Posts Tagged ‘Bibb County Glades’

Bibb County Glades

Thursday, July 11th, 2013

Bibb County Glades

guest post by intern Ian Hazelhoff

On June 1, I was fortunate to attend the annual Bibb County Glades field trip for the Certificate in Native Plant Studies program.  Fred Spicer and John Manion led the charge on a spectacularly overcast day prime for botanizing.  Several other enthusiastic individuals, ranging from Master Gardeners to The Gardens’ Director of Library Services, Hope Long, filled in the ranks of our troop.  Insect repellant was applied, wide-brimmed hats adjusted, and introductions were shared.  In total, the fieldtrip itinerary listed three glade sites and concluded with a tour of the Cahaba River’s largest lily site.  Ambitious and driven by a unanimous desire to see some of the nation’s rarest plant species in habitats as unique as separate planets, we entered the glades.

To comprehend fully how this beautiful suite of rare plants can exist in such obscurity takes an understanding of this unique landscape.  The Bibb County Glades sit perched on small veins of a rock named Ketona dolomite, which possess higher concentrations of magnesium than more regionally common formations of limestone. Species that thrive in magnesium rich soils are prevalent.  The glades are also an “ecotone” region, where full forest environments gradually transition to more open, grassy areas.  Nestled within this gradient are species specialized to thrive with exposure to more light and wind.  Without a complete tree canopy, the glades represent an assemblage of highly specialized succession species existing in near total isolation. 

In areas with Ketona dolomite based substrate, magnesium and often aluminum levels are so high as to be toxic to many more common species found in the region.  As a historical note, Fred Spicer pointed out that seams of Ketona dolomite were once found scattered throughout Jefferson County, AL, however, these were the first to be mined during Birmingham’s steel boom.  Dolomitic limestone is a precursor material for steel production, and to think that it also supports the livelihood of some of the rarest plants on Earth!  With visions of steel furnaces and open pit mines at the helm, I quickly became aware of the true importance and special nature of the Bibb County Glades. 

As the fieldtrip came to a close, I found myself traveling the winding waterside road to see one of my home state’s secret treasures: Cahaba lilies blooming in their prime.  Pockets of lilies, with proud green stalks and exuberant white flowers, dotted the river’s center.  John Manion was quick to point out that the heaviness of the lily’s seed allows it to sink and become lodged between rocks on the river’s bed.  Cool water, sand, and fields of aquatic botanical wonder - not bad for a day at the office.

To learn more about the Certificate in Native Plant Studies series, and to register for any of its core classes, electives or field trips online, visit www.bbgardens.org/plantstudies.

Photos: Beth Maynor Young

Glade Hopping in Bibb County

Friday, July 27th, 2012

Glade Hopping in Bibb County

by: Hunter McBrayer

I recently had the opportunity to botanize at the Bibb County Glades in Bibb County, Alabama, with a small group of plant enthusiasts from The Gardens.  We rendezvoused with Tom Diggs, a doctoral student at The University of Alabama at Birmingham studying evolutionary biology.  Tom’s research is on the unique array of plants growing at The Glades and the reasons so many of them are endemic to the area. 

The Bibb County Glades are truly a remarkable anomaly in the Alabama landscape.  Largely ignored by humans until 1992, the glades were considered a treeless barren by most people of that region until Jim Allison, a botanist from Georgia, explored the area.  He noticed that several familiar looking plants, upon closer inspection, were unknown species.  He continued exploring the area and eventually discovered eight new species of plants; a rare occurrence in today’s world of plant exploration.  

Many factors contribute to the fact that the area holds so many endemic plants, but most scientists agree that the primary reason for such a high degree of endemism is the unique substrate on which they grow. Ketona limestone, a very specific type of dolomitic limestone, is the primary geological formation underlying The Glades’ very thin soil; the type of limestone contains very high levels of magnesium.  In addition to the preceding factor, arid climate has contributed to the unique evolution of plants that thrive there. One third of Alabama’s twenty-four endemic plant species are found growing at The Glades, which collectively comprise approximately 250 acres.  

Although some of these plants were already past flowering, we still had the opportunity to view several of them in flower.  This list includes Coreopsis grandiflora var. inclinata, reclining large-flowered tickseed; Dalea cahaba, Cahaba prairie clover; Croton alabamensis var. alabamensis, Alabama croton (a somewhat ubiquitous plants The Gardens); and Spigelia alabamensis (syn. Spigelia gentianoides var. alabamensis,  gentian pinkroot. We were also able to examine a population of a new species in the genus Trautvetteria, tassel-rue, which as of yet has not been assigned a name; at present, it is being referred to as Trautvetteria species 1. 

Due to the unique character of this area and its rare flora, conservation is of upmost importance.  To that end, The Nature Conservancy has acquired 480 acres and named it the Kathy Stiles Freeland Bibb County Glades Preserve.  The Preserve is located along a very picturesque section of the Little Cahaba River and makes a delightful day trip; when there take time to appreciate Alabama’s unique natural heritage.

Spigillia gentianoides var. alabamensis

Croton alabamensis, Alabama croton

Trautvetteria species 1