Research Progress on Distribution,Sources and Ecological Effects of Phthalate in Soil

Phthalate esters(PAEs)are widely used as main plasticizers in plastic products,agricultural regulators,toys,and other fields.This paper reviewed the research progress on the distribution,sources,and ecological effects of PAEs.The effects of PAEs on soil microorganisms,animals,plants and soil properties were explored in sequence,providing effective theoretical basis for future research on PAEs.

Ecological effects of crude oil residues on the functional diversity of soil microorganisms in three weed rhizospheres

Ecological effects of crude oil residues on weed rhizospheres are still vague. The quantitative and diversity changes and metabolic responses of soil-bacterial communities in common dandelion （Taraxacum officinale）, jerusalem artichoke （Silphiurn perfoliatum L.） and evening primrose （A colypha australis L.） rhizospheric soils were thus examined using the method of carbon source utilization. The results indicated that there were various toxic effects of crude oil residues on the growth and reproduction of soil bacteria, but the weed rhizospheres could mitigate the toxic effects. Total heterotrophic counting colony-forming units （CFUs） in the rhizospheric soils were significantly higher than those in the non-rhizospheric soils. The culturable soil-bacterial CFUs in the jerusalem artichoke （S. perfoliatum） rhizosphere polluted with 0.50 kg/pot of crude oil residues were almost twice as much as those with 0.25 kg/pot and without the addition of crude oil residues. The addition of crude oil residues increased the difference in substrate evenness, substrate richness, and substrate diversity between non-rhizospheric and rhizospheric soils of T. officinale and A. australis, but there was no significant （p〉0.05） difference in the Shannon＇s diversity index between non-rhizospheric and rhizospheric soils of S. perfoliatum. The rhizospheric response of weed species to crude oil residues suggested that S. perfoliatum may be a potential weed species for the effective plant-microorganism bioremediation of contaminated soils by crude oil residues.

Land use change and its ecological effect in Qian’an County of Jilin Province

Based on GIS and statistical methods, with the help of searching historical literatures and calculating the landscape indices, the land use changes of Qian'an County in both spatial and temporal aspects from 1945 to 1996 has been analyzed in this paper. And the driving forces of land use changes and their ecological effects are discussed too. The main findings of this study are as follows: (1) Land use changed greatly in Qian'an during 1945-1996, characterized by a decrease in grassland, wetland and water bodies, and an increase in cultivated land, saline-alkali land, and the land for housing and other construction purposes. Grassland decreased by 175,828.66 ha, and cultivated land increased by 102,137.23 ha over the half century. Accordingly, the main landscape type changed from a steppe landscape to a managed agricultural ecosystem. (2) Results of correlation analysis show that the land use change in the study area was mainly driven by the socioeconomic factors. (3) The ecological effects of land use change in the area are characterized by serious salinization, degression of soil fertility and the weakening of landscape suitability.

Ecological effects of the microbial weathering of silicate minerals

1 Introduction Global climate change is one of the greatest challenges facing humankind in the 21st century.Studying,and utilising,the carbon sink caused by the weathering of silicate minerals has been a key research focus for

Simulation Experiments of Land Surface Physical Processes and Ecological Effect over Different Underlying Surface

Based on the existing Land Surface Physical Process Models(Deardorff, Dickinson, LIU, Noilhan, Seller, ZHAO), a Comprehensive Land Surface Physical Process Model (CLSPPM) is developed by considering the different physical processes of the earth's surface-vegetation-atmosphere system more completely. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feas...

