By Devin Floyd
On March 16, 2020, The CUH Stewardship Team accomplished a small prescribed burn in an HOA regulated neighborhood. The burn was implemented at the site of a 2,000 sq.ft. prairie restoration experiment. The experiment has been focused on quantifying methods and costs for converting lawns that are dominated by tough non-native species (such as Bermudagrass, Kentucky bluegrass, goosegrass, Korean-clover, Southern crabgrass, white clover, and others) to natural prairie over a 3-year period. We utilized a remarkable natural grassland very close to the project site (Piedmont Acidic Prairie/Savanna, Preddy Creek Park upland) as the restoration reference site, and we conducted periodic vegetative assessments to track richness, diversity, and exotic species abundance in the restoration area.
In May of 2017, the mown lawn contained only 17 species, dominated by Bermuda grass, Southern crabgrass, Korean-clover, and a couple other exotics. Richness (# of species) was low, Diversity index was below 3.5 (Shannon-Weiner), and exotic species made up more than 50% of the individual plants and vegetative cover. By November of 2019 there were 107 species in the same area and Diversity had climbed to 4.22, a figure that is in-line with natural grasslands of the region. While non-native vegetative abundance dropped sharply during the restoration, non-native species richness climbed from 15 to 33 across the project (due to continuous disturbance, including mowing, weeding, etc.). Furthermore, 18 conservative prairie species in the restoration plan have not emerged yet. The missing ingredient for the project is fire.
Native plantings require the installation of plants AND the introduction of the natural disturbance regimes they are adapted to. The burn objectives for this small prescribed burn included increasing native species richness and diversity, reducing non-native species richness while maintaining low vegetative cover, and to spur on the emergence of fire-adapted prairie forbs and grasses. The overarching objective is to introduce a natural wild prairie to a backyard in order to support pollinators, birds, and other wildlife and increase the occurrence and awareness of the rare natural community (Piedmont prairie/savanna) in the area. One lawn conversion at a time, one old field restoration at a time, grassland biodiversity can make a comeback. Prescribed burns are absolutely critical for success.