Minjiang River Research Articles

Spatiotemporal evolution and driving factors of ecosystem service value in the Upper Minjiang River of China.

The stability of ecosystems in high mountain canyon areas is poor, and the interaction between humans and the land is complex, making these ecosystems more vulnerable to destruction. Quantitatively assessing the ecosystem service value (ESV) in high mountain canyon areas and revealing its spatiotemporal evolution patterns and driving factors play a crucial role in the construction of regional ecological barriers and the assurance of ecological security. This study focuses on the Upper Minjiang River as the research area, using the InVEST model and the Equivalent Factor Method to estimate ESV. This combination aims to address the inadequacy of the Equivalent Factor Method in reflecting the variability of ESV across different regions, and the sensitivity of the InVEST model to data changes that results in insufficient accuracy of ESV assessments. By harnessing spatial au-tocorrelation and the geodetector method, we unravel the spatiotemporal evolution characteristics and driving factors of ESV. The results show that: (1) From 2000 to 2020, the ESVs estimated by the two estimations increased by 31.28% and 22.47%, respectively, both indicating that the eco-environment quality of the upper Minjiang River has been continuously improved. (2) When Moran's I was greater than 0.5 (p < 0.05), the spatial clustering of "High-High" and "Low-Low" ESV was obvious. It is clear that the ESV varies geographically. High values are primarily found in the study area's center and southern regions, as well as on both banks of the Minjiang River, whereas low values are more common in the region's northern region. (3) Slope and human activity intensity (HAI) are the principal contributors to the spatial differentiation of the ESV, more than 60% of the interaction types between the two factors were classified as dual-factor enhancement. The synergistic reinforcing effects of HAI, slope, elevation, and temperature collectively shape the shifts in ESV spatial distribution. This study offers a novel evaluative lens on the ESV of the Upper Minjiang River area, supplying a sturdy data support for crafting specific ecological preservation and rejuvenation strategies in the coming years.

Optimized Coordination of Urban Water Usage in China’s Minjiang River Basin under the Influence of Climate Change

Optimized Coordination of Urban Water Usage in China’s Minjiang River Basin under the Influence of Climate Change

New chronology evidence of prehistoric human activities indicated by pottery luminescence dating in the humid subtropical mountains of South China

The age of prehistoric human sites serves as a fundamental basis for studying the relationship between human activities and landscape changes in the humid subtropical mountains of South China. The presence of pottery in these archaeological sites is widespread and offers a valuable resource for precise dating purposes. The Longtoushan (LTS) site, located in the northern mountains of Fujian Province, contains a rich variety of pottery types from various periods, representing a rare multi-period stratigraphic overlap in this area and playing a crucial role in constructing the cultural sequence and lineage of prehistoric and ancient times in this region. In this study, we employed thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques to establish the age of pottery samples collected from the LTS site situated in the upper Minjiang River region of southeast China for the first time, while also comparing our findings with other dating methods to construct a chronological framework for the site. The results showed that: (1) The samples analyzed in this study can be classified according to the peak strength of 325 °C TL signal at natural and regenerative doses of quartz. Samples with weak TL signal at 325 °C (type II samples) showed high recuperation and equivalent dose underestimation at a low preheat temperature (220 °C) in OSL test. (2) Conventional SAR procedures employed for type I samples are not suitable for type II samples. Type II samples require additional OSL stimulation towards the end of the cycle and an extended stimulation duration. (3) The application of various dating methods has revealed that the LTS site represents a long-term settlement in the humid subtropical mountains of South China, commencing around 4.6–4.4 thousand years ago (ka). Specifically, the dating of pottery pieces from kiln sites and tombs in the late Neolithic period provides a specific temporal reference for further understanding of prehistoric human culture and production behavior in the humid mountains of Fujian.

