Georgia Wildlife Resources Division
2067 U.S. Hwy. 278, SE, Social Circle, GA 30025
Piedmont literally means foothills. Nationally the Piedmont forms a gentle "S" curve from New York State to Montgomery Alabama, bordered to the west by the Appalachian Mountains and to the east by the flat Coastal Plain. Crystalline rocks (mostly granite) underlay the Piedmont. The low-relief landscape found in the Piedmont is a result of millions of years of erosion, gradually transforming mountains into a gentle rolling landscape that is not yet flat like the Coastal Plain.
The Piedmont covers about one third of the state of Georgia (18,100 square miles) and is typically associated with rough hilly terrain in the north and gentle rolling hills further south. The Piedmont extends south from the mountains of north Georgia to the fall line and ranges from 500-1,500 feet in elevation. The fall line marks the boundary between the crystalline rocks of the northern part of the state and the mostly unconsolidated sediments of the coastal plain. It is thought to be the furthest inland extent of the prehistoric coastline. The fall line is often associated with waterfalls and rapids formed as rivers tumble from the Piedmont to the coastal plain.
Much of the Piedmont that early settlers found would have been
covered with broad-leaf hardwood trees dominated by the now rare
American Chestnut (Castanea dentata). Today much of
the Piedmont is covered with pine forests, a result of
silvicultural rather than natural processes.
Habitat Highlight: Flint River Basin
The Flint River is often considered the most scenic river in the Georgia Piedmont and Coastal Plain. The uppermost headwaters originate under Hartsfield International Airport. From such inauspicious beginnings the Flint rapidly forms a dramatically carved channel through the red hills region of the Georgia Piedmont and is one of only 40 rivers in the United States that stretches for over 200 miles virtually unimpeded (without dams).
Like the Etowah River in north Georgia, the Flint River exhibits remarkable biotic diversity, exhibiting a particular abundance of freshwater mussel species. Freshwater mussels are unrelated to marine mussels and clams and are mostly members of the Unionoid family. The Flint originally was home to 29 mussel species, though recent surveys suggest that only 22 remain. Though certainly not the most charismatic and high profile species, our fresh water mussels have a fascinating natural history.
Freshwater Mussels filter water through elaborate gill structures to collect oxygen and food. One of the most fascinating aspects of our freshwater mussels is their parasitic dependence upon fish for reproduction. Mussel larvae must attach to the gills of specific fish in order to survive. After several weeks, they drop off, and continue their development independently. In order to lure the required fish host within range, the adult mussels produce elaborate lures which look remarkably like the host fish. Once a suitable host approaches, the mussel expels the larvae (glochidia) into the water. This form of reproduction aids in mobility of an otherwise immobile species.
Sedimentation, dams, pollution and channelization threaten many species of Unionoid mussels today.
Habitat Highlight: Rock Outcrops
A particularly harsh habitat type found mostly on the Piedmont is the rock outcrop. Georgia boasts a large number of rock outcrops including the largest in the world, Stone Mountain. Rock outcrops can be either Manadnocks, which rise above the surrounding piedmont like Stone Mountain, Arabia Mountain and Panola Mountain, or they can be simple flat-rock or pavement rock outcrops, like Heggies Rock. Most outcrops are composed of granite, an igneous rock that crystallized from slow cooling magma underground (intrusive igneous rock). The molten domes of magma that cooled to form our outcrops were generated from the heat and friction at the edges to colliding continental plates about 500 million years ago. The softer rock surrounding these granite domes gradually eroded away, leaving the granite exposed at ground level. In some cases, such as Arabia Mountain, the granite was changed into gneiss (a metamorphic rock) due to high heat and pressure long before the surrounding rock eroded and exposed it.
Rainwater falling on rock outcrops fill pools of standing water. These pools are called solution pits and provide habitat for rare plants and animals. If rainfall is consistent these wet depressions support dish gardens, a unique rock outcrop community that exhibits distinctive rings of progressively drier habitat further from the wet center. Standing water in the center of a dish garden may contain Fairy Shrimp (Branchinella sp.) and Mat-forming Quillwort (Isoetes tegetiformans), species that only occur on rock outcrop pools. Both species can survive desiccation as the outcrop pools often dry up in summer.
Because of their harsh exposed environment, rock outcrops offer a good place to observe primary succession and early soil development. The first organisms that can survive on the bare rock surface are lichens and mosses. These organisms actually dissolve rock with weak acids. After many years, through chemical and physical decomposition, a thin soil layer is formed. Soil allows other tolerant plants to establish, such as Diamorpha and Sedum, both succulent plants (fleshy leaves that hold moisture) well designed to withstand long periods of dry weather. As the soil continues to thicken, Broomsedge (Angropogon sp.), Sandworts (Caryophyllacea sp.) and Orange grass (Ctenium aromaticum) can colonize the rock. Confederate Daisy (Viguiera porteri), an endangered and endemic species, is quick to follow. Eventually small shrubs and trees will entirely cover the rock outcrop. This entire progression from rock to forest can often be seen on a single rock outcrop transect starting on bare rock and walking towards the encroaching forest at the outcrops edge.
Rock outcrop plants are vulnerable to disturbance of vehicle and even extensive foot traffic. Many of the rock outcrops in Georgia are or have been actively quarried for granite, making Georgia the worlds largest granite producer.
Key Species: Birds of Prey
Georgia is home to over twenty species of birds of prey. These range in size from the massive Bald Eagle (Haliaeetus leucocephalus) to the diminutive Eastern Screech-Owl (Otus asio). Birds of prey share a suite of impressive adaptations allowing them to catch and kill live prey. Talons, or sharp curved claws, are the principal weapons of the bird of prey, although a formidable hooked beak is also put to good use. Birds of prey are known for their eyesight, which approaches the limits of vision possible with the vertebrate eye.
Our diurnal birds of prey (those that hunt by day), include the hawks, eagles, falcons, harriers and osprey. Our only nocturnal birds of prey are the owls. In Georgia we have three breeding species of owl and several others that winter sporadically throughout the state. Owls eyes see only in black and white but are extremely sensitive to low light conditions, allowing them to fly through the woods chasing prey in the middle of the night. Owls hearing is particularly acute, allowing them to pinpoint the location of their prey before they can even see it. Owls are also well known for their ability to fly almost completely silently, allowing them to sneak up on their prey without being detected.
Outcrop Sites to Visit:
Davidson-Arabia Mountain Heritage Area - Lithonia (770) 484-3060
Heggies Rock - Columbia County - 11 endemic species and 21 species
that are characteristic of rock outcrops. Nature Conservancy (404)
Panola Mountain State Park Lithonia (800) 864-7275
Stone Mountain Park Stone Mountain (770) 498-5690
Piedmont Sites to Visit:
Charlie Elliott Wildlife Center Mansfield (770) 784-3069
Hard Labor Creek State Park Rutledge (706) 557-3001
McDuffie Environmental Education Center - Dearing (706) 595-2755
Newman Wetland Center Jonesboro (770) 603-5606
Piedmont National Wildlife Refuge Juliette (478) 986-5441
Rum Creek Wildlife Management Area/Nongame-Endangered Wildlife Program Office - Forsyth (478) 994-1438
Ocmulgee Indian Mounds National Monument - Macon (478) 752-8257
Project WILD Activities:
Birds of Prey
Seeing is Believing
Quick Frozen Critters
To Dam or Not to Dam
Silt: a Dirty Word