Piedmont Grasslands Assessment research update!

Above: Co-Principal Investigator, Dr. Mary Jane Epps, records species in a remarkable remnant hardpan grassland over Triassic sedimentary rocks in the Richmond Basin.

We wanted to take a moment and let you know what the research department has been up to. This summer, the CUH team has been hard at work documenting old growth grassland remnants in a 9-county area of the central Virginia Piedmont. This joint public/privately funded project is in its second year of research this summer. We are so grateful to have the support of the Virginia Native Plant Society and several private matching donors for this ongoing research. Over the past few months three teams have been launching from our field station to compete in what we call a Grasslands Big Day. This involves driving the highways and backroads of the study area in search of diverse groups of native plants that are indicators for unplanted, high quality grassland ecosystems. The goal is to be the team that can locate, and prove, previously unrecognized natural prairie and savanna remnants. The most ever documented and proven in a single day is 25 (this has happened three times). Just this season the trio of research teams have documented 321 high-quality sites (self-assembled/not-planted ecosystems, with conservative/rare heliophytes, little or no invasive species presence, and minimal ground disturbance, etc.) and 408 strong indicator species across these sites. 

A view of “classic” Piedmont prairie vegetation. Little bluestem (Schizachyrium scoparium), Hyssop-leaved Thoroughwort (Eupatorium hyssopifolium), Pineywoods Goldenrod (Solidago pinetorum), Indiangrass (Sorghastrum nutans), and tick-trefoils (Desmodium spp.) dominate this late August view of a large remnant grassland in western Amelia County. 

As summer turns to fall, we are reviewing these several hundred sites to prioritize roughly 75-80 for further study. At those locations we will gather vegetative community data, with the aim of studying the highest quality sites across the full geologic and geographic spectrum of the region. This process should give us enough data to begin to see regional patterns in quality and unique type trends that could help further inform our understanding of pre-colonial ecosystems in the region.

Among the remarkable species found during the general reconnaissance phase are long-tubercled spikerush (Eleocharis verrucosa), hoary mountain-mint (Pycnanthemum incanum) (rare in the outer Piedmont region), dwarf chinquapin oak (Quercus prinoides), clasping St. John’s-wort (Hypericum gymnanthum), and bog bunchflower (Melanthium virginicum) in the northern parts of the study area. In the southern region we located large colonies of sandhill goldenrod (Solidago tarda), rattlesnake-master (Eryngium yuccifolium), long-leaved panic grass (Coleataenia longifolia), Dichanthelium filiramum, and glade wild quinine (Parthenium auriculatum). We have vouchered around 60 county records associated with grasslands research this season. These include prairie phlox (Phlox pilosa, Albemarle Co.), sandhills goldenrod (Solidago tarda, Chesterfield Co.), purple milkweed (Asclepias purpurascens, Nelson Co.), swollen meadow beauty (Rhexia ventricosa, Amelia, Goochland, and Powhatan Cos.), hoary mountain-mint (Pycnanthemum incanum, Spotsylvania Co.), and long-leaved panic grass (Coleataenia longifolia, Amelia Co.). The trend as we head east toward the Fall Line is remarkable. The flatter terrain hosts a variety of species not seen in the western Piedmont’s hillier uplands. Hardpan upland depression wetlands are much more prevalent, and the eastern part of the study area is underlain in some areas by terrace deposits, and Pliocene and Miocene sands, over which occur species of the Coastal Plain, creeping westward across the Fall Line in these suitable habitats. These deposits are very young (2.5-5 million years old) compared to the other substrates of the Piedmont region. These tend to serve as small islands of disjunct coastal plain species and groupings of plants. Many species with a wide distribution in the Virginia Piedmont are much more frequent in this year’s study area as well, occurring at many more sites than in the previous year’s study area. A few of these include pineywoods goldenrod (Solidago pinetorum), hairy elephant’s-foot (Elephantopus tomentosus), big bluestem (Andropogon gerardii), staggerbush (Lyonia mariana), and pineland golden-aster (Pityopsis aspera var. adenolepis)

The Grasslands Big Day field crew prepares to embark on another round of recon work. Each team drives an average of 95 miles of back roads per day during the effort! Left to right: Jessie Wingo, Ezra Staengl, Drew Chaney, Emily Luebke, Evie Sackett. 

The impacts of urban and suburban development are most noticeable in Henrico and Chesterfield Counties, which is unsurprising given centuries of population growth focused around Richmond and the rich terrain along the James River. Despite the impacts, we are finding some high quality prairie and savanna sites in completely unexpected areas. Small remnants growing on unplowed, undeveloped land tucked amongst heavy development and sprawl still contain a rich and diverse mixture of grassland flora. 

Images (left to right, top to bottom):

  1. Co-Principal Investigator, Devin Floyd collects data in a 100 square meter study plot in a remnant grassland in Chesterfield County, 2 miles from the ecoregion line. Over 90 species were found in this plot, many of them more typical of the Coastal Plain.
  2. The state Critically Imperiled Dwarf Chinquapin Oak (Quercus prinoides). The study plot this species was photographed in is dominated by Upland Ironweed (Vernonia glauca) and Hairy Angelica (Angelica venenosa) and hosts 123 native species, more than any other in Virginia. 
  3. The aptly named Curlyheads (Clematis ochroleuca). This species is near-endemic to the Piedmont from Virginia to Georgia, and only occurs in base-rich soils of intact grasslands. 
  4. Tall Coreopsis (Coreopsis tripteris) and Hollow Joe-pye Weed (Eutrochium fistulosum) bloom in a wet prairie remnant along a roadside in Goochland County. The Coreopsis is one of over 60 county records we have documented in association with grassland plant communities this season.
  5. Glade Wild Quinine (Parthenium auriculatum). This species is very scarce in the Piedmont, occurring only in high-quality grasslands over soils with a high magnesium content. 
  6. A bumblebee (Bombus sp.) nectars on Scaly Blazing Star (Liatris squarrosa). Healthy native grasslands are critical to the long-term survival of countless pollinator species.