Effects of the vegetation restoration years on soil microbial community composition and biomass in degraded lands in Changting County,China

We evaluated the effects of the number of years of restoration of vegetation on soil microbial community structure and biomass in degraded ecosystems.We investigated the microbial community structure by analyzing their phospholipid fatty acids then examined microbial biomass carbon and nitrogen by chloroform fumigation extraction of restoration soils over several years.The data were compared with those of highly degraded lands and native vegetation sites.The results show that the duration of vegetation on the sites substantially increased microbial biomass and shifted the microbial community structure even after only 4 years.However,microbial communities and biomass did not recover to the status of native vegetation even after 35 years of vegetation cover.A redundancy analysis and Pearson correlation analysis indicated that soil organic carbon,total nitrogen,available potassium,soil water content,silt content and soil hardness explained 98.4%of total variability in the microbial community composition.Soil organic carbon,total nitrogen,available potassium and soil water content were positively correlated with microbial community structure and biomass,whereas,soil hardness and silt content were negatively related to microbial community structure and biomass.This study provides new insights into microbial community structure and biomass that influence organic carbon,nitrogen,phosphorus and potassium accumulation,and clay content in soils at different stages of restoration.

Sequences and genesis of the Yellow River terraces from Sanmen Gorge to Kouma

Based on field landscape investigations, thermoluminescence （TL）, magnetostratigraphy and Ioess-paleosol sequence, we found that there are at least four Yellow River terraces, whose ages are 0.86 Ma, 0.62 Ma, 0.13 Ma and 0.05 Ma, in Yuxi Fault-Uplift （from Sanmen Gorge to Mengjin） and at least three Yellow River terraces, whose ages are 1.24 Ma, 0.25 Ma and 0.05 Ma, in Huabei Fault Depression （from Mengjin to Kouma）. All the terraces have a similar structure that several meters of paleosols directly develop on the top of fluvial silt. It shows that the Yellow River incised and consequently abandoned floodplain converted to terrace during the interglacial period. Therefore, there may be a link between the formation of terraces and glacial-interglacial climatic cycles. However, the differences in the Yellow River terrace sequences and ages between Yuxi Fault-Uplift and Huabei Fault Depression indicate that the surface uplift should play an important role in the formation of these terraces.

Landscape structures of different rural landscape connectivity in typical plateau karst regions: Taking the Houzhai River area of Anshun City, Guizhou Province as an example

Landscape connectivity is important for energy and material flow in ecosystems as well as for the survival of species. The landscape structure influences and reflects the degree of landscape connectivity. In order to study the coupling relationship between landscape structure and connectivity and reveal the succession relationship between its structure and connectivity in the typical karst plateau area. The study analyzed the typical area of Houzhai River in Puding County, Anshun City, Guizhou Province, according to the landscape pattern index and probability landscape connectivity index. The results show:(1) The landscape structure of the study area A is mainly characterized by large patches and uniform distribution. The main land is woodland and cultivated land, and the overall landscape is low fragmentation.(2) The landscape structure of the study area B is mainly characterized by the clustering of a certain type of land cover and the uneven distribution of the patches, for example, cultivated land. Other types of patches are scatteredly distributed, and the overall landscape is highly fragmented.(3) The study area A, B in 100, 500, 1000, 2000, 3000, 5 distance thresholds of landscape connectivity were 1.55, 1.99, 2.26, 2.49, 2.58 and 0.02, 0.10, 0.15, 0.19, 0.20, respectively. The average landscape connectivity is 2. 18 and 0. 13, respectively. Study Area A has a higher degree of landscape connectivity than B. Landscape pattern indicators can represent the landscape structure and probability landscape connectivity index calculates the landscape connectivity in the study area. The results of the study can provide a basis for ecological restoration of plateau karst regions and well-oriented rural development planning.

Research on the Eco-tourism and Environment-friendly Land Use Patterns in Shangri-La

Through the analysis of the geographical features of the Shangri-La,the eco-tourism and environment-friendly land use patterns were proposed. And the significances of the mode of economic development in Shangri-La were analyzed.

Response of artificial lake algae growth to water quality and meteorological conditions in plateau area

The problem of water environment caused by algal blooms is very common and serious.Effective methods of algal bloom control are one of the focuses of current research.Compared to natural lakes,the artificial lake environment is relatively simple,and it is a good place to study the effects of meteorology and water quality on algae growth.The study selected three typical artificial lakes in Kunming City of Yunnan province as research areas.The water quality,meteorology and algae growth characteristics of these three artificial lakes were monitored and analyzed,the response relationship of artificial lake algae growth to water quality and meteorological conditions were revealed.Results showed that nitrogen nutrients,N/P ratio and the temperature of water environment,air CO2 concentration are the mainly factors affecting the growth of algae in these three lakes,and the total phosphorus concentration has no significant effect on algae growth.The research conclusions can provide a basis for exploring the mechanism of environmental factors affecting algae growth and the governance of eutrophication of lakes in the plateau.