Terrace formation linked to outburst floods at the Diexi palaeo-landslide dam, upper Minjiang River, eastern Tibetan Plateau

Abstract. River terraces are frequently investigated with the aim of extracting information regarding tectonic or climate forcing on the evolution of landscapes. Terraces formed following the blockage of valleys by large-scale landsliding have received limited attention despite the high likelihood of their prevalence in landslide-dominated mountain belts. Here, we investigate the geomorphology, sedimentology, and chronology of two outstanding sets of terraces upstream of the giant river-blocking Diexi palaeo-landslide on the upper Minjiang River, eastern Tibetan Plateau. The first set occurs at Tuanjie village and has seven levels (T1–T7); the second set, at Taiping village, has three levels (T1–T3). All the terraces display a consistent sedimentary sequence comprising lacustrine muds topped by fluvial gravel sometimes capped by loess and a palaeosol. Based on field examination, lithofacies analysis, elevation data, and chronometric data (optically stimulated luminescence and radiocarbon dating), we correlate T1, T2, and T3 at Taiping with T5, T6, and T7 at Tuanjie. Our analysis suggests that two damming and three outburst events have occurred at the Diexi palaeo-landslide over the past 35 000 years. A giant landslide (&gt; 300 m high) blocked the river before 35 ka, followed by the first outburst flood at ∼ 27 ka; the river was blocked again between 27 and 17 ka, followed by a second outburst at ∼ 17 ka. A third outburst at ∼ 12 ka was followed by gradual fluvial incision of the palaeo-dam crest to its current level. We attribute the terraces at Diexi to the recurrent blockage and outburst events, which reflect the shifting sediment transport capacity and incision at the palaeo-dam crest. Here, climatic fluctuations play a minor role in terrace formation, and tectonism plays no role at all.

Analysis of Runoff Changes and Their Driving Forces in the Minjiang River Basin (Chengdu Section) in the Last 30 Years

Analysis of Runoff Changes and Their Driving Forces in the Minjiang River Basin (Chengdu Section) in the Last 30 Years

Disentangling the Response of Vegetation Dynamics to Natural and Anthropogenic Drivers over the Minjiang River Basin Using Dimensionality Reduction and a Structural Equation Model

Disentangling the Response of Vegetation Dynamics to Natural and Anthropogenic Drivers over the Minjiang River Basin Using Dimensionality Reduction and a Structural Equation Model

The influence of human activities on rainfall-runoff relationships at different time scales in the Minjiang River Basin

The influence of human activities on rainfall-runoff relationships at different time scales in the Minjiang River Basin

Evolution and Projection of Carbon Storage in Important Ecological Functional Areas of the Minjiang River Basin, 1985–2050

The alteration of land use and cover (LULC) and the landscape ecological risk index (LERI) significantly impact carbon storage. Examining the carbon storage services in ecologically significant places is crucial for achieving a harmonious relationship between economic development in the region, conservation of terrestrial ecosystems, and mitigation of carbon sink depletion. This study aims to provide a complete framework that integrates the PLUS, Fragstats, and InVEST models. This framework will be utilized to optimize LULC and LERI, specifically maximizing carbon storage. The analysis will be carried out over an extended duration and from various viewpoints. The results indicate that the MJRB ecosystem experienced three clearly defined phases: enhancement (1985–1995), degradation (1995–2010), and subsequent enhancement (2010–2020). The LERI of high-level and carbon storage patterns showed similar trends. The degradation of local terrestrial ecosystems can primarily be due to the widespread use of ecological land caused by socio-economic development. The Ecological Preservation Scenario is projected to increase 41.97 Tg and 115.18 Tg in carbon storage. In contrast, the urban development scenario showed a substantial decrease in carbon storage rates, namely 0.89% and 1.34%, primarily evident in the Chengdu urban zone. An analysis of coupling coordination revealed a negative relationship between carbon storage and high LERI, while a positive connection was observed with low LERI. This study established a framework for rapidly assessing and forecasting the trajectory of carbon storage. It aids in optimizing land use patterns, conserving areas with high carbon sequestration, and ensuring the establishment of high-quality ecosystems. This study serves as a guide for achieving regional “dual carbon” objectives.