Changes of landuse form and their ecological effect on desert-steppe area in Ningxia

The central part of Ningxia is a desert-steppe area with a sparse population and fragile ecosystem where over-grazing has caused serious degeneration of steppe ecosystem; however, the southern part is a populous loessic hilly area subject to serious soil erosion. The central desert steppe has become an oasis with immigrants from southern loessic hilly area thanks to the implementation of new irrigated projects by pumping water from the Yellow River. Using government investment and loan of World Bank, the new irrigated area has been developed which covers an area of 32,527 ha with 145 thousand immigrants moving there from the southern loessic hilly area in 1984-1994. A new ecosystem of oasis economy has been established, socio-economic, and environmental benefits achieved, and changes in land use were prominent. In the central desert steppe of Ningxia, except the original pasture and dryland farming, irrigational farming, horticulture and livestock breeding have been developed. As a result, artificial ecosystems of various types have been formed in the irrigated areas mentioned above. This paper will particularly discusses the changes of landuse patterns in resultant ecological effects, and the environemntal problems for sustainable development in the irrigated area. For the changes of landuse patterns, four aspects are relevant: the dryland was changed into irrigated land, the grassland became irrigated farmland, the agricultural landuse pattern changed and the cropping patterns also altered. The ecological benefits of the irrigated area are as follows: 1) the desert-steppe has been partially replaced by man-made oasis; 2) drinking water for human and livestock was guaranteed; 3) the shifting sand dunes in some areas were brought under control; 4) soil erosion was mitigated; 5) soil mellow process was accelerated and soil fertility increased; and 6) the eco-economic system was diversified. Finally, the authors identifies solutions to the environmental problems, including water pollution. Soil secondary salinization, soil strucrure, improvement shelterbelt construction, all related to sustainable development in irrgational area.

Stability and Ecological Effects of Main Plant Communities in Minqin Desert Area

[ Objective ] To elucidate the change trend in stability and ecological effects of plant communities in desert along with global wanning. [ Method ] The data of site-specific observation on five main plant communities at ten plots in Minqin desert area were used to analyze the stability and ecological effects of desert plant communities by using two indicators vegetation coverage and projective cover degree. [ Results ] The vegetation coverage of Artemisia arenaria and Ephedra przewalskii, and the projective cover degree of A. arenaria and man-made Haloxylon ammodendron forest decreased remarkably; and the vegetation coverage of Ni- traria tangutorum was also decreased to some extent. [ Conduslon] （1） The plant communities with poor vegetation coverage gives a relatively strong stability, while that with high vegetation coverage has a relatively poor stability; （2） the yearly precipitation is the determinant of vegetation coverage and projective cover deglee; （3） the ecological function is found to be most remarkable in per unit area N. tangutorum, followed by E. przewalskii and N. tangutorum ＋H. ammodendron, and least in per unit area A. Arenaria. The vegetation is sparse in desert and plant branches does not distribute regularly, thus the crown-based vegetation coverage can not reflect the actual surface coverage.

The impact of urban morphology on multiple ecological effects:Coupling relationships and collaborative optimization strategies

Urban morphology significantly affects the ecological effects of urban heat islands,ventilation,and atmospheric pollution.Here,we reveal the mechanisms linking the ecological effects of urban morphology to develop a planning approach for the collaborative optimization of multiple ecological effects.Considering Shenyang,a cold city in northern China,as the study area,a multiple regression model of morphological parameters and ecological effects was established,and the impact of morphological parameters on ecological effects was explored.The results show that the aspect ratio of the streets,building density,and vegetation coverage are sensitive to multiple ecological effects.The inflection point of the ecological effect function curve occurs when the aspect ratio of the building and building density are 0.2 and 0.3,respectively.In addition,for optimal design applications in typical areas of the city,to obtain a Pareto-optimal urban morphology,Grasshopper is used to establish a parametric platform,wherein a genetic algorithm solves the multiple regression equation set.Ultimately,five ecological effect indicators are optimized and show 8.4%,5.0%,31.6%,33.1%,and 12.5%improvement.The study effectively constructs a collaborative optimization planning and design method for multiple ecological effects.

