Search Results (26)

Payments for Watershed services (PWSs) have been emerging as a critical tool for environmental governance in watershed, yet their comparative effectiveness across implementation models has remained poorly understood. Based on a comparative analysis of Eco-Compensation (EC) and Payments for Ecosystem Services (PESs) frameworks, examining both theoretical foundations and implementation practices, this study aims to quantitatively assess and compare the effectiveness of two dominant PWSs models—the EC-like model (Phase I: October 2008–April 2017) and the PESs-like model (Phase II: 2017–December 2021). Using the Liaohe River in China as a case study, utilizing ecosystem service value (ESV) as an indicator and employing the corrected unit-value transfer method, we compare the effectiveness of different PWSs models from October 2008 to December 2021. The results reveal the following: (1) Policy Efficiency: The PESs-like model demonstrated significantly greater effectiveness than the EC-like model, with annual average increases in ESV of 3.23 billion CNY (491 million USD) and 1.79 billion CNY (272 million USD). (2) Functional Drivers: Water regulation (45.1% of total ESV growth) and climate regulation (24.3%) were dominant services, with PESs-like interventions enhancing multifunctionality. (3) Stakeholder Impact: In the PESs-like model, the cities implementing inter-county direct payment showed higher growth efficiency than those without it. The operational efficiency of PWSs increases with the number of participating stakeholders, which explains why the PESs-like model demonstrates higher effectiveness than the EC-like model. Our findings offer empirical evidence and actionable policy implications for designing effective PWSs models across global watershed ecosystems. Full article

With accelerating urbanization and agricultural modernization, the scale, structure, and land use conditions of rural settlements in China’s three northeastern provinces (TNPs) have changed dramatically, impacting regional food production and sustainable rural development. Based on multitemporal land use datasets and socioeconomic statistics, we used spatial pattern analysis, machine learning models, and the Shapley additive explanation (SHAP) method to investigate the spatial evolutionary characteristics and driving factors of rural settlements in China’s TNPs from 1980 to 2020. The results show that (1) the spatial evolution of rural settlements followed a four-stage “expansion–stabilization–re-expansion–restabilization” trend; arable land conversion was the primary source of expansion, with limited conversion from forests, grasslands, and water bodies. (2) Rural settlements demonstrated marked agglomeration, with the spatial distribution evolving from “single-center clustering” to “multiregional contiguous clustering”. Rural settlements in the Sanjiang Plain evolved into large patch clusters, while those in the lower Liaohe River Basin became small patch clusters. (3) Rural settlements at low elevations and near roads and waterways presented a large-scale, agglomerative distribution, while settlements at high elevations and far from rivers and roads showed a small-scale, high-agglomeration pattern. (4) The rural population, total power of agricultural machinery, total grain output, and primary industry value added predominantly drove settlement spatial expansion, with an “initial suppression, then promotion” trend, while the urbanization rate and GDP per capita had a negative impact, with the opposite trend. The interaction effects among high-contributing factors transitioned from suppressive to promoting. Our results provide theoretical insights for spatial planning and sustainable development in agricultural rural settlements. Full article

Acid drainage resulting from mining operations has led to significant iron contamination in surface waters, posing serious ecological and public health hazards. Elevated iron levels in freshwater ecosystems can severely affect aquatic organisms and human health. However, there remains a considerable gap in the establishment of benchmark values and ecological risk assessments (ERAs) for iron in surface waters in China. This study collected and screened 47 acute and chronic toxicity data points of 22 species for ferric iron (Fe³⁺) from various studies and databases. Three widely utilized methodologies were applied to derive long-term and short-term water quality criteria (LWQC and SWQC, respectively) for Fe³⁺; the logistic fitting curve based on the species sensitivity distribution (SSD) method was identified as the most optimal method, yielding an acute HC₅ of 689 μg/L and an SWQC of 345 μg/L. The LWQC of Fe³⁺ was estimated to be 28 μg/L by dividing HC₅ by the acute-to-chronic ratio (ACR), owing to the inadequacy of chronic toxicity data for model fitting. Utilizing these benchmarks, an ecological risk assessment (ERA) was conducted to compare the benchmarks with 68 iron exposure data points collected from surface waters across 30 provinces from eight river basins of China. The findings of 30% of the acute risk quotients and 83% of the chronic risk quotients raise substantial ecological concerns, primarily regarding the Yellow River Basin, Huaihe River Basin, and Songhua and Liaohe River Basin. This research provides critical insights into Fe³⁺ toxicity data collection and benchmark derivations, offering a benchmark data foundation for the remediation of surface water iron contamination and water quality management in China. Full article