Material characterization revealing production models of the Late Ming silver hairpins

The Site of Jiangkou in Pengshan, Sichuan province revealed the largest assemblage of silver artefacts ever known in China. These artefacts were collected by Zhang Xianzhong, the rebellion general of the Late Ming and Early Qing period, from Sichuan and adjacent provinces, and sunk in the Minjiang River after his failure in 1644 CE. This research focuses on silver hairpins from this assemblage and explores their production system via detailed typological investigation and material characterization. According to their style, forming techniques and material provenance, the Jiangkou hairpins can be divided into three groups corresponding with three different types of production workshops. The first group was made in independent silversmiths mainly serving non-official civilians. Metallographic analysis shows they were made with varied forming techniques, including forging, folding, casting and welding. They were alloyed with varied amount of copper. The other two types have much more standardized forming techniques and are associated with the commercial workshops capable of mass production and government institutions. The commercial workshops commonly used forging-annealing method to make their hairpins and maintained a well consistent chemical composition across their products. The silver hairpins made by government institutions were all cast into shape, suggesting a highly standardized system. This type of hairpins were mostly found in tombs of royal families and high elites. This research revealed a stratified silver production system in the Late Ming period and demonstrated the strength of material characterization in revealing production organization models.

The impact of flooding from the Minjiang River on the succession of harmful algal blooms (HABs) caused by diatoms in China's offshore waters

This study examines diatom assemblages in the Matsu Archipelago, an area influenced by Minjiang River runoff. It focuses on harmful algal blooms (HABs) that occurred between August 2021 and July 2022. Utilizing 18S rRNA metabarcoding and microscopic analysis, we observed a significant diatom bloom during early summer runoff, peaking at 5 × 105 cells L−1. The research reveals dynamic community changes during the runoff season, with dominant genera including Pseudo-nitzschia, Chaetoceros, and Skeletonema. Skeletonema cell density correlated with NO3 levels, Chaetoceros had a slight PO4 affinity, and Pseudo-nitzschia showed a negative correlation with Skeletonema. Pseudo-nitzschia, which prefers high light and pH conditions, had notably high concentrations in the flood season and in the autumn. In both, it was dominated by potential toxin-producing species - P. multistriata and P. pungens during the flooding, and P. cuspidate in the autumn. These findings highlight the intricate relationship between diatom dynamics and environmental factors, providing essential insights for managing HABs, especially Pseudo-nitzschia species, amidst environmental changes.

Response of Vegetation Coverage to Climate Drivers in the Min-Jiang River Basin along the Eastern Margin of the Tibetan Plat-Eau, 2000–2022

Ecological zonation research is typically conducted in the eastern margin of the Tibetan Plateau. In order to enhance the structure and function of regional ecosystems and monitor their quality, it is crucial to investigate shifts in the coverage of vegetation and the factors that contribute to these shifts. The goal of this study is to assess the spatial and temporal variations in vegetation covering and the partitioning of its drivers in the Minjiang River Basin on the eastern edge of the Tibetan Plateau between 2000 and 2022. The Mann-Kendall test, Hurst index, Theil-Sen median trend analysis, and other techniques were used to look at the features of temporal and geographical changes in regional vegetation coverage as well as potential development trends. The climatic influences leading to the spatial differentiation of vegetation NDVI (Normalized Difference Vegetation Index) were quantified through partial and complex correlation analyses of NDVI with temperature and precipitation. The results of the study showed that (1) the NDVI of the watershed performed well with a stable upward trend, indicating that the vegetation growth was generally good; (2) the spatial analysis showed that the coefficient of variation of the NDVI reached 0.092, which highlighted the stability of the vegetation change in the region; (3) the future development trend of the vegetation coverage in the watershed is low, and there is a certain degree of ecological risk; and (4) the main driver of the vegetation coverage is the non-climate factor, distributed in most parts of the watershed; (5) the climate driver shows localized influence, especially concentrated in the southwest, downstream and part of the upstream areas of the watershed.