Compound contamination and secondary ecological effects of Cd and As in soil－alfalfa ecosystems

d and As both have harmful effects on the growth,development and seed germination of alfalfa, especially in such a condition as the coexistence of Cd and As in soil environment The research using the pot-culture imitative method first found that if soil was simultaneously polluted by Cd and As,function of alfalfa absorbing Cd from soil may be promoted because of the existence of As,in conversely,Cd may inhibit alfalfa plant from absorbing As It was also found that secon- dary ecological effects were most likely to be brought out due to the coexistence of Cd and As. For example,alfalfa is passive to excessively absorb Cu and Pb .The harmful effects undoubtedly intensi- fy the contamination of alfalfa, The results showed that the mechanism of the interaction among Cd,As,Pb and Cu in soil-alfalfa ecosystems is very complicated.

Clearcuts and related secondary dieback undermine the ecological effectiveness of FSC certification in a boreal forest

Background:Over the last 25 years,the prominent forest certification system established by the Forest Stewardship Council(FSC)has used by many companies worldwide for claiming responsible forest management.The objectives of the Russian National FSC standard to decrease the size of clearcuts and the retention of forest elements such as residual seed trees need on-site validation to proof the effectiveness of FSC.To assess the ecological impacts of harvesting practices and benefits of FSC certification,we geospatially compared logging activities with and without FSC certification.Within a sample area covering approximately 3,000 km^(2) in the east of the Russian Arkhangelsk Region,we used available data on tree cover loss and satellite images to assess secondary impacts of clearcuttings on adjacent remnant forests and to quantify the logging intensity.Additionally,the size and structure as well as the density of skidding trails of ten specific clearcuttings located within the sample area were surveyed using satellite images and in the field observation to delineate the boundaries of clearcuts and forested remnants within the clearcuts.Results:We found a significant increase of small-scale tree cover loss in the proximity of the clearcuts.Patchy dieback is possibly linked to the scale and intensity of logging in the surroundings.On the investigated clearcuts,FSC failed to reduce the size,to increase the retention of forest remnants including seed trees on logged areas,and to maintain larger tracts of undisturbed ground and soil compared to clearcuts that were logged before they received FSC-certification.Conclusions:Trees and forest remnants remaining inside an increasingly stressed forest ecosystem matrix may not resist further harvesting-related and climate change-induced stresses and disturbances.Large-scale clearcuttings seem to have negative impacts even in adjacent forests and undermine the ecological effectiveness of FSC certification in the study area.The Russian FSC standard is not clearly setting effective guidelines that induce a change in clearcutting practices in order to reduce ecological risks.

Ecological and socioeconomic effects of China's policy for grassland eco-compensation

To reverse the continuous deterioration of grassland ecology and to improve the well-being of herders, China has been formulating many national policies on payments for grassland ecological conservation. One of them, the Grassland Eco-compensation Policy(GEP), is the biggest program for grassland protection in China since 1949. The GEP conserves natural grassland by paying herders cash subsidies. It also has worldwide significance because it can increase vegetative cover, improve the ecological balance, increase carbon sequestration and lessen the amount of dust reaching other countries through inhibiting soil erosion. Overall, we find that its ecological and socioeconomic effects are beneficial and further benefits may be observed in the future because while the socioeconomic effects usually appear quickly, ecological effects may take longer to manifest. 2015 is the last year for the first round of the GEP policy implementation and the extended policy for the GEP will be approved and continued by the central government. To make the policy more successful, we suggest coordinated planning, a comprehensive overview, higher compensation and collaborative study. Efficient implementation of the GEP could also provide valuable experience for other eco-compensation programs in China and numerous other regions of the world.

Variations of nutrient elements and its effect on ecological environment off the Changjiang estuarine waters

On the basis of the date obtained in two cruises during October 1997 and May 1998, the concentration distribution and the variation of present species of nutrient elements in the water masses are described. The transform mechanism of present species of nutrients and the of differrnt water masses, frontal area and thermohaline transition layer on convergence or divergence and the biogeochemical cycle of nutrient elements off the Changjiang Estuary are studied. Meanwhile, the environmental capaci- ty of nutrients is primarily estimated: they are 1.803 x 104t DIN and 6.18 x 102t PO43- -P in autumn, and 4.20x 102t PO43- -P in spring.

