Search

Based on the significant weather report, CG lightning, composite radar reflectivity, and ERA5 reanalysis data, we first studied the spatiotemporal distribution characteristics of four types (only severe convective wind (SCW); SCW and hail; SCW and short-duration heavy rainfall (SDHR); and SCW, hail, and SDHR) of convective weather events related to SCW during the warm season (May to September) from 2011 to 2018 in North China. Second, severe convective cases producing SCW were selected to statistically analyze the initiation, decay, lifetime, and organizational characteristics of convective systems. Finally, using ERA5 reanalysis data and conventional surface observation data, preconvective soundings were constructed to explore the differences in environmental conditions for initiating convective systems between SCW and non-SCW. The results indicate that mixed-type of SCW and SDHR events occur more frequently over plains, while other types of convective weather occur more frequently over mountains. The frequency peak of SCW occurs in June, while mixed convective weather peaks in July. The initiation time of convective systems is concentrated between 1000 and 1300 BST, with apeak at 1200 BST. Over mountains, the daily peaks of ordinary and significant SCW generally occur at 1700–1800 BST and 1600–1700 BST, respectively, while over plains, the peak of ordinary SCW typically lags behind that of mountains by 1–2 hours. Additionally, SCW systems are mainly initiated over mountains, with most lifetimes lasting 7–13 hours. Nonlinear convective systems produce the most SCW events, followed by trailing-stratiform convective systems. The convective available potential energy (CAPE), downdraft convective available potential energy, and the temperature difference between 850 and 500 hPa can all distinguish between SCW systems and non-SCW systems occurring over plains. Compared to non-SCW convective systems, SCW convective systems over mountains are more likely to occur in environments with less precipitable water, while SCW convective systems over plains are more likely to occur in environments with higher CAPE and stronger deep-layer wind shear. [ABSTRACT FROM AUTHOR]

Simple Summary: Through a preliminary analysis of animal remains from the large settlement site of Yucun, located east of the Longshan Mountain and associated with the Zhou people during the first half of the first millennium BC, the authors investigated the subsistence practices in relation to the exploitation of animal resources by the site's residents. The examination of animal species representation and the mortality profiles of major domesticates suggest similarities between Yucun and sites associated with the Qin people, located to the west of the Longshan Mountain. However, differences were observed when comparing Yucun to other contemporaneous sites in the middle and lower Yellow River valley. These patterns in animal use strategies appear to have been influenced by local environmental conditions. The first millennium BC saw the expansion of the Western Zhou dynasty in its northwestern frontier, alongside the rise and development of the Qin State in the Longshan Mountain region of northern China. Exploring the subsistence practices of these communities is crucial to gaining a better understanding of the social, cultural, and political landscape in this region at the time. While much of the research to date has focused on the Qin people, the subsistence practices of the Zhou people remain poorly understood. In this study, we analyzed animal remains from Yucun, a large settlement site associated with the Zhou people, located to the east of the Longshan Mountain. These animal remains were recovered in the excavation seasons of 2018–2020. Our results show that pigs, dogs, cattle, caprines, and horses, which were the major domestic animals at Yucun, accounted for over 90.8% of the animal remains examined in terms of the number of identified specimens (NISP) and 72.8% in terms of the minimum number of individuals (MNI), with cattle and caprines playing dominant roles. In terms of the taxonomic composition and the mortality profiles of pigs, caprines, and cattle, Yucun shared similarities with Maojiaping and Xishan, two contemporaneous Qin cultural sites located to the west of the Longshan Mountain, and differ from other farming societies in the middle and lower reaches of the Yellow River valley. Considering the cultural attributes and topographic conditions of these various sites, these findings imply that environmental conditions may have played a more significant role than cultural factors in shaping the animal-related subsistence practices in northern China during the first millennium BC. [ABSTRACT FROM AUTHOR]

In order to explore whether tea/tree intercropping plantations have positive effects on soil ecosystem services functions, the possible effects of intercropping cultivation of 151 different tea and other species' intercropping setups were summarized and analyzed in terms of three aspects of soil ecological service functions (supply services, support services, and regulating services). An ArcGIS map was plotted to show the distribution of existing intercropping plantations in China up to June 2021. Furthermore, it was concluded that the benefits of intercropping tea plantations exceeded those of monocropping tea plantations in terms of soil ecosystem service functions, such as water retention capacity, mineral contents, effects on energy transformation, and regulating environmental conditions. Intercropping tea plantations were more sustainable than regular tea plantations because of the different degrees of variability and benefits in all three aspects mentioned above. However, tea and tree intercropping plantations often require careful planning and preliminary experimentation to determine the type of intercropping that will have positive impacts, especially in the long term. [ABSTRACT FROM AUTHOR]

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Simple Summary: Life-history theory includes that trade-offs between reproduction and survival are critical for organisms to adapt to different environments. Therefore, understanding how organisms adapt their reproductive investment can provide insights into the evolution of life history. Our results showed that the testes size of Bufo andrewsi significantly differed among populations. We found no geographic trends explaining the variability in testes size, as relative testes size did not vary with altitude and/or latitude. Although rainfall cannot directly affect testes size, the coefficient of variation of temperature showed effects on testes size, indicating declined male reproductive investment under environments with fluctuating temperature and thus highlighting important implications for amphibian conservation. Reproductive investments influenced by environmental conditions vary extensively among geographically distinct populations. However, investigations of patterns of intraspecific variation in male reproductive investments and the mechanisms shaping this variation in anurans remain scarce. Here, we focused on the variation in testis size in 14 populations of the Andrew's toad Bufo andrewsi, a species with weak dispersal ability but wide distribution in southwestern China, to establish whether male reproductive investment varies on an environmental gradient. Our analysis revealed a significant variation in relative testis size across populations, and a positive correlation between testis size and body condition. We, however, found no geographic trends explaining the variability in the testis size. The relative testis size did not increase with increasing latitude or altitude. We also found no relationship between relative testis size and rainfall, but a negative correlation with the coefficient of variation of temperature, with larger testes under stable environments. These findings suggest that the decreased male reproductive investment of this species may be a consequence of harsher or fluctuating environmental conditions. [ABSTRACT FROM AUTHOR]

