Impact of groundwater depth and soil salinity on riparian plant diversity and distribution in an arid area of China

Yong Zeng,Chengyi Zhao,Guanghui Lv,Fengzhi Shi,Michael Schneider,Yan Li

doi:10.1038/s41598-020-64045-w

Abstract

Riparian plant diversity in arid regions is sensitive to changes in groundwater. Although it is well known that groundwater has a significant influence on plant diversity, there have been few studies on how groundwater and soil salinity impact plant community in desert riparian ecosystems. Therefore, we surveyed 77 quadrats (100 m × 100 m) to examine the relationship between groundwater depth, groundwater salinity, soil salinity and plant community in the upper reaches of the Tarim River. Data were analyzed with two-way indicator species analysis (TWINSPAN), detrended canonical correspondence analysis (DCCA) and principal component analysis (PCA). The results indicated that Populus euphratica, Tamarix ramosissima, and Phragmites australis were the dominant plants among trees, shrubs and herbs, respectively. Five plant community types were classified. There were significant differences in species diversity, soil moisture, soil salinity, groundwater depth and groundwater salinity across the community types. The composition and distribution of plant community are significantly influenced by groundwater depth, groundwater salinity, soil moisture, distances from the river to the quadrats, soil pH, electrical conductivity, total salt, CO32−, Cl−, SO42−, Ca2+, Mg2+, Na+ and K+. Shallow groundwater depth, low groundwater salinity, and high soil moisture and soil salinity were associated with higher plant diversity.

Highlights

Riparian areas are in the transition zone between aquatic and terrestrial ecosystems and play a significant role in the energy and nutrient fluxes between the two types of ecosystems[1]
22 plant species were found in the upper reaches of the Tarim River, which is higher than the number of species recorded in the lower reaches[33]
The plant importance value analysis showed that P. euphratica and T. ramosissima were the most significant species in the tree and shrub layers, respectively (Table 1)

Summary

Introduction

Riparian areas are in the transition zone between aquatic and terrestrial ecosystems and play a significant role in the energy and nutrient fluxes between the two types of ecosystems[1]. Riparian vegetation has become less stable as groundwater tables have dropped, leading to declines in arid desert river systems[4]. Salt accumulation associated with high rate of evaporation of shallow groundwater through the unsaturated zone has been shown to influence plant composition in many arid riparian systems[13]. It is necessary to understand the relationship between groundwater, soil salinity and the plant community in arid riparian ecosystems. Many studies have examined the relationship between community and groundwater depth in the lower reaches of the Tarim River[6,11,18]. It is well known that groundwater has a significant influence on plant diversity, there have been few studies on how groundwater and soil salinity impact the plant community in desert riparian ecosystems. The upper reaches, constituting the core area of the Tarim River riparian zone, are less well studied[25]

Objectives

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Results

Conclusion