Document: CHR-3-37-22

Morphological variation in twelve salt marsh plant species on Sapelo Island, GA.

RICHARDS, C.L.* ¹, S.C.PENNINGS ² and L.A.DONOVAN ¹

University of Georgia,Athens, GA, USA ¹
University of Georgia Marine Institute, Sapelo Island, GA, USA ²

Abstract:
Plants adopt different strategies to deal with environmental heterogeneity ranging from phenotypic plasticity to microscale genetic differentiation. Salt marshes are stressful habitats on a temporally and spatially variable scale making them ideal to study the different strategies plants have evolved for coping with environmental heterogeneity. We investigated morphological variation of the twelve most common salt marsh plants on Sapelo Island: Aster tenuifolius, Batis maritima, Borrichia frutescens, Distichlis spicata, Iva frutescens, Juncus roemerianus, Limonium carolinianum, Salicornia biglovii, Salicornia virginica, Spartina alterniflora, Spartina patens, and Sporobolus virginicus. For each species, eight sites around the perimeter of the island were chosen to encompass the full morphological range of that species on the island. At each site, transects sampled the full range of distribution across elevational and salinity gradients for each species. Soil samples were collected for each plant (N=1060) in August 1999 and processed for relative water content and salinity. Salinity was a significant predictor (P <.05) of height and leaf length for B. frutescens, D. spicata, J. roemerianus, L. carolinianum, S. biglovii, S. virginica, S. alterniflora, S. patens as well as predicting height in B. maritima and leaf length in I. frutescens. Soil relative water content was a significant predictor of height and leaf length in D. Spicata, J. roemerianus and S. patens as well as predicting height in A. tenuifolius and S. virginicus and leaf length in S. biglovii. Variation in plant height (determined by coefficient of variation) was greatest for S. virginica) (64.3), B. maritima) (57.66), and A. tenuifolius (53.3), and least for J. roemerianus(25.5). Differences in variation of leaf length were not as pronounced. Although these salt marsh plants species span different ranges of salinities, most respond phenotypically to the heterogeneous environment of the marsh.

Keywords: salt marsh plants, phenotypic plasticity, environmental heterogeneity, Sapelo Island

This abstract is being presented at: 10:30 AM in session:
SALT MARSHES