Saturday, April 18, 2009

In April, Life Blooms Rich 'in the Pits' at Piedmont Outcrops

On an April afternoon fresh from heavy rains and swept by steady winds, Mary Terry asks a question atop Arabia Mountain in Dekalb County:

“Why can’t everybody see this?”

What Terry, a wildlife biologist and state Project WILD coordinator with the Georgia Wildlife Resources Division, sees is more than a miles-wide view and 200 acres of rock. The former ranger and overseer of Davidson-Arabia Mountain Nature Preserve is also referring to mats of tiny plants and layers of lichens and moss that cling to the sloping shoulders of gneiss, Arabia’s dominant rock.

“When you get closer and start examining, that’s when you really start seeing the true, true beauty,” Terry said.

That beauty is harder to miss in April, when shallow pools of rainwater sprout “vegetation islands” with colors ranging from pink and red to yellow, green and blue on rock outcrops. But the zoom lens approach fits outcrops all year. Georgia is home to almost 90 percent of the known granite outcrops in the Piedmont. The best known is Stone Mountain. But much smaller outcrops emerge from forest and pasture across the region.

Outcrops support a stubborn yet fragile web of life. Four federally listed plants are connected to these microhabitats: little Amphianthus, also known as snorkelwort and pool sprite (Amphianthus pusillus); black-spored quillwort (Isoetes melanospora); mat-forming quillwort (Isoetes tegetiformans); and Harperella (Ptilimnium nodosum). Many outcrop plants depend on vernal or seasonal pools. The lineup of life also includes lichens, mosses, wildflowers, pine trees, shrubs, frogs and, in some pools, even miniature crustaceans called fairy shrimp.

Salamanders lay clouds of eggs in marsh at the base of outcrops. But on the rock, life is geared for extremes: summer’s searing heat, winter’s icy cold and the most meager of soils.

Terry said the diminutive red and white diamorpha (Diamorpha smallii) carries its seeds high, lifting them away them from heat that shrivels pools and plants and toward fall rains that knock the seeds loose into the shallow soil, where they can germinate. So-called rabbit ears or woolly ragwort (Packera tomentosa) turn their long leaves flat toward the early sun for photosynthesis, then sideways, showing only a paper-thin profile, as temperatures rise.

Some of the plants can tolerate the hot, dry summers, said botanist Lisa Kruse of Wildlife Resources Nongame Conservation Section. Others “live their full life cycle in the spring months when moisture collects in the pools,” Kruse said.

“When the water dries up in late spring, they have already set seed for next year.”

The outlook for outcrops is as tenuous. Threats vary from quarrying to ATV traffic to shading from trees. Even foot-traffic can harm the plants. Georgia’s Wildlife Action Plan, the guiding document for state conservation efforts, rates granite rock outcrops a priority habitat. A U.S. Fish and Wildlife Service review found that the number of snorkelwort sites in Georgia and Alabama has shrunk from 61 to about 40, black-spored quillwort sites from 15 to about five, and mat-forming quillwort sites from 13 to 10.

Only six granite rock outcrops are protected in Georgia, according to the state Wildlife Action Plan.

But the Wildlife Resources Division’s Nongame Conservation Section is researching the effects of land management on outcrop vegetation communities, seeking the best methods for caring for the fragile plant groups. The Nongame Conservation Section, the Fish and Wildlife Service and The Nature Conservancy also monitor rare plant sites, collecting seeds in emergency situations to preserve the species’ genetic diversity. Seeds from the federally endangered Harperella have been grown in greenhouses and re-planted at a protected granite outcrop.

Minus human intervention, change on outcrops occurs at glacier speeds. Lichens dissolve rock to dirt over thousands of years. The spread of plants feeding off the sandy soil is measured in inches, and centuries. Terry said most life on outcrops is described as in the pits.

But in April, when the color on outcrops peaks, life in the pits can be a mountaintop experience. Even for those who, unlike Terry, have never been hired to guard a rock that became a devotion.


** Options include Stone Mountain Park in Atlanta, Davidson-Arabia Mountain Nature Preserve near Lithonia, Panola Mountain State Park in Stockbridge and lesser-known Eatonton Outcrop on Oconee Wildlife Management Area near Eatonton.

** If you go, don’t take pets, walk around pools not through them and stay on marked trails (if trails are marked).

** Spring is the peak season, but some plants will bloom throughout summer. One showy outcrop plant in fall is the Confederate daisy.

Georgia Front Page
Fayette Front Page

No comments: