Georgia Eocene Chalk Prairies

Georgia Eocene Chalk Prairies are a variation of the blackland prairies that are found in a narrow belt across the southeast.  Most blackland prairies are dominated by 2 species of grass–Indian grass (Sorghastram nutans) and little bluestem grass (Schizachium scoparium), but Georgia Eocene Chalk Prairies are considered unique because little bluestem is absent and deceptive bluestem (Andropogen virginicus) occurs as a dominant instead.  Prairie clovers, a common component of most blackland prairies, are absent here as well.  Botanists recently recognized and designated Georgia Eocene Chalk Prairies as a unique and rare environment.

Location of Houston (pronounced howston) County in Georgia.  The Oaky Woods Wildlife Management Area is in the southeastern part of the county.  Remnant blackland prairies occur within this WMA.

Canebreaks 003

Map of Blackland Prairies from the below reference.  Georgia Eocene Chalk Prairies are a disjunct from the more extensive areas located to the west of the state.  They host hundreds of plant species found in the south, the west, and nowhere else on earth.

Blackland prairies exist within forested zones because the qualities of the soil allow grass to outcompete trees.  During the Cretaceous and Eocene epochs, the ocean inundated the coastal plain of southeastern North America.  Feldspar-laced sediment from the piedmont washed down the rivers into the ocean where it accumulated along the marshy shorelines.  This sediment eventually became kaolin clay.  Limestone formed from sea shells and coral and mixed with the clay, making it alkaline.  This combination of shrink-swell clay and an alkaline ph favors grass over trees.

This is a photo on google images I found of a blackland prairie in Mississippi.

A Georgia Eocene Chalk Prairie.

Shrink-swell clay soil.

Botanists surveyed 6 tracts totaling 106 acres of Georgia Eocene Chalk Prairie located in the Oaky Woods and Ocmulgee Wildlife Management Areas, and they found 351 species.  Characteristic species of Georgia Chalk Prairies include Indian grass, deceptive bluestem, old field goldenrod, globular cone flower, diamond flower, coralbeads, milkpea, dropseed, panic grass, sages, asters (49 species such as sunflowers and rosinweed), hawthorn, persimmon, redbud, chinquapin oak, bastard oak, dogwood, elm, and southern black haw.  The site hosts western species, southern species, and species found nowhere else (endemics).  Rare species such as wedgeleaf draba, heartleaf noseburn, and Durands skullcap are found here.  Bastard oak (Quercus sinuata) is an example of a species that is common in the west, especially in Texas, but occurs as a disjunct relic in Georgia’s chalk prairies.  Kudzu, Japanese honeysuckle, Johnson grass, and white clover are problematic invasive species.

Diamond flower (Houstonia nigricans) occurs with dropseed (Sporobolus vaginaflorus) in disturbed areas of the prairies.

Coralbeads (Cocculus carolinus) is common.  Birds like the berries which may be poisonous to humans.

Globular Prairie Coneflower (Ratibida pinnata).  Perhaps the most beautiful flower here. 

Redbud (Cercis canadensis).  This is in the legume family.  A caterpillar that feeds upon this plant is known as the catalpa worm.  It’s a popular fishbait.

Fringed campion (Silene catesbaei).  This is a rare plant found in only a few locations in the entire world.

Last year, the state of Georgia protected this unique environment when the legislature moved to stop a real estate developer from building a 20,000 home subdivision in the middle of the Oaky Woods Wildlife Management Area.  The Nature Conservancy offered to help fund the purchase of the land in 2002 but that deal fell through and some asshole was going to dam Big Grocery Creek, creating a lake that would have flooded 3 state record trees, centuries-old oaks and beeches, and Eocene fossils found on the exposed creek bed.  The development would have greatly fragmented the last population of black bears in the entire piedmont region of southeastern North America.  But an outcry from outdoorsmen stopped that travesty.  It ended up costing the state a lot more than it would have, if they’d made the original deal with the Nature Conservancy.  Unfortunately, the Georgia DNR opened a hunting season on the 300 black bears still living here, and 10% were killed on the first day of the hunt.  I think the Oaky Woods WMA was saved from developers, so rednecks could shoot bears and wild boars.  I guess rednecks are the lesser of 2 evils.

I would like to visit Oaky Woods, but my wife and daughter are not enthusiastic about a potential trip there.  It’s called Oaky Woods because a lush forest of upland hardwoods grows on rich soil in a geographcal region otherwise dominated (formerly) by open pine savannah and floodplain forests.  (Of course, today it’s surrounded mainly by tree farms and agricultural fields.)  12 species of oaks grow in Oaky Woods, and a southern disjunct population of chestnut used to be a component, as evidenced by still sprouting stumps. Weyerhauser used to own the land, and they grew pine trees on the uplands, but the area around Big Grocery Creek had not been logged in over 80 years, and it was never clear cut, so there are some trees as old as 150 years there.  Big Grocery Creek cuts through an Eocene fossil deposit that contains 40 million year old shark’s teeth, whale bones, sea shells, and sand dollars.  I’m sure glad it wasn’t destroyed by some greedy real estate developer.

Reference:

Echols, Lee; and Wendy Zomlefer

“Vascular Plant Flora of the Remnant Blackland Prairies in Oaky Woods Wildlife Management  Area, Houston County, Georgia”

Castanea 75 (1) March 2010

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5 Responses to “Georgia Eocene Chalk Prairies”

  1. tinatimebomb Says:

    Bravo!

  2. markgelbart Says:

    Thanks.

  3. Second Elasmosaurus Fossil Skeleton Found in Alabama | GeorgiaBeforePeople Says:

    […] trees in black belt prairies.  Parts of this black belt prairie extend into Georgia (See https://markgelbart.wordpress.com/2013/02/01/georgia-eocene-chalk-prairies/ ).  Many Cretaceous-age vertebrate fossils are found in the black belt prairie region because it […]

  4. John Trussell Says:

    Hi- Great job on your info- I would like to include it into our website, saveoakywoods.com, for public information, with your permission?Thanks! John Trussell, founder- Save Oaky woods

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