Coordination analysis of flood-sediment transportation, eco-environment, and socio-economy coupling in the governance of the Yellow River Basin system.

The watershed system has a complex game relationship between the benign operation and coordinated development of various elements of flood-sediment transportation, eco-environment, and socio-economy (FES). With the increasing breadth, depth, and intensity of human activities in watersheds, it is urgent to coordinate the FES. The relationship of water-sediment in the Yellow River Basin (YRB) is complex, with a prominent contradiction in water supply and a fragile ecosystem. This research tries to build a comprehensive evaluation model for FES and explore the complex interaction between FES in the YRB from 2000 to 2020. The results demonstrated that (1) the comprehensive flood-sediment transportation index (CFTI) and comprehensive eco-environment index (CEI) presented fluctuating growth. In contrast, the comprehensive socio-economy index (CSI) revealed a linear growth trend. The CFTI of Sanmenxia, CEI of Toudaokuan, and CSI of Ningxia had the highest growth rates, with 36.03%, 6.48%, and 107.5%, respectively. (2) FES's positive and negative effects were alternating, with heterogeneity in both time and space. (3) The coupling coordination degree (CCD) in the YRB indicated an increasing trend, ranging from 0.53 to 0.87, from reluctantly coordinated development to good coordinated development. The lagging subsystem was CFTI (2000-2001 and 2008-2020) and CSI (2002-2007), and the CEI was not lagging. (4) Exploratory Spatial Data Analysis (ESDA) demonstrated significant differences in the CCD of the YRB, and areas with similar CCD within the basin tend to be centrally distributed in space. At the same time, there was negative spatial autocorrelation in coordination. The results provide a scientific theoretical and methodological framework for strategic research on the YRB system's governance, protection, and management.

Establishing a quantitative assessment methodology framework of water conservation based on the water balance method under spatiotemporal and different discontinuous ecosystem scales.

Water conservation (WC) is an essential terrestrial ecosystem service that mitigates surface runoff and replenishes groundwater, which has received considerable attention under the dual pressures of climate change and human activity. However, there is insufficient understanding of the trends in WC changes on temporal (annual, monthly, daily), spatial, and ecosystem scales. This study proposed a quantitative assessment methodology framework (QAMF) for analyzing the spatiotemporal variation of WC under different discontinuous ecosystems. The QAMF mainly used models and methods such as the hydrological model (SWAT), calibration and uncertainty program (SWAT-CUP), WC calculation formula (water balance method), and spatial analysis method (empirical orthogonal function and wavelet analysis). It was applied to the source region of the Yellow River (SRYR), where the ecological landscape pattern underwent varying degrees of degradation, and WC capacity decreased. The results show that: Firstly, the constructed SWAT in the SRYR had high accuracy, and the proposed formula for calculating WC was suitable for multi-temporal scale analysis of WC in spatially distributed discontinuous basins. Secondly, the annual and monthly WC were respectively 81.00-184.13 mm and -28.58-107.64 mm, and daily WC was positive during extreme precipitation periods and negative during dry periods. The regulating effect of WC was fully reflected on the daily scale, partially reflected on the monthly scale, and absent on the annual scale. Third, the crucial WC area was mainly distributed in the southeast, and there was a significant primary yearly cycle of WC in the SRYR. Finally, different ecosystems exhibited different WC capabilities, and protecting the diversity of ecosystems played an essential role in maintaining and improving the WC function in the SRYR. This project has great scientific significance and technological support for scientifically evaluating the WC capacity in the SRYR.

Quantitative assessment methodology framework of the impact of global climate change on the aquatic habitat of warm-water fish species in rivers.

Global climate change (GCC), with global warming as the main characteristic, has become a global issue widely concerned by people. GCC impacts the hydrological regime at the watershed scale and affects the hydrodynamic force and the habitat conditions of freshwater ecosystems at the river scale. The impact of GCC on water resources and the water cycle is a research hotspot. However, there are few studies on water environment ecology related to hydrology and the influence of changes in discharge and water temperature on warm-water fish habitats. This study proposes a quantitative assessment methodology framework for predicting and analyzing the impact of GCC on the warm-water fish habitat. This system integrates GCC, downscaling, hydrological, hydrodynamic, water temperature and habitat models and was applied to the middle and lower reaches of the Hanjiang River (MLHR), where there are four major Chinese carps resource reduction problems. The results showed that the calibration and validation of the statistical downscaling model (SDSM) and the hydrological, hydrodynamic, and water temperature models were carried out using the observed meteorological factors, discharge, water level, flow velocity and water temperature data. The change rule of the simulated value was in good agreement with the observed value, and the models and methods used in the quantitative assessment methodology framework were applicable and accurate. The rise of water temperature caused by GCC will ease the problem of low-temperature water in the MLHR, and the weighted usable area (WUA) for spawning of the four major Chinese carps will appear in advance. Meanwhile, the increase in future annual discharge will play a positive role in WUA. In general, the rise in confluence discharge and water temperature caused by GCC will increase WUA, which is beneficial to the spawning ground of four major Chinese carps.

