||Conservation grasslands reduce soil loss, improve water quality, are important wildlife habitat, and have the potential to be a source of biomass for biofuel production. Most currently established conservation grasslands in the northeastern United States are on land with marginal crop production potential. Little is known about the plant composition or amount of biomass produced on these grasslands. To assemble a database for the resource assessment of warm season
grasslands in the northeastern United States, we determined plant species composition at multiple scales using the modified Whittaker plot technique, measured various soil properties, and quantified biomass yield on CRP, WHIP, mine reclamation, and other grasslands. A total of 34 sites were sampled in New York, Pennsylvania, New Jersey, Maryland, and Virginia during late August through mid-October in 2002 and 2003. We identified more than 280 different plant species across the study region. Total plant species richness ranged from 12 to 60 species with an average of about 34 per 0.1ha. Perennial forbs were the most diverse functional group, but perennial grasses had about five times more cover than perennial forbs. The top five native plant
species accounted for more than 65% of the cover, whereas the top five nonnative species accounted for only about 12%. Nonnative species richness and cover decreased with native cover. However, as native species richness increased, so did nonnative species richness.
Aboveground biomass decreased with species richness but increased with the percentage cover of switchgrass, big bluestem, and indiangrass. Aboveground biomass averaged 6.6 Mg per ha across sites and years. To predict potential biomass yield on conservation grasslands, corn yield based on site soil series in the NRCS soil survey may be able to be used.