This study aims to investigate the response mechanisms of groundwater microbial-toxicological indicators, specifically total bacteria count (TBC) and total coliform count (TCC), to water quality indicators and environmental conditions. Using data from a water source in the western plateau of China, a predictive model focusing on TBC and TCC was developed. An orthogonal experimental design was employed to manipulate environmental conditions such as temperature, pH, and porosity, facilitating laboratory experiments. These experiments measured pH, chemical oxygen demand (COD), oxidation-reduction potential (ORP), TBC, and TCC at varying depths and environmental conditions. Principal component analysis elucidated the mechanisms by which water quality indicators and environmental conditions affect groundwater microbial-toxicological indicators. A prediction model for these indicators in plateau regions was established based on a backpropagation neural network (BP-NN), using TBC and TCC as target variables and the newly extracted principal components as influencing factors. The results demonstrate that environmental conditions and water quality indicators primarily influence the evolution of groundwater microbial-toxicological indicators by altering the ionic charge quantities, redox conditions, and temperature of the groundwater. The predictive model for groundwater microbial-toxicological indicators shows trends consistent with experimental outcomes, with an average relative error of less than 15%, meeting engineering requirements. PRACTITIONER POINTS: The values of total bacteria count (TBC) and total coliform count (TCC) under different conditions were obtained by column experiments. The influence mechanism of environmental conditions and groundwater indicators on TBC and TCC was elaborated by principal component analysis. TBC and TCC prediction models were established through the investigation of water sources in a plateau area and laboratory experiments., (© 2024 Water Environment Federation.)

Aim: Understanding the biodiversity–stability relationship has become a central issue in ecology and conservation biology. Although the stabilizing effects of tree species diversity on ecosystem productivity are well recorded in small local communities, they remain poorly understood across scales (from local to larger spatial scales). This study evaluates biodiversity–stability effects from local to larger spatial scales in a large temperate forest region, considering a range of environmental conditions and environmental heterogeneity. Location: North‐eastern China (c. 700,000 km2). Time period: 2005–2017. Major taxa studied: Woody plants. Methods: We define stability as the temporal invariability of biomass productivity. Regional metacommunities representing larger spatial scales were developed by aggregating multiple sets of local field plots. Simple regression analysis was used to test biodiversity–stability relationships in metacommunities. Piecewise structural equation modelling was then used to disentangle the effects of diversity and abiotic variables on forest stability at local and larger spatial scales. Multiple mixed‐effects regression models were used to determine the relative contribution of individual predictive variables to stability across spatial scales. Results: We found that local diversity (alpha diversity) was positively related to the stability of local communities (alpha stability), whereas species turnover across space (beta diversity) was positively related to asynchronous dynamics among local communities (spatial asynchrony), regardless of whether abiotic factors were considered or not. We also found that environmental conditions and environmental heterogeneity affected forest stability across scales. The effect of spatial asynchrony on gamma stability was greater than that of alpha stability. Main conclusions: Our results imply that spatial asynchrony is a key to maintaining the stability of ecosystem productivity within a large temperate forest region. We suggest that diverse forests and heterogeneous landscapes should be sustained at multiple spatial scales to buffer the negative effects of climate change and forest degradation. [ABSTRACT FROM AUTHOR]

Understanding the multiple biotic and abiotic controls of aboveground biomass (AGB) is important for projecting the consequences of global change and to effectively manage carbon storage. Although large-scale studies have identified the major environmental and biological controls of AGB, drivers of local-scale variation are less well known. Additionally, involvement of multiple causal paths and scale dependence in effect sizes potentially confounds comparisons among studies differing in methodology and sampling grain. We tested for scale dependence in evidence supporting selection, complementarity and environmental factors as the main determinants of AGB variation over a 50 ha study extent in subtropical China, modelling this at four sampling grains (0.01, 0.04, 0.25 and 1 ha). At each grain, we used piecewise structural equation models to quantify the direct and indirect effects of environmental (topographic and edaphic properties) and forest attributes (structure, diversity and functional traits) on AGB, while controlling for spatial autocorrelation. Direct scale-invariant effects on AGB were evident for structure and community-mean traits, supporting dominance of selection effects. However, diversity had strong indirect effects on AGB via forest structure, particularly at larger sampling grains (≥ 0.25 ha), while direct effects only emerged at the smallest grain size (0.01 ha). The direct and indirect effects of edaphic and topographic factors were also important for explaining both forest attributes and AGB across all scales. Although selection effects appeared to be more influential on ecosystem function, ignoring indirect causal pathways for diversity via structural attributes risks overlooking the importance of complementarity on ecosystem functioning, particularly as sampling grain increases. [ABSTRACT FROM AUTHOR]

Aim: Tree species diversity can increase the stability of ecosystem productivity by increasing mean productivity and/or reducing the standard deviation in productivity. However, stand structure, environmental and socio‐economic conditions influence plant diversity and might strongly influence the relationships between diversity and stability in natural forest communities. The relative importance of these factors for community stability remains poorly understood in complex (species‐rich) subtropical forests. Location: Subtropical area of southern China. Time period: 1999–2014. Major taxa studied: Forest trees. Methods: We conducted bivariate analyses to examine the mechanisms (overyielding and species asynchrony) underlying the effects of diversity on stability. Multiple regression models were then used to determine the relative importance of tree species diversity, stand structure, socio‐economic factors and environmental conditions on stability. Structural equation modelling was used to disentangle how these variables directly and/or indirectly affect forest stability. Results: Tree species richness exerted a positive effect on stability through overyielding and species asynchrony, and this effect was stronger in mountainous forests than in hilly forests. Species richness positively affected the mean productivity, whereas species asynchrony negatively affected the variability in productivity, hence increasing forest stability. Structural diversity also had a positive effect, whereas population density had a negative effect on stability. Precipitation variability and slope mainly had indirect influences on stability through their effects on tree species richness. Main conclusions: Overall, tree species diversity governed stability; however, stand structure, socio‐economic conditions and environmental conditions also played an important role in shaping stability in these forests. Our work highlights the importance of regulating stand structure and socio‐economic factors in forest management and biodiversity conservation, to maintain and enhance their stability to provide ecosystem services in the face of unprecedented anthropogenic activities and global climate change. [ABSTRACT FROM AUTHOR]

