Title

Water Uptake Patterns of an Invasive Exotic Plant in Coastal Saline Habitats

Authors

Sharon Ewe, Department of Biology, University of MiamiFollow
Leonel da Silveira Lobo Sternberg, Department of Biology, University of MiamiFollow

Abstract

Schinus terebinthifolius Raddi (Schinus) is one of the most widely found woody exotic species in South Florida. This exotic is distributed across environments with different hydrologic regimes, from upland pine forests to the edges of sawgrass marshes and into saline mangrove forests. To determine if this invasive exotic had different physiological attributes compared to native species in a coastal habitat, we measured predawn xylem water potentials (Ψ), oxygen stable isotope signatures (δ¹⁸O), and sodium (Na⁺) and potassium (K⁺) contents of sap water from plants within: (1) a transition zone (between a mangrove forest and upland pineland) and (2) an upland pineland in Southwest Florida. Under dynamic salinity and hydrologic conditions, Ψ of Schinus appeared less subject to fluctuations caused by seasonality when compared with native species. Although stem water δ¹⁸O values could not be used to distinguish the depth of Schinus and native species' water uptake in the transition zone, Ψ and sap Na⁺/K⁺ patterns showed that Schinus was less of a salt excluder relative to the native upland species during the dry season. This exotic also exhibited Na⁺/K⁺ ratios similar to the mangrove species, indicating some salinity tolerance. In the upland pineland, Schinus water uptake patterns were not significantly different from those of native species. Differences between Schinus and native upland species, however, may provide this exotic an advantage over native species within mangrove transition zones.

Comments

Sharon Ewe is currently a faculty member in the Department of Earth Sciences and the Southeast Environmental Research Center at Florida International University.

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Ewe, S.M.L., L.d.S.L. Sternberg. 2007. Water Uptake Patterns of an Invasive Exotic Plant in Coastal Saline Habitats. Journal of Coastal Research 23(1): 255-264.