A forty-seven year comparison of the vascular flora at three abandoned rice fields, Georgetown, South Carolina, U.S.A.

Abstract

The vascular flora identified in 1968–1969 in three rice fields of the Winyah Bay Estuary at the Bell W. Baruch Institute for Marine Biology and Coastal Research, Georgetown County, South Carolina, abandoned in 1915, was compared with the vascular flora present in 1987–1991 and 2013–2015. Twenty vascular plant species were identified in 1968–1969 and 22 in 2013–2015 at the most saline marsh, Thousand Acre Rice Field. Forty-seven taxa were reported at Airport Marsh in 1968–1969 and 27 in 2013–2015. Fifty-six taxa were reported at Alderly in 1968–1969 with 41 identified there in 2013–2015. A parsimony algorithm was used to evaluate the distribution and co-occurrence of vascular brackish marsh species in these fields sampled at the three intervals. There was a reduction in flora at the two least saline sites, Alderly and Airport Marsh, from 1968–69 to 1987–91 and 2013–2015. Three factors—rising sea level, an increase in water salinity, and invasion by Phragmites australis—may explain this shift. There was also a shift in the flora at Thousand Acre Rice Field from 1967–1969 to 1987–1991 and 2013–2015 after the marsh was savaged by Hurricane Hugo in 1989. Invasion by non-native Phragmites australis at all sites and increase in water salinity at all sites best explain the reduction in vascular plant species at Airport Marsh and Alderly over the 47-year collection period.