Contaminated gases emissions from livestock industry are becoming one of the most significant contributors to the increasingly serious environmental pollution. To find a way to reduce gases emissions, it is essential to reveal the factors that can affect the gases emissions. In this study, the concentrations of typical gases (including ammonia (NH3), carbon dioxide (CO2), hydrogen sulfide (H2S), and sulfur dioxide (SO2)) generated from naturally-ventilated dairy cow barns were detected through the sample-data method in Tianjin, northern China. Indoor environmental conditions, such as temperature (T) and relative humidity (RH), were measured simultaneously. After applying the carbon dioxide mass balance method, ammonia, hydrogen sulfide and sulfur dioxide emissions were determined. The correlation analysis and regression analysis between the climate condition and gas emissions were conducted to assess the data collected in dairy cow barns during the whole study period. There was a significant relationship between environmental conditions and gas emissions. NH3, H2S and SO2 emissions from the building are in the range of 0.98-2.36 g/LU⋅h, 0-0.034 g/LU⋅h, and 0-0.069 g/LU⋅h, respectively. The numerical analysis shows that the NH3 emission is highly correlated with the temperature and relative humidity. The ventilation rate shows a positive correlation with all the three gases. [ABSTRACT FROM AUTHOR]

Two contradictory niche-based processes, environmental filtering and competitive exclusion, are important ecological processes in community assembly. Quercus wutaishanica forests are the climax communities in the Qinling Mountains and the Loess Plateau, China. Since these areas are characterized by different climate and evolutionary histories, these forests could be a suitable study system to test the phylogenetic niche conservatism hypothesis. We compared variation in community assembly of two distinct Q. wutaishanica forest communities and analyzed how the variations are formed. Quercus wutaishanica forest communities had significantly different species pool, phylogenetic structure and phylogenetic diversity between the two regions that were driven by inconsistency in environment conditions and evolutionary history at the local scale. Soil ammonium nitrogen, soil water content, and nitrate nitrogen play a major role in phylogenetic beta diversity patterns. The effect of environmental filtering on community assembly was more significant on the Loess Plateau than in the Qinling Mountains. Our study also found that local environment is important in mediating the patterns of phylogenetic structure. These findings provide insights into the mechanisms of local community assembly. [ABSTRACT FROM AUTHOR]

Forest productivity may be determined not only by biodiversity but also by environmental factors and stand structure attributes. However, the relative importance of these factors in determining productivity is still controversial for subtropical forests.Based on a large dataset from 600 permanent forest inventory plots across subtropical China, we examined the relationship between biodiversity and forest productivity and tested whether stand structural attributes (stand density in terms of trees per ha, age and tree size) and environmental factors (climate and site conditions) had larger effects on productivity. Furthermore, we quantified the relative importance of environmental factors, stand structure and diversity in determining forest productivity.Diversity, together with stand structure and site conditions, regulated the variability in forest productivity. The relationship between diversity and forest productivity did not vary along environmental gradients. Stand density and age were more important modulators of forest productivity than diversity.Synthesis. Diversity had significant and positive effects on productivity in species‐rich subtropical forests, but the effects of stand density and age were also important. Our work highlights that while biodiversity conservation is often important, the regulation of stand structure can be even more important to maintain high productivity in subtropical forests. [ABSTRACT FROM AUTHOR]

• We modeled the HDR of Chinese fir by using random forest. • We further examined the interactive effects of neighborhood variables and environmental conditions on the HDR of Chinese fir. • Our findings can provide guidance for managing Chinese fir forests to improve their stability. In forest dynamics modeling and estimation, the nonlinear relationship between response and explanatory variables is often concerned, while the interaction among variables is neglected. Height-to-diameter ratio (HDR) is an important indicator for evaluating tree stability and performance. Based on the data from 112 forest inventory plots across Hunan province, China, we modeled the HDR of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) by using random forest and examined the interactive effects of neighborhood variables (neighborhood competition, density and mean diameter) and environmental conditions (dominant height, topography and climate) on the HDR of Chinese fir. Neighborhood competition contributed the most to HDR variation and affected HDR positively. Dominant height and elevation also had a strong influence on HDR. Furthermore, the changes in HDR were jointly dominated by neighborhood features and environmental conditions. For example, HDR varied from 50.5 to 80.3 under the interactive influence of neighborhood competition and dominant height, but varied from 56.8 to 70.2 under the influence of neighborhood competition alone. The relationship between HDR and neighborhood variables might be mediated by environmental conditions, while neighborhood variables did not change the overall trend of HDR responses to environmental factors. When the dense Chinese fir stand is located at low elevation (<500 m) or rich sites (>20 m), frequent and systematic thinning should be carried out in the early stages of forest development. Our findings can provide guidance for managing Chinese fir forests to improve their stability. [ABSTRACT FROM AUTHOR]

High levels of ammonium in water can compromise the ecological environment and be harmful to human beings. It is of great significance to understand the source and controlling factors of ammonium in waters. However, the distribution and controlling factors on ammonium in the central Yangtze River Basin have been rarely reported. The results showed that 6.58% of the surface water (SW) exceeded the China national guideline of category III for NH 4 +-N (i.e., 1.0 mg/L) and 30.19% of the groundwater (GW) exceeded the China national guideline of category III for NH 4 +-N (i.e., 0.5 mg/L). Notably, the ammonium concentrations of the plain area in the middle were much higher, which reached to the highest value at the junction of the Yangtze River and Dongting Lake. Nitrogen in SW may originate from manure but more nitrogen sources in GW. The net anthropogenic nitrogen input (NANI) can provide enough organic nitrogen for the mineralization. NH 4 +-N in SW was more affected by fertilizer nitrogen and feed nitrogen input but more affected by agricultural nitrogen fixation in GW. Agricultural and industrial activities controlled NH 4 +-N in SW and GW by increasing nitrogen input and changing hydrological conditions. In general, this research exposed the controlling of different types of factors on ammonium in waters, providing a guidance for the water pollution prevention in study area. [Display omitted] • 6.58% and 30.19% of the SW and GW exceeded the China national guideline of category III for NH 4 +-N. • Nitrogen in SW may originate from manure and sewage but more nitrogen sources in GW. • NH 4 +-N in SW and GW were more affected by fertilizer and agricultural nitrogen fixation, respectively. • Anthropogenic activities controlled NH 4 +-N in waters through nitrogen input and hydrological conditions [ABSTRACT FROM AUTHOR]

