Seed banks and propagule dispersal in crested wheatgrass stands.
Abstract
4 sites in SE Idaho previously sown to Agropyron cristatum were compared with adjacent native plant communities. Sites 1 and 2 were essentially monoculture stands of A. cristatum, while sites 3 and 4 showed some reinvasion by the predominating native sp. Artemisia tridentata. Native understorey vegetation comprised mainly cool season perennial grasses including Elymus elymoides, Pseudoroegneria spicata [Elymus spicatus] and Oryzopsis hymenoides. A cristatum was found to predominate in seed banks under pure stands and was codominant with A. tridentata on sown sites 3 and 4. The distribution of viable propagules of A. tridentata, E. elymoides and A. cristatum in the soil was closely associated with the distribution of mature plants, although dispersal of E. elyomoides into stands of A. cristatum was very sparse despite an abundant seed source. It was concluded that there was little dispersal of propagules from native communities into adjacent A. cristatum stands.