The community structure and diversity characteristics of soil fungi in Minjiang River Estuary Wetland

The community structure and diversity characteristics of soil fungi in Minjiang River Estuary Wetland

Stackelberg game based optimal water allocation from the perspective of energy-water nexus: A case study of Minjiang River, China

Energy and water are interdependent. Water is essential for energy production, and energy is indispensable for water processes. This paper develops a Stackelberg game based bi-level multi-objective model for optimal water allocation under uncertainties from an energy-water nexus perspective, which considers energy-related water consumption and water-related energy production. It handles the hierarchical decision-making problem between the river basin authority and the subareas, as well as the tradeoffs between social equality and ecological damage. The upper level of the model makes schemes on water allocation for multiple subareas, and the lower level decides on water allocation for different types of power generation. To generate reasonable and practical strategies for water allocation, ɛ-constraint method and KKT conditions are used. A case study of Minjiang River, China is given to demonstrate the applicability and practicality. Scenarios analysis is also conducted to demonstrate the effectiveness of the model and the effects of the control parameter changes. The results indicate that the river basin authority would allocate larger water resources to the subareas with higher energy demand. It is concluded that the proposed allocation method is advantageous to the subareas with higher water utilization efficiency. The proposed bi-level model demonstrates its reasonableness and superiority to the single-level model. Policy implications are finally provided to support the sustainable development of energy-water nexus.

Sedimentary records of giant landslide-dam breach events in western Sichuan, China

Introduction: Landslide-dammed lake outburst floods (LLOFs) are common natural disasters in high-mountain regions, posing serious safety threats to residents’ livelihoods and properties and causing major damage to engineering facilities. Giant landslides and river damming events commonly occur in the Eastern Tibetan Plateau in southwestern China. Dam failure generate LLOFs that form outburst deposits (ODs). This phenomenon is particularly common in some giant ancient landslide-dammed lakes.Methods: This study conducted a detailed investigation of the sedimentary characteristics of large-scale landslide-dammed lake outburst deposits in the Diexi Reach of the Upper Minjiang River and Tangjiashan Reach of the Tongkou River Basin, West Sichuan Plateau, China. Meanwhile, typical evidence of high-energy ODs was recorded.Results and Discussion: The longitudinal distribution of these ODs is similar to an elongated fan-shaped terrace along the river channel, presenting a distinctive sedimentary disordered–sub-ordered–ordered sequence from upstream to downstream. Several typical units of “sedimentary facies” are developed in the OD profiles, such as boulder units deposited by high-energy outburst flood (OF) events and the gravel and sand units representing pulsating-flow sedimentary environments during the recession stage. The grain size frequency curves are bimodal, and the granularity accumulated curves are upward convex, which reflect that the detrital characteristics of the sediment source area are mainly composed of coarse gravel and boulders. This indicates that the coarse gravel sediment gradually become decreased from upstream to downstream. Moreover, the OD hydrodynamic intensity displays a gradual weakening, and sediment sorting is improved. From upstream to the downstream, the mean particle-size and sorting of the ODs gradually decrease. The skewness become larger, and the kurtosis of the ODs is distributed in all the types. In addition, the different combinations of quartz sand surface microtextures indicate the transformation from high-to low-energy impacts over a short distance, which is controlled by flood hydrodynamics and regime.Significance: These sedimentary characteristics of ODs explain the hydrodynamic changes during the propagation of OFs, and are also important records for distinguishing between ODs, and “normal” floods.

