scholarly journals Temporal and Spatial Distributions of Ecological Vulnerability under the Influence of Natural and Anthropogenic Factors in an Eco-Province under Construction in China

2018 ◽  
Vol 10 (9) ◽  
pp. 3087 ◽  
Author(s):  
Qian Ding ◽  
Xun Shi ◽  
Dafang Zhuang ◽  
Yong Wang
Keyword(s):  
Yangtze River ◽  
Principal Component ◽  
Anthropogenic Factors ◽  
Land Resource ◽  
The Yangtze River ◽  
Irrigation Channel ◽  
The North ◽  
Ecological Vulnerability ◽  
Under Construction ◽  
Natural And Anthropogenic Factors

Ecological vulnerability evaluations can provide a scientific foundation for ecological environment management. Studies of ecological vulnerability have mainly focused on typical ecologically vulnerable regions with poor natural conditions or severe human interference, and such studies have rarely considered eco-provinces. Taking Jiangsu, an eco-province under construction in China, as the study area, we evaluated the spatiotemporal distributions of ecological vulnerability in 2005, 2010 and 2015 at the kilometer grid scale and analyzed the effects of natural and anthropogenic factors on ecological vulnerability. The pressure state response model (PSR), geographic information systems (GIS), spatial principal component analysis, spatial autocorrelation analysis, and correlation analysis methods were used. The results of the study are as follows: (i) the effects of anthropogenic factors on ecological vulnerability are greater than those of natural factors, and landscape evenness and the land resource utilization degree are the main factors that influence ecological vulnerability. (ii) Jiangsu Province is generally lightly to moderately vulnerable. Slight vulnerability is mainly observed in areas with water bodies. Light vulnerability is concentrated in paddy fields between the Main Irrigation Channel of North Jiangsu and the Yangtze River. Medium, heavy and extreme vulnerability areas are mainly composed of arable and built-up land. Medium vulnerability is mainly distributed to the north of the Main Irrigation Channel of North Jiangsu; heavy vulnerability is scattered to the south of the Yangtze River and in north-western hilly areas; and extreme vulnerability is concentrated in hilly areas; (iii) Ecological vulnerability displays a clustering characteristic. High-high (HH) regions are mainly distributed in heavy and extreme vulnerability regions, and low-low (LL) regions are located in slight vulnerability areas. (iv) Ecological vulnerability has gradually deteriorated. From 2005 to 2010, the vulnerability in hilly areas considerably increased, and from 2010 to 2015, the vulnerability in urban and north-eastern coastal built-up land areas significantly increased. Emphasis should be placed on the prevention and control of ecological vulnerability in high-altitude, urban and coastal areas.

scholarly journals Evaluation Analysis of Forest Ecological Security in 11 Provinces (Cities) of the Yangtze River Economic Belt

2021 ◽  
Vol 13 (9) ◽  
pp. 4845
Author(s):  
Yiran Wang ◽  
Dahong Zhang ◽  
Yahui Wang
Keyword(s):  
Principal Component Analysis ◽  
Yangtze River ◽  
Principal Component ◽  
Ecological Security ◽  
Economic Pressure ◽  
The Yangtze River ◽  
Upward Trend ◽  
Response Index ◽  
Pressure Index ◽  
Resource Index

