Regional ecological security anddiagnosisof obstaclefactors in underdevelopedregions：acasestudy in Yunnan Province,China

In order toclarify regional ecological security status and formation mechanism of regional ecological security barriers in underdeveloped regions of China,we took Yunnan province as a case to evaluate its regional ecological security by using entropy matter-element model,comprehensive index and GIS spatial method,and we diagnosed itsobstacle factors through obstacle degree model. We found a low overall level of regional ecological security in Yunnan. Only Kunmingfell into the good level, 68% of the regions were below the critical safe level. For the vast majority of regions in Yunnan, their regional ecological security was unstable. The indexes related to per capita resources, geological and topographyenvironment, economic, and technologywere at the unsafe or dangerous level.The indexes related to urban expansion, level of income, cultivated land quality were at the level of critical safety. The indexes concerning urban management capacity, airqualityand waterenvironment were at the good or ideallevel. Yunnan's regional ecological security was not good due to natural obstructive environment itself, simultaneously lower backward economic and social level restricted the ability of ecological security response to manage ragile ecological environment. The results of the composite index wereroughly consistent with those of the entropy weight matterelement model. The mean values of the classification index,from high to low, were: the state index>the response index>the pressure index. The state index and the response index had a significant mutual promotion to each other.The regions with good composite index, state index and response index mainly distributed in the central regions of Yunnan Province. Spatial autocorrelation of regional ecological security level in Yunnan was not obvious. Water resources, economic and social development were main obstacle factors of the regional ecological security.When distinguishing with obstacle type, Kunming belonged to natural ecological environment barrier type, while other regions belonged to economic and social barrier type.

Optimization of Rural Settlement Distributions Based On the Ecological Security Pattern: A Case Study of Da’an City in Jilin Province of China

Following the trends of Chinese rural transformation development, and the sustainable development goals for resources and environment, reasonable arranging the potential development space and the ecological space, so as to optimize the distributions of rural settlement would be the key challenge for rural areas in ecologically fragile regions. From the perspective of maintaining regional ecological security, this paper takes Da’an City, a typical ecological fragile region in Jilin Province, as the case area, constructing the comprehensive ecological security pattern(ESP) on basis of landscape ecology, and applying the landscape pattern indexes to quantitative analysis the spatial distribution characteristics of rural settlements. Then, different optimization directions and management strategies are put forward for rural settlements in each secure zone under the comprehensive ESP. The experimental results showed that 1) the area of the low security zone, the general security zone, the moderate security zone and the extreme security zone was 1570.18 km^2, 1463.36 km^2, 1215.80 km^2 and 629.77 km^2, representing 32.18%, 29.99%, 24.92% and 12.91% of the total area of the target area, respectively. 2) The rural settlements in Da’an City were characterized by a high degree of fragmentation with a large number of small-scale patches. 3) The area of rural settlements in the ecological relocation zone, the in situ remediation zone, the limited development zone and the key development zone was 22.80 km^2, 42.31 km^2, 36.28 km^2 and 19.40 km^2, accounting for 18.88%, 35.03%, 30.04% and 16.06% of the total area of rural settlements, respectively. Then, different measures were proposed for settlements in different optimization zones in order to scientifically plan important ecological space, production space and living space in rural areas. This paper aims to provide fundamental support for rural settlements based on redistribution from the perspective of landscape ecology and provide insights for rural planning and rural habitat environmental improvement.

Land development suitability analysis for transport planning evaluation and optimization in mountainous ecological region

Transportation planning is a critical component for creating an orderly,intensive,and sustainable pattern of land development.By comprehensively considering the potential and suitability of transport construction,a comprehensive method combining resources and environmental carrying capacity(RECC)and land development suitability(LDS)was developed by using techniques of GIS,analytic hierarchy process(AHP)and threedimensional magic cube.Taking Aba prefecture in Sichuan Province of Southwest China as a case study,LDS for transportation was analyzed from three aspects,including overall planning layout,different transport modes,and transportation projects.The results showed that the transport planning scales of most counties in Aba were suitable,and the order of LDS of different transport modes was railway>highway=superhighway>tourism track,which already included 42 new transportation projects.We found that two counties(Maoxian County and Jiuzhaigou County)should improve the ecological protection level of transportation,in which the railway network construction should be encouraged,and some transportation projects with low LDS should be postponed or constructed harmlessly.We suggest the combination of RECC and LDS for transportation could enhance the territorial space optimization and sustainable transport construction.

Research on the Regional Ecological Environment Evaluation and Application under the Influence of the Severe Earthquake Disaster

To conduct the ecological restoration and reconstruction of disaster areas after the severe earthquake, such as Wenchuan Earthquake and Lushan Earthquake, this article uses region al ecological environment evaluation and ecological footprint to construct a quantitative analysis model on the basis of ecololgical environment indexes in Mianzhu City. Through this model, resource status of the regional environment in Mianzhu is analyzed, as well as the ecological capacity and the ecological security. Based on the evaluation and analysis, this paper provides multi-path development strategies of ecological restoration and sustainable development of human settlements after the earthquake.

Assessment of Calcimetric and Titrimetric Methods for Calcium Carbonate Estimation of Five Soil Types in Central Sudan

Despite the CaCO3 estimation using titration method was not reliable, but up to the present time, some soil laboratories in Sudan still used this method. The objective of this study was to compare and assess the results of calcimetric and titrimetric methods of quantitative estimation for soil calcium carbonate of different soils in Sudan. 26 soil samples from five soil profiles were collected from different climatological and ecological regions in central Sudan. CaCO3 equivalent was estimated using calcimeter and titration methods in order to find accurate, rapid and suitable method for soils of Sudan. The results revealed that there are no significant differences between calcimeter and titration methods for calcium carbonate estimation in all studied samples except in samples from Gedaref area. We concluded that when the Calcimeter method used for CaCO3 estimation, the differences between one person and another in detecting titration end point would be avoided, rapid and accurate results would be obtained compared to titration method. Additionally, time would be saved;fewer amounts of chemicals would be used. From this study, we highly recommend using calcimeter method for CaCO3 estimation for soils of Sudan.

Spatiotemporal analysis of land use/cover changes in Nanchang area, China

Based on remote sensing and Geographic Information System techniques,multi-temporal Landsat data were used to monitor land use/cover changes(LUCC)in the Nanchang area during 1989–2010.Quantitative and spatiotemporal indicators derived from the transition matrix for overall changes,intensity analysis for inter-category transitions,and spatiotemporal analysis of intra-category variations were constructed to analyze the spatiotemporal LUCC evolution.The study results show that urban and industrial land rapidly and continually expanded.The spatial extent of rural settlements shrunk while their distribution density increased.Cultivated land showed a tendency of spatially continuous loss and fragmented distribution,whereas the spatial pattern of forest tended to concentrate.The extents of ponds and reservoirs remained stable,but spatial changes were obvious.Rivers and bottomlands decreased significantly and tended toward fragmentation.The overall LUCC pattern showed that construction land rapidly sprawled while cultivated land decreased substantially,indicating an acceler-ating stage of urbanization and industrialization.Although rigid land requirements for urbanization had to be satisfied,land development and consolidation across forests and water body areas,as well as adjustment of agricultural structure,laid the foundation for a transition toward intensive land use in the Nanchang area.