EFFECTS OF CONSERVATION RESERVE PROGRAM FIELD AGE ON AVIAN RELATIVE ABUNDANCE, DIVERSITY AND PRODUCTIVITY

Introduced grass dominated Conservation Reserve program (CRP) fields w ere monitored in summer 1992 in Gratiot County, Michigan, to determine the relationship between field age and avian relative abundance, dive rsity, and productivity. Younger CRP fields (1-2 years old), best desc ribed as a combination of forbs and bare ground, had the greatest dive rsity and relative abundance of avian species. Older CRP fields (3-5/6 years old) were a combination of grasses and deep litter cover and ha d the greatest avian productivity. We recommend that after 3-5 growing seasons CRP fields be manipulated to provide a variety of successiona l stages to maintain simultaneously high avian relative abundance, div ersity, and productivity.