An Assessment of Native Grasslands of the East-Central Piedmont of Virginia, 2022-2023

This post is adapted from a proposal submitted to the Virginia Native Plant Society, with Devin Floyd of CUH as co-principal investigator along with Dr. Mary Jane Epps of Mary Baldwin University.

The Piedmont region of Eastern North America is considered the most lived-in ecological region on the continent. Modern humans have managed to occupy, modify, and impact nearly all parts of it. Tens of millions of people live there and suppress a natural world they often don’t know exists. There is a general lack of awareness of the unique and remarkable biodiversity of the Piedmont. Even some practitioners in the conservation community have written the region off as one vast abandoned agricultural wasteland. This generalization is dangerous for the protection of the natural spaces that survived and persist, and it undermines opportunities for restoration. Add to this fact the myth of the pre-colonial “virgin forest” and it’s no wonder our society has collective amnesia around the topic of natural Piedmont Grasslands. As Reed Noss so pointedly puts it in the title of his seminal book, these are the “Forgotten Grasslands of the South”.

2021 Grasslands Intern, David Bellangue, tallies an initial inventory of a newly discovered high-quality remnant grassland. The prevalent species in the view are Danthonia sericea and Aletris farinosa.

Hiding in millions of small and overlooked places are the whispers of a rich natural world that not only echoes the past, but speaks of a future of wondrous potential. The biologically rich grasslands that have been suppressed for centuries are not lost. They hang by a thread as a scattered collection of small and remarkable biological sites, and we must make room for them to expand and thrive before they are lost. It is not too late for most of the thousands of animal species that rely upon them, and now is the time to act.

Before we can make room for natural grasslands, or begin to inspire others to love and steward them, we must learn how to see them, and then acknowledge and protect high quality remnants that remain. We must first objectively consider their quantity, variety, distribution, and condition. With that purpose in mind, we propose to expand and continue our successful 2021 Central Virginia survey to conduct a survey of the high-quality grasslands in 9 new counties of the east-central Virginia Piedmont, to the Fall Line.

The 2021 research season was very successful, and we look forward to reporting the results to the VNPS and publishing the findings. Until those are delivered, we’d like to offer a few highlights from 2021:

Pycnanthemum torreyi (G2/S2) was found in large colonies and drifts at multiple sites in the study area and we expect to see more as our project expands.
  • More amazing sites than predicted. High Quality Remnants located in the 8 County research area: 405
  • Accomplished more than double the goal. Total number of 100m2 sample plots proposed in 2021 was 40. Actual # accomplished in 2021: 85
  • Flora of Virginia. New County Record Species Occurrences: 81
  • Richness. Total number of species documented in 2021 grassland plots: 869
  • Diversity. Plots with more than 90 native species: 7
  • The Pycnanthemum Complex: Central Virginia Pycnanthemum complex, including 4 county records for Pycnanthemum torreyi (G2/S2), 3 county records of Pycnanthemum clinopodioides (G1G2/S1), and hybrid types that do not key cleanly (Samples are being considered by Pycnanthemum experts). Also observed during the grasslands project were P. verticillatum, P. virginianum, P. pycnanthemoides, P. incanum. and P. tenuifolium.
  • More types than currently acknowledged. Initial data crunching efforts using standard methods for distinguishing unique community types suggest that, rather than having just one type of prairie (Piedmont Prairie GH/SH) there may be several other predictable and unique types worth acknowledging and conserving. The cluster diagram in Figure 1 shows two unique floristic community groups within the “Piedmont Prairie” classification. A quick analysis of the flora across the data set created a split into two vegetative groups. When these two prairie types (noted in blue and red) are compared to physiographic characteristics such as soil chemistry, landform, and slope, they cluster into areas of the diagram. The “blue” prairie type is a set of grassland flora that tends to associate with sloped, often sandy, acidic, and nutrient poor substrates. The “red” prairie type is a group of flora that associates with higher pH, moderate base saturation, and clayey soils relatively flat to rolling upland terrain. This thus strongly suggests that a split in the “Prairie” class, to Acidic Prairie and Basic Prairie, may be warranted.
  • Size doesn’t matter, quality does. Despite the small size of some of these surviving old grasslands, their resilience and quality make a strong case for their protection, whether they have rare species affiliated with them or not. It is likely that these survive on unplowed soils. This is important because many of them occur in highly visible, heavily managed, and at-risk places (such as roadsides and utility rights-of-way).
  • Bombus pensylvanicus. The North American bumble bee was observed in association with many of the high quality remnants we documented. This declining species will likely be federally listed within the next five years, and we are excited to see that it appears to thrive in the diverse remnant grasslands of the Piedmont.
  • Restoration Data. The data produced during the 2021 survey effort is already providing guidance for grassland restorations in the region studied. High quality reference sites are critical for restoration projects.
  • Contextual Data. While it is important to keep track of and protect rare species, it is critical to understand the habitats that sustain them. Our research provides contextual, community data for rare and uncommon heliophyte species.
  • Education. The data collected during our 2021 research season is being utilized by students for school-yard restoration projects. We are connecting important natural heritage data to youth in ways that are actionable. We are spawning stewards of the future.
Scatterplot diagram for two-dimensional NMDS ordination of 41 Upland Prairie plots in our 2021 study area. Diagram highlights two distinct prairie groups: Acidic (in blue) and Basic (in red).

Objectives

  1. Assess the quantity, distribution, and condition of unplanted, high quality grassland communities in a 9-county area in East-Central Virginia.
  2. Investigate and quantify relationships between geologic soil characteristics (chemical and physical) and local variations in plant assemblages.
  3. Determine degree of indicator assemblage fidelity as it relates to physiographic characteristics.
  4. Investigate relationships between exotic species prevalence and three factors: geologic soil class, native species richness, and floristic quality.
  5. Identify threats and generate recommendations for the expansion of natural grasslands focused around these nodes of resilience, and the conservation of existing resources to help prevent further habitat and species loss.

Proposal

  1. Preliminary inventory of hypothesized high quality grassland remnants within a 9-county study area in East-Central Virginia, to include the counties of Spotsylvania, Caroline, Hanover, Goochland, Henrico, Cumberland, Powhatan, Chesterfield, and Amelia.
  2. Quantitative assessments of select examples of high-quality grasslands from the preliminary inventory sites, to include the characterization of physiography, geology, soil chemical and physical attributes, vegetative cover, species richness, floristic quality, and exotic species impact. Sample number will include a minimum of 50 plots (100 m2).
  3. Summary of the condition of each site that receives a sample plot.
  4. Report of findings.
  5. Partnerships with public and private land owners and managers to gain access to sites for intensive study.
  6. Matching funding and volunteer effort to increase the data set for the study.

Detailed information on methodology can be found here at the Piedmont Grasslands Assessment page.

2022 9-County study area in the Piedmont Region of east-central Virginia, to include portions of the Northern Inner (45e), Northern Outer (45f), and Triassic Basins (45g) Ecoregions. Shown in the inset are the 2021 Project Area (gray) and proposed 2022 project area (red).