Water N-NO₃⁻ (mg L⁻¹) pollution is attracting global concern in the face of combating climate change and human health risks. However, there have been comparatively few comprehensively researched studies on water N-NO₃⁻ pollution with respect to N-NO₃⁻ deposition, soil nitrogen, and land-use changes. We collected a total of 7707 published sampling points on N-NO₃⁻ surface and groundwater during flooding and non-flooding seasons during 2000–2020 in China. The types of water N-NO₃⁻ pollution (>20) can be categorized as point pollution (ΔTN ≤ 0 or > 1.5) and non-point pollution (0 < ΔTN ≤ 1.5), which were then assessed with respect to soil nitrogen (ΔTN g kg⁻¹) and water N-NO₃⁻ changes in this study. We found non-point pollution was concentrated in the Huaihe River Basin and Haihe River Basin with higher urbanization (+6%, +4%), cropland (72%, 45%), nitrogen fertilization (g m⁻² yr⁻¹) (>10), and increased wet N-NO₃⁻ deposition (WND) (kg ha⁻¹ yr⁻¹) (+4.6, +3). The Haihe River Basin was found to have the highest N-NO₃⁻ on its surface (306) and in its groundwater (868) and nitrogen fertilization (32). Point pollution was concentrated in the Songhua and Liaohe River Basin with the highest WND (+7.9) but slow urbanization (+1%). N-NO₃⁻ increased during the flooding season compared with the no-flooding season in serious pollution areas. N-NO₃⁻ increased in the Liaohe River and middle and low Yangtze River but was reduced in the Weihe River. Therefore, stringent criteria and management, especially during the flooding season are urgently required to mitigate the degree of N-NO₃⁻ water pollution that occurs due to intensive agriculture and urbanization with increased N-NO₃⁻ deposition. Full article

Satellite precipitation products (SPPs) are of great significance for water resource management and utilization in China; however, they suffer from considerable uncertainty. While numerous researchers have evaluated the accuracy of various SPPs, further investigation is needed to assess their performance across China’s nine major water resource regions. This study used the latest precipitation dataset of the China Meteorological Administration’s Land Surface Data Assimilation System (CLDAS-V2.0) as the benchmark and evaluated the performance of six SPPs—GSMaP, PERSIANN, CMORPH, CHIRPS, GPM IMERG, and TRMM—using six indices: correlation coefficient (CC), root mean square error (RMSE), mean absolute error (MAE), probability of detection (POD), false alarm rate (FAR), and critical success index (CSI), at both daily and hourly scales across China’s nine water resource regions. The conclusions of this study are as follows: (1) The performance of the six SPPs was generally weaker in the west than in the east, with the Continental Basin (CB) exhibiting the poorest performance, followed by the Southwest Basin (SB). (2) At the hourly scale, the performance of the six SPPs was weaker compared to the daily scale, particularly in the high-altitude CB and the high-latitude Songhua and Liaohe River Basin (SLRB), where observing light precipitation and snowfall presents significant challenges. (3) GSMaP, CMORPH, and GPM IMERG demonstrated superior overall performance compared to CHIRPS, PERISANN, and TRMM. (4) CMORPH was found to be better suited for application in drought-prone areas, showcasing optimal performance in the CB and SB. GSMaP excelled in humid regions, displaying the best overall performance in the remaining seven basins. GPM IMERG serves as a complementary precipitation data source for the first two. Full article

