Groundwater Depth and Soil Properties Are Associated with Variation in Vegetation of a Desert Riparian Ecosystem in an Arid Area of China

Abstract

Abstract:Groundwater is a major driving force for plant community distribution in arid areas worldwide. Although it is well known that groundwater has a significant impact on soil and vegetation, there is little information on how groundwater depth affects soil and vegetation in an arid inland basin desert riparian ecosystem. Therefore, quantitative analysis of the relationships among groundwater depth, soil properties and plant community distribution is necessary. A desert riparian ecosystem in the lower reaches of the Heihe River in an arid area of Northwest China was used to determine quantitative relationships among groundwater depth, soil and vegetation. Groundwater depth significantly increased with increased distance from the river. Soil and vegetation characteristics showed a significant trend with increasing groundwater depth. With increasing groundwater depth, soil water content, soil total nitrogen, soil total carbon, soil available phosphorus and soil available potassium decreased, while the soil bulk density and soil carbon:nitrogen (C:N) ratio increased. Soil pH and soil electrical conductivity followed quadratic function relationships with groundwater depth. Species richness, aboveground biomass, community coverage, community height, foliage projective cover and leaf area index all significantly decreased with increased groundwater depth. Groundwater depth and soil were associated with vegetation variance, explaining 85.8% of the vegetation variance. Groundwater depth was more important in explaining vegetation variance than soil properties (soil bulk density) and soil pH. Our observations indicate that changes in groundwater depth would have a significant influence on desert riparian forest vegetation, and that maintaining appropriate groundwater depth is necessary to preserve the riparian ecosystem.

Spatial variation in leaf nutrient traits of dominant desert riparian plant species in an arid inland river basin of China

“…Groundwater was the critical water resource for the survival of desert plants, and it also regulated plant growth and nutrient fluxes through interactions with environmental factors (Tamea et al, ; Zhang et al, ). In our previous study, soil nutrients decreased significantly along the groundwater depth gradient (Zhang et al, ), and leaf nutrient traits were closely associated with soil properties (Table ); increased groundwater depth and soil nutrient properties affected the leaf C, leaf N, leaf P, and leaf K, as these factors all decreased significantly with groundwater depth. In the desert riparian, vegetation with shallow groundwater, water conditions, and soil nutrients at these sites might be generally sufficient, and more nutrients could be used by plants.…”

“…Groundwater was the critical water resource for the survival of desert plants, and it also regulated plant growth and nutrient fluxes through interactions with environmental factors (Tamea et al, 2009;Zhang et al, 2018b). In our previous study, soil nutrients decreased significantly F I G U R E 3 Redundancy analysis (RDA) ordination of all variables for leaf nutrient traits.…”

“…In our previous study, soil nutrients decreased significantly F I G U R E 3 Redundancy analysis (RDA) ordination of all variables for leaf nutrient traits. Abbreviations: groundwater depth (GWD), soil moisture in 0-30 cm (SM30), soil moisture in 30-50 cm (SM50), soil bulk density (SBD), soil total carbon (STC), soil total nitrogen (STN), soil C:N (SCN), soil available P (SAP), soil available K (SAK), soil electrical conductivity (SEC) along the groundwater depth gradient (Zhang et al, 2018b), and leaf nutrient traits were closely associated with soil properties (Table 1); increased groundwater depth and soil nutrient properties affected the leaf C, leaf N, leaf P, and leaf K, as these factors all decreased significantly with groundwater depth. In the desert riparian, vegetation with shallow groundwater, water conditions, and soil nutrients at these sites might be generally sufficient, and more nutrients could be used by plants.…”

Sand Dune Height Increases Water Use Efficiency at the Expense of Growth and Leaf Area in Mongolian Pine Growing in Hulunbeier Steppe, Inner Mongolia, China

“…The increase in the number of tree deaths on Mongolian pine plantations may be attributed to a lack of water on the sandy land in this arid climate [11]. Water is one of the most important limiting factors in the survival and growth of trees on sandy land [10], where its two main sources are precipitation and underground reservoirs [10,12].…”

“…In arid regions, soil moisture is affected primarily by groundwater, because of low precipitation and high evaporation [13][14][15]. Studies show that soil moisture decreases significantly with increased groundwater depth [12,16,17]. An increasingly dry climate leads to significantly reduced groundwater levels, and Populus euphratica and Tamarix spp.…”