|Tracy, Benjamin - UNIVERSITY OF ILLINOIS|
Submitted to: Proceedings of the National Conference on Grazing Lands
Publication Type: Proceedings
Publication Acceptance Date: December 5, 2000
Publication Date: December 8, 2000
Citation: Sanderson, M.A., Tracy, B.F., Skinner, R.H., Gustine, D.L., Byers, R.A. 2000. Changes in plant species composition of northeastern grazinglands during the 20th century. Proceedings of the National Conference on Grazing Lands.365-373. Interpretive Summary: Several ecological studies have shown that increased plant diversity can benefit ecosystem processes such as nutrient cycling. Our goal is to determine whether increasing plant diversity will result in similar benefits in northeastern grazinglands. Comparison of pasture surveys spanning the 20th century revealed that the species composition of pastures shas remained relatively stable with bluegrass and white clover predominating. There appears to have been a decrease in weedy grasses such as povertygrass and sweet vernalgrass, which may indicate improved soil fertility management on grazinglands or abandonment of marginal agricultural land. The stability of plant species richness of grazinglands in the northeastern U.S. is one indicator of the sustainability of pasture- based livestock systems.
Technical Abstract: Recent developments in grassland-based livestock production systems have created a need for new information on pasture and forage ecology and management. Several ecological studies suggest that increased plant species diversity may improve ecosystem functioning and productivity. During 1998 to 2000, we surveyed pastures on several farms in the northeastern U.S. for plant species richness as a first step in a long-ter research program with the goal of understanding the role of species diversity on grazingland ecosystem functioning and productivity. Results indicate a wide range in plant species diversity (16 to 49 species per pasture); however, two or three cool-season grasses and legumes dominated most grazing systems. We related these new survey results to historical data on plant species composition in northeastern pastures to assess landscape and regional scale changes in plant diversity. Our analysis indicated that although land use has changed dramatically in the northeast during the 20th century, plant species composition in pastures does not seem to have changed much. Pasture surveys in the 1920's and 1930's revealed that bluegrass and white clover were among the most abundant plant species across the northeast. In early surveys, however, povertygrass (Danthonia spicata), sweet vernalgrass (Anthoxanthum odoratum), and Agrostis species were more abundant than in our surveys during the late 1990's. This difference may reflect improved soil fertility management on farms, or abandonment of marginal agricultural land. Pastures in the northeast have remained relatively stable in plant species composition during the last 70 to 80 years.