title: Water utilization of tropical hardwood hammocks of the Lower Florida Keys.
abstract: Predawn water potential of representative plant species, together with stable isotope composition of stem water and potential water sources were investigated in four low-elevation tropical hardwood hammocks in the Lower Florida Keys, during a one year period. Hammock species had the lowest water potentials when soil water content was low and/or soil salinity was high, but differences in groundwater salinity had no effect on the water potential. Comparison of D/H ratio of plant stem water with soil and ground water corroborates the conclusion that they are primarily utilizing soil water and not groundwater. Thus, tropical hardwood hammocks are buffered from saline groundwater, and are able to thrive in areas where groundwater salinity is as high as 25‰. The effect of sea level rise on these forests may depend more on changes in the frequency of tidal inundation of the soil surface than on changes in groundwater salinity.
authors.affiliation: Department of Biology, University of Miami, P.O. Box 249118, 33124, Coral Gables, FL, USA.
authors.forename: Naomi
authors.initials: N
authors.lastname: Ish-Shalom
authors.affiliation: Department of Biology, University of Miami, P.O. Box 249118, 33124, Coral Gables, FL, USA.
authors.forename: Leonel da Silveira Lobo
authors.initials: LD
authors.lastname: Sternberg
authors.affiliation: National Audubon Society, 115 Indian Mound Trail, 33070, Tavernier, FL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Ross
authors.affiliation: National Audubon Society, 115 Indian Mound Trail, 33070, Tavernier, FL, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: O'Brien
authors.affiliation: National Audubon Society, 115 Indian Mound Trail, 33070, Tavernier, FL, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Flynn
keywords: Groundwater; Salinity; Stable isotope ratio; Tropical hardwood hammock; Water relations