee Natural Heritage Program in the 1980s, shared a portion of a manuscript that he wrote in the late 1980s. Bridges co-described Pyne's Groundplum as a new species and in his original manuscript he had a section in the paper that he intended to be a part of his publication, but that reviewers suggested he remove. The section included a discussion of why he thought the Nashville Basin was much more open historically. It is unfortunate that this element of his paper was excluded from his final publication because it could have helped create a paradigm shift nearly 30 years ago, instead of that shift happening just within the past five years.

So, aside from the land survey data and anecdotal observations (experimental in the case of Pyne's Groundplum), what other evidence do we have in support of there historically being extensive savannas in the Nashville Basin?

Ordinarily, we would ideally go back and search for descriptions by early naturalists. The earliest references I've been able to find and that are reported in the primary papers on cedar glade ecology (e.g. the Baskins, Quarterman papers) date to just after the Civil War. Unlike some areas of the South (e.g. Georgia and the Carolinas), where there are excellent descriptions of the landscape and vegetation from times of early settlement, there are apparently no such descriptions from the Nashville Basin prior to the Civil War other than very vague references to salt licks near Nashville. 

James M. Safford, the State Geologist for Tennessee after the Civil War, published extensively on the geology and physiography of the state during that period. He mentioned glades and noted that they were surrounded by forests of large redcedars. It is my opinion that this report was taken by later researchers, such as Quarterman and the Baskins, and used to justify that the matrix vegetation around glades should be dense forests with a high abundance of redcedar--a paradigm which endured throughout the 20th century even up until about five years ago, but one that contrasts sharply with evolving concepts that the glades were embedded in savannas, not dense forests. These forests and woodlands, which may be artificial in part, are recognized as a globally rare community by NatureServe, the Redcedar-Blue Ash Limestone Woodland.

The Redcedar-Blue Ash Woodland, recognized as a rare community (G3) by NatureServe, may in fact be somewhat an artifact of fire suppression, though this woodland probably would have been the natural type in some extremely rocky woodlands with abundant karst exposures that would have been difficult for fire to move through. Photo credit: Dwayne Estes.

The Redcedar-Blue Ash Woodland, recognized as a rare community (G3) by NatureServe, may in fact be somewhat an artifact of fire suppression, though this woodland probably would have been the natural type in some extremely rocky woodlands with abundant karst exposures that would have been difficult for fire to move through. Photo credit: Dwayne Estes.

One thing to keep in mind is that the Nashville Basin was settled in the 1780s-90s, some 70-80 years before Safford's description. This is plenty of time to allow for growth of large cedar trees in response to fire suppression that commenced right after settlement, which has been documented elsewhere across the South soon after settlement.

So, I contend that the conservation paradigm that we've held close to for so long now, that of not using fire in the glades, was based off descriptions of an already artificial landscape, greatly altered from its original state. How much harm has been done to the species of plants and animals (Northern Bobwhite, Eastern Meadowlark) that need more open conditions as a result of this paradigm?

Old-growth post oak (Quercus stellata), Couchville Glades and Barrens State Natural Area, Nashville, Davidson Co., TN. Note the heavy, contorted side branches. In spite of their relatively small size, these trees could easily be 200+ years old as they are growing in extremely harsh conditions and are very slow growing. In the background thicket, such trees can still be found. Removal of cedar thickets and leaving these old oaks, combined with restoration of fire, has been demonstrated to do an effective job of restoring some limestone savanna in the Nashville Basin. Photo credit: Dwayne Estes.

Old-growth post oak (Quercus stellata), Couchville Glades and Barrens State Natural Area, Nashville, Davidson Co., TN. Note the heavy, contorted side branches. In spite of their relatively small size, these trees could easily be 200+ years old as they are growing in extremely harsh conditions and are very slow growing. In the background thicket, such trees can still be found. Removal of cedar thickets and leaving these old oaks, combined with restoration of fire, has been demonstrated to do an effective job of restoring some limestone savanna in the Nashville Basin. Photo credit: Dwayne Estes.

If we look around the Nashville Basin, we can still see signs of the former savannas. Buried among the dense cedar thickets one can often find gnarled post oaks, chinkapin oaks, or even rarely blackjack oaks, that have heavy side branches, contorted trunks, and wide branches. It is entirely possible that many of these trees date to the period of first settlement. A dendroecological study is needed to be sure. There is no shortage of these old-growth trees throughout the Basin and many can be seen within the eastern city limits of Murfreesboro. Post oaks are most common in the rockier ground or areas with hydroxeric soils due to presence of a fragipan, which combined tend to occur in what is known as the Inner Nashville Basin (the heart of the glade ecosystem). In the deeper and richer-soiled Outer Nashville Basin, one tends to see large Chinkapin Oaks and an absence of Post Oak. In and north of Nashville in mesic areas along creeks or in pastures large Bur Oaks are sometimes seen. These three species are all known to be associated with savanna habitats in other parts of the eastern and midwestern US.