Severe air pollution associated with the rapid urbanization is a pressing issue in China. Moreover, the public awareness of environmental protection in China is awakening, which poses enormous pressure on governments to enforce environmental regulations. The study of environmental problems from the public perspective plays a crucial role in effective environmental governance. The Baidu search engine is the China's largest search engine. The search index of haze based on Baidu search engine reflects the public concern on air quality in China. The aim of this study is to uncover important relationships between public concern and air quality monitoring data based on the case study of haze pollution crisis in China. The results indicate that: (1) the year 2013 is the turning point of the public concern on air quality in China; (2) according to daily data analysis, the search index of haze has increased progressively with increased PM 2.5 concentration with a time lag of 0–4 days and the lag time has a declining tendency from 2013 to 2017; (3) according to annual data analysis, the public concern showed a weak correlation with air quality and they showed an opposite temporal trend. However, when the long-term annual trend was removed, the strong positive correlation emerges between the fluctuation parts of the search index of haze and monitoring data of air quality. This indicates the public is more sensitive to the short-term fluctuation of air quality. The results of this paper provide statistical evidence on the evolution of public concern on air quality from 2013 to 2017. This study will help policy makers to better understand the patterns of the public's perception of environmental problems and consequently improve the government's capability to deal with these challenges. [ABSTRACT FROM AUTHOR]

Cool roofs and green roofs are two important methods used to mitigate the urban heat island (UHI) effect. The Weather Research and Forecasting Model was used to investigate the UHI effect and the effectiveness of cool and green roof mitigation strategies in the Suzhou-Wuxi-Changzhou metropolitan area during an extreme heat wave episode in the summer of 2013. Both urban land-cover change and anthropogenic heat releases exacerbated high temperatures in the urban area. Notably, urban land-cover change and anthropogenic heat release were responsible for 64% and 36% of the UHI intensity, respectively. Both cool and green roofs decreased near-surface air temperatures. The most dramatic decrease in near-surface air temperature occurred in the late morning; nocturnal air temperature decreased slightly because of the decrease in urban heat storage associated with the cool roof strategy. In addition, the UHI mitigation strategies affected the entire urban boundary layer. The decrease in the potential temperature and static stability created a stable urban boundary layer in which turbulent kinetic energy (TKE) decreased simultaneously. Analysis of an urban belt near a large water body showed that the decrease in the surface skin temperature difference between land and the water body weakened the daytime lake breeze. This effect was observed in both the inflow in the boundary layer and the return flow above the boundary layer, and it decreased the heat and moisture exchange between the lake and land boundary layers. [ABSTRACT FROM AUTHOR]

Understanding the composition and content of carotenoids in red-flesh navel orange “Cara Cara” cultivated in different regions is valuable for its nutrition assessment and fruit processing control. Herein, the carotenoids of “Cara Cara” fruits, harvested from five typical citrus growing regions of China, were identified and quantified by HPLC-DAD coupled with HPLC-DAD-APCI-MS/MS. In saponified extracts, 19 free carotenoids including 8 carotenes and 11 xanthophylls were identified. In unsaponified extracts, 83.83–93.83% xanthophylls were esterified and 19 esters were inferred, with the 9- cis -violaxanthin ester confirmed as the dominant component. The carotenoid contents showed difference among the “Cara Cara” fruits from different growing regions, which might be attributed to the local environmental conditions, and the temperature was found directly correlated with total carotenoids content of “Cara Cara”. The data obtained in this study will facilitate the nutritional evaluation of “Cara Cara” and provide beneficial guidance for fruit processing. [ABSTRACT FROM AUTHOR]

The Late Jurassic to Early Cretaceous depositional environments of the Qiangtang Basin in Tibet have the potential to provide significant insight into mechanisms of black shale deposition, organic matter accumulation, and the timing of closure of the Mesotethys Ocean. However, the depositional setting has not been well constrained. Here we apply multiple geochemical proxies and petrologic analyses to representative samples of black shale, marl, and micrite collected from a section in the region. These indicate a transitional marine–continental environment, with brackish to saline water. Redox conditions were weakly oxic to suboxic. Environments represented by the studied section varied over time. The lowermost marls were deposited in a low-salinity, weakly oxic shore to shallow lake environment, under a warm and humid climate regime. The micrites in the middle part of the section were deposited in a lagoonal environment, with intense evaporation, high salinity, and water column stratification. The uppermost shales were deposited in a reducing, semi-enclosed lagoon environment during a marine transgression. These results suggest that the Late Jurassic–Early Cretaceous succession was deposited in a tidal-flat or lagoonal environment. [ABSTRACT FROM AUTHOR]

The rapid and timely evaluation of urban environmental change is highly important for understanding urban sustainability in China. However, the comprehensive understanding of urban environmental change in China based on multi-source remote sensing data remains inadequate because current studies have mainly focused on a single aspect of the urban environment using a specific source of remote sensing data. In this study, we developed a comprehensive evaluation index (CEI) combining the remote sensing data of the fine particulate matter (PM 2.5 ) concentration, land surface temperature (LST) and vegetation cover (VC) to assess the urban environmental change in China at the national scale, among urban agglomerations and across the rapidly urbanized regions. We found a trend of environmental degradation in the urban areas of China between 2000 and 2012. Environmentally degraded and moderately degraded urban areas accounted for 48.14% of the total urban area in China. In particular, the expanded urban areas exhibited the most extensive environmental degradation, with 52.33% of the total expanded urban areas from 1992 to 2012 exhibiting environmental degradation or moderately environmental degradation. The increase in the PM 2.5 concentration was one of the main manifestations of the environmental degradation in the expanded urban areas. We suggest that more attention should be paid to urban environmental issues during future urban development in China. [ABSTRACT FROM AUTHOR]