Urban development and climate change have strengthened the possibility of floods and droughts in cities. In this study, we evaluated the influences of these disasters and related social damage in nine major basins during the past 50 years. Unusually, the following conclusions were drawn from the analysis of relevant indicators before and after urbanization: (1) agricultural loss area (flood), grain loss, and direct economic loss showed an upward trend, while other indicators showed the opposite. (2) Floods most often occur in the Yangtze River Basin (58, 26.2%), followed by the Liaohe River Basin (49, 22.2%), which is closely related to the topography and economic progress of the area. (3) The modified Mann–Kendall (MK) analysis results are consistent with the indicators trend. Finally, the regularity of the climate change and urbanization process is revealed by the migration of the standard deviation ellipse and the mean center of the four indicators. China needs to integrate urban water/drought policy development with sustainable urbanization policy development to cope with the changing natural and social environment and to minimize urban ecological risks. Full article

It is an important issue to explore achieving high accuracy long-term crop classification with limited historical samples. The West Liaohe River Basin (WLRB) serves as a vital agro-pastoral ecotone of Northern China, which experiences significant changes in crop planting structure due to a range of policy. Taking WLRB as a case study, this study constructed multidimensional features for crop classification suitable for Google Earth Engine cloud platform and proposed a method to extract main grain crops using sample augmentation and model migration in case of limited samples. With limited samples in 2017, the method was employed to train and classify crops (maize, soybean, and rice) in other years, and the spatiotemporal changes in the crop planting structure in WLRB from 2014 to 2020 were analyzed. The following conclusions were drawn: (1) Integrating multidimensional features could discriminate subtle differences, and feature optimization could ensure the accuracy and efficiency of classification. (2) By augmenting the original sample size by calculating the similarity of the time series NDVI (normalized difference vegetation index) curves, migrating the random forest model, and reselecting the samples for other years based on the model accuracy scores, it was possible to achieve a high crop classification accuracy with limited samples. (3) The main grain crops in the WLRB were primarily distributed in the northeastern and southern plains with lower elevations. Maize was the most predominant crop type with a wide distribution. The planting area of main grain crops in the WLRB exhibited an increasing trend, and national policies primarily influenced the variations of planting structure in maize and soybean. This study provides a scheme for extracting crop types from limited samples with high accuracy and can be applied for long-term crop monitoring and change analysis to support crop structure adjustment and food security. Full article

Recently, the economic traits of Chinese mitten crab (Eriocheir sinensis) varieties have had a negative tendency. Meanwhile, the status of wild germplasm resources of E. sinensis is unknown, hindering the utilization of wild germplasm resources and the green development of the E. sinensis industry. Thus, the conservation of the wild E. sinensis germplasm resource is of great significance. To this end, we collected wild E. sinensis from two different river basins, the Yangtze River basin, and the Liaohe River basin, and analyzed the genetic diversity as well as the genetic differentiation in E. sinensis populations. Based on eight microsatellite markers, we found moderate genetic diversity in E. sinensis populations regardless of river basin. Based on the mitochondrial D-loop region, we found that all populations are at mutation drift equilibrium, while the Nm between any two populations is greater than 1. We hypothesized the existence of island model gene flow patterns among E. sinensis. Interestingly, genetic differentiation among E. sinensis populations was low, except that between Liaohe and Anqing or Shanghai populations. Additionally, geometric morphological analysis could distinguish E. sinensis from different basins, with an accuracy of 94.2–100%. Given the similar genetic diversity in the two basins, the genetic convergence of E. sinensis from different basins deserves further attention. Full article

