The Anisoptera of the Savannah River Plant, South Carolina, United States: thirty years later

In 1955, W.H. CROSS (7. Elisha Mitchell scient. Soc. 71: 9-17) surveyed the Anisoptera of a 778 km2 site (Savannah River Plant, SRP) on the upper Coastal Plain of South Carolina, U.S.A. However, since his study, the streams and swamps of the SRP have undergone dramatic changes associated directly with the discharge of thermal effluent into three of the stream systems and construction of a 1206 ha reservoir system on another. — The anisopteran spp. composition is discussed in terms of habitats sampled: (1) unimpacted blackwater streams, (2) post-thermal streams, (3) thermal streams, (4) thermally-altered delta-swamp, (5) post-thermal delta-swamp, (6) ponds and Carolina Bays, (7) Par Pond Reservoir system, and (8) the Savannah River. — Overall, there was no significant difference between the total number of anisopteran spp. collected by Cross (58) and during this study (63), despite the dramatic changes of aquatic habitats of the SRP. This was not surprising when considering the following: (1) the majority (75%) of the spp, collected during both studies were common ubiquitous limnophilic forms; (2) many of these were adapted for the fluctuating and unpredictable temperature and water levels occurring in the lentic habitats of the SRP; and (3) the colonization of newly-created habitats was enhanced by the long flight periods of many spp., and by the asynchronous multivoltinism of some. However, we could not find 6 spp. reported by Cross, but did collect 11 spp. not reported by him.