Community development following gamma radiation at a pine-oak forest, Brookhaven National Laboratory, Long Island, New York1.

We investigated a unique source of forest disturbance: gamma radiation. While the temporal patterns of ecological succession are well understood for the forests of eastern North America, this is not the case for massively irradiated forests. Our objective was to compare vascular plant community change after irradiation at the five vegetation zones described in 1962 by Woodwell at Brookhaven National Laboratory, Long Island, New York. No follow-up studies have been done since the gamma radiation experiments were terminated in 1978. Ecological successional theory (e.g., Bormann and Likens, 1994, Likens and Bormann, 1995) does not explain long-term forest recovery after radiation damage. Our null hypothesis was that 47 yr after initial gamma ray exposure, the sites would have recovered such that floristic composition would be the same as the pine-oak forest control. This hypothesis was rejected statistically. In 2007/2008, the five concentric zones of vegetation centered about the gamma source retained their floristic heterogeneity as measured by Jaccard coefficients.