Altered Ecosystem Processes as a Consequence of Juniperus virginiana L. Encroachment into North American Tallgrass Prairie

Abstract

Expanding cover and abundance of woody plants in grasslands and savannas (afforestation) is a worldwide phenomenon with the potential to alter ecosystem structure and function in a variety of important ways (Van Auken 2000; Archer et al. 2001). Increases in woody plant cover, or conversion of grasslands to woodlands, may alter ecosystem processes such as nutrient cycling and availability, which influence primary productivity, resource competition, species richness, and composition, as well as the interactions between plants, animals, and microorganisms (Vitousek 2004). Nutrient cycling dynamics and the long-term stability of carbon (C) and nitrogen (N) pools may also change as a result of a shift in the allocation of plant biomass and ecosystem C and N stocks from largely belowground in grasslands to aboveground in woodlands. These ecosystem changes may, in turn, alter regional terrestrial and atmospheric biogeochemistry if newly established woodlands act as a sink for C and N (Moiser 2001).