SAWGRASS SEEDLING RESPONSES TO TRANSPLANTING AND NUTRIENT ADDITIONS

Understanding Cladium jamaicense (sawgrass) seedling establishment is an important component of an Everglades restoration program because th e degree of sawgrass recovery and concurrent Typha domingensis (cattai l) decline will be used to evaluate restoration success. To understand sawgrass recovery at locations with increased soil nutrients, we test ed the effects of transplanting sawgrass seedlings to pots at differen t densities and investigated how nutrient additions affect seedling gr owth. Survivorship of seedlings transplanted into moist commercial pot ting soil at three densities ranged from 61% to 95%. After 6 months, m aximum survivorship (90%) occurred at medium densities (2-4 seedlings per pot 16 cm in diameter). Nutrient additions, totaling 6.5 N g/m(2), 9.8 P g/m(2), 6.5 g/m(2), were applied approximately 4 months after s eedlings were transplanted. The biomass of the plants receiving nutrie nt additions (pulsed) was significantly higher (by over 30%) than plan ts with no nutrient addition (control). Photosynthetic rates for nutri ent-enriched plants (measured 6-weeks after the nutrient additions) we re significantly greater (by 32-45%) than for control plants. Instanta neous leaf water use efficiency increased significantly (by more than 20%) in pulsed plants. The results suggest that preventing root damage is crucial for the success of transplanted sawgrass seedlings and tha t nutrient additions enhanced seedling growth.