The forest ecological security of the Yangtze River Economic Belt has an important influence on improving the regional environment and promoting the sustainable development of the social economy. Therefore, the aim of this paper is to provide countermeasures and suggestions for improving the level of regional ecological security by quantitatively analyzing the forest ecological security status of the Yangtze River Economic Belt and the tributaries of the Yangtze River. Using three main aspects, i.e., resources, socio-economic pressure and maintenance response, the study established 26 indicators that affect the forest ecological security of 11 provinces (cities) in the Yangtze River Economic Belt. The index weights were determined by principal component analysis, and the forest ecological security levels of 11 provinces (cities) in the Yangtze River Economic Belt were classified and evaluated by the grey clustering method. The results show the following: (1) the principal component analysis determined the weight of the three aspect indicators. The order is as follows: resource index > socio-economic pressure index > maintenance response index. This means that the basic environmental condition which the forest growth depends on and quality and quantity of forest is most important, and the maintenance activities performed by human beings in forest resources need to be strengthened. (2) The level of the forest ecological security in all the provinces (cities) of the Yangtze River Economic Belt is relatively good, with an upward trend. The level of forest ecological security in each province (city) decreases from the upper reaches of the Yangtze River basin to the lower reaches, and the level of forest ecological security in the central cities is lower. (3) The resource index, socio-economic pressure index and maintenance response index of all the provinces and cities showed an upward trend in these four years. The provinces with a significantly higher forest resource index include Yunnan and Guizhou. Shanghai, Chongqing, Sichuan, Hunan and Jiangxi were the provinces with significantly higher socio-economic pressure values; Yunnan province, Shanghai, Jiangxi Province and Hubei province were the provinces with higher forest maintenance response values.

Phytoplankton of cold-water lake ecosystems under the influence of natural and anthropogenic factors

2021 ◽  
pp. 42-49
Author(s):  
Andrey N. Sharov
Keyword(s):  
Heavy Metals ◽  
Cold Water ◽  
Arctic Lakes ◽  
Water Bodies ◽  
The Arctic ◽  
Anthropogenic Factors ◽  
Large Lakes ◽  
Arctic Water ◽  
The North ◽  
Natural And Anthropogenic Factors

Based on the study of the spatio-temporal aspects of the development of phytoplankton in the lakes of the North and North-West of the European territory of Russia (large lakes – Imandra, Onega and Chudsko-Pskovskoye and small lakes of the Arctic and Subarctic), the features of its structure and dynamics under the influence of natural and anthropogenic factors (eutrophication, heavy metal pollution, acidification, thermification). The species composition and quantitative characteristics of phytoplankton of large lakes of the North of Russia, small arctic lakes and lakes of subarctic regions are studied. It has been shown that diatoms predominate in arctic water bodies according to species diversity, and green and diatoms predominate in boreal ones. By biomass, diatoms dominate mainly in all cold-water lakes, with the exception of small arctic lakes, where golden algae lead. The features of the reorganization of phytoplankton in response to the action of anthropogenic factors are revealed. It is proved that in the northern water bodies the complex action of heavy metals and nutrients does not lead to inhibition of phytoplankton, and the effect of acidification in combination with heavy metals enhances the toxic effect of the latter. A feature of the response to acidification is an increase in the variability of the dynamics of the biomass of phytoplankton. It has been shown that in different types of lakes of East Antarctica under severe climate conditions under light and biogenic limitation, redistribution of autotrophic components in the formation of the biota of water bodies occurs: against the background of a decrease in the abundance and diversity of phytoplankton, the role of microphytobenthos and periphyton increases.

scholarly journals A modeling study of the influences of Yangtze River and local catchment on the development of floods in Poyang Lake, China

2016 ◽  
Vol 47 (S1) ◽  
pp. 102-119 ◽  
Author(s):  
Xianghu Li ◽  
Jing Yao ◽  
Yunliang Li ◽  
Qi Zhang ◽  
Chong-Yu Xu
Keyword(s):  
Yangtze River ◽  
Lake Level ◽  
Poyang Lake ◽  
Hydrological Regime ◽  
The Yangtze River ◽  
Lake Level Changes ◽  
The North ◽  
Physically Based ◽  
North And South ◽  
Catchment Runoff

