Driving factors of community‐level plant functional traits and species distributions in the desert‐wetland ecosystem of the Shule River Basin, China

Abstract

Groundwater, as the limiting resource in arid ecosystems, can have profound effects on the functional structure and distribution of plant communities. However, studies are too few to unveil the impacts of groundwater depth on plant functional traits in such communities. We collected data on vegetation, topography and soil properties from 180 quadrats (60 trees/shrubs and 120 herbaceous) in the desert-wetland ecosystem of Shule River Basin in Northwest China. We measured 10 key communitylevel functional traits, together with the resource topography (i.e., groundwater depth) and seven soil properties. We found that the increase of groundwater depth significantly reduced community-level specific leaf area and maximum leaf photosynthesis rate, while boosted leaf dry mass content and leaf thickness. However, the leaf phosphorus content remained relatively stable. By contrast, with the increase of groundwater depth, soil carbon, soil nitrogen, soil phosphorus and total dissolved salts first increased but then declined, while soil pH and soil bulk density exhibited the opposite trend. The soil moisture content decreased drastically with the decline of groundwater. The change in groundwater depth, thus, was found the main driver of species distribution in the arid zone, contributing 21.16%, followed by soil K + (9.94%) and soil total nitrogen content (4.9%), as well as a strong interaction of the three (41.7%). Changes in groundwater depth can thus alter the structure and nutrient enrichment of the soil, which in turn affects the distribution of vegetation through water-soil-plant interactions.

Impact of altered groundwater depth on soil microbial diversity, network complexity and multifunctionality

“…Our research on soil properties and microbial diversity with contrasting three groundwater depths revealed a decline in soil biodiversity and multifunctionality induced by the decreasing groundwater level. This finding has been extensively documented that the increase in groundwater depth can result in the reduction of soil nutrients, degradation of soil structure, reduction in soil moisture content, and decline in soil functionality, all of which have a detrimental impact on soil microbial diversity and composition (Prieto et al, 2012;Sun et al, 2020;Chen et al, 2021). Whereas, the impact of rising groundwater depth on soil microbiota has been relatively overlooked (Zhang et al, 2022), and it has not been clearly defined whether the alterations in soil microbial diversity caused by increasing groundwater depth are associated with a decline in multiple soil functions.…”

Effects of Groundwater Depth and Salt Content on Vegetation in Dry Lake Basins: A Case Study of Chahan Lake, Northern China

“…Relationships among Groundwater, Species, and Soil Properties. Many environmental factors affect the distribution of vegetation [32], and the changes in groundwater conditions and soil properties are the most important factors [19,43]. Groundwater degradation and soil salinization threaten ecosystems in arid and semiarid regions where rainfall is scarce and evaporation is intense [17].…”

“…In arid and semiarid areas, the community composition and species distribution of the vegetation are significantly correlated with the groundwater. Because of the scarce precipitation, shallow groundwater is an important water source for vegetation growth [18], and changes in the groundwater depth are the main factor controlling the species distribution in arid areas [19]. At present, the influence of the groundwater depth on the vegetation population distribution has mainly been studied using a combination of remote sensing and mathematical and statistical methods, such as the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI) [20].…”

The combined effect of surface water and groundwater on environmental heterogeneity reveals the basis of beta diversity pattern in desert oasis communities

“…In desert ecosystems in arid and semi-arid regions, surface water resources are severely scarce in most areas. Groundwater enrichment is mainly controlled by stratigraphic lithology and stratigraphic structures, and its dynamics is strongly linked to the evolution of surface processes, which is one of the key drivers that determine the growth status of vegetation, the establishment or loss of populations, and the existence or extinction of oases in desert areas [ 27 , 28 ]. For areas where surface water processes are present, three adaptation mechanisms are thought to occur in plant communities affected by a river overflow.…”