Publications by authors named "Guishan Yang"

Correction for 'How do ecosystem service functions affect ecological health? Evidence from the Yangtze River Economic Belt in China' by Wei Wang , , 2024, https://doi.org/10.1039/D4EM00296B.

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Ecosystem services play an essential role as intermediaries, linking natural ecosystem resources to socio-economic demands. Understanding their impact on ecological well-being is pivotal for ensuring regional environmental security and promoting sustainable societal and economic development. However, there is insufficient research on the relationship between the two.

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Humans have played a fundamental role in altering lake wetland ecosystems, necessitating the use of diverse data types to accurately quantify long-term changes, identify potential drivers, and establish a baseline status. We complied high-resolution historical topographic maps and Landsat imagery to assess the dynamics of the lake wetlands in the Yangtze Plain over the past century, with special attention to land use and hydrological connectivity changes. Results showed an overall loss of 45.

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Long-term mapping of floodplain wetland dynamics is fundamental for wetland protection and restoration, but it is restricted to decadal scales using satellite observations owing to scarcity of spatial data over long-term scales. The present study concentrates on the centennial dynamics of floodplain wetland in Poyang Lake, the largest freshwater lake in China. Historical topographic maps and Landsat imagery were combined to reconstruct the centennial floodplain wetland map series.

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Water level decline in the largest freshwater lake in China (Poyang Lake) has raised grave concerns and continuous debates regarding the proposal of a water control project. Previous hydrologic investigations on the water level decline in Poyang Lake were conducted mostly during recession season and typical dry years and hence lacked the comprehensive view of associated risks and possible spatial heterogeneity of trend during low water level periods. The present study reassessed the long-term trend and regime shift of low water level variations and their associated risks based on hydrological data across multiple stations in Poyang Lake during 1952-2021.

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Payment for ecosystem services (PES) plays a vital role in coordinating the relationship between ecosystem services supply and demand sides in watersheds. The upstream soil retention service brings significant off-site benefits to the downstream stakeholders. To fill gaps in the supply and demand of soil retention services for PES, we developed an approach that combined long-term observation data, hydrological model, and cost-benefit analysis.

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Lake wetlands (LWs) are essential components of the ecosystem and play an irreplaceable role in flood regulation, carbon fixation, and biodiversity maintenance. Continuous monitoring of LWs' change is necessary in the context of increased human disturbance and climate change, particularly in Taihu Lake Basin, China, an area exposed to early human exploitation. Yet, long-time series of LWs detection in this region is still unavailable due to the data limitation.

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The driving effects of landscape metrics on water quality have been acknowledged widely, however, the guiding significance of human activity intensity and landscape metrics based on reference conditions for water environment management remains to be explored. Thus, we used the self-organized map, long- and short-term memory (LSTM) algorithm, and geographic detectors to simulate the response of human activity intensity and landscape metrics to water quality in Taihu Lake Basin, China. Fitting results of LSTM displayed that the accuracy was acceptable, and scenario 2 (regional heterogeneity) was more efficient than scenario 1 (regional consistent) in the improvement of water quality.

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Understanding the key drivers of eutrophication in floodplain lakes has long been a challenge. In this study, the Chlorophyll a (Chla) variations and associated relationships with environmental stressors along the temporal hydrological connectivity gradient were investigated using a 11-year dataset in a large floodplain lake (Poyang Lake). A geostatistical method was firstly used to calculate the hydrological connectivity curves for each sampling campaign that was further classified by K-means technique.

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Poyang Lake, the largest freshwater lake in China, serves critical ecosystem function for water regulation and biodiversity conservation. However, it experienced dramatic changes in lake inundation due to recent climate change and human activities, causing ecological and economic problems. Here, we applied a multiple-index water detection rule to integrated Landsat and MODIS products to reconstruct surface water series at 30-m and 8-day resolutions and quantified the spatio-temporal inundation dynamics in Poyang Lake over the past 20 years (2000-2019).

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Large lakes provide various types of ecosystem services (ESs), of which stocks and variations induced by hydrological alterations are largely unquantified. The present study investigates the long-term changes of five key ESs (i.e.

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Landscape pattern changes induced by rapid urbanization and intensified agricultural activities have exerted great pressure on regional water purification services. Relationship between landscape metrics and nitrogen-related ecosystem services has been a major concern of many scholars and has been widely used for guidance for land use and cover (LULC) management. However, clear zonal differences may exist, especially in highly developed reticular river network area, thus limiting our understanding of nitrogen output (NOP) to landscape pattern in the details.

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Faced with huge environmental problems of ecosystem degradation, "Ecological Redline Policy (ERP)" in China is a new key national-level policy to manage different land use functions in accordance with development and environmental limits. As the water-land complex ecosystem with the largest freshwater lake, wetland natural reserves and ecological importance in China, Poyang Lake Region (PLR) is selected to quantify and map multiple ecosystem services, investigate the ecological function zoning as part of research on ecological zoning control and major ecological source areas to illustrate and address the implementation of this strategy based on the importance and vulnerability analysis of ecosystem services. According to ecological function zoning results, extremely important, highly important, medium important and important zones respectively account for 26.