The Research on Land-Use Change and Ecological Environment Effect of Urban Landscape in China

The rapid expansion of urban construction land has become the major characteristic of urban land-use change in China today. Meanwhile, the rapid urbanization process has led to the great changes of urban landscape in China, and it also has had certain impacts on environmental factors such as climate, soil, hydrology, biodiversity, etc., then it has made the overall ecological environment deteriorated. This study is based on the summary and analysis of research on land-use change and ecological environment effect of urban landscape in recent 20 years in China, and it aims at providing scientific bases and theoretical supports for the planning and construction of urban landscape, the sustainable land-use of city and the protection of ecological environment in China.

ECOLOGICAL LANDSCAPE EFFECTS OF WINDBREAK SYSTEMS IN DESERT ZONE OF WESTERN CHINA

This paper, by applying the theories of landscape ecology, illustrates the role and mechanism of windbreak system in the establishment and maintenance of oasis ecosystem on the basis of systematic analysis of characteristics and ecological crises of China's desert, and especially of desert zone in western China. Furthermore, direct economic benefits are summarized.

Quantitative Evaluation of Ecological Cumulative Effects and Zoning Regulations for Prefectural Mining Units in China

Although the development of energy and mineral resources strongly supports China’s rapid industrialization and urbanization,it has led to a series of ecological and environmental problems.Strengthening the spatial regulation considering the ecological and environmental protection on energy and mineral resource development areas is an important aspect of realizing China’s sustainable development.In this study,we mapped,categorized,and analyzed the ecological cumulative effects of the Chinese 134 prefectural mining units based on the pressure-state-response model,which is demonstrated as impact of mining activities on ecological environment,ecological environmental fragility,and ecological function.This investigation developed a stress zoning typology of the mining units based on scores of three dimensions of the ecological cumulative effects and classified 134 prefectural mining units into eight types of stress zones.A series of regulation and policy suggestions have been proposed to different types of zones from three aspects:space control,intensity control,and development mode control.The application of this evaluation and spatial zoning system will contribute to the refined spatial management of China’s mining areas.

A review of ecological mechanisms for management practices of protective forests

A protective forest,including shelterbelt,windbreak,and shelter forest as its synonyms,is characterized by the protective functions of various forest types distributed or planted on ecologically fragile areas or nearby the objects that need to be protected using the ecological effects of forests.Ecological mechanisms for management practices of protective forests is one of the disciplinary orientations in forest ecology and management.Most protective forest studies are dependent on forestry eco-engineering,such as the Great Plains Shelterbelt Project in the United States,the Great Plan for the Transformation of Nature in the Soviet Union,and the Three-North Afforestation Program in China.The development of sustainable management of protective forests has been given increasing attention by governments,scientists,and media due to their impacts on environment conservation and global change.We introduce forestry ecoengineering and provide a review of their main ecological mechanisms for management practices of protective forests.Ecological mechanisms for management systems currently applied are emphasized,i.e.,the theory of protection maturity and phase-directional management;the relationship between structure and protective functions and structural optimization measures;and,the decline mechanism and ecological restoration strategies.In addition,several unresolved problems in management practices of protective forests are discussed as well as the prospects for ecological mechanisms for management practices of protective forests in the future,which include:(1)theories and technologies for management practices of protective forests at the landscape or regional scale;(2)the decline mechanisms and corresponding ecological restoration approaches across multiple scales;and,(3)the comprehensive assessment of forestry eco-engineering at large-scales based on ecosystem principles.

