Changes in Ecological Environment of the Tarim River Confirmed by Tree Rings

The tree ring is an important carrier of the evolution of climate in the study of global change.It enjoys advantages of accurate dating,strong continuity,high resolution ratio and high reconstruction precision.This paper tested the changes of Populus euphratica tree ring and the runoff in the upper and middle reaches of the Tarim River through the monotonic trend and analyzed the response of the tree ring in the lower reaches of the Tarim River to the water supply through the combined tree ring data and the historical literature,so as to confirm the accuracy of the response of Populus euphratica tree ring to river diversion.The results were included as follows.(1)From 1957 to 2010,the radial growth of Populus euphratica in the upper and middle reaches of the Tarim River decreased gradually in the time series,which was the same as the runoff.The downtrend was significant,and|Zc|was more than 0.96.(2)From1913 to 2000,the radial growth of Populus euphratica as a whole in the lower reaches of the Tarim River decreased.The downtrend was significant between 1973 and 2001,reaching the lowest level in the past 100years.The formation and diversion of the Layi River was as described in the historical literature.(3)The development of the ecological water delivery project has improved the ecological environment of the lower reaches,which has been verified from the Populus euphratica tree ring in the lower reaches.However,despite the ecological water delivery project in recent years,the growth of Populus euphratica tree ring has not reached to the level before 1920,indicating that the existing ecological water delivery is of limited value in recovering desert riparian forest.(4)In the analysis of the response of the Populus euphratica to the water resources,the wavelet analysis method and the historical literature review method have drawn the same conclusion.

Analysis of ecological effects of comprehensive treatment in the Tarim River Basin using remote sensing data

Based on multi-type,multi-temporal remote sensing data,we have monitored recent changes in cultivated land use and vegetation,in sandy areas and salinized desertification in the Green Corridor zone of the main channel of the Tarim River Basin.The results of our investigation show that the ecological environment in the Green Corridor of the main channel of the Tarim River Basin has conspicuously improved from 2002 to 2004.These improvements show up largely in such aspects as an increase in the rate of vegetation cover,a reduction in desertification land areas and a weakening in the intensity of sandy and the salinized land.On the other hand,the cultivated area in the Tarim River Basin significantly increased from 2002 to 2004.The rate of growth in cultivated areas during this period was significantly higher than that from 1999 to 2002.The increase in the use of irrigation resulting from the substantial increase in cultivated areas has a long-term potential restraining effect on the restoration of ecological functions of the Tarim River.

Ecological health analysis of wetlands in the middle reaches of Yangtze River under changing environment

Changes in wetland ecosystems have a critical impact on the local ecology and species diversity.Different development scenarios and policies are key factors influencing their changes.Therefore,we studied changes of wetlands in the middle Yangtze River basin(MYRB)in 2001-2020,and a patch-generated land use simulation(PLUS)model and random forest(RF)method were applied to predict and analyze the changes under different scenarios in the MYRB in the future(i.e.2035-2095).The results indicated that:(1)The regions with high wetland proportions were concentrated in the central and eastern MYRB in 2001-2020,with a 1.5%decrease in overall wetland area;(2)The RF could simulate the future ecological quality with training and testing accuracies of 0.98 and 0.92,respectively;(3)Remote Sensing Ecological Index(RSEI)less than 0.5 in the central and eastern regions and 13.3%reduction in the northwest in the SSP245 scenario.In general,the study provides a basis for future regional studies of ecosystem quality and provides data to support wetland conservation and management.

The Analysis of NGOs' Organizational Ecosystem in Participating in Climate Change Issues in the United States

How many NGOs were there in the climate change field in the United States？ Who were they？ And what was the relationship between them？ In the United States,climate change was only a branch of environmental issues at the beginning; therefore there were no specific quantitative statistics and network analysis of NGOs in climate change. Diversity was an important feature of NGOs in American climate change fields,and it showed a complex organizational ecology through varieties of networks and interaction among organizations. In order to make a difference in climate field,Chinese NGOs firstly needed to improve and enhance their own abilities.

A review of ecological impacts of global climate change on persistent organic pollutant and mercury pathways and exposures in arctic marine ecosystems

Bioaccumulative and biomagnifying contaminants, such as persistent organic pollutants （POPs） and mercury （Hg）, have for decades been recognized as a health concern in arctic marine biota. In recent years, global climate change （GCC） and related loss of arctic sea ice have been observed to be driving substantial change in arctic ecosystems. This review summarizes findings documenting empirical links between GCC-induced ecological changes and alterations in POP and Hg exposures and pathways in arctic marine ecosystems. Most of the studies have reported changes in POP or Hg concentrations in tissue in relation to GCC-induced changes in species trophic interactions. These studies have typically focused on the role of changes in abun- dance, habitat range or accessibility of prey species, particularly in relation to sea ice changes. Yet, the ecological change that re- suited in contaminant trend changes has often been unclear or assumed. Other studies have successfully used chemical tracers, such as stable nitrogen and carbon isotope ratios and fatty acid signatures to link such ecological changes to contaminant level variations or trends. Lower sea ice linked-diet changes/variation were associated with higher contaminant levels in some popula- tions of polar bears, ringed seals, and thick-billed murres, but the influence of changing trophic interactions on POP levels and trends varied widely in both magnitude and direction. We suggest that future research in this new area of GCC-linked ecotox- icology should focus on routine analysis of ancillary ecological metrics with POP and Hg studies, simultaneous consideration of the multiple mechanisms by which GCC and contaminant interactions can occur, and targeted research on changing exposures and toxicological effects in species known to be sensitive to both GCC and contaminants [Current Zoology 61 （4）： 617-628, 2015].

Spatial quality： analysis of China＇s eco-environmental 1990-2010

Over the past two decades in China, stress on the environment has increased continuously. This paper will assess the change in environmental quality over time, and its spatial variation using data from the statistical yearbooks of 31 provincial administrative regions in 1990, 1995, 2000, 2005, and 2010. These books provide a general assessment of the environment at the provincial level, and the three major economic regions from western to eastern China. By using the geographic information system （GIS） and SPSS, we analyzed the changing trend of China＇s eco-environment and calculated the changing trajectory in the gravity center of the eco-environmental quality. We conclude the following. （1） From 1990 to 2010, the rate of deterioration of the environment went down. We argue that the cause of this trend was neither the result as ＂the deterioration trend was under control＂ noticed by the government departments concerned, nor ＂the deterioration rate of the environment was increasingly intensified＂ suggested by many researchers. （2） Since 1990, the general environment has been worsening in China, but it was improved in some regions; however, the ecological deficit is still expanding and will last for a long time. （3） From western to eastern China, the deterioration rate of environmental quality was slowed down. The reasons include a good natural environment, a developed regional economy, and technology and finance in eastern China. （4） After extensive economic development in China, there are imbalances of population, economy, society, and the environment in the 31 provincial regions. The governments at all levels should play an important role in research and protecting the environment. In addition, it is imperative to implement positive measures such as controlling population, improving the environment, and promoting smart development to balance the socio-ecological system.