Seasonal water use by deciduous and evergreen woody species in a scrub community is based on water availability and root distribution

Patrick Z. Ellsworth, Leonel S.L. Sternberg

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

In a seasonally dry plant community of central Florida, USA, that experiences water limitation in the dry season and high water availability in the wet season, we first tested whether evergreen woody species shift from shallow water in the wet season to deep water in the dry season. Second, we tested whether deciduous woody species restrict water uptake to the shallow soil during the wet season and cease water uptake during the dry season. To address these questions, we measured water source use of two deciduous and three evergreen species over 13months using stable isotopes. As hypothesized in previous studies, we showed that leaflessness in deciduous plants is an important source of stem water isotopic fractionation. Therefore, we compared stable isotope ratios of stem water only when deciduous species had leaves and found that all species, except the evergreen Lyonia ferruginea, used proportionally the same water sources. Early dry season water use was based on water availability for all species except L. ferruginea, and deep soil (50-150cm) was the most important water source. During the late dry and wet seasons, water uptake from each soil layer was based on its respective proportion of fine roots. Nevertheless, deep water remained an important water source throughout the year. This study clearly demonstrates the limitations of using stable isotopes of stem water when comparing deciduous versus evergreen species. Further, this study is the first to directly quantify depth of water uptake via isotope analysis and couple these findings with root distribution.

Original languageEnglish (US)
Pages (from-to)538-551
Number of pages14
JournalEcohydrology
Volume8
Issue number4
DOIs
StatePublished - Jun 1 2015

Keywords

  • Deciduous
  • Dry seasonal plant community
  • Evergreen
  • Florida sandhill
  • Rooting depth
  • Stable isotopes
  • Water source use

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology
  • Earth-Surface Processes

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