Agricultural land use has been established as the dominant prehistoric human activity in early cultural centers for thousands of years. However, because of lack of data, there is still considerable debate about the amount and spatial distribution of prehistoric land use across the world. Quantitative reconstruction of it on the basis of human activity records, for example, archaeological data, is the key to resolving the issue. Here, we focus on one of the most representative regions for prehistoric human activity in northern China, the Wei River valley. Based on archaeological and environmental data, a recently developed quantitative prehistoric land use model (PLUM) is applied to reconstruct spatial and temporal changes of land use between 8 and 4 ka BP. The results reveal that in line with increases in the total number of archaeological sites (from 24 to 3222) and population (from 4000 to 1,550,000), the land area of the valley used by humans increased from 0.2% to 12% during the study interval, expanding from the gentle slopes along the lower reaches of the river to the middle and upper reaches. Meanwhile, the average population for an individual site increased from 160 to 481, but the average land use area per site decreased from 12.84 to 4.68 km2. Since 6 ka BP, the significant land use increase occurred synchronously in the Wei River valley and other key regions of agricultural origin across the world, which highlights the important role of agriculture activity in transforming the nature of global land cover during the prehistoric period. [ABSTRACT FROM AUTHOR]

Poor urban air quality in China has received global attention. This article analyses the extent to which the urban form of all provincial and prefectural cities in China affects urban air quality. A geographically weighted regression model was used to quantify the relationship between the urban form indices, as well as the satellite-derived pollutant column density of NO2 and SO2. The results show that urban form has a significant effect on the urban air quality in China. The effect of urban form on air quality varies among the cities in this vast region. The compact ratio index is negatively correlated with both NO2 and SO2 column density for most of the cities. An ‘X’- or ‘H’-shaped city has less air pollution than a rhomboid-shaped city when the city is located in northern or central China. In comparison, the fractal dimension index is not a statistically significant predictor of air quality. Urban form can have effects on air quality that are equivalent to some meteorological and socioeconomic factors. [ABSTRACT FROM AUTHOR]

Atmospheric aerosol particle samples were collected using an Ambient Eight Stage (Non-Viable) Cascade Impactor Sampler in a typical urban area of Beijing from 27th Sep. to 5th Oct., 2009. The surface chemistry of these aerosol particles was analyzed using Static Time of Flight-Secondary Ion Mass Spectrometry (Static TOF-SIMS). The factors influencing surface compositions were evaluated in conjunction with the air pollution levels, meteorological factors, and air mass transport for the sampling period. The results show that a variety of organic ion groups and inorganic ions/ion groups were accumulated on the surfaces of aerosol particles in urban areas of Beijing; and hydrophobic organic compounds with short- or middle-chain alkyl as well as hydrophilic secondary inorganic compounds were observed. All these compounds have the potential to affect the atmospheric behavior of urban aerosol particles. PM 1.1–2.1 and PM 3.3–4.7 had similar elements on their surfaces, but some molecules and ionic groups demonstrated differences in Time of Flight-Secondary Ion Mass Spectrometry spectra. This suggests that the quantities of elements varied between PM 1.1–2.1 and PM 3.3–4.7 . In particular, more intense research efforts into fluoride pollution are required, because the fluorides on aerosol surfaces have the potential to harm human health. The levels of air pollution had the most significant influence on the surface compositions of aerosol particles in our study. Hence, heavier air pollution was associated with more complex surface compositions on aerosol particles. In addition, wind, rainfall, and air masses from the south also greatly influenced the surface compositions of these urban aerosol particles. [ABSTRACT FROM AUTHOR]

The temporal and spatial characteristics of meteorological drought have been investigated to provide a framework of methodologies for the analysis of drought in the Beijing-Tianjin-Hebei metropolitan area (BTHMA) in China. Using the Reconnaissance Drought Index (RDI) as an indicator of drought severity, the characteristics of droughts have been examined. The Beijing-Tianjin-Hebei metropolitan area was divided into 253 grid-cells of 27 x 27km and monthly precipitation data for the period of 1960-2010 from 33 meteorological stations were used for global interpolation of precipitation using spatial co-ordinate data. Drought severity was assessed from the estimated gridded RDI values at multiple time scales. Firstly, the temporal and spatial characteristics of droughts were analyzed, and then drought severity-areal extent-frequency (SAF) annual curves were developed. The analysis indicated that the frequency of moderate and severe droughts was about 9.10% in the BTHMA. Using the SAF curves, the return period of selected severe drought events was assessed. The identification of the temporal and spatial characteristics of droughts in the BTHMA will be useful for the development of a drought preparedness plan in the region. [ABSTRACT FROM AUTHOR]

