POSTFIRE POPULATION-DYNAMICS OF BROMUS-JAPONICUS

The introduced Bromus japonicus density, seed production and viable seed in surface litter and upper 3 cm of soil were followed for 5 yr in a South Dakota mixed prairie. Density in April was a function of litter accumulation and autumn precipitation. The importance of litter accumulation to B. japonicus density increased as autumn precipitation decreased. Managed nature preserves in the northern mixed prairie which have effectively excluded fire have improved conditions for the establishment of B. japonicus, at the expense of native species. -from Author