Research Projects:
SAVING THE SMOOTH CONEFLOWER
Heather Alley
Heather Alley, "Saving the Smooth Coneflower," Garden News, State Botanical Garden of Georgia, Fall 2002.
With less than half of the historically recorded populations remaining, and the majority of these populations in decline, recovery of Smooth Coneflower (Echinacea laevigata) is one of five priority projects of the Georgia Plant Conservation Alliance. Smooth Coneflower is closely related to the more familiar Purple Coneflowers (Echinacea angustifolia and E. purpurea), popular garden perennials and medicinal herbs. Smooth Coneflower, however, is quite rare. It is endangered or threatened in each of the four states (Georgia, North Carolina, South Carolina, and Virginia) where it remains. It was listed as a federally endangered species in 1992.
Smooth Coneflower is native to early successional prairie-like habitats of the piedmont and Appalachian foothills historically sustained by forest fires. Scientists believe that suppression of fires, which became widespread practice in the early 1900's, has greatly decreased the abundance of these open, prairie-like habitats. Currently, the majority of known Smooth Coneflower populations are found on roadsides and are at risk due to collecting and road maintenance activities. The few natural populations that grow away from roadsides are declining in number and size as successional species shade the understory. The recovery plan for Smooth Coneflower calls for monitoring and management of existing populations, and for reintroduction of new populations into the wild.
Since the fall of 1999, I have been working on Smooth Coneflower's recovery under the direction of Dr. Jim Affolter. My masters thesis involved reintroducing Smooth Coneflower experimentally to its native habitat in Stephens County, Georgia, and quantificataion of the light environment needed for the species to grow and reproduce. The reintroduction experiment was designed to test various planting strategies in order to develop a protocol for reintroduction of Smooth Coneflower on a larger scale. The light experiment was designed to identify optimal light requirements for managing the light environment for wild and reintroduced populations.
The experimental reintroduction tested the effects of plant age (at the time of transplanting), spacing, and soil supplementation (potting soil) on survival, growth, and flowering. Seeds were collected from the largest roadside population in Georgia with permission from the US Fish and Wildlife Service. Plants from these seeds were grown at the State Botanical Garden before being planted at the reintroduction site. The reintroduction site in the Chattahoochee National Forest was carefully selected based on its proximity and resemblance to Smooth Coneflower habitat. Because rapid population growth is important in preserving a reintroduced population's genetic diversity, it is important to establish protocols that maximize survival and reproduction. The experiment suggested that Smooth Coneflower has equally high initial survival rates regardless of age of the plant, spacing, or soil supplementation; survival rates in the first two years ranged from 75 to 100 percent. Monitoring will continue for many years to determine the effects of planting methods on long-term survival, growth, and flowering. After the experiment is complete, the population will be maintained by the US Forest Service.
The light experiment involved growing plants under different light levels at the Botanical Garden. After three months under a range of light intensities, photosynthetic capacity, biomass, and number of flowers were compared. It was determined that below 40 percent of full sunlight, Smooth Coneflower can no longer maintain its biomass, flowering or seed production capacity. This is valuable information for managers of Smooth Coneflower, who can target habitat management practices (prescribed burning and mechanical clearing) to maintain light levels above 40 percent of full sun.
In addition to my thesis work, I have been working with International Garden curators Debbie Mitchell and Mary Attaway, to create a Smooth Coneflower habitats in the Threatened and Endangered Plant Garden at the State Botanical Garden and at Tallulah Falls State Park. The display with interpretive signs features grasses and wildflowers typical of the Smooth Coneflower meadow habitat. Through education, research, management, and reintroduction, the future of the Smooth Coneflower is becoming brighter.