Another clue can be found along a few streams and rivers in the Basin. In southern Rutherford County along Dry Fork Creek and West Fork Stones River, the streambanks are lined in many areas with stands of Eastern Gamagrass (Tripsacum dactyloides). This species is most often associated with moist grasslands. This provides a clue that Gamagrass might have at one time been an important grass in deeper-soiled natural grasslands, meadows, and mesic savannas prior to the widespread introduction of European cool-season grasses such as fescue and bluegrass. 

And perhaps the best clue of all is that there are still a couple of remnants of dry, rocky, savanna in the Inner Basin, but this grassland type no doubt remains as one of the rarest and most imperiled natural grasslands in the Southeast. Perhaps the best example can be seen east and southeast of the city of Murfreesboro. Along Factory Road, which incidentally is not far from one of the original localities where Edwin Bridges reported Pyne's Groundplum, is a remnant savanna of several acres. This savanna is located on private property directly adjacent to the road and across from Flatrock Glades and Barrens State Natural Area. 

Top row: Limestone savanna along Factory Rd, Rutherford Co., TN with scattered post oaks. Note with fire the redcedar would not be nearly as abundant. Lower left: Baptisia aberrans (Blue Wild Indigo) is indicative of savanna. Bottom row, second from left: savanna at Gladeview Barren, Rutherford Co., TN. Second from right, bottom: Muhlenbergia capillaris grows in restored savanna at Flatrock Glades and Barrens State Natural Area. Bottom right: old-growth but small Chinkapin Oak, Couchville Glades and Barrens State Natural Area, Nashville, Davidson Co., TN. All photos by: Dwayne Estes.

The Rough Rattlesnake Root (Nabalus asper) was recently discovered in limestone savanna at Flatrock Glades & Barrens State Natural Area by Dr. Ashley Morris (Middle Tennessee State University). This species is endangered in Tennessee. Restoration of savanna on this protected natural area will greatly benefit this species that, under the conservation paradigm of the last 50 years, would probably have otherwise disappeared. It now has hope. Photo credit: Ashley Morris.

The Rough Rattlesnake Root (Nabalus asper) was recently discovered in limestone savanna at Flatrock Glades & Barrens State Natural Area by Dr. Ashley Morris (Middle Tennessee State University). This species is endangered in Tennessee. Restoration of savanna on this protected natural area will greatly benefit this species that, under the conservation paradigm of the last 50 years, would probably have otherwise disappeared. It now has hope. Photo credit: Ashley Morris.

This roadside probably looks to many like a typical rocky pasture to most, but a closer examination shows scattered post and chinkapin oaks, a lack of dense shrubs and redcedars, and a rich groundcover of grassland species that prefer deeper (but again still shallow and rocky) soil than those typical of open glades. Within this "field" are several small limestone glades that harbor typical glade endemics. This savanna remnant contains Glade Blue Wild Indigo (Baptisia aberrans), Gray-headed Coneflower (Ratibida pinnata), Cutleaf Prairie Dock (Silphium pinnatifidum), Wavy-Leaved Purple Coneflower (Echinacea simulata), and Naked-Stem Sunflower (Helianthus occidentalis). Across the road in the natural area are more species characteristic of limestone savanna, including Boykin's Milkwort (Polygala boykinii), Rough-leaved Rattlesnake Root (Nabalus asper), Prairie Gentian (Gentiana puberulenta), Cylindrical Blazingstar (Liatris cylindracea), and Prairie Dropseed (Sporobolus heterolepis). It seems that the most important native grasses in these xeric calcareous savannas is Little Bluestem (Schizachyrium scoparium) and Sideoats Grama (Bouteloua curtipendula). Prairie Dropseed was probably more frequent at one time.

The usual dominant grasses of Midwestern savannas, such as Indian Grass (Sorghastrum nutans) and Big Bluestem (Andropogon gerardii) are surprisingly rare in the Nashville Basin. Big bluestem is abundant southeast of Murfreesboro at what Dr. Hal R. DeSelm (Univ. of Tennessee) called the Gladeview Barren, named for the nearby Gladeview Church. At this site are other indicator species of savanna, as opposed to glades, including several of the species noted above, but also one of the few places in Tennessee for Purple Prairie Clover (Dalea gattingeri), Gattinger's Goldenrod (Solidago gattingeri), and White Four O'Clock (Mirabilis albida).  The deeper-soiled rocky grasslands at Gladeview are dominated by Big Bluestem and Indian Grass.