River bends are distinguished by high biodiversity and elevated rates of biogeochemical activities due to complex hydromorphological processes that form diverse geomorphic units, making it challenging to elucidate the impact of trophic interactions on community assembly and biogeochemical processes. Here, we clarify the effect of trophic interactions in determining the assembly of multi-trophic microbial communities and the impact on nitrogen transformation potential by distinguishing the direct and cascading effects of environmental conditions based on 32 samples collected from a typical urban river bends. It was found that both bacterial and micro-eukaryotic communities were determined by homogeneous selection (indicated by β-nearest taxon index, accounted for 85% and 48.3%, respectively), whereas the dominant environmental factors were different, being sediment particle size (P < 0.05) and nitrogen (P < 0.05), respectively. Both the microbial co-occurrence network and the significant association (P < 0.05) between β-nearest taxon index and trophic transfer efficiency changes showed that the trophic interactions strongly shaped microbial communities in the urban river bends. The path modeling suggested that environmental conditions resulted in an increase in abundance of multi-trophic microbial communities via direct effects (mean standardized effects = 0.21), but reductions in abundance of bacteria via cascading effects, i.e., trophic interaction (mean standardized effects = -0.1). When considering direct and cascading effects together, environmental conditions in urban river bends were found to enhance the abundance of microbial communities, with decreasing magnitude at the higher trophic level. Analogously, the path modeling also indicated the nitrogen transformation potential enhanced by environmental conditions via direct effects, but partly counteracted by trophic interactions via cascading effects. The obtained results could provide a theoretical basis for the regulation and restoration of urban rivers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The controlling factors of oil shale formation within the Upper Cretaceous Qingshankou and Nenjiang Formations of the Songliao Basin are investigated by petrological and geochemical methods. Sediment deposition was balanced by basin subsidence, resulting in the accumulation of Cretaceous strata of high thickness. Global sea level fluctuations have been related to periods of oil shale deposition within the basin. The results indicate a comparable depositional environment during oil shale formation within the two Upper Cretaceous strata with respect to palaeotectonic and palaeoclimate, but differences in the accommodation space during accumulation of the two formations. The larger accommodation space during deposition of the Nenjiang Formation resulted in the higher thickness and wider distribution of the oil shale members (total thickness: 11.2–32 m; distribution area 4.48 × 10 3 km 2 ) within the basin, as compared to the oil shale of the Qingshankou Formation (total thickness: 2–19.3 m; distribution area 1.3 × 10 3 km 2 ). Further differences exist with regard to the palaeoenvironment of oil shale formation and primary productivity. Deposition of the Qingshankou Formation 1st member and Nenjiang Formation 1st member took place within a saline-brackish lake under anoxic conditions in the bottom water. Preservation of organic matter is suggested to have been less favorable during deposition of the Nenjiang Formation 2nd member. Higher primary productivity is believed to be the responsible factor for the accumulation of organic-rich sediments in the Qingshankou Formation 1st member. The interplay of these two factors (i.e. preservation, productivity) leads to the formation of oil shale in the Qingshankou Formation (average TOC: 8.32%; TOC max : 13.52%; average oil yield: 5.57%/) with better hydrocarbon source rock potential and slightly higher oil yield during pyrolysis as in the Nenjiang Formation (average TOC: 7.76%; TOC max : 9.7%; average oil yield: 5.54%). Primary productivity is suggested as the main controlling factor on differences in oil shale quality and source rock potential between the two formations, whereas the variations in quality within each formation mainly depend on the preservation of organic matter. The high thickness, wide spatial distribution and excellent hydrocarbon potential of the Upper Cretaceous oil shales in the Songliao Basin are suggested to have been the result of large accommodation space, stable palaeoenvironmental conditions, and high primary productivity. [ABSTRACT FROM AUTHOR]

Coupled human and natural systems (CHANS) are characterized by many complex features, including feedback loops, nonlinearity and thresholds, surprises, legacy effects and time lags, and resilience. Agent-based models (ABMs) are powerful for handling such complexity in CHANS models, facilitating in-depth understanding of CHANS dynamics. ABMs have been employed mostly on a site-specific basis, however. Little of this work provides a common infrastructure with which CHANS researchers (especially nonmodeling experts) can comprehend, compare, and envision CHANS processes and dynamics. We advance the science of CHANS by developing a CHANS-oriented protocol based on the overview, design concepts, and details (ODD) framework to help CHANS modelers and other researchers build, document, and compare CHANS-oriented ABMs. Using this approach, we show how complex demographic decisions, environmental processes, and human–environment interaction in CHANS can be represented and simulated in a relatively straightforward, standard way with ABMs by focusing on a comparison of two world-renowned CHANS: the Wolong Nature Reserve in China and the Chitwan National Park in Nepal. The four key lessons we learn from this cross-site comparison in relation to CHANS models include how to represent agents and the landscape, the need for standardized modules for CHANS ABMs, the impacts of scheduling on model outcomes, and precautions in interpreting “surprises” in CHANS model outcomes. We conclude with a CHANS protocol in the hope of advancing the science of CHANS. [ABSTRACT FROM PUBLISHER]

Abstract: In this study, polychlorinated biphenyls (PCBs) pollution in the surface water of the Yangtze River Delta (YRD) was investigated. A total of 26 samples were collected from water bodies in three cities within the YRD during the dry season from October to November of 2009. The total PCBs (dissolved plus particulate) ranged from 1.23 to 16.6ngL−1 and were dominated by tri-, tetra-, and penta-chlorinated biphenyls. The mean PCBs in the Beijing–Hangzhou Grand Canal and the Yangtze River were 8.84 and 3.36ngL−1, respectively. A t-test showed that there were no significant differences in the concentration of samples from the metropolitan area and the development zone. According to the Chinese national environmental quality standards for surface water (GB 3838-2002), the concentrations of PCBs observed in this study do not pose a hazard to aquatic or human health. Overall, this study described the PCB concentration and homolog distribution patterns in one of the most rapidly developing areas in China, and the results can be used as reference levels for future PCB monitoring programs. [Copyright &y& Elsevier]

Abstract: Recently there have been reports of forest regrowth occurring in different regions across the world. There is also a growing recognition of the potential beneficial impact that secondary forests may have on the global environment: providing crucial ecosystem services such as soil conservation, stabilization of hydrological cycles, carbon sequestration, and support for forest dependent communities. Consequently, there is a growing awareness of the need to recognize that landscapes are complex shifting mosaics wherein forest clearing and reforestation take place. In this study, the rates of reforestation, deforestation, forest regrowth and degradation were measured using multi-temporal Landsat images of Danjiangkou, China. Landsat data from 1990, 1999 and 2007 were (1) classified as dense forest, open forest and non-forest areas and (2) compared between years to identify forest cutting, regeneration and degradation. The results showed that there was a net gain of 29,315ha of forest area (including dense and open forest) from 1990 to 2007, showing a clear trend of reforestation in the study area. Forest modification (degradation and regrowth) and change categories (deforestation and reforestation) occurred simultaneously during the observation time period. Socioeconomic data from public statistics and environmental attributes allowed the assessment of the socioeconomic factors and the environmental conditions that caused these changes using non-metric multidimensional scaling (NMDS). The research showed that the socioeconomic factors due to different policies were major driving forces of forest transition, whereas environmental attributes of the underlying landscape constrained forest cover changes. These findings have led to a better understanding of forest transition at a local scale in our study region. Comprehensive knowledge of these relationships may be useful to reconstruct past forest transitions and predict future changes, and may help to enhance sustainable management practices aimed at preserving essential ecological functions. [Copyright &y& Elsevier]

