Restoration Has Rare Plant on the Rebound
By BETH QUILLIAN
On a woodland knoll overlooking Anthony Shoals on the Broad River, something rare has been spreading underground.
It’s a warm summer morning and Dr. Mincy Moffett Jr., a botanist with DNR’s Wildlife Conservation Section, is pointing out a plant that makes this site on the Lower Broad River Wildlife Management Area unique. The knoll is home to the incredibly rare dwarf sumac.
Known originally from only five states (Florida, Georgia, South Carolina, North Carolina and Virginia), dwarf sumac (Rhus michauxii) has been extirpated from Florida and South Carolina, leaving the remaining states as the species’ last refuge.
The plant is listed as endangered under the Endangered Species Act and protected in Georgia through the state’s Wildflower Preservation Act. Of five sumac species found in Georgia, dwarf sumac is the smallest, growing only 1-3 feet tall. The plant features hairy stems and leaves, and dense clusters of red fruits and foliage that turn a deep red and purple in the fall. Another feature, however, is that it’s also able to survive underground with few stems visible.
In Georgia, dwarf sumac naturally occurs in only two places – Lower Broad River WMA near Elberton and a population near Covington.
Rare for a Reason
Why is this species so rare?
Moffett explains that dwarf sumac requires an open sunny habitat, usually in a rocky or sandy woodland or savanna. It’s important to note, he says, that woodlands are different from forests. The latter has a closed canopy, whereas woodlands are much more open and let in more light.
Historically, woodlands and savannas were kept open by fire and grazing and browsing animals. Fires were set by lightning strikes and Native Americans. However, aggressive suppression of fire over the last 100 years has led to a dramatic decrease in the burns needed to keep these landscapes open. Without fire, woodlands and savannas have grown into forests with closed canopies, and the species dependent on the once-sunlit habitats have declined.
That’s exactly what happened at the Lower Broad River. But about 15 years ago, DNR and the Georgia Plant Conservation Alliance, a network focused on conserving native plants, began intensively managing the site. The half-acre pocket opening on the knoll was a closed-canopy forest before the restoration project began.
At that time, there were only two dwarf sumac stems above ground. The foundation of the habitat was there, but it needed life support and broader habitat improvement for the expansion of rare plants like dwarf sumac.
The restoration project is guided by Georgia’s State Wildlife Action Plan, a statewide strategy to conserve populations of native wildlife species and the natural habitats they need before these animals, plants and places become rarer and more costly to conserve or restore.
One of the plant’s fascinating features is its ability to persist below ground in a root and rhizomal mat, with few stems showing above the surface. While only two stems were visible on the Lower Broad River knoll in 2005, after fire was reintroduced to the area, the dormant dwarf sumac emerged, and it has been spreading ever since. After a couple of prescribed burns, the stem count increased to 150.
In addition to fire, 50 trees were felled and annual work parties removed woody shrubs and other sprouts from the site. Herbicide was judiciously applied to hardwoods outside of the sumac zone.
Guess how many stems are visible now? More than 1,500. That’s right, 1,500 where there once were only two.
Another noteworthy part of the restoration involved matchmaking. This was necessary to address another factor in dwarf sumac’s rarity: low reproductive capacity resulting from small, single-sex populations.
Dwarf sumac is dioecious, meaning individual plants are either male (with only male flowers) or female (with only female flowers). This is rare among flowering plants: More than 90 percent of them have both male and female flowers on the same plant. The dwarf sumac population at Lower Broad River was an all-male clonal population that reproduced asexually through root sprouts and rhizomes.
On Valentine’s Day in 2010, female plants from Georgia’s population of dwarf sumac in Covington were transplanted at the Broad River site. The Covington population is all-female, and had persisted asexually as did the male population. The hope is the combined population will begin to reproduce sexually.
Worth the Work
Since 2010, some fertile fruits have been produced. But the work is not done yet. There also are concerns the dwarf sumac will hybridize with smooth sumac and winged sumac, also growing at the site.
With continued restoration efforts, however, it looks like dwarf sumac will make a comeback.
Dwarf sumac is not the only thing that makes Lower Broad River WMA special. The view from the top of the knoll to the river is breathtaking. Here, the river widens before flowing into Clark’s Hill Lake and on to join the Savannah River. Anthony Shoals, spared twice from proposed hydropower dams, is home to one of the few remaining populations of shoals spiderlilies in the Savannah watershed.
Restoring rare species and rare natural communities is a long-term proposition. What took a century or more to degrade will take more than a few years to restore.
Success requires patience, persistence and resolve, as well as some creativity.
For the dwarf sumac at Lower Broad River WMA, the effort is paying off.
Watch and Learn
Beth Quillian works with Public Affairs in DNR’s Wildlife Resources Division.