Challenges and impacts of climate change and human activities on groundwater-dependent ecosystems in arid areas – A case study of the Nalenggele alluvial fan in NW China

Xu, Wei; Su, Xiaosi

doi:10.1016/j.jhydrol.2019.03.082

Cited by 53 publications

(27 citation statements)

References 41 publications

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“…The topography is gradually flattened from the top to the bottom of the alluvial fan (Yang et al, 2019) and as observed in this study, the total number of individuals was increasing from the top to the bottom of the alluvial fan. The same observation was made by Xu and Su (2019), and they found that majority of the vegetation is distributed over the margin of alluvial fan with shallow and buried groundwater. Meanwhile, the individual growth showed difference, and the middle of the alluvial fan had the best growth.…”

Section: Discussionsupporting

confidence: 79%

Stability and micro‐topographic effects of Sophora moorcroftiana population on a restored alluvial fan, Southern Tibetan Plateau

Liao

et al. 2021

Land Degrad Dev

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The Tibetan Plateau, a vulnerable eco-region undergoing global change, is hard to revegetate where land has become desertified due to the harsh habitat conditions. Sophora moorcroftiana shrubs, which are widely distributed in the middle reaches of the Yarlung Zangbo River basin of Tibet, China, have been naturally restored on desertified land during the last few decades. However, the influences of microtopography on the distribution and structure of the S. moorcroftiana population have been rarely reported. Here, we first describe the spatial variation of S. moorcroftiana population on a restored alluvial fan, and then explore the effects of microtopography on the restored S. moorcroftiana population, through a series of field surveys combined with the data collected by terrestrial laser scanning. The results indicate that the dominant age structure was adult shrubs (30-60 cm). Although the topographic effect had no significant impacts on soil organic matter and some other structural traits, which remained stable on the restored alluvial fan, it changed population density, plant growth, and distribution. The habitat conditions on the southwest aspect wapproximately 20-25 slope with altitudes ranging between 3,593-3,643 m, conditions that mostly favouring the distribution of the shrub population. The micro-topography played an important role in species distribution and growth of the S. moorcroftiana population. Our findings could help to understand the effect of micro-topography on plant population structure and distribution for ecological restoration of desertified land in the Southern Tibetan Plateau.

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Section: Discussionsupporting

confidence: 79%

Stability and micro‐topographic effects of Sophora moorcroftiana population on a restored alluvial fan, Southern Tibetan Plateau

Liao

et al. 2021

Land Degrad Dev

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“…In arid areas, the essentials of life, economic growth, agriculture, and industries highly rely on groundwater as essential natural storage to make up against a shortage of surface water [1]- [4]. While the climate change, rapid urban development, unsewered disposal, constructions, mining, and other industrial pollutants are constantly threatening the quality and quantity of groundwater; generally the oil and gas production, as well as agricultural practices of overusing pesticides and fertilizers more than any anthropogenic activities, are contributing to the groundwater contamination and scarcity [5]- [16].…”

Section: Introductionmentioning

confidence: 99%

Groundwater Salinity Susceptibility Mapping Using Classifier Ensemble and Bayesian Machine Learning Models

et al. 2020

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Risk and susceptibility mapping of groundwater salinity (GWS) are challenging tasks for groundwater quality monitoring and management. Advancement of accurate prediction systems is essential for the identification of vulnerable areas in order to raise awareness about the potential salinity susceptibility and protect the groundwater and top-soil in due time. In this study, three machine learning models of Stochastic Gradient Boosting (StoGB), Rotation Forest (RotFor), and Bayesian Generalized Linear Model (Bayesglm) are developed for building prediction models and their performance evaluated in the delineation of salinity susceptibility maps. Both natural and human effective factors (16 features) were used as predictors for groundwater salinity modeling and were randomly divided into the training (80%) and testing (20%) datasets. The models were evaluated using testing datasets after calibration using the selected features by recursive feature elimination (RFE) method. The RFE indicated that modeling with 8 features had better performance among 1 to 16 features (Accuracy = 0.87). Results of the groundwater salinity prediction highlighted that StoGB had a good performance, whereas the RotFor and Bayesglm had an excellent performance based on the Kappa values (> 0.85). Although spatial prediction of the models was different, all of the models indicated that central parts of the region have a very high susceptibility which matches with agricultural areas, lithology map, the locations with low depth to groundwater, low slope, and elevation. Additionally, areas near to the Maharlu lake and locations with a high decline in groundwater are also located in the very high susceptibility zone, which can confirm the effects of saltwater intrusion. The susceptibility maps produced in this study are of utmost importance for water security and sustainable agriculture.

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“…Excessive use of water resources leads to ecological system degradation, including wetland degradation and plant ecosystem deterioration [1,2]. For example, climate change and water resource exploitation currently threaten groundwater-dependent ecosystems and put vegetation at risk of degradation in the Nalenggele River Basin, located in the southwest Qaidam Basin in the Qinghai province of northwest China [3]. Due to intense water usage in the Junggar Basin of northwestern China over the last few decades, the water flowing into Ebinur Lake has been greatly reduced.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Water Transfer during Non-growing Season on the Wetland Ecosystem via Surface and Groundwater Interactions in Arid Northwestern China

Qiao

Sun

et al. 2020

Remote Sensing

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The use of ecological water transfer to maintain the ecological environment in arid or semiarid regions has become an important means of human intervention to alleviate vegetation ecosystem degradation in arid and semiarid areas. The water transfer to downstream in a catchment is often carried out during the non-growing season, due to the competitive water use between the upper and middle reaches and lower reaches of rivers. However, the impacts and mechanism of artificial water transfer on vegetation and wetland ecosystem restoration have not been thoroughly investigated, especially in northwest China. Taking the Qingtu Lake wetland system in the lower reaches of the Shiyang River Catchment as the study area, this study analyzed the spatial and temporal distribution surface area of Qingtu Lake and the surrounding vegetation coverage before and after water transfer, by interpreting remote sensing data, the variation of water content in the vadose zone, and the groundwater level by obtaining field monitoring data, as well as the correlation between the water body area of Qingtu Lake and the highest vegetation coverage area in the following year. The conclusion is that there is a positive correlation between the water body area of Qingtu Lake in autumn and the vegetation coverage in each fractional vegetation coverage (FVC) interval in the next summer, especially in terms of the FVC of 3050%. The groundwater level and soil water content increase after water transfer and remain relatively high for the following months, which suggests that transferred water from upstream can be stored as groundwater or soil water in the subsurface through surface water and subsurface water interaction. These water sources can provide water for the vegetation growth the next spring, or support plants in the summer.

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Challenges and impacts of climate change and human activities on groundwater-dependent ecosystems in arid areas – A case study of the Nalenggele alluvial fan in NW China

Cited by 53 publications

References 41 publications

Stability and micro‐topographic effects of Sophora moorcroftiana population on a restored alluvial fan, Southern Tibetan Plateau

Stability and micro‐topographic effects of Sophora moorcroftiana population on a restored alluvial fan, Southern Tibetan Plateau

Groundwater Salinity Susceptibility Mapping Using Classifier Ensemble and Bayesian Machine Learning Models

The Effect of Water Transfer during Non-growing Season on the Wetland Ecosystem via Surface and Groundwater Interactions in Arid Northwestern China

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