The total methane emission to the atmosphere and hydrosphere, and its seasonal variation, were estimated using an enclosed static chamber technique from a tidal marshes dominated by Phragmites australis (common reed) in the Min River estuary, southeast China. Measurements were taken at three tidal stages (before flood, during the flooding and ebbing process, and after ebb). Potential rates of methane production from the marsh sediment layers were also measured using an incubation technique. This P. australis tidal marsh was a net methane source, emitting 32.59 and 6.87 g CH4· m-2· yr-1 to the atmosphere and hydrosphere, respectively. There was considerable monthly variation with emissions greater before flood in some months, whereas at other months emission was greater after ebb. The average methane fluxes were 5.13, 5.06 and 4.74 mg CH4 m-2 h-1 before flood, during flooding and ebbing, and after ebb, respectively. Emissions to the tidewater and the atmosphere during the flooding and ebbing process were 2.98 and 2.08 mg CH4 m-2 h-1,respectively. Sediment methane production potential (0-40 cm depth) ranged from 0.028-0.123 μ g CH4· g-1· d-1, with the greatest production was in the surface soil. Methane fluxes had a significant correlation with atmospheric, sediment temperature and above ground biomass. The implications of these data for global warming are discussed briefly. [ABSTRACT FROM AUTHOR]

Abstract: Archaeological excavations and environment–archaeology studies over many years in the Yangtze Delta region have provided exceptional information about climatic variations, growth and demise of human civilization and human–environment interactions. The archaeological excavations show that the cultural layers of the Neolithic sites are interrupted by barren layers without any cultural relics (so-called cultural interruptions), which may be the result of harsh environmental conditions (arid, flooding, extreme cold or warmth). Temporal and spatial analyses of 14C-dates for buried trees, peat, shell ridges, and Neolithic sites show that environmental changes are responsible for the rise and fall of human civilization. The progress of human civilization was interrupted at least 5 times in the Yangtze Delta, matching 5 periods of high sea level, peat accumulation, and burial of trees. The collapse of the Liangzhu culture about 4000 BP was followed by the less-developed Maqiao culture and resulted from extreme environmental and hydrological conditions such as floods. [Copyright &y& Elsevier]

The ability to achieve urban sustainability has become an indication of the competence of a municipal government aiming to gain world class status for the city. While both Guangzhou and Hong Kong are Chinese cities having their own formulation of urban sustainability, the implementation details and the actual sustainability blueprints are very different. As a result, the outcomes and prospects for urban sustainability are also different. Hong Kong has adopted a less integrative and more institutionally-oriented approach for urban sustainability Guangzhou has used the conventional approach to formulate an integrated sustainability programme for its local Agenda 21. Hong Kong's action plan emphasizes improving coordination, making objective assessments and achieving consistency in policy-making. Guangzhou, on the other hand, emphasizes the meeting of concrete environmental targets. Unfortunately, the new institutional arrangement and monitoring tools adopted by Hong Kong have not been able to achieve the original intent and neither is there the intention to go tot) far beyond the weak sustainability approach. On the contrary, Guangzhou has planned and attempted to incorporate industrial ecology in its development regime while heavily investing into pollution control programmes and pushing forward a green community programme at the grass-roots level. [ABSTRACT FROM AUTHOR]

Studies on the variation in the particulate matter (PM) content, Saturation Isothermal Remanent Magnetization (SIRM), and particle grain-size distribution at a high spatial resolution are helpful in evaluating the important role of urban forests in PM removal. In this study, the trees located in dense urban forests (T0) retained more PM than trees located in open spaces (T1-T4); the SIRM and PM weight of T0 were 1.54-2.53 and 1.04-1.47 times more than those of T1-T4, respectively. In addition, the SIRM and PM weight decreased with increasing distance to the road, suggesting that distance from pollution sources plays a key role in reducing the air concentration of PM. The different grain-size components were determined from frequency curve plots using a laser particle-size analyzer. A unimodal spectrum with a major peak of approximately 20 μm and a minor peak between 0.1 and 1 μm was observed, indicating that a large proportion of fine air PM was retained by the needles of the study trees. Additionally, more <2.5 μm size fraction particles were observed at the sampling site near the traffic source but, compared to a tree in a row of trees, the percentage of the >10 μm size fraction for the tree in the dense urban forest was higher, indicating that the particles deposited on the needle surface originating from traffic sources were finer than those from natural atmospheric dust. The exploration of the variation in the PM weight, SIRM, and grain size of the particles deposited on the needle surface facilitates monitoring the removal of PM by urban forests under different environmental conditions (e.g., in closed dense urban forests and in open roadside spaces), different distances to roads, and different sampling heights above the ground.

• Species diversity enhanced soil organic carbon storage in subtropical forests. • Soil organic carbon storage decreased with MAT and MAP in subtropical forests. • Soil organic carbon storage was closely related to leaf litter C/N and root biomass. Tropical and subtropical forest ecosystems play an important role in the global carbon regulation. Although positive relationships between biodiversity and soil organic carbon (SOC) storage have been found in experimental grasslands, biodiversity effects on SOC storage in natural forests remain debated. Based on a large dataset from 523 forest inventory plots across subtropical forests in China, we tested the relationship between biodiversity and SOC storage and examined whether environmental conditions (temperature, precipitation, soil properties) and litter quantity (leaf litter and root biomass) and quality (leaf litter carbon to nitrogen ratio [leaf litter C/N]) had effects on SOC storage. Furthermore, we used linear mixed-effects models to test the relative effects of biodiversity, environmental conditions, and litter quantity and quality on SOC storage. We used structural equation models to test how these variables directly or indirectly affected SOC storage. We found that species diversity, together with climatic factors (mean annual temperature and mean annual precipitation), leaf litter C/N and root biomass determined SOC storage in subtropical forests at a large spatial scale. SOC storage was most strongly affected by climatic factors, followed by leaf litter C/N. Species diversity had both direct and indirect (through root biomass and leaf litter C/N) effects on SOC storage after accounting for environmental conditions. We also found that the positive diversity–SOC storage relationships were stronger in low and medium mean annual precipitation. Our findings highlight that higher species diversity can lead to higher SOC storage and therefore the conservation of biodiversity could play an important role in climate change mitigation. [ABSTRACT FROM AUTHOR]

