Leaf Level Gas Exchange in Wetland Plant Species: Implications for Estimating Climate Scenarios and Water Use
Abstract
Leaf-level gas exchange determines the tradeoff between carbon assimilation and water loss in wetland ecosystems. In restored wetlands built for climate mitigation, characterizing transpiration is critical to a complete understanding of the ecosystem services provided. There has been speculation that wetland plants that are adapted to growing in a flooded landscape may not undergo stomatal closure in response to stressors because their environments are never water limited. In this study we investigated the leaf-level response of photosynthesis, transpiration, and stomatal conductance to varying levels of light, vapor pressure deficit (VPD), and temperature in the San Francisco-San Joaquin Delta. Measurements were taken using a Licor 6400 on typha (cattail), a non-native species in this ecosystem, and Schoenoplectus (tule), a native species, at two sites in the Delta. Average light response curves for each species were determined to explore water use efficiency by both species. In both species transpiration increased with increasing temperature. When examining the response of transpiration to VPD, we observed a stronger decreasing trend from tule than cattail. Furthermore, we observed a synergistic effect of temperature and VPD on stomatal conductance. The data suggest a more pronounced decrease in conductance in response to increasing VPD at high temperatures compared to low temperatures, and a more pronounced increase of conductance with increasing temperature at low VPD compared to high VPD. By gaining deeper insight into leaf level gas exchange of wetland plant species, we will be able to build more accurate ecosystem models, further our understanding of the carbon assimilation-water loss tradeoff, and craft more effective and informed policy regarding wetland restoration.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H23P2125C
- Keywords:
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- 0416 Biogeophysics;
- BIOGEOSCIENCES;
- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES;
- 1813 Eco-hydrology;
- HYDROLOGY;
- 1818 Evapotranspiration;
- HYDROLOGY