Serpentine barrens are a unique ecosystem found in parts of the United States in small but widely-distributed areas of the Appalachians and the Coast Ranges of California, Oregon and Washington. The barrens occur on outrops of altered ultramafic ophiolites. They are named for minerals of the serpentine group, resulting in serpentine soils, with unusually high concentrations of iron, chromium, nickel and cobalt. These minerals are toxic to most species of plants, resulting in an unusual community of plants, including many near-endemic species. Serpentine barrens often consist of grassland or savannas in areas where the climate would normally lead to the growth of forests.

The ecology of Serpentine Barrens is poorly understood: the evolution of plants adapted to such areas and the relationship between the soil geology and ecology, particularly the ways in which plants handle high concentrations of metals such as nickel, is largely unexplored.

Examples

Rock Springs Nature Preserve in southern Lancaster County, PA is a 176-acre property conserved by the Lancaster County Conservancy that is a prime example of a serpentine barren. It was originally a grassland, but fire suppression led to the conversion of the area to forest. This barren contains the rare serpentine aster, as well as a number of rare species of moth and skippers.

In Chester County, PA, the Nottingham Park Serpentine Barrens was recommended by UMCES as deserving of National Natural Landmark designation, on numerous grounds, including supporting a number of rare and endemic species, an intact population of pitch pine, and also the site having historic significance.

References

1. Anderson, Roger C., et. al., Savannas, Barrens, and Rock Outcrop Plant Communities of North America, Ch. 19, Cambridge University Press, 1999, ISBN 052157322X
2. "Evaluation of the Nottingham Park Serpentine Barrens", UMCES-AL, Retrieved May 10, 2009.
3. Nishanta Rajakaruna, Tanner B. Harris, Earl B. Alexander, "Serpentine Geoecology of Eastern North America: A Review", Rhodora, Vol. 111, No. 945, pp. 21-108. (2009)
4. "Rock Springs Nature Preserve", Lancaster County Conservancy Website, Retrieved May 10, 2009.