Seasonal co-occurrence patterns of bacteria and eukaryotic phytoplankton and the ecological response in urban aquatic ecosystem

Microorganisms play a key role in aquatic ecosystems.Recent studies show that keystone taxa in microbial community could change the community structure and function.However,most previous studies focus on abundant taxa but neglected low abundant ones.To clarify the seasonal variation of bacterial and microalgal communities and understand their synergistic adaptation to diff erent environmental factors,we studied the bacterial and eukaryotic phytoplankton communities in Fenhe River that runs through Taiyuan City,central China,and their seasonal co-occurrence patterns using 16S and 18S rDNA sequencing.Results indicate that positive interaction of eukaryotic phytoplankton network was more active than negative one except winter,indicating that the cooperation(symbiotic phenomenon in which phytoplankton are interdependent and mutually benefi cial)among them could improve the adaption of microbial community to the local environmental changes and maintain the stability of microbial network.The main genera that identifi ed as keystone taxa in bacterial network were Salinivibrio and Sphingopyxis of Proteobacteria and they could respond to the variation of nitrite and make use of it,while those that identifi ed as keystone taxa in eukaryotic phytoplankton network were Pseudoschroederia and Nannochloris,and they were more susceptible to nitrate and phosphate.Mychonastes and Cryptomonas were closely related to water temperature.However,the loss of the co-occurrence by environmental factor changes aff ected the stability of network structure.This study provided a reference for analyzing relationship between bacteria and eukaryotic phytoplankton and revealing potential importance of keystone taxa in similar ecological domains in carbon,nitrogen,and phosphorus dynamics.

Landscape changes and their ecological eff ects of Miaodao Archipelago with human disturbances and under natural conditions in the past 30 years

The modern landscape patterns of islands usually show obvious spatial heterogeneity and complex ecological effects due to the vulnerability of ecosystems with natural characteristics under increasing human activities.In this work,we studied the variation in landscape pattern of the Miaodao Archipelago in Bohai Sea,North China,from 1990 to 2019,and an evaluation index system was established to explore the impacts of natural conditions and human disturbances on the ecological effects in the pressure-state-response(PSR)framework.Empirical analysis was conducted on the natural conditions,human disturbances,and ecological effects.The results show that forest was the main component of the landscape pattern in the archipelago.Both of the areas offorest and construction land were increasing,and the areas of cropland and grassland were declining.Other landscape types changed slightly,and the landscape fragmentation was increasing.The natural condition exhibited positive effects while human disturbance showed negative effects on the local ecology.Human disturbances come mainly from shoreline use while the natural conditions were mainly from the elevation change.The ecological effects were resulted mainly from the net primary productivity and water yield.

Effects of an ecological conservation and restoration project in the Three-River Source Region, China

The first-stage of an ecological conservation and restoration project in the Three-River Source Region（TRSR）, China, has been in progress for eight years. However, because the ecological effects of this project remain unknown, decision making for future project implementation is hindered. Thus, in this study, we developed an index system to evaluate the effects of the ecological restoration project, by integrating field observations, remote sensing, and process-based models. Effects were assessed using trend analyses of ecosystem structures and services. Results showed positive trends in the TRSR since the beginning of the project, but not yet a return to the optima of the 1970 s. Specifically, while continued degradation in grassland has been initially contained, results are still far from the desired objective, ‘grassland coverage increasing by an average of 20%–40%＇. In contrast, wetlands and water bodies have generally been restored, while the water conservation and water supply capacity of watersheds have increased. Indeed, the volume of water conservation achieved in the project meets the objective of a 1.32 billion m^3 increase. The effects of ecological restoration inside project regions was more significant than outside, and, in addition to climate change projects, we concluded that the implementation of ecological conservation and restoration projects has substantially contributed to vegetation restoration. Nevertheless, the degradation of grasslands has not been fundamentally reversed, and to date the project has not prevented increasing soil erosion. In sum, the effects and challenges of this first-stage project highlight the necessity of continuous and long-term ecosystem conservation efforts in this region.