Spatial distribution,biomass,and soil seed bank of a naturalized population of alfalfa in native mixed‐grass prairie

摘要

The occurrence of naturalized yellow‐flowered alfalfa ( YFA) ( Medicago sativ a subsp.f alcata) on private and adjacent public rangeland in northwestern South Dakota, USA presents a dilemma.The capacity for natural reseeding demonstrates value for rehabilitating depleted rangelands by increasing soil organic C and N and forage production ( Smith 1997).However, spread of YFA in native rangeland potentially threatens native biological diversity and may result in changes in ecological processes and stability.Study objectives were :1) to describe spatial distribution patterns of YFA,2) to determine associations between YFA occurrence and species richness and biomass production of native plant communities, and 3 ) to examine density and viability of seed bank of YFA.