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Flooding is an important factor influencing the biomass production of vegetation in natural wetland ecosystems. However, how biomass production is linked to flooding patterns in wetland areas remains unclear. We utilized gauging station data, a digital elevation model, vegetation survey data, and a Landsat 8 image to study the effects of average inundation depth (AID) and inundation duration (IDU) of flooding on end-of-season biomass of vegetation in Poyang Lake wetland, in particular, after operation of Three Gorges Dam.

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This study examines rice-wheat agroecosystems in the Taihu Lake Basin: one of China's largest commercial grain-farming areas and a region that has faced severe deterioration in water quality. Spatiotemporal changes over the period 1986-2015 in four key ecosystem services (ESs) - grain yield, nitrogen loss, NO emission, and soil organic carbon (SOC) accumulation - were examined by applying the Agricultural Production Systems Simulator (APSIM) across the basin at county level. Two straw return modes (namely, full straw return versus no return) and three fertilizer-use reduction modes (-5%, -10%, and -20%) were set up to generate six combined scenarios, to propose pathways that reduce the variability of grain production and improve water quality by reducing loss of nitrogen (N loss) - in consideration of the Basin's vital role in agricultural production and the need to protect water quality.

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Poyang Lake, the largest freshwater lake of China, provides critical ecological functions for water circulation and biodiversity conservation as a dynamic wetland system. However, recent climate change and human activities exerted strong pressures on this ecosystem. In this paper, we applied object-based image analysis (OBIA) and Radom Forests (RF) classifier to ten Landsat images to examine the land cover composition and its change during 1987-2017 low water season at Poyang Lake.

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Poyang Lake is the largest freshwater lake in China and a globally important wetland with various functions. Exploring the multidecadal trend of water quality and hydroclimatic conditions is important for understanding the adaption of the lake system under the pressure from multiple anthropogenic and meteorological stressors. The present study applied the Mann-Kendall trend analysis and Pettitt test to detect the trend and breakpoints of hydroclimatic, and water quality parameters (from the 1980s to 2018) and the trend of monthly-seasonal ammonia (NH-N) and total phosphorus (TP)concentrations (from 2002 to 2018) in Poyang Lake.

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Total phosphorus (TP) standards for lakes differ from those for rivers in GB3838-2002. This disjunction may lead to the failure of lake-water quality improvement plans that control nutrient inputs from inflow rivers. With monthly monitoring data for the period 2009-2015, Northwest Lake Taihu was regarded as a case study and the BATHTUB model was utilised to simulate the correspondence between concentrations of TP in the lake and in its inflow rivers.

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Soil erosion induced by rainfall has become one of the major environmental disasters. It can lead to degradation of land productivity and water pollution, which limit human survival and development. Therefore, understanding the effects of rainfall intensities on soil nutrient and sediment transportation from farmland via surface runoff is important.

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Food security has become a global policy concern due to its important role in sustaining development and human well-being. Using spatial autocorrelation analysis of statistical data at the county-level, this study quantifies the change in spatial and temporal patterns of crop production in the Yangtze River Basin of China since 1990 and draws out policy implications for food security in the country. Four panel models were constructed to examine in what ways and to what extent four major factors (climate variation, sown area, fertilizer use intensity, and population size) influence the capacity for crop production.

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Floodplain lakes are valuable to humans because of their various functions and are characterized by dramatic hydrological condition variations. In this study, a two-dimensional coupled hydrodynamic and water quality model was applied in a large floodplain lake (i.e.

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Ecosystem services (ES) play an important role in sustaining ecological security, sustainable development and human well-being. This study investigates spatio-temporal changes in five key ES in the Yangtze River Economic Belt of China in 2000-2015-water conservation (WC), soil retention (SR), carbon sequestration (CS), biodiversity conservation (BC) and food supply (FS), by applying three ecological models (InVEST, RUSLE, CASA). Employing scenario simulations, the study quantifies distinct effects of significant factors on ES changes.

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Comprehensive understanding of the long-term trends and seasonality of water quality is important for controlling water pollution. This study focuses on spatio-temporal distributions, long-term trends, and seasonality of water quality in the Yangtze River basin using a combination of the seasonal Mann-Kendall test and time-series decomposition. The used weekly water quality data were from 17 environmental stations for the period January 2004 to December 2015.

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Comprehensively evaluating water quality with a single method alone is challenging because water quality evaluation involves complex, uncertain, and fuzzy processes. Moreover, water quality evaluation is limited by finite water quality monitoring that can only represent water quality conditions at certain time points. Thus, the present study proposed a dynamic fuzzy matter-element model (D-FME) to comprehensively and continuously evaluate water quality status.

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We examined foliar nitrogen (N) and phosphorus (P) stoichiometry of 3 wetland plants (Phalaris arundinacea, Miscanthus sacchariflorus, and Carex brevicuspis) distributed along an elevation gradient in the Dongting Lake, China, and how this stoichiometry is related to soil physico-chemical characteristics, elevation, and flooding days. Plant and soil samples were collected from 3 lakeshore sites. Total N and P concentrations of plants and six physico-chemical characteristics of the soil were measured, in addition to the elevation and flooding days.

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