Urban green space can bring various ecosystem benefits to diverse social groups. Among those ecosystem benefits, intangible social values are often neglected but highly relevant to human welfare. Existing research on the social values of urban green space often focusses on the perspective of urban inhabitants rather than tourists, even though tourists are also major beneficiaries. By combining different data sources into a comprehensive source about green-space social values, we investigated the disparity between inhabitants' and tourists' perceptions about space-associated social values, and further explored the underlying environmental conditions in the East Lake scenic area, Wuhan. For this, we collected 347 questionnaires through an on-site survey and 11,908 photos uploaded by 2165 social media users (Sina Blog), and we used SolVES (Social Value for Ecosystem Services) to uncover the spatial patterns of social values and the relationships between social value indicators and natural surroundings. Social-value hotspots occurred near water and trails. Perceptions differed, however, between inhabitants and tourists. Inhabitants perceived a larger scale of social values and could benefit more from recreation and economic values. Tourists, on the other hand, showed greater appreciation for aesthetic and cultural values. Environmental features were associated with social values to differing extent; distance to water and land use/cover exerted significantly influence. These findings should be taken into consideration to improve urban spatial planning and to optimize green infrastructures for human welfare., (Copyright © 2020 Chen, Ke, Min and Cheng.)

Tropical and subtropical forest ecosystems play an important role in the global carbon regulation. Despite increasing evidence for effects of biodiversity (species diversity, functional diversity and functional dominance), stand structural attributes, stand age and environmental conditions (climate and topography) on tree carbon storage, the relative importance of these drivers at large scale is poorly understood. It is also still unclear whether biodiversity effects on tree carbon storage work through niche complementarity (i.e. increased tree carbon storage due to interspecific resource partitioning) or through the mass-ratio effect (tree carbon storage regulated by dominant traits within communities). Here we analyze tree carbon storage and its drivers using data of 480 plots sampled across subtropical forests in China. We use multiple regression models to test the relative effects of biodiversity, stand structural attributes, stand age and environmental conditions on tree carbon storage, and use a partial least squares path model to test how these variables directly and/or indirectly affect tree carbon storage. Our results show that tree carbon storage is most strongly affected by stand age, followed by climate, biodiversity and stand structural attributes. Stand age and climate had both direct and indirect (through species diversity, functional dominance and stand structural attributes) effects. We find that tree carbon storage correlates with both species diversity and functional dominance after stand age and environmental drivers are accounted for. Our results suggest that niche complementarity and the mass-ratio effect, not necessarily mutually exclusive, both play a role in maintaining ecosystem functioning. Our results further indicate that biodiversity conservation might be an effective way for enhancing tree carbon storage in natural, species-rich forest ecosystems., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Non-methane hydrocarbons (NMHCs) play an important role in the atmospheric environment. However, NMHC emissions from agricultural fields, especially their variations with straw return, are poorly understood. Therefore, a field study comprising two treatments, i.e., (1) S0 (straw removal) and (2) S1 (incorporation of maize straw at a rate of 9000 kg ha -1 ), was conducted in a straw-returned maize cropping system to characterize NMHC emissions as well as to estimate the effect of straw return on those emissions. Using a Gas Chromatography-Mass Spectrometer (GC-MS) method, 28 types of NMHCs were identified. The total NMHC emission from S0 was 2018 g ha -1 , where 1-methyl-3-propyl-benzene, (1-methylethyl)-benzene, and toluene were obviously predominant, whereas the total NMHC emission from S1 was 1903 g ha -1 , where 1-methyl-3-propyl-benzene, 2-methyl-pentane, and (1-methylethyl)-benzene were the main species. The results showed that straw return had opposing effects on NMHC emissions, ranging from -55.4% to 478.6%. Overall, the total NMHC emission with returned straw alone decreased by 2963 ng kg straw -1  h -1 . Furthermore, NMHC fluxes had higher correlations with soil temperature than with soil moisture or pH. Notably, the higher correlations of NMHC fluxes with 10 cm soil temperature than with 5 cm soil temperature indicate that soil in the deeper layer might play a more important role in NMHC fluxes. The results also suggest that more field study is needed to accurately estimate the effect of straw return on NMHC emissions from agroecosystems and fully understand its underlying mechanism., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The article discusses how the stripping of rain forest and natural flora for rubber plantations is posing a threat to conservation efforts in China. As rubber prices have tripled, these plantations have boomed in the province of Xishuangbanna, where they cover approximately 400,000 hectares. The economic benefits of the rubber trade are evident in the province's capital city of Jinghong. Numerous conservation problems are associated with this, as rubber trees are invasive plants that require copious amounts of water, a process that reduces evaporation. Hasan Moinuddin of the Asian development Bank provides quotes.

Primary and secondary metabolism in grape berries is under the control of complex interactions among environmental conditions, genotypes, and management practices. To obtain an interpretation from the view of transcriptome on distinct metabolite accumulation between ecologically different regions in China, next-generation sequencing technology was performed on E-L 31, 35, and 38 stages of Cabernet Sauvignon grape berries from Changli (CL, eastern) and Gaotai (GT, western). The transcript abundance of epoxycarotenoid dioxygenase and xanthoxin dehydrogenase required for ABA biosynthesis was significantly higher in the GT berries at E-L 35 and 38 stages compared with the CL berries, which may explain the relatively short maturation period of berries in the western region. Some genes required for carbohydrate metabolism, such as hexose transporter, L-idonate dehydrogenase, and phosphoenolpyruvate carboxylase, were significantly up-regulated in the CL berries in relation to the GT berries, which positively correlated with the sugar and organic acid accumulations. Pathway enrichment analysis of differentially expressed genes revealed that the CL berries had higher levels of phenylpropanoid biosynthesis at E-L 38 stage than the GT berries, which may relate to the quick fading of the GT wines because of weak co-pigmentation. This observation lays a foundation for further study concerning the molecular basis for environmental effects on berry quality formation., (Copyright © 2015 Elsevier GmbH. All rights reserved.)