Revegetation following artificial disturbance. Progress report, 1 March 1976--28 February 1977. [Irradiation]

Seedbeds were prepared and seedings made in May, August, and September of 1976 using 5 different seed mixtures at Rocky Flats. Early observations indicate very poor results. The vegetation receiving chronic exposure to irradiation at the Grasslands Irradiation Site appears to be at equilibrium as measured by diversity or coefficient of community with a 50 percent response value of approximately 15 R/h. Recovery patterns in the short-term seasonally exposed vegetation and those non-irradiated plots that were burned, scraped, or rototilled were essentially the same as last year. Diversity values had returned to normal in all plots. Cover by Bouteloua gracilis had returned to normal in the burn plots and those partially damaged by ionizing radiation. B. gracilis cover in the plots heavily damaged by ionizing radiation and those plots scraped or rototilled was essentially zero although there were some B. gracilis seedlings present in those plots.