Wetland tree transpiration modified by river-floodplain connectivity

Journal of Geophysical Research G: Biogeosciences
By: , and 

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Abstract

Hydrologic connectivity provisions water and nutrient subsidies to floodplain wetlands and may be particularly important in floodplains with seasonal water deficits through its effects on soil moisture. In this study, we measured sapflow in 26 trees of two dominant floodplain forest species (Celtis laevigata and Quercus lyrata) at two hydrologically distinct sites in the lower White River floodplain in Arkansas, USA. Our objective was to investigate how connectivity-driven water table variations affected water use, an indicator of tree function. Meteorological variables (photosynthetically active radiation and vapor pressure deficit) were the dominant controls over water use at both sites; however, water table variations explained some site differences. At the wetter site, highest sapflow rates were during a late-season overbank flooding event, and no flood stress was apparent. At the drier site, sapflow decreased as the water table receded. The late-season flood pulse that resulted in flooding at the wetter site did not affect the water table at the drier site; accordingly, higher water use was not observed at the drier site. The species generally associated with wetter conditions (Q. lyrata) was more positively responsive to the flood pulse. Flood water subsidy lengthened the effective growing season, demonstrating ecological implications of hydrologic connectivity for alleviating water deficits that otherwise reduce function in this humid floodplain wetland.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Wetland tree transpiration modified by river-floodplain connectivity
Series title Journal of Geophysical Research G: Biogeosciences
DOI 10.1002/2015JG003208
Volume 121
Issue 3
Year Published 2016
Language English
Publisher Wiley
Publisher location Hoboken, NJ
Contributing office(s) Wetland and Aquatic Research Center
Description 14 p.
First page 753
Last page 766
Country United States
State Arkansas
Other Geospatial Dale Bumpers White River National Wildlife Refuge
Online Only (Y/N) N
Additional Online Files (Y/N) N