Ecophysiology of Schinus terebinthifolius contrasted with native species in two south Florida ecosystems

Both field and greenhouse studies were carried out to determine physiological aspects of Schinus terebinthifolius Raddi (Schinus ) that could potentially contribute to its widespread distribution in Florida. Water uptake and gas exchange of the invasive exotic Schinus were compared with native species in two ecosystems in South Florida, in saline coastal Southwest Florida and in the upland communities of Everglades National Park. Two communities were compared in each ecosystem. Growth and gas exchange patterns of Schinus under controlled saline and flooded conditions were also compared against native species.In saline southwest Florida, Schinus showed salinity tolerance based on predawn water potentials and sodium-potassium ratios. Differences among species were pronounced in the dry season, when soilwater salinity was high. Although Schinus water uptake patterns indicated that it was not as affected by seasonality as native species, its gas exchange was significantly reduced and appeared to be the most curtailed relative to native species during the dry season in the saline transition zone site.In the rock pineland of Everglades National Park, Schinus proved to be the species least affected by root flooding in terms of water potentials during the wet season. Gas exchange of the exotic was however not significantly different from native species.Glasshouse studies of Schinus under saline conditions showed the exotic to have similar gas exchange as the native species; this finding did not agree with field gas exchange data most likely because the controlled study had a maximum salinity of 15 parts per thousand (p.p.t.) while 38 p.p.t. was recorded during field measurements. Schinus growth was not affected by salinity, unlike most native species. The exotic allocated more biomass to stems for all treatments than native species. Under controlled flooding in the glasshouse however, Schinus responded similar to native species.Schinus\u27 distinct water uptake patterns relative to native species, as shown by the field studies, could contribute to its presence both in the saline Southwest Florida communities and the upland Florida Everglades