Submitted to: Landscape Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 1, 2010
Publication Date: April 21, 2010
Citation: Goslee, S.C., Sanderson, M.A. 2010. Landscape Context and Plant Community Composition in Grazed Agricultural Systems. Landscape Ecology. 25:1029-1039. Interpretive Summary: The environment at a site - soils, climate, topography - largely determines what species can thrive at that site. For some groups, including plants, birds and insects, the landscape surrounding a site also influences species at that site by altering seed dispersal or animal movements, or by its effect on predators or pathogens in the local area. The potential importance of landscape context to grazed pastures has never been examined for the northeastern United States. Forage species were little affected by surrounding land use or landscape pattern, but composition of nonforage species was strongly related to local land use and landscape pattern, as well as to soils and climate. Nonforage species found in pastures contribute greatly to local and regional biodiversity in agricultural landscapes. This knowledge of landscape effects will aid producers, landscape planners and ecologists in managing local and regional plant diversity.
Technical Abstract: Temperate humid grazinglands are an important component of the landscape of the northeastern United States, as well as of the economy of this region, yet unlike their European counterparts, little is known about their basic ecology. During an eight-year survey of 28 farms across the northeastern United States, we sampled 239 modified Whittaker plots on grazed grasslands, and collected data on the topography, climate and soils of each site. Surrounding land use and landscape metrics were calculated from the NLCD 2001 for six radii (250 - 2000 m) surrounding each site. Species diversity can be divided into planned (forage) species and associated (nonforage) species. Composition of forage species was not strongly related to environmental factors or landscape context. Composition of nonforage species was influenced by elements from all classes of explanatory variables, particularly the presence of species in 1000-m**2 plots. The lower variability in the forage species pool and the management applied to forage species, but only incidentally to nonforage species, probably explains the differences in responses of the two groups of species. Seed dispersal pathways may also contribute to differences between the two groups. Site management for forage species only probably does not need to consider the landscape context, but landscape management, biodiversity management, and land use planning must consider pastures as functional plant communities that are components of the interconnected regional landscape.