Ecology of fire-influenced Cladium jamaicense marshes in Guadeloupe, Lesser Antilles

Abstract

The sawgrass Cladium jamaicense forms extensive, quite monospecific stands within coastal swamps of the Caribbean region. Fire acts as an important ecological factor in the control of vegetation dynamics in these marshes. In the archipelago of Guadeloupe, during the dry season, fires are set as a customary practice nearly each year. The purpose of this study was to characterize the ecology of Cladium marshes in Guadeloupe and to assess more specifically floristic and structural changes that might occur within these marsh communities once the setting of fires has been discontinued. Fifty-four 2 × 10 m plots were set up along seaward/landward transects including mangrove and swamp forest edges. The main characteristics of soil and vegetation in a regularly burned marsh were compared to those of two marshes where the setting of fires had been discontinued for at least 15 years. Cladium height and species richness were negatively correlated to water level, redox potential, and salinity, and followed decreasing landward/seaward gradients. Discontinuation of fire regime modified the vertical structure of the vegetation and the marsh flora by promoting woody species vs. herbaceous species. Paleoecological investigations are needed for a better understanding of the influence of anthropogenic fires in the long-term dynamics of such marshes.