A COMPARISON OF THE VEGETATION OF TWO SAND DUNE AREAS IN NORTHWESTERN SOUTH DAKOTA, U.S.A.

To document and compare vascular plant species and soils present in each of two sand dune areas in Harding and Perkins Counties of northwestern South Dakota, six transects were established. Two transects ran across dune tops, two in parallel swales and two in blowout areas. In transects monitored four times per year vascular plant species were determined for five years in Harding County and for four years in Perkins County. Eighty-three species were found in transects in Harding County, and 75 species were found in the Perkins County transects for a total of 98 species observed in the study. Relatively high numbers of native species (86-100%) were present in all transects. The mean coefficient of conser vatism of the Harding County transects was 4.5 and that of the Perkins County transects was 4.7. Floristic Quality Indices were 38.7 and 39.0 for Harding and Perkins County sites, respectively. Analyses of soil and vegetation characteristics showed that blowout transects of the two areas were most similar, and swale transects were least similar.