Poyang Lake, one of the most frequently flooded regions in China, connects with the Yangtze River and the five sub-tributaries in the local catchment. The lake's hydrological regime is complicated by a complex hydraulic connection and strong river–lake interaction, especially for the extreme hydrological regime. This study analyzes the relationships between the lake level changes and the flow regimes of Yangtze River and local catchment during the flood season and employs a physically based hydrodynamic model to quantify their relative contributions to the development of floods. The study found that the large catchment runoff and Yangtze River discharge were both significant contributors to flood development but that their contributions were unevenly distributed in time and space. The local catchment imposed more influence during the period of April–May and at the middle parts of the lake, and its influence decreased toward the north and south; in contrast, the most remarkable lake level changes were observed in July–August and at the northern lake for the Yangtze River cases, and these changes reduced from north to south. Moreover, Yangtze River imposed far stronger influences on the lake level changes than the catchment runoff and dominated the duration of floods to a great extent.

Principal Component Analysis of Eutrophication in the Yangtze River Estuary

2012 ◽  
Vol 209-211 ◽  
pp. 1910-1914
Author(s):  
Qiang An ◽  
Lu Lin ◽  
Yuan Yuan Liu ◽  
Ning Qiu Huang ◽  
Bin Zhao
Keyword(s):  
Principal Component Analysis ◽  
Yangtze River ◽  
River Estuary ◽  
Principal Component ◽  
Component Analysis ◽  
Yangtze River Estuary ◽  
Adjacent Area ◽  
The Yangtze River ◽  
Chl A ◽  
The Yangtze River Estuary

The Yangtze River Estuary has become increasingly challenged by various destructive threats to its ecosystem such as the frequent occurrence of harmful algal blooms. Four cruises were carried out in the Yangtze River Estuary and its adjacent area in 2006. Ten variables including CODMn, PO43--P, SiO3-Si, NO3--N, NO2--N, NH4+-N, TN, TP, TOC and chl-a were analyzed by exploratory data analysis. Nitrate was the dominant form of TN throughout the year. Principal component analysis (PCA) was applied to estimate the sources of nutrients contamination in 2006. Two principal components (PCs) were extracted, namely, CODMn, PO43--P, NO3--N and TN for PC1, NO2--N and chl-a for PC2. Influenced by anthropogenic sewage, PC1 near Shidongkou, Bailonggang, Xinhe and Zhuyuan outlets was higher than other stations. The primary influencing factor of PC1 were the contaminants carried by runoff from the Yangtze River. And the dominating factors of eutrophication in 2006 were CODMn, PO43--P, NO3--N, TN and chl-a in the Yangtze River Estuary and its adjacent area.

Chinese Communist Treatment of the Origins and the Foundation of the Chinese Empire

1965 ◽  
Vol 23 ◽  
pp. 78-105 ◽  
Author(s):  
A. F. P. Hulsewé
Keyword(s):  
Yangtze River ◽  
Fourth Century ◽  
Fifth Century ◽  
The Yangtze River ◽  
The South ◽  
The West ◽  
Warring States ◽  
North East ◽  
The North ◽  
Chinese Empire

In antiquity, China was far from being the China we know today, neither in extent, nor in political and social organisation. To the south it did not extend beyond the Yangtze River, to the north it stopped short of the Mongolian steppe, to the north-east, only a small part of the south Manchurian plain was included, whereas in the west it merely went up to the easternmost part of what is now Kansu Province; the Szechwan plain was only included at the end of the fourth century B.C. Politically, the King of Chou was theoretically the overlord of most of this area, but in actual practice, independent rulers reigned over a congeries of larger and smaller states. As a result of wars of conquest, seven large states had come to be formed by the middle of the fifth century B.C. and these were engaged in a ceaseless struggle for supremacy. The time between the middle of the fifth century and 221 B.C., when the western state of Ch'in finally conquered all its rivals, is known as the period of the Warring States.

