PS 34-234 - Working and Restored Grasslands Incompletely Conserve Native Biodiversity in Northern Virginia

Abstract: Despite their high biodiversity and ecosystem service value, temperate grasslands have faced habitat loss and degradation due to the anthropogenic pressures of agricultural expansion, development, disrupted disturbance regimes, climate change, and human neglect. The native grasslands of the Southeastern United States have lost over 90% of their historic range due to these pressures. The loss of these ecosystems and the biodiversity they harbor have been poorly documented, partially because most of the grasslands that remain in the Southeast are on private property. To assess the impacts of human use on grassland biodiversity and to determine the effectiveness of grassland restoration efforts on private land, we surveyed plant community composition in 130 public and privately owned working, restored, and native remnant and semi-natural grasslands using modified Whittaker plots in Northern Virginia. The working grasslands were actively grazed or used for hay production, while the restored grasslands were planted with warm-season grassland species and maintained to provide habitats for wildlife. The native remnant and semi-natural grasslands were grasslands with indicative native grassland plant communities that were not known to have been planted or seeded. PERMANOVA and NMDS ordination of these plant community data indicate that working, restored, and native remnant and semi-natural grasslands diverge based on their dominant land use and management strategies (P< 0.0001, R²=0.177). Projections of plant community variables onto the NMDS ordination suggest that this divergence is due to the high native species richness found in native remnant and semi-natural grasslands (P< 0.01, R²=0.69) and the high introduced and invasive species cover in working and restored grasslands, respectively (P< 0.01, R²=0.64; P< 0.01, R²=0.38). These results suggest that many current grassland management and restoration strategies used by private landowners in Northern Virginia may be insufficient to support and restore native biodiversity in degraded grasslands.