Freshwater and saltwater flooding response for woody species common to barrier island swales

Abstract

Flood sensitivity of five woody species common to barrier island swale habitats was quantified in a glasshouse study to examine potential mechanisms affecting observed small-scale distribution patterns. Differential response to short-term (30 d duration) freshwater and saltwater flooding occurred among the five species. OnlyBaccharis halimifolia was sensitive to freshwater flooding. At both low (2 and 5 g L−1) and mid-range (10 g L−1) salinity,Myrica cerifera, Pinus taeda, andB. halimifolia were more sensitive thanJuniperus virginiana orIva frutescens. At low salinity, stomatal conductance was significantly reduced forM. cerifera, P. taeda, andB. halimifolia, although recovery occurred and there was no mortality. At midrange salinity, all five species showed reduced stomatal conductance, but recovery differed. Mortality was highest forM. cerifera andB. halimifolia (60%), followed byP. taeda (40%),I. frutescens (25%), andJ. virginiana (20%). In contrast, 100% mortality occurred for all species in high salinity treatments of 20 and 30 g L−1. Interspecific differences in response to flooding may be a mechanism affecting small-scale distribution patterns of woody species in barrier island swales.