Effects of two categorically differing emergent wetland plants on evapotranspiration

Authors: Kiniry, James; Williams, Amber; REISNER, LOUISE - Texas A&M University; Hatfield, Jerry; KIM, SUMIN - Dankook University

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2022
Publication Date: 1/4/2023
Citation: Kiniry, J.R., Williams, A.S., Reisner, L., Hatfield, J.L., Kim, S. 2023. Effects of two categorically differing emergent wetland plants on evapotranspiration. Agrosystems, Geosciences & Environment. 6(1). Article e20331. https://doi.org/10.1002/agg2.20331.
DOI: https://doi.org/10.1002/agg2.20331

Interpretive Summary: Wetlands are an important component of many landscapes. However, emergent plants have had variable impacts on reported water loss from wetlands. In this study, we investigated the impacts of black willow and Pennsylvania smartweed on water loss from standing water relative to water loss with no emergent plants. We measured water temperature, leaf cover, and water levels weekly during the growing season. Open water evaporation was lower than black willow and smartweed evapotranspiration. Smartweed increased water use 37% relative to the control and black willow increased water use 66% on average over three years. These differences were even more dramatic when calculated for only the last two years. Smartweed increased water use by 40% and black willow by 92%. Pans with plants had a lower water temperature than that of the control in the summer. Smartweed transpired more than the willows. The willow root system and leaf area greatly increased after the first year, resulting in more water loss and lower summer water temperature. Low and high density treatments on the whole had no significant differences in any metrics gathered, with few exceptions. This evapotranspiration (ET) information informs wetland water balance questions and is useful for process-based models.

Technical Abstract: While wetlands are an important component of many landscapes, emergent plants have had variable impacts on reported wetland hydrology. In present study, we investigated the impacts of black willow (Salix nigra) and Pennsylvania smartweed (Persicaria pensylvanica) on water loss from standing water relative to water loss with no emergent plants. We measured water temperature, leaf area index (LAI) and water levels weekly during the growing season. Open water evaporation was lower than black willow and smartweed evapotranspiration. Mean increases in water use relative to the control were 37% for smartweed and 66% for black willow. These differences were even more dramatic when calculated for only the last two years. Smartweed increased water use by 40% and black willow by 92%. Pans with plants had lower water temperatures than those of the control in the summer. Smartweed transpired more than willows. The willow root system and leaf area greatly increased after the first year, resulting in more water loss and lower summer water temperature. Low and high density treatments on the whole had no significant differences in any metrics gathered, with few exceptions. This evapotranspiration (ET) information informs wetland water balance questions and is useful for process-based models.