The precipitation conce ntration degree (PCD) and precipitation concentration period (PCP) in the Liaohe River basin (LRB) from 1960 to 2020 were calculated depending on the daily precipitation data derived from meteorological stations. The mutations of the PCD and PCP were identified by sliding t-test, and spatiotemporal evolution characteristics before and after the mutation point were further analyzed. Cross wavelet transform (CWT) was used to reveal the influence of four low-frequency climate factors (Pacific Decadal Oscillation (PDO), Arctic Oscillation (AO), El Niño -Southern Oscillation (ENSO), and Sunspots (SS)) on precipitation concentration. The results were presented as follows: Mutations occurred in the PCD sequence in 1980 and the PCP sequence in 2005 in the LRB. Spatial distribution of the PCD generally increased from the southeast to the northwest and tended to flatten. Over the past 60 years, the annual PCD tended to decrease, with a variation range of 0.53 to 0.80. The PCP was relatively concentrated in early July to early August, decreasing before and increasing after the mutation. Important climatic factors driving the mutation of PCD included PDO, SS, and AO. However, the resonance between climate factors and the PCD was characterized by complexity and diversity. The PCP was mainly affected by AO and SS before the mutation. ENSO had an important influence on both PCD and PCP, but had no significant correlation with mutation occurrence. Full article

Drought is complex and is also one of the main disasters affecting China. Exploring the response of agricultural drought and meteorological drought to climatic factors helps us to understand the causes of drought. In this paper, we evaluated the temporal and spatial characteristics of soil drought and meteorological drought (SMD) and explored their responses to climatic factors and latent heat fluxes (LHF), and then explained their variation from the perspective of atmospheric circulation. The following results were obtained. (1) Meteorological drought has gradually increased in the Liaohe River Basin, on the North China Plain, and on the Loess Plateau while average soil moisture has been maintained at only approximately 25%. The impacts of drought are very serious in these regions. (2) LHF response to short time-scale (3-month scale) drought performance is high in the dry season, and the regions with high correlation coefficients are spatially distributed and concentrated in the monsoon climate zone. The regions with high correlation coefficients between drought and LHFs on long time scales (12-month scale) are concentrated in the coastal basin of southeast China. (3) Short- and long-term SMDs showed highly responsive and significant relationships with PDO, showing variations in the southeast coastal basin, the Pearl River basin, the northwest inland basin and the eastern part of the Heilongjiang basin, with a maximum correlation coefficient of 0.21 (p < 0.01). The short-term SMD in the northwestern inland region was significantly negatively correlated with AMO (correlation coefficient of −0.19, p < 0.01). the Nino3.4 index is significantly positively correlated with the SMD in the southeast coastal region of China, with a maximum correlation coefficient of 0.23 (p < 0.01). The decrease in convective precipitation led to a stronger association between soil and meteorological drought and climatic factors. This study helps to reveal the changing patterns of SMDs and can also be used globally to identify the local development patterns of drought under climate change. Full article

Wastewater treatment plants play a critical role in reducing point source pollution in watersheds; however, in taking on the task of reducing pollutants such as COD and NH₃-N, they also consume energy intensively, which can result in additional greenhouse gas (GHG) emissions and operating (OAM) costs. Therefore, appropriate effluent targets should be implemented to achieve a balance between pollution load reduction, greenhouse gas emissions and operating costs, depending on the field conditions of the wastewater plant. In this study, four different wastewater treatment technologies, namely, A²/O, CASS, MBR and A/O-MBR, which are mainly operated in the Liaohe River Basin of Jilin Province, were selected using the coupled AHP and fuzzy TOPSIS models, and the appropriate effluent standards were preferred according to the characteristics of these technologies. Firstly, the AHP model is used to determine the criteria layer (environmental, economic and social benefits) of the four treatment technologies and the weights of each indicator, and then the fuzzy TOPSIS model is used to determine the indicator values of the different alternatives (effluent standards) of the four treatment technologies, and finally the optimal value of the effluent standard is determined, in terms of COD, 30 mg/L for A²/O and CASS process and 50 mg/L for MBR and A/O-MBR. Full article

