A Tale of Two Rare Plants

In the last month, I have had to pleasure of going out to the woods with the National Forests in North Carolina ecologist twice to help the recovery of two rare species on the Grandfather Ranger District with very different life histories.

First, we visited the Federally Listed Mountain Golden Heather (Hudsonia montana) at a high elevation site on the Grandfather Ranger District. Mountain Golden Heather, listed as Threatened in 1980, is endemic to the district where it is only known to occur in two sites. Golden Mountain Heather is a fire-adapted species that needs full sun and bare mineral soil to germinate. It is found on rocky, open ridges where lightning-strikes were historically common. Without fire, the species is quickly overtopped by taller shrubs and trees.

Unscathed Golden Mountain Heather follow a prescribed burn

Unscathed Golden Mountain Heather after a wildfire

In 2007, an intense summer wildfire burned through one of the Golden Mountain Heather populations. Surveys following the fire found a 10 to 100-fold increase in the number of plants. The second population, however, has not seen the intense heat needed to clear competing growth in decades. Recently, the location was incorporated into a prescribed burn unit as part of the Grandfather Restoration Project. Under the guidance of US Fish and Wildlife Service and US Forest Service biologists, we went out to that site to open up the area ahead of the next prescribed burn. By simply removing select surrounding shrubs and pine trees, we increased the available habitat for the species and set it up for the prescribed burn planned for next winter. We targeted plants that were starting to overtop Golden Mountain Heather as well as those that were blocking wind-borne seed dispersal into nearby suitable habitat.

Mountain Golden Heather habitat after removing select shrubs and pines

Mountain Golden Heather habitat after removing select shrubs and pines

Next, we visited the State Listed Endangered Northern Oconee Bells (Shortia galacifolia var. brevistyla) at a low elevation stream-side site on the Grandfather Ranger District. Found only in McDowell County, this rare plant has an even narrower range than Golden Mountain Heather, but a very different life history. Northern Oconee Bells is restricted to the moist slopes of steep ravines, where fire is naturally excluded. It requires shade, good drainage, and bare mineral soil to germinate. Bare mineral soil in these environments is created where the ground is too steep to hold leaf litter, but where Northern Oconee Bells can still find a small roothold.

Northern Oconee Bells in bloom

Northern Oconee Bells in bloom

Unfortunately, Northern Oconee Bells has limited reproduction by seed in its natural environment. Although there is suitable habitat close-by, the species is limited to a small area of that available habitat. To help the population recover, the US Forest Service is working with a former chemistry professor from UNC who has extensively studied reproduction in Northern Oconee Bells. With a permit from the NC Department of Natural Resources, and working under the guidance of the National Forests in NC ecologist, he will collect a limited amount of seed from this population of Northern Oconee Bells this year. He will propagate the species at a nearby site and replant the seedlings in the suitable habitat upstream from the existing population in 3 years. With greater numbers of plants on the site, the species will be better protected from population loss.

Habitat of Northern Oconee Bells

Habitat of Northern Oconee Bells where seed collection will take place

We hope that these efforts will help to maintain viable populations of both the Golden Mountain Heather and Northern Oconee Bells into the future.

Long Term Study on Prescribed Burning in Eastern Forests

A study was recently published in the journal of Forest Ecology and Management that looks at prescribed fire use over 60 years. Scientists monitored control, annual burn, and periodic burn plots in an Oak-Hickory stand in Missouri. Results showed that understory species richness was over three times greater in both burn treatments when compared to the control.

Results from this study support our hypothesis that long-term, repeated prescribed burning can be used to reach Knappseveral objectives related to woodland restoration and management in hardwood ecosystems, including creating a two-layered vertical structure and increasing the abundance, richness, diversity, and evenness of the understory plant community. Although previous studies demonstrated the effects of long-term burning on the structure of pine ecosystems, this study is the first to document similar effects in oak-hickory communities. Silvicultural prescriptions for reaching woodland objectives in hardwood ecosystems often include combinations of thinning and burning to reduce canopy density and increase the herbaceous vegetation response (Peterson et al., 2007; Kinkead et al., 2013; Brose, 2014). Our results suggest that, over long time periods, burning alone can reduce canopy density to create conditions associated with woodlands.

View the article here: Structure and composition of an oak-hickory forest after over 60 years of repeated prescribed burning in Missouri, U.S.A