Porous Properties of Nano-fibriform Silica from Natural Chrysotile

With the TEM and physical gas adsorption techniques, porous properties of nano-ribriform silica （MLD： 92.73%） from natural chrysotile are studied in this paper. The results indicate that porous nano-fibriform silica results from brucite octahedral sheets of nature chrysotile dissolved completely and Si-O tetrahedral sheets collapsed by acid leaching. Its length is at a micron or nanometer scale. There are two types of pores： pores among neighboring fibers and pores in nanoriber. These pores （less than 6.5 nm in diameter, mostly 2.1 nm and 3.8 nm） all belong to mesopores. The pores in fibers consist of those among SiO2 particles, those among aggregates, remnant nanotubes and capillary tubes. Nanoribriform silica proves better than the traditional silica as a carrier of catalyzer and a filler for reinforce rubber and plastics.

Composition and Spatial Distribution of Soil Mesofauna Along an Elevation Gradient on the North Slope of the Changbai Mountains, China

The Changbai Mountains, located in northeastern China, show clear vertical zonation of vegetation types. Six different habitats,namely Pinus koraiensis mixed broad-leaved forest, Pinus koraiensis-Picea forest, spruce-fir forest, Betula ermanii forest, alpine meadow and alpine semi-desert, at elevations ranging from 780 to 2 480 m, covering almost all ecosystems on the north slope of the Changbai Mountains, were investigated to determine: i) whether or not the community composition of soil mesofauna varied significantly at different elevations; ii) if different soil mesofauna groups would respond differently to elevation and iii) which factors influenced the spatial distribution of soil mesofauna along elevation. Soil mesofauna were collected from each habitat in spring(May),summer(July) and autumn(September) of 2009. The soil mesofauna communities were comprised of at least 44 groups and were dominated by Acari and Collembola, followed by Coleoptera, Diptera larvae and Enchytraeidae. The composition, diversity and abundance of soil mesofauna varied among the six habitats. Meanwhile, significant seasonal variations were observed in the composition,abundance and diversity of the soil mesofauna in each habitat. The taxonomic richness and Shannon index were affected by elevation and soil properties, while the abundance was only significantly affected by soil properties. With regard to taxa, the habitats and seasons had significant effects on almost all the abundances of the major taxonomic groups. The abundance of more taxonomic groups was significantly influenced by the soil properties, while those of Geophilomorpha, Araneae and other taxa were affected by elevation.It is concluded that the composition and spatial distribution of the soil mesofauna varied along the elevation gradient on the north slope of the Changbai Mountains, which might be largely related to the variations of the plant community, soil properties and climate change resulting from the elevation gradient.

The Bowen Ratio of an Alpine Grassland in Three-River Headwaters, Qinghai-Tibet Plateau, from 2001 to 2018

The Bowen ratio(β) is used to quantify heat transfer from the land surface into the air, which is becoming a hot topic in research on the biogeophysical effects of land use and cover changes. The Three-River Headwaters(TRH), as a sensitive and fragile region, was selected as the study area. The β for 2001–2018 was estimated from the evapotranspiration product(ETMOD16) of MODIS and the net radiation of the land surface through the albedo from GLASS. The ETMOD16 data were evaluated against the observation data(ETOBS) at two alpine grassland flux towers obtained from ChinaFLUX. The interannual trend of the β was analyzed by multiple linear regression(MLR) and structure model(SEM) with the multiple factors of precipitation, temperature, humidity, albedo, and normalized difference vegetation index(NDVI, MOD09 Q1). The results show that the ETMOD16 values were significantly correlated with ETOBS, with a correlation coefficient above 0.70(P < 0.01) for the two sites. In 2001–2018, the regional mean β was 2.52 ± 0.77 for the whole grassland, and its spatial distribution gradually increased from the eastern to western region. The interannual β showed a downward trend with a slope of-0.025 and a multiple regression coefficient(R^(2)) of 0.21(P = 0.056). Most of the variability(51%) in the interannual β can be explained by the linear regression of the above multiple factors, and the temperature plays a dominant role for the whole region. The SEM analysis further shows that an increasing NDVI results in a decreasing albedo with a path coefficient of-0.57, because the albedo was negatively correlated with NDVI(R^(2) = 0.52, P < 0.01), which indicates a negative and indirect effect on β from vegetation restoration. An obvious warming climate was found to prompt more evapotranspiration, and restoring vegetation makes the land surface receive more radiation, which both resulted in a decreasing trend in the annual β. This study revealed the biogeophysical mechanisms of vegetation restoration under a changing climate, and demonstrated the Bowen ratio can be applied as an indicator of climate-regulating functions in ecosystem assessments.