Characterisation of extreme precipitation changes in the upper reaches of the Yangtze River, China

ABSTRACT The paper analyses the spatial and temporal characteristics of extreme precipitation in the upper reaches of the Yangtze River through extreme precipitation indicators based on the trend method, the Mann–Kendall trend test, and the rescaled extreme deviation extreme deviation using daily precipitation data from 1961 to 2021. The following conclusions were obtained: The overall precipitation in the upper reaches of the Yangtze River is reduced, and the number of rainy days is reduced. The frequency of extreme precipitation is generally reduced, but the spatial difference in the intensity of extreme precipitation is greater, which makes the occurrence of extreme precipitation more concentrated and more destructive. Extreme precipitation indicators showed relatively large fluctuations after 2000, especially in terms of extreme precipitation intensity. The frequency of extreme precipitation in the upper reaches of the Yangtze River is the highest in the main stream of the Yangtze River Basin and the Wujiang River Basin, the intensity of extreme precipitation is in the Jialing River and the Wujiang River Basin, and the accumulation of extreme precipitation is the highest in the Jialing River and the Wujiang River Basin, whereas the maximum value of the station extreme precipitation intensity and frequency is in the Minjiang River Basin.

Characteristics of very-large-scale motions in natural rivers based on large eddy simulation

Exploring very-large-scale motions (VLSMs) in open channel flows (OCFs) is crucial for comprehensively understanding material transport and energy exchange. While previous studies focused on OCFs in ideal flumes with simple boundaries, this paper presents large eddy simulation (LES) results on the existence and scale characteristics of VLSMs in complex river morphologies with the Minjiang River in southwestern China as a case study. This research demonstrates that the OpenFOAM-based LES model is capable of accurately reconstructing the time-averaged flow field and providing instantaneous velocity data that capture VLSMs with sufficient resolution. Spectrum analysis of the streamwise fluctuating velocity shows that VLSMs are present in the straight segment of the river, with streamwise wavelengths approximately (16–22) times the water depth but are absent in the bend and confluence segments due to the suppression by secondary currents. This article validates the effectiveness of LES in examining the characteristics of VLSMs in natural rivers, thereby laying a good foundation for further studies on the impacts of such structures on sediment transport and pollutant dispersion.

Post-disaster spatial reconstruction from the perspective of a rural settlement niche in the upper reaches of the Minjiang River

Post-disaster spatial reconstruction from the perspective of a rural settlement niche in the upper reaches of the Minjiang River

Risk Analysis and Visualization of Merchant and Fishing Vessel Collisions in Coastal Waters: A Case Study of Fujian Coastal Area

The invasion of ship domains stands out as a significant factor contributing to the risk of collisions during vessel navigation. However, there is a lack of research on the mechanisms underlying the collision risks specifically related to merchant and fishing vessels in coastal waters. This study proposes an assessment method for collision risks between merchant and fishing vessels in coastal waters and validates it through a comparative analysis through visualization. First of all, the operational status of fishing vessels is identified. Collaboratively working fishing vessels are treated as a unified entity, expanding their ship domain during operation to assess collision risks. Secondly, to quantify the collision risk between ships, a collision risk index (CRI) is proposed and visualized based on the severity of the collision risk. Finally, taking the high-risk area for merchant and fishing vessel collisions in the Minjiang River Estuary as an example, this paper conducts an analysis that involves classifying ship collision scenarios, extracts risk data under different collision scenarios, and visually analyzes areas prone to danger. The results indicate that this method effectively evaluates the severity of collision risk, and the identified high-risk areas resulting from the analysis are verified by the number of accidents that occurred in the most recent three years.

Landscape Feature Extraction and Floristic Division of Traditional Villages in the Minjiang River Basin

