Water Analysis of Habitats of Sphagnum in the Coastal Plain of North and South Carolina

Abstract

The habitats of approximately 20 species of Sphagnum in the Coastal Plain of North and South Carolina are briefly described. Water samples from a range of specific habitats showed generally low pH values (3.5-5.6) and low spe- cific conductivity (18 to 118 pmho). Data relating species presence to height above the local water table confirm the widespread observation that Sphagnum species tend to be narrowly distributed along a gradient from strictly aquatic to variously less aquatic species. Coastal Plain habitats, such as pocosins and savannahs, differ sufficiently from more northern bogs and fens to continue the use of separate names for them. There are approximately 20 species of Sphagnum in the Coastal Plain of North and South Carolina. Including varieties, the total number of taxa is about 25. Although most of these taxa were illustrated and discussed briefly by Blomquist (1938) following the taxonomy of Andrews (1913), essentially no information is available about the ecological relationships of Coastal Plain sphagna. Extensive observations and collecting in the field, often aided by Sphagnum specialists from other regions, left the distinct impression that the Coastal Plain species of Sphagnum have definite habitat preferences. Following the general habitat classification of Wells (1928, 1942), a preliminary description of these habitats and their associated species, based on field notes and presence lists, was given by Lane (1979), and is summarized briefly below. Sphagnum does not occur commonly in such habitats as pine flatwoods, oak-hickory- pine forest, wire-grass sandhills, or in any seaside habitats, including maritime forests and salt marshes. Sphagnum is generally common in swamps, especially cypress (Taxodium distichum (L.) Rich. and T. ascendens Brognm.) and gum Nyssa sylvatica Marsh., N. biflora Walt., and N. aquatica L.) swamps along creeks or lake shores that may include Atlantic white cedar (Chamaecyparis thyoides (L.) BSP) as well. In these swamps two varieties of S. macrophyllum often occur floating in deep pools. Sphagnum forms a sig- nificant portion of wet evergreen shrub bogs, or pocosins, and grass-sedge bogs, also known as savannahs. Pocosins, which can be quite variable as to both the species of dominant shrubs and individual site conditions, often contain members of the Sphagnum section of the genus, such as S. perichaetiale, S. imbricatum, S. henryense and S. ma- gellanicum, as well as other species. Drainage ditches through pocosins or along roadsides often provide disturbed habitats for these species. The habitat with the most unusual assemblage of species is the savannah. Savannahs often result from repeated fires that eliminate the shrub layer of pocosins (Christensen 1977) leaving scattered trees (Pinus serotina Michx. or P. palustris Mill.) over a diverse mixture of herbs and wire grass