Discovery of bacteriopheophytin-a in lacustrine deposits from Lake Zigetang on the central Tibetan Plateau and its paleoenvironmental significance

Lake Zigetang is located on the central Tibetan Plateau(TP) and represents a rare but typical meromictic lake in China.The lake's stable meromixis sustains microflora communities, and changes in these communities are relatively independent of climate. Therefore, these communities can be used as paleoclimate proxies. In this paper, the stratification properties and their relationships with the microflora of Lake Zigetang were analyzed. We found that water depth and climate conditions were two important factors for maintaining meromixis in Lake Zigetang. Generally, stratification was enhanced during warm periods, while temperature differences between the mixolimnion and monimolimnion were decreased during cold periods. The presence of anoxygenic phototrophic bacteria(APB) was demonstrated by the discovery of bacteriopheophytin-a(Bph-a) in the sediments.This bacterial community is mainly concentrated at the bottom of the chemocline and the top of the monimolimnion, where it forms a thin APB layer. Moreover, total APB productivity is mainly affected by the light intensity penetrating to the APB layer,which exponentially increases as the thermocline becomes shallow. Therefore, high Bph-a values in the lake corresponded to a shallow thermocline and warm periods, low Bph-a values corresponded to cold periods, and zero changes indicated that the water was completely mixed and reflected an extreme cold climate or low lake level period. Thus, Bph-a can be used as a climate proxy to reconstruct the history of lake stratification and climate changes.

Quantitative analysis of planation surfaces of the upper Yangtze River in the Sichuan-Yunnan Region, Southwest China

Identification of the planation surfaces (PSs)is key for utilizing them as a reference in studying the long- term geomorphological evolution of the Upper Yangtze River Basin in the Sichuan-Yurman region,Southwest China.Using a combined method of DEM-based fuzzy logic and topographic and fiver profiles analysis and based on a comprehensive analysis of four morphometfic parameters:slope,curvature,terrain raggedness index, and relative height,we established the relevant fuzzy membership functions,and then calculated the membership degree (MD)of the study area.Results show that patches with a MD>80% and an area>0.4 km^2 correspond well to the results of Google Earth and field investigation,representing the PS remnants.They consist of 1764 patches with an altitude,area,mean slope,and relief of mostly 2000-2500 m above sea level (asl),0-10 km^2,4°-9°,0-500 m,respectively,covering 9.2% of the study area's landscape,dipping to southeast,decreasing progressively from northwest to southeast in altitude,and with no clear relation between each patch's altitude and slope,or relief.All these results indicate that they are remnants of once regionally continuous PSs which were deformed by both the lower crust flow and the faults in upper crust,and dissected by the network of Upper Yangtze River.Additionally,topographic and river profiles analysis show that three PSs (PS1-PS3)well developed along the main valleys in the Yongren-Huili region, indicating several phases of uplift then planation during the Late Cenozoic era.Based on the incision amount deduced from projection of relict river profiles on PSs, together with erosion rates,breakup times of the PS 1,PS2,and PS3 were estimated to be 3.47 Ma,2.19 Ma,and 1.45 Ma,respectively,indicating appearance of modem Upper Yangtze River valley started between the Pliocene to early Pleistocene.

Hydrodynamic process of Tibetan Plateau lake revealed by grain size:Case study of Pumayum Co

Under the background of global warming,some lakes on the Tibetan Plateau(TP) are potentially sensitive to temperature change.With a case study of Pumayum Co,where glacier meltwater is important to supply(we call this a glacier-fed lake hereafter),we analyze the sensitivity of lake sediment grain size to temperature change.This is done by resolving the modern hydrodynamic process,coupled with comparison of paleoclimatic proxies.According to the spatial distributions of parameters,percentage of grain size and the grain size frequency distribution curve,hydrodynamic processes are analyzed.Five clastic sedimentation types are thereby discriminated.In the open lake area,suspended load transport is the main transport agent.Grain Size Trend Analysis(GSTA),a sediment dynamics model,reveals a trend toward eastward transport.This indicates that the largest and glacier-fed river,the Jiaqu River,influences the entire lake(not just the subsurface alluvial fan),and that lake sediment grain size may serve as a temperature indicator.Time series comparison between grain size of a short core from the central lake and meteorological data confirms this temperature indication,which in turn shows reliability of the method discriminating the hydrodynamic process.This case study will improve the ability of paleoclimatic reconstruction using lake sediment in glacier-fed lakes on the Tibetan Plateau.

