The smooth purple coneflower (Echinacea laevigata)
is a perennial herb that grows up to 1.5 meters tall. Each plant produces
one or more clusters of basal leaves from a stout rootstock. These
leaves may reach 20 cm in length, although those on young plants are
smaller. Leaves generally emerge in March and die in the fall. Flowering
plants produce a smooth stem with a few smaller leaves and a single
flower in May or June. In sunny habitats, plants may produce a second
flower in late summer. The petal-like rays of the flower are light
pink to purplish, usually drooping, and 5-8 cm long.
Typical coneflower habitat is open woods, cedar barrens,
roadsides, clearcuts, dry limestone bluffs, and power line rights-of-way,
usually on magnesium- and calcium-rich soils. Optimal sites have abundant
sunlight and little competition in the herbaceous layer. Natural fires,
as well as large herbivores, are part of the history of the vegetation
in this species range; coneflowers are dependent upon periodic
disturbances to reduce the shade and competition from woody plants.
The reported historical range of the smooth purple
cone-flower included Pennsylvania, Maryland, Virginia, North and South Carolina, Georgia, Alabama, and Arkansas.
The species now is known to survive only in Virginia, North and South
Carolina, and Georgia. Of the seven populations known from South Carolina,
two are located on the Department of Energys Savannah River
Site (SRS), one on Burma Road and the other in a power line right-of-way
along Road B-9. Echinacea laevigata was listed as federally
endangered on October 8, 1992 and also is listed as a sensitive species
by the U.S. Forest Service; it is the only known federally endangered
plant on the SRS. These designations require that DOE avoid actions
with deleterious impacts to the populations.
The Savannah River Ecology Laboratory (SREL) and the
USFS Savannah River Institute (SRI) have been collaborating for several
years to develop methods to maintain population viability of the smooth
purple coneflower on the SRS. Both populations are exposed to threats
such as power line maintenance activities and accidental herbicide
application. Collaborative research also tests management activities,
including forest thinning and burning, that might improve coneflower
Management of the
smooth purple coneflower on the SRS....
The objectives of endangered species management go
beyond protection of existing populations. Management can improve
habitat quality and encourage population expansion, with the ultimate
goal of achieving a natural, self-sustaining coneflower population.
Future management of SRS coneflower populations is guided by these
goals. Past management of the two SRS smooth purple coneflower populations
focused on protection of the immediate area surrounding each population.
Over time, complete protection of these areas from most management
activities has led to slight degradation of habitat quality
and no obvious increase in population size at one site.
SRI now will take a more proactive approach to smooth
purple coneflower management on the SRS. A management plan has been
drafted and is pending approval by site managers and the U.S. Fish
and Wildlife Service.
If approved, future management will include expanding both of the
areas being managed for coneflower habitat to allow populations to
expand without impacts from other land uses. These areas will become
open, fire-maintained woodland savanna settings with enhanced plant
diversity and fewer, but larger trees. Such habitat, thought to have
once been commonplace throughout the Coastal Plain, is highly suited
for the smooth purple coneflower. Smaller trees will be hand-removed
to create sunny-to-partially sunny conditions on the forest floor.
Controlled fires will be set at regular intervals to reduce the establishment
of competing plants and encourage smooth purple coneflower flowering
and seedling establishment. Changes in habitat quality and coneflower
population size will be monitored to determine response to the management
Future management may also include the establishment
of a research coneflower population from SRS seed sources. This research
population will further improve the status of the smooth purple coneflower
on the SRS and provide opportunities for study of the species
biology and its habitat. Such opportunities will include manipulative
studies and activities that could not be performed on naturally existing
federally protected populations.
SREL has been monitoring the two SRS populations of
smooth coneflower since 1988 (Burma Road) and 1994 (Road B-9). Associated
research is investigating population biology, including pollination
biology and genetics, and response to experimental burning and overstory
thinning to provide a baseline for assessing response to disturbance
or management activities. SREL research collaborates with and complements
SRI programs for rare and endangered species. In collaboration with
the Coneflower Man-agement Plan being pre-pared by SRI, SREL will
monitor the effects of alternative management practices on the research
and research results....
- Echinacea seedlings and small plants were
observed in early summer 1998 at the Burma Road location. This was
the first time in recent years that new individuals were documented.
- The Burma Road coneflower population fluctuates,
with the number of individuals varying from 146 plants in 1995,
to 150 in 1996, 137 in 1997, and 156 plants in 1998. All of
these recent counts indicate fewer plants are now present than the
approximately 250 plants documented in this population in the late
- The Burma Road population has declined because
plants are dying, but very few new plants are establishing. Recruitment
varied from no new plants in most years, to 1 new plant in 1991
and 1993, 4 new plants in 1989, and 5 new plants in 1992. Mortality
of established plants varied between 7 and 38 plants per year.
- The Road B-9 coneflower population, when
first discovered in 1994, was documented to contain 600 plants and
740 stems. The 1995 census of this population included 609 plants
and 851 stems; the 1998 census included 655 plants and 1,492 stems.
- In th Road B-9 population, Echinacea flowers
in the open received more visits from potential pollinators, including
butterflies, honeybees, and bumblebees, than did plants in the shade.
Management strategies that maintain a more open canopy may promote
cross pollination and help maintain genetic diversity.
- Along the geographical range from Georgia to Virginia,
nearby Echinacea populations are more similar genetically
to one another than they are to more distant populations. The Burma
Road population on the SRS is slightly different genetically from
all other populations.
- Past management treatments (limited to minimal
experimental burning and overstory thinning) have had little effect
on the population dynamics of the Burma Road population. Treatments
proposed in the new management plan will provide further information
on whether such treatments result in cumulative beneficial effects.
Purple Coneflower on the SRS