Farmland Changes and Their Ecological Impact in the Huangshui River Basin

Wei, Hui; Lu, Chunxia; Liu, Yaqun

doi:10.3390/land10101082

Cited by 10 publications

(5 citation statements)

References 32 publications

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“…Chloroform as a kind of organic chlorine is generally harmful to human health [23,24]; it is widely used in the manufacture of refrigerants, pharmaceuticals, and household cleaning products, and is also formed as a byproduct of chlorination disinfection in drinking water, wastewater, and swimming pools [25]. In our research, we found that the residential areas, factories, and recreational parks close to the sampling sites provided evidence that human activities aggravate chloroform accumulation, as shown in other papers [26][27][28]. Methylene chloride was another main VOC found in the water samples during the spring and winter with the highest concentration of 14.29 µg/L (near the national standard for 20 µg/L).…”

Section: Analysis Of the Main Vocs In Different Seasonssupporting

confidence: 83%

Human Activities Aggravate VOC Pollution in the Huangshui River of the Tibetan Plateau

Yang

Deng

et al. 2022

Sustainability

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Many xenobiotic compounds can threaten human health and natural ecosystems. The ability to predict the level of human activities and identify major impact factors is crucial for the design of pollutant risk-reduction plans. In this study, a total of 25 volatile organic compounds (VOCs) including eight alkenes, six alkanes, and eleven aromatics were identified at 11 monitoring locations along the Huangshui River of the Tibetan Plateau. GC-MS analysis was applied to detect the concentrations of the VOCs. The results showed that the alkene, alkane, and aromatic concentrations in the sediment were significantly higher than in the water in all seasons (p < 0.001). The VOC concentrations in summer were significantly higher than in spring and winter (p < 0.01). In addition, several VOCs were found to surpass the national standard, i.e., bromoform reached 312.43 μg/L in water during the summer (the national standard is 100 μg/L), carbon tetrachloride was 209.58 μg/L (the national standard is 2 μg/L), and vinyl chloride was 10.99 μg/L (the national standard is 5 μg/L), which were all related to human activities. Principal component analysis (PCA) was used to comprehensively evaluate the water quality and the VOCs. The total organic carbon (TOC) was found to be responsible for the presence of the VOCs in the river, accounting for 77.93%, 81.97%, and 82.13% of the total variance in the datasets in spring, summer, and winter, respectively.

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Section: Analysis Of the Main Vocs In Different Seasonssupporting

confidence: 83%

Human Activities Aggravate VOC Pollution in the Huangshui River of the Tibetan Plateau

Yang

Deng

et al. 2022

Sustainability

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“…Our results also show that areas near the development area are more likely to impact polders adversely due to construction. Wei et al [50] reached a similar conclusion in their research on cultivated land in Harbin; they argued that the increase in industrial and urban land demand led to the occupation of cultivated land. However, development and construction may also benefit the polder, which we believe may be related to the development of ecotourism.…”

Section: Mechanisms Of Changementioning

confidence: 71%

Spatiotemporal Evolution and Mechanisms of Polder Land Use in the “Water-Polder-Village” System: A Case Study of Gaochun District in Nanjing, China

Zhou,

Zhang,

Tang

2023

Land

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This study tries to gain an understanding of the unique spatial patterns of polder areas. Starting from a typical “water-polder-village” combination of spatial elements, our study begins by identifying land use in the polder area using Sentinel-2 data and unsupervised machine learning techniques, taking Gaochun District, Nanjing (China), as an example. Next, we conducted a spatial analysis of change for different years using multiple land-use change indices. Finally, geographically weighted regression (GWR) was developed to account for the heterogeneity of spatial patterns and visualize the spatial distributions of the estimated coefficients. The results, derived from the indices we have constructed, indicate that the water-polder-village is the main subject of spatial pattern changes, with spatial replacement of water and polder and incremental quantitative changes in village areas. Additionally, the main source of existing village land comes from the occupation of polders. Furthermore, the impacts of natural and ecological, development and construction, population, and economic factors on the spatial patterns of the polder area exhibit spatiotemporal heterogeneity. Meanwhile, in rapidly developing areas, population, economy, and construction development may negatively impact the protection of polders. The results provide a reference for the construction and protection of production, living, and ecological spaces in polder areas.

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“…The Huangshui basin, situated approximately between 36 • 04 N to 37 • 43 N and 100 • 68 E to 103 • 26 E, lies on the border between the Qinghai province and the Gansu province (Figure 1), in China. It exhibits a diverse topography characterized by substantial elevation changes, steep slopes, and an intricate network of rivers crisscrossing the landscape [35]. The topography of the basin is higher in the northwest and lower in the southeast, with an altitude of 1542-4800 m. Due to the influence of the climatic and topographic factors associated with the Qinghai-Tibet Plateau, the area features an uneven precipitation distribution and variations in the local temperature.…”

Section: Study Regionmentioning

confidence: 99%

Crop Mapping and Spatio–Temporal Analysis in Valley Areas Using Object-Oriented Machine Learning Methods Combined with Feature Optimization

Fu,

Zhou,

Zhou

et al. 2023

Agronomy

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Timely and accurate acquisition of crop planting areas and spatial distribution are deemed essential for grasping food configurations and guiding agricultural production. Despite the increasing research on crop mapping and changes with the development of remote sensing technology, most studies have focused on large-scale regions, with limited research being conducted in fragmented and ecologically vulnerable valley areas. To this end, this study utilized Landsat ETM+/OLI images as the data source to extract additional features, including vegetation index, terrain, and texture. We employed the Random Forest Recursive Feature Elimination (RF_RFE) algorithm for feature selection and evaluated the effectiveness of three machine learning algorithms—Support Vector Machine (SVM), Random Forest (RF), and Rotation Forest (ROF)—for crop extraction. Then, based on the optimal classifiers, the main crops in the Huangshui basin for the years of 2002, 2014, and 2022 were extracted. Finally, the transfer matrix, the gravity center model, and the Standard Deviation Ellipse (SDE) model were used to analyze the spatio—temporal changes of crops over the past 20 years in the Huangshui basin. The results showed that the spectral, vegetation index, and terrain features played a crucial role in crop extraction. Comparing the performance of the classifiers, the ROF algorithm displayed superior effectiveness in crop identification. The overall accuracy of crop extraction was above 86.97%, and the kappa coefficient was above 0.824. Notably, between 2002 and 2022, significant shifts in crop distribution within the Huangshui basin were observed. The highland barley experienced a net increase in planting area at a rate of 8.34 km2/year, while the spring wheat and oilseed rape demonstrated net decreases at rates of 16.02 km2/year and 14.28 km2/year, respectively. Furthermore, the study revealed that highland barley exhibited the most substantial movement, primarily expanding towards the southeast direction.

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Farmland Changes and Their Ecological Impact in the Huangshui River Basin

Cited by 10 publications

References 32 publications

Human Activities Aggravate VOC Pollution in the Huangshui River of the Tibetan Plateau

Human Activities Aggravate VOC Pollution in the Huangshui River of the Tibetan Plateau

Spatiotemporal Evolution and Mechanisms of Polder Land Use in the “Water-Polder-Village” System: A Case Study of Gaochun District in Nanjing, China

Crop Mapping and Spatio–Temporal Analysis in Valley Areas Using Object-Oriented Machine Learning Methods Combined with Feature Optimization

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