Land use and land cover (LULC) contribute to both carbon storage and carbon emissions. Therefore, regulating the LULC is an important means of achieving carbon neutrality under global environmental change. Here, the West Liaohe River Basin, a semiarid watershed, was taken as a case study. Based on the assessment of the carbon storage and emissions induced by LULC from 2000–2020, we set up three different coupled shared socioeconomic pathway (SSP) and representative concentration pathway (RCP) scenarios (SSP119, SSP245, and SSP585), from 2030–2060, to optimize the LULC. Then, the LULC patterns under each scenario were simulated using the patch-generating land use simulation (PLUS) model, and the corresponding changes in carbon storage and emissions were compared and analyzed. It was found that, since 2000, with the expansion of forest, cropland, and construction land, as well as the degradation of grassland, the carbon storage and emissions induced by LULC have significantly increased, but the increase in storage was lower than that of emissions. The scenario simulations revealed that, when we optimize the LULC, mainly including the protection and expansion of ecological land such as forest and grassland in the western and southern edges of the basin, as well as the control and management of cropland land and construction land in the northeast and central parts of the basin, there will be a significant increase in the carbon storage and a significant reduction in carbon emissions from 2030–2060. This indicates that zone-based management measures with rational LULC regulation can contribute to the achievement of carbon neutrality in the study area. Supported by the results of this study, a direct decision-making basis for land use policy regulation to promote regional sustainable development can be undertaken in the basin. This study also provides a reference for low-carbon development in other regions. Full article

Drought is a multifaceted natural disaster that can impact the ecological environment, crop yield, and social economy through the hydrological cycle process. Meteorological drought occurs first, which then propagates to other forms. This study presents the propagation characteristics of meteorological to hydrological drought in different river basins of China. The main drivers of drought propagation are also quantitatively analyzed in this study. The standardized precipitation index (SPI) and standardized runoff index (SRI) were used to describe meteorological and hydrological drought, respectively. The Songhua and Liaohe River Basin (SLRB), Haihe River Basin (HARB), Huaihe River Basin (HURB), Yellow River Basin (YRB), Yangtze River Basin (YARB), Pearl River Basin (PRB), Southeast Basin (SEB), Southwest Basin (SWB), and Continental Basin (CB) were analyzed in this study. The precipitation and runoff datasets were used to compute the SPI and SRI, respectively. The results showed that the drought propagation time was mainly 1–3 months in China. In general, drought propagation had a stronger relationship in the central and eastern river basins of China than in the western river basins (SWB and CB). Spring and winter had a weaker drought propagation relationship than autumn and winter. Drought propagation was driven by precipitation in the HURB, YARB, SEB, and PRB; soil moisture and precipitation were drivers in the HARB and YRB; moreover, soil moisture and potential evapotranspiration were drivers in the SLRB and CB. This study improves the understanding of the characteristics and drivers of drought propagation in droughts in river basins. Therefore, this study might provide a reference to reveal the mechanism of drought. Full article

The construction of ecological civilization plays an important role in realizing the harmonious coexistence between man and nature. The aims of this study were to explore the development of ecological civilization in China’s top 10 river basins from 2004 to 2018 and construct an evaluation index system of ecological civilization. Factor analysis was used for the evaluation, and intergroup gap and panel regression analyses were utilized to determine the evolution of the spatiotemporal patterns and factors affecting the development level of ecological civilization in Chinese river basins. The results show that areas with a high level of ecological civilization development gradually spread to peripheral basins such as the Liaohe, Yellow, and Songhua River basins. The level of ecological civilization in China’s watersheds is undergoing continuous development. The degree of opening up, forest cover, and education have markedly positive effects on the development of ecological civilization in the basins, whereas urban development and financial autonomy have significant negative effects. The results of this study provide new ideas for evaluating the level of ecological civilization construction, as well as a reference for the government to formulate policies related to the construction of ecological civilization in river basins. Full article