Evaluating the influence of water table depth on transpiration of two vegetation communities in a lake floodplain wetland

Qi Zhang,Xianghu Li,Xiuli Xu,Yunliang Li

doi:10.2166/nh.2016.011

Qi Zhang, Xianghu Li + Show 2 more

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https://doi.org/10.2166/nh.2016.011

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Abstract

Groundwater plays an important role in supplying water to vegetation in floodplain wetlands. Exploring the effect of water table depth (WTD) on vegetation transpiration is essential to increasing understanding of interactions among vegetation, soil water, and groundwater. In this study, a HYDRUS-1D model was used to simulate the water uptake of two typical vegetation communities, Artemisia capillaris and Phragmites australis, in a floodplain wetland (Poyang Lake wetland, China). Vegetation transpiration was compared for two distinct hydrological conditions: high water table (2012) and low water table (2013). Results showed that vegetation transpiration in the main growth stage (July–October) was significantly influenced by WTD. Under high water table conditions, transpiration of A. capillaris and P. australis communities in the main growth stage totaled 334 and 735 mm, respectively, accounting for over 90% of the potential transpiration. Under low water table conditions, they decreased to 203 and 510 mm, respectively, due to water stress, accounting for merely 55% of the potential transpiration. Scenario simulations found different linear relationships between WTD and the ratio of groundwater contribution to vegetation transpiration. An increase of 1 m in WTD in the main growth stage may reduce the ratio by approximately 25%.

Highlights

Xiuli Xu Qi Zhang Yunliang Li Xianghu Li Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, INTRODUCTION
When the land was flooded from May 17, 2012 to August 31, 2012, the soil profile was saturated and vegetation transpiration and evaporation were both assigned at the potential rate
In floodplain wetlands, understanding the effect of water table depth (WTD) on vegetation transpiration is important for revealing the interactions between soil water and vegetation

Summary

Introduction

Wetland degeneration caused by water table drawdown, drying of rivers, and rainfall reduction has become an increasingly acute problem In areas with a shallow water table, upward movement of groundwater into the root zone plays an important role in supplying water to plants (Hurst et al ; Satchithanantham et al ). Xu et al | Effects of water table depth on vegetation water use in Poyang Lake wetland

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