Initial Results of Native Species Establishment on Highway Corridors in West Virginia

Abstract

Introduced and invasive species have been recognized as potential threats to natural plant communities. Many such plant species are introduced along roadways, which then can spread to adjacent fields and forests. The West Virginia Division of Highways is required to develop seeding mixtures comprised of native plants for revegetating highway corridors and thereby to reduce the potential for introducing non-native species along roads. Therefore, the objective of this project was to identify native plants that are suitable for seeding on highway sites, and to document survival and growth of these species after seeding on highway cut and fill areas. Three sites (Baker, Hazelton, and Parkersburg) in West Virginia were chosen as demonstration sites and seeded in April 2002. At each site, five seed mixes (Control, Native, DOH, DOH-Native, and DOH½- Native) were seeded into fertilized and unfertilized plots. Plots were 2m by 2m and each treatment (seed mix and fertilizer) was replicated four times (40 plots per site). First year results show that fertilized plots showed a trend for promoting higher ground cover compared to unfertilized plots. Unseeded, unfertilized plots generally had more weedy species than other plots. Native species establishment was poor and plots seeded to native species were mostly colonized by non-native species from adjacent areas. Regardless of seed mixture, most plots contained birdsfoot trefoil (Lotus corniculatus L.) and annual ryegrass (Lolium multiflorum Lam.) as dominant plants. Due to their slow-establishing nature, native species were not seen during the first year. In subsequent years, it is anticipated that the native species will emerge and become a more prominent contributor to the ground cover. It is also anticipated that plots with a combination of less- aggressive introduced species with low fertilizer rates will allow opportunities for the later-establishing native plants to develop and grow.