The savannas of the Nashville Basin are truly rare and nearly extinct ecosystems. There were likely at least three or four types of savanna. Dry, rocky, areas with several inches of soil over bedrock supported xeric Post Oak Savanna. There are definite relicts of this community here and there throughout the Basin, though intact sites more than a fraction of an acre in size are nearly non-existent. The savannas of deeper, richer, moister soils are gone. They represent an extinct ecosystem and there are no intact remnants. A future blog will discuss how we are working to re-imagine this historical community and how we hope to rebuild it at sites in and around Nashville. The third type, wet calcareous savannas, likely developed over fragipan soils at a few select spots in the Inner Basin. With fire suppression these likely developed into close-canopied forested wetlands. Very small and fragmentary examples exist still of this essentially extinct community. Mostly they exist today as wet or seasonally wet meadows with an abundance of sedge and rush diversity, but their original composition has been greatly altered and we will never know what they were truly like.

One of the goals of the Southeastern Grasslands Initiative is to bring these lost ecosystems to light, to help coordinate and fund conservation efforts on the ground, to help fund the research needed to inform conservation, and to lead efforts to build essential seedbanks needed for conservation projects. 

The staff of the Tennessee Division of Natural Areas have already shown it is possible to restore these savannas with their efforts at Flatrock State Natural Area. By using heavy machinery to remove thickets of recedar in combination with prescribed fire they have been able to restore savanna conditions. Several conservative species are recolonizing what were thickets.

Brian Bowen and Todd Crabtree of the Tennessee Division of Natural Areas discuss the agency's approach to savanna restoration at Flatrock Glades and Barrens State Natural Area, Rutherford Co., TN. Photo credit: Dwayne Estes.

Brian Bowen and Todd Crabtree of the Tennessee Division of Natural Areas discuss the agency's approach to savanna restoration at Flatrock Glades and Barrens State Natural Area, Rutherford Co., TN. Photo credit: Dwayne Estes.

We believe that we will be able to restore this forgotten part of the history of Middle Tennessee. It was this open landscape that Mississippian-era Native Americans called home up until the 1400s. It was the mutual hunting grounds of the Shawnee, Cherokee, Creek, Koasati, and Chickasaw tribes for centuries. It was in this open landscape that the bison roamed and carved traces that are today's highways and the abundant salt licks (like French's Lick which became downtown Nashville) that supported abundant game served as one of the main attractants for the earliest French and English explorers in the 1700s. 

In rebuilding these lost ecosystems, we have the capacity to not only improve habitat for critically rare birds or birds once common but now in severe decline (e.g. Northern Bobwhite, Eastern Meadowlark) and rare plants, but we have the opportunity to tell an essential part of our early history, which presently cannot be shown to anyone because it really doesn't exist in an intact form. 

There is no single place one can go now to learn more about these extinct savannas. There are no museum exhibits dedicated to them. There are no historical roadside markers that read "here was once extensive savanna." The remnants themselves and the sites that can be restored are fortunately still here and can serve as living museums and classrooms. 

There is still hope...

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Dr. Ashley Morris (Middle Tennessee State University) and her colleagues with MTSU's Center for Cedar Glade Studies are working to document the flora of Flatrock Glades State Natural Area. Her stunning photo shows Wavy-Leaved Coneflower (Echinacea simulata) and Gray-Headed Coneflowers (Ratibida pinnata) in spectacular display in the recently restored savannas.

Dr. Ashley Morris (Middle Tennessee State University) and her colleagues with MTSU's Center for Cedar Glade Studies are working to document the flora of Flatrock Glades State Natural Area. Her stunning photo shows Wavy-Leaved Coneflower (Echinacea simulata) and Gray-Headed Coneflowers (Ratibida pinnata) in spectacular display in the recently restored savannas.

#2 Blue Ridge Montane Basins Shortleaf Pine-Post Oak Savanna

Blue Ridge Mountains Montane Basins Shortleaf Pine-Post Oak Savanna (background). Foreground is an acidic seepage slope grassland.

Blue Ridge Mountains Montane Basins Shortleaf Pine-Post Oak Savanna (background). Foreground is an acidic seepage slope grassland.