Biogeographic patterns of complete ammonia oxidizers (comammox) within the Yangtze River continuum

2021 ◽  
Author(s):  
Shufeng Liu ◽  
Haiying Wang ◽  
Jinren Ni
Keyword(s):  
Yangtze River ◽  
Ammonia Oxidation ◽  
Gene Clusters ◽  
Anthropogenic Factors ◽  
Ammonia Oxidizing Bacteria ◽  
The Yangtze River ◽  
Related Gene ◽  
Biogeographic Patterns ◽  
Environmental Selection ◽  
Phylogenetic Resolution

<p>The recent discovery of comammox <em>Nitrospira </em>performing complete ammonia oxidation to nitrate has fundamentally renewed the 120-year-held perspective of “two-step” nitrification. Rivers are known as the “Arteries” of the Earth, coupling the biogeochemical cycling of continents and oceans. Frequent human activities usually increase nitrogen load, and nitrifying microorganisms are crucial for the management of nitrogen load in rivers. The ecological roles of truncated nitrifiers, including canonical ammonia-oxidizing bacteria, ammonia-oxidizing archaea and nitrite-oxidizing bacteria in rivers have been fully understood, however, investigations of the newly discovered comammox <em>Nitrospira </em>are very scarce. To fill this gap, we used the metagenomic shotgun sequencing to provide the first biogeographic patterns of comammox <em>Nitrospira </em>in the Yangtze River over a 6030 km continuum.</p><p>First, ten novel comammox genomes (71~96% completeness) were reconstructed with the metagenome assemblies from fluvial water in the upper reach and surface sediments from the middle reach to the estuary. Gene arrangements in ammonia oxidation-related gene clusters of these novel genomes were more complex and diverse than those of the previously discovered ones. For instance, multi-copy <em>amoA </em>or <em>amoB </em>genes, peptidases, cupredoxin and <em>fkpA</em>-cytochrome <em>c</em>-<em>nirK </em>gene sets were first found within the ammonia oxidation-related gene clusters of comammox <em>Nitrospira</em>, which might confer them advantages in adapting to the relatively oligotrophic environments and stabilizing the ammonia-oxidation process in rivers. Taxonomic analysis demonstrated that all riverine comammox genomes (constituting four new species) belonged to clade A. Based on the phylogenies of their 37 “elite” conserved marker genes, we further separated all reported comammox clade A into five sublineages, named clade A-Ia, A-Ib, A-Ic and A-IIa, A-IIb. The reclassified sublineages were sufficiently divergent to be meaningful in expanding the taxonomic/functional diversity and improving the phylogenetic resolution.</p><p>Second, based on the improved phylogenetic resolution, we explored the biogeographic patterns of planktonic and benthic comammox <em>Nitrospira </em>subjected to natural and anthropogenic factors along the Yangtze River. Our study revealed the wide existence of comammox <em>Nitrospira </em>and their significant contributions to nitrifier abundances, constituting 30% and 46% of ammonia-oxidizing prokaryotes (AOPs) and displaying 30.4- and 17.9-fold greater abundances than canonical <em>Nitrospira </em>representatives in water and sediments, respectively. Comammox <em>Nitrospira </em>were found to contribute more to nitrifier abundances (34~87% of AOPs) in typical oligotrophic environments with a higher pH and lower temperature, particularly in the plateau (clade B), mountain and foothill (clade A-Ic) of the upper reach. Environmental selection determined the niche replacement of planktonic comammox <em>Nitrospira </em>by canonical ammonia-oxidizing bacteria and <em>Nitrospira </em>sublineages I/II from upstream to downstream, leading to a higher spatial turnover rate than observed for the benthic counterpart, while the dissimilarity of benthic comammox <em>Nitrospira </em>was moderately driven by geographic distance. A considerable decrease (83%) in benthic comammox <em>Nitrospira </em>abundance occurred immediately downstream of the Three Gorges Dam, which was consistent with a substantial decrease in the overall bacterial taxa in sediments.</p><p>Together, this study highlights the previously unrecognized dominance of comammox <em>Nitrospira</em> in major river systems and underlines the importance of revisiting the distributions of and controls on nitrification processes within global freshwater environments.</p>

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