Traditional villages reflect the integration and collision of cultures from many aspects such as culture, function and site selection, and reflect the cooperation and struggle between man and nature. They hold outstanding historical, cultural, artistic, scientific and social values, and are important carriers of national culture. As an important birthplace of civilization in the southeastern region of China, the Minjiang River Basin has profound historical and cultural accumulation. The unique, diverse and abundant traditional village resources in the basin embody the Fujian traditional culture with distinctive local characteristics. In order to accurately identify the landscape characteristics of traditional villages in the Minjiang River Basin, the research first introduces the concept of landscape gene similarity on the basis of landscape gene theory, and quantitatively evaluates the similarity of traditional village landscapes, which reduces the influence of subjective judgment in the process of landscape gene extraction, strengthens the repeatability of the conclusions, and makes the results more accurate. Secondly, based on five batches of Chinese traditional village lists, field visits and literature review, 111 national traditional villages with complete data and well preserved in Minjiang River Basin are determined as research objects. Finally, based on the dialect and folk beliefs, the cultural characteristics of the villages are judged, and the landscape characteristics of the villages are described based on the characteristics of the residential landscape. Six types of indicators that can best reflect the characteristics of village landscape are selected to construct the index system. By calculating the similarity of each traditional village landscape and combining with spatial statistical analysis, the traditional villages in Minjiang River Basin are divided into 9 landscape regions and 4 landscape sub-regions as a whole, and construct the landscape gene map of traditional villages in Minjiang River Basin. Through the calculation of the similarity between the traditional village landscape and spatial statistical analysis, the traditional villages in the Minjiang River Basin are divided into 9 landscape areas and 4 landscape sub-areas, then mapping the landscape gene map of traditional villages in Minjiang River basin. The results show that there are differences in landscape gene composition of traditional villages in different regions in Minjiang River Basin. Based on the differences of landscape gene among traditional villages in Minjiang River Basin, combined with the administrative division and landscape gene similarity, traditional villages in Minjiang River Basin can be divided into 9 landscape areas and 4 landscape subareas which include Hakka courtyard area, Shaojiang Courtyard area, Central Fujian Courtyard area, Central Fujian enclosed building area, Eastern Fujian enclosed building area, Eastern Fujian mixed area, Southern Fujian compound area and Northern Fujian compound area, Northern Fujian gabled roof courtyard area, Northern Fujian mixed roof courtyard area, Shaojiang independent courtyard area and Shaojiang combined courtyard area. The similarity of landscape genes between two adjacent landscape areas was higher than other areas. To some extent, this is due to the role and influence of natural conditions, cultural customs and social economy in different periods. Among them, the natural conditions affecting the residence form and construction of the overall arrangement of the choice of material, culture affects the residential spatial structure characteristics such as shape, function partition, the social and economic conditions determine the scale and fineness of dwellings. Any change of conditions will produce different morphological characteristics of residential buildings, major historical events are important catalysts for this transformation process, which can accelerate or slow down the entire process. In the future, the research will take the major historical events that affect human activities in the watershed as the time node, analyze the development and evolution laws of buildings in different periods, and conduct in-depth analysis and exploration of this conclusion.

Deep optimization of water quality index and positive matrix factorization models for water quality evaluation and pollution source apportionment using a random forest model

Effective evaluation of water quality and accurate quantification of pollution sources are essential for the sustainable use of water resources. Although water quality index (WQI) and positive matrix factorization (PMF) models have been proven to be applicable for surface water quality assessments and pollution source apportionments, these models still have potential for further development in today's data-driven, rapidly evolving technological era. This study coupled a machine learning technique, the random forest model, with WQI and PMF models to enhance their ability to analyze water pollution issues. Monitoring data of 12 water quality indicators from six sites along the Minjiang River from 2015 to 2020 were used to build a WQI model for determining the spatiotemporal water quality characteristics. Then, coupled with the random forest model, the importance of 12 indicators relative to the WQI was assessed. The total phosphorus (TP), total nitrogen (TN), chemical oxygen demand (CODCr), dissolved oxygen (DO), and five-day biochemical oxygen demand (BOD5) were identified as the top five significant parameters influencing water quality in the region. The improved WQI model constructed based on key parameters enabled high-precision (R2 = 0.9696) water quality prediction. Furthermore, the feature importance of the indicators was used as weights to adjust the results of the PMF model, allowing for a more reasonable pollutant source apportionment and revealing potential driving factors of variations in water quality. The final contributions of pollution sources in descending order were agricultural activities (30.26%), domestic sewage (29.07%), industrial wastewater (26.25%), seasonal factors (6.45%), soil erosion (6.19%), and unidentified sources (1.78%). This study provides a new perspective for a comprehensive understanding of the water pollution characteristics of rivers, and offers valuable references for the development of targeted strategies for water quality improvement.