We used microfossils preserved in salt-marsh peat to understand the landscape processes (both natural and anthropogenic) that have influenced the environment. Variations in the abundance of fossil pollen of native species suggest that the vegetation of this small, exposed island has been dominated by low, shrubby vegetation since before the arrival of Europeans in the early 1600s. Increases in non-native species since that time may reflect disturbance of the soil associated with grazing and other activities. Sorrel (Rumex) pollen, which indicates local grazing, declines by the late 19th century, whereas Chenopodiaceae/Amaranthaceae pollen, an indicator of disturbed soil, is most abundant since 1900. Charcoal abundance shows that fires, probably ignited by humans both before and after 1600 A.D., have burned on the island throughout the last 1000 years. In addition, increases in soot and opaque spherules in sediments reflect increased air pollution during the last 100 years. Our analyses provide benchmarks for modern management by documenting pre-European conditions as well as the extent to which the modern environment differs from that prior to the settlement of Massachusetts Bay by Europeans.