Fractionation, source, and ecological risk assessment of heavy metals in cropland soils across a 100-year reclamation chronosequence in an estuary, South China.

Coastal reclamation for cropland has led to the accumulation of heavy metals in soils, bringing about pervasive and severe risks for environment and human health. However, less is known about the influence of long-term reclamation on heavy metals risk, mobility and bioavailability in cropland soil. In this study, we determined six heavy metals (Cd, Cr, Ni, Cu, Zn and Pb) and their fractionations in soils from five croplands across a 100-year reclamation chronosequence in the Pearl River estuary. Results showed that across five reclaimed soils, Cd posed seriously ecological risk and bioavailability according to assessments based on both total contents (single-metal pollution index: Cd > Cu > Zn > Ni > Cr > Pb) and fractionations (risk assessment code: Cd > Zn > Cu > Ni > Pb > Cr). Cr, Ni, Cu, Zn and Pb posed slightly to moderately ecological risks, and were mainly bound to residual (73.70%) and reducible (15.86%) fractions with lower mobility and bioavailability. With the highest risks level, mobility, toxicity and bioavailability (5.67% exchangeable and 11.75% carbonate fractions bound), Cd was identified as the main pollution factor in study area. Principal component analysis and Pearson's correlation analysis revealed that anthropogenic reclamation activities (including phosphate fertilizers, pesticides and sewage irrigation) were the major sources of these heavy metals. Long-term reclamation activities induced the increases of soil organic matter, clay contents, total concentrations and non-residual fractions of heavy metals by 46.14%, 538.98%, 42.87% and 219.78%, respectively, demonstrating significant promotions in level and mobility of heavy metals due to longer-term agricultural activities, higher soil clay and organic matter content.

River health assessment of the Yellow River source region, Qinghai-Tibetan Plateau, China, based on tolerance values of macroinvertebrates.

For decades, the river health of the Yellow River source region (YRSR) on the Qinghai-Tibetan Plateau has been a focal issue owing to its unique geographic location and ecological functions. This study investigated the ecological status of the headwater streams, the main stem, and the tributaries of the Yellow River in the YRSR using the tolerance values of macroinvertebrates and those related to biotic indices. The macroinvertebrate assemblages of the headwater streams were characterized by lower biodiversity than the tributaries downstream, based on comparisons of taxonomical composition, functional feeding group composition, and the pollution-tolerant capacity of taxa. The headwater streams had a lower ratio (16%) of pollution-sensitive macroinvertebrate taxa than that of the tributaries downstream (30%). The biotic indices (family- and genus-level biotic indices) indicated that the ecological health of the headwater streams was comparably poorer than that of the downstream tributaries. The combined effect of vulnerable natural conditions and increasing human disturbance is likely the main cause of eco-environmental degradation in the Yellow River headwater streams.

Accurate Assessment of Wheat and Triticale Cultivar Resistance to Septoria tritici and Stagonospora nodorum Infection by Biotin/Avidin ELISA.

Specific and quantitative biotin/avidin-enzyme-linked immunosorbent assays (BA-ELISA) were evaluated for their ability to assess resistance of wheat and triticale cultivars to Septoria tritici (leaf blotch) and Stagonospora nodorum (leaf and glume blotch) in field trials. Using BA-ELISAs, the antigen amounts of S. tritici and of Stagonospora nodorum were measured in the flag leaf (F) and the first leaf below it (F-1) of five cultivars of triticale at Zadok's growth stage (GS) 75-80 and in 11 cultivars of wheat at GS 73-75 in 2001 and 2002. The presence of the pathogens was found to be specific to parts of the plants, cultivar, and plant species. Stagonospora nodorum was the dominant leaf blotch pathogen in triticale, while both Septoria tritici and Stagonospora nodorum occurred commonly in wheat. Close correlations were obtained between the pathogen amount measured by BA-ELISA and the percentage of necrotic leaf area in the tested cultivars. The BA-ELISA values for the tested triticale and wheat cultivars were ranked, and they correlated well with the susceptibility ratings given in the cultivar list recommended by Bundessortenamt (German Federal Office of Plant Variety), which is based on visual assessment of the leaf blotch complex caused by S. tritici and Stagonospora nodorum. The relative susceptibilities of individual wheat cultivars to both pathogens were similar. In conclusion, BA-ELISA provided for an accurate diagnosis and quantification of S. tritici and Stagonospora nodorum in infected plant tissue, and therefore can be used to assess resistance to these fungi in a disease complex in both early-stage breeding lines and field trials.