Sediment change under climate changes and human activities in the Yuanjiang-Red River Basin

气候变化和人的活动是到多山的河里的沉积变化的主要影响因素。基于超过 40 年“记录，在在 Yuanjiang 河(上面的红河) 的更低的活动范围计量车站的 Manhao 的推迟的沉积负担(SSL ) 变化。在这篇论文，沉积和它的驱动程序的变化通过象同步数据比较，传统的关联，线性回归，和 Granger 诱发性那样的不同方法被分析。结果证明(1 ) 年度平均沉积集中(SSC ) 和在 Manhao 车站的 SSL 的一般趋势从 1960 年代正在增加到 1990 年代，并且在 1984 以后有一个快变化时期；( 2 )在1960年代，1970年代，1980年代和1990年代的不同时期期间，在 Manhao 车站的 SSL 和 SSC 是 1.87 ， 2.49 ， 3.129 3.63 kg/m ( 3 )，和 28.7x 10 ( 6 )， 40.3 x 10 ( 6 )， 44.1 x 10 ( 6 )， 60.3 x 10 ( 6 ) t/a 分别地；( 3 )关联分析和 Granger 诱发性测试证明在集水的气候变化是到在1960年代和1990年代的时期的沉积变化的主要开车因素，但是由沉积变化上的多山的人的行动的影响由气候在1970年代和1980年代改变的本地人是比那强烈的；(4 ) 在沉积变化和森林范围变化之间的关联是否定的，它进一步证明沉积变化被人的活动强烈在盆影响。

Value and Heterogeneity: Using a Choice Experiment to Evaluate the Coastal Recreational Environment

The management of the coastal park environment is a major ecological and economic development issue. In developing effective policies, relevant information is essential, especially the economic valuation of various recreation-related environmental attributes. This study used Dalian coastal parks as a pilot study area and estimated the willingness to pay(WTP) of tourists using three different discrete choice models. In this study, we analyzed the preference heterogeneity among the respondents regarding a combination of park attributes, and the individual respondent’s WTP values were estimated for each attribute. The results indicate that water quality amelioration and trash reduction had the highest economic values among the given attribute factors. In addition, the estimated tourist WTP varied considerably among different segments, such as among the visitors who preferred different recreational activities. These findings provide valuable information that will allow coastal park managers to develop policies which maintain a balance between tourism development and improvement of the coastal environment.

Optimum Solution for the Safe Drinking Water Crisis in Tala Upazila, Bangladesh

Coastal areas of Bangladesh are especially vulnerable due to their physiographic location and exposure to natural calamities. Around 35 million people living in coastal areas have no access or limited access to safe drinking water. Contamination of water sources by salinity, arsenic or iron are the principal causes of water scarcity. Rising sea levels and unevenness of climatic events due to climate change will exacerbate the situation in coastal areas, especially in the southwestern coastal zone. This study examines one of the vulnerable coastal upazila Tala at Satkhira(an 'upazila' is a medium level administrative unit in Bangladesh) in the southwestern zone of Bangladesh to understand the gravity of the problems. The study develops a GIS based multi-criteria analysis to identify suitable options and locations of fresh water as part of a current and future solution to the problems and further deterioration. To fulfill the objectives, a questionnaire-based GPS guided field survey was conducted to collect details of field level conditions in order to find a suitable solution. Because aquifers are considered the primary source of drinking water, field data have been analyzed for two distinct aquifers, one relatively shallow and one deeper, to understand aquifer quality. Potentiality of different water sources the socioeconomic status of communities, types of water use and corresponding sources and water demand are also evaluated. The analysis finds that alternative water sources that are safe are difficult to find, because both surface and groundwater-based sources are already contaminated, and there are no nearby, easily accessible safe sources. Groundwater-based sources are contaminated by arsenic, iron or salinity, and surface water-based sources are not in use due to maintenance and management issues. In some cases, surface water sources are polluted by flash flooding of high saline water during storm surges or seepage from saline water-based aquacultures. Multiple limitations identified during field observations and field data analysis were considered as an analytical parameter A GIS based multi-criteria analysis incorporated field data, including Geo-spatial and socioeconomic information for road networks, settlement locations, number of households, quality and quantity of existing water sources, water demand and business opportunities. The analysis found some potential options in distributed locations which are consistent with community demand. Suggested options made use of technologies that are already understood and commonly used by communities, like deep tubewells, PSFs(Pond Sand Filter) and WTPs(Water Treatment Plant). In the study area, PSF is the most commonly used method and to make this surface water-based technology sustainable some precautionary measurements are suggested.