#2. Blue Ridge Montane Basins Shortleaf Pine-Post Oak Savanna

The second grassland featured here is one that is extremely poorly known. The Montane Basins Ecoregion comprises portions of southwestern North Carolina near Hayesville, northern Georgia, and extreme southeastern Tennessee (Copper Basin).

The historical vegetation of this ecoregion needs to be clarified (at least it does for me!). One of the earliest references to vegetation from this region is the 1818 boundary survey of the Georgia state line. Surveyors recorded shortleaf pine and post oak in TN in this ecoregion. Witness tree records from the Georgia Land Lottery need to be evaluated for this area to see what species were common prior to 1850. A high incidence of shortleaf pine and post oak would suggest adaptation to fire.

Much of the original vegetation of the Montane Basin ecoregion has long been altered. The broad rolling basin supports more agriculture compared to more mountainous areas nearby. The Copper Basin of Tennessee was devastated in the late 19th-early 20th centuries by the copper mining industry. The trees in the basin were harvested to fuel the smelting of copper ore and the sulfuric acid pollution killed much of the original vegetation.

Today, it is common to see species indicative of grasslands/savannas/open woodlands on roadsides and powerline corridors (e.g. Baptisia albescens, B. tinctoria, Sorghastrum nutans and S. elliottii, Liatris spp., etc.).

In Towns Co., GA along Chatuge Lake is an example of what may have at one time been a more savanna-like setting and that may be one of the few high-quality grassland remnants remaining in the ecoregion.

The site is the Basin proper and you must walk through an old field to get to it. Once past the blackberries, fescue, Johnson grass, and other weedy species, you enter a diverse, short-statured dry grassland.

Here grows the highly conservative American Bluehearts (Buchnera americana), prairie willow (Salix humilis) and a diverse array of native grasses, goldenrods, asters, thoroughworts.

This small-patch grassland is prone to being easily dismissed and overlooked because on its downslope side it grades into a seepage slope grassland (a type of slope wetland) that includes such rarities as green pitcher plant (Sarracenia oreophila), coreopsis rosea, sundews, yellow-eyed grasses, and ten-angle pipewort (Eriocaulon decangulare). More about this wet grassland community later....

In the meantime, more work is needed to better understand this extremely rare Blue Ridge grassland. Additional examples should be sought and consideration given to restoration. Unlike most of the surrounding mountain land which is largely owned by the US Forest Service, most of the basin lands are in private ownership, complicating conservation efforts.

#1 Blue Ridge Serpentine Barrens

Buck Creek Serpentine Barren, Blue Ridge Mountains Ecoregion, Clay Co., North Carolina. Credit: Alan Cressler.

Buck Creek Serpentine Barren, Blue Ridge Mountains Ecoregion, Clay Co., North Carolina. Credit: Alan Cressler.

To highlight the incredible diversity of Southeastern grasslands, SGI will feature a different grassland system each day, from now until the New Year.

Let's get this party started by introducing what may be one of the rarest of all grassland types in the world:

#1. Blue Ridge Mountains Serpentine Barrens.

This community is represented by just a couple of examples in western North Carolina with one of these, Buck Creek Barrens, Clay Co., NC being of exceptional quality.

This mountainside grassland is located in the Nantahala National Forest between the towns of Franklin and Hayesville at approximately 3,000 ft elevation. The heavy metals in the soil resulting from the underlying serpentine rock combined with shallow soils, make these steep mountainsides more suitable to open woodlands and grassy barrens instead of forests.

Two plant species, Rhiannon's Aster and the Buck Creek Ragwort, are found only here and nowhere else in the world. The site is home to an incredible array of species more typically found in open prairies. Here, big bluestem, little bluestem, switchgrass, and Indian grass are dominant but prairie dropseed is also abundant. Numerous rare species are found here, including several that are far removed from their main territory.

This site is currently being managed by the US Forest Service with prescribed fire.

For more photos of this incredible barren, check out Alan Cressler's FLICKR page: https://www.flickr.com/…/alan_cres…/albums/72157627172534334

The Clarksville, Tennessee newspaper, the Leaf Chronicle, features the Southeastern Grasslands Initiative and its local impact on the Clarksville community (authored by Jimmy Settle, 2 June 2017)

Dwayne.png

Dwayne Estes, executive director of the Southeastern Grasslands Initiative at APSU, stands in a field at Dunbar Cave on May 30, 2017. In a few years, the 15 acres of land will be restored to a prairie grassland. (Photo: Erica Brechtelsbauer / USA TODAY NETWORK - Tennessee)