The Impact of Urban Expansion on Plant Diversity Change in Karst Regions of Southwest China

Biodiversity is vital for the integrity and stability of ecosystems and sustainable development.Karst regions of Southwest China is featured for undulating and broken karst terrain as well as high plant diversity.Land use changes induced by the growing population and expanding human settlement have threatened biodiversity preservation in this region.However,the impact of urban expansion on plant diversity remains unclear here.This study focuses on how expanding countryside landscapes affect the recovery rate of plant diversity and demonstrate how urban expansion affects plant diversity conservation in karst regions of Southwest China.In situ biodiversity investigations and multisource remote sensing images were combined to analyze the role of human settlement evolution in the conservation of plant diversity using descriptive statistics and regression analysis.Unmanned vehicle images,historical aerial photographs,and long-term remote sensing images were used to observe the human settlement pattern changes over 40 yr and found that plant diversity is restored faster in countryside ecosystems than in island ecosystems restricted by water.Forests,however,contribute the most to plant diversity conservation in both ecosystems.While the forest area is stable during urban expansion,massive forest patches play an essential role in plant diversity conservation.Arable lands and grasslands shrank but with a fragmenting trend,which was conducive to preserving plant diversity,whereas increased and regularized large patches of built-up areas were not beneficial to plant diversity.Accordingly,forest protection should be prioritized to coordinate future socioeconomic development and plant diversity conservation in karst and broader regions.Furthermore,large built-up patches should be limited,and the irregularity should be improved during urban expansion.Irregular shaped cultivated land and grassland were suggested to promote biological information exchanges as landscape corridors.

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.

The comprehensive evaluation of sustainabledevelopment in karst regions-Taking Shishanareas in Guangxi of China as an example

This paper works out a practical evaluation method of sustainable development for theundeveloped the regions and take Shishan areas of Guangxi Zhuang Autonomous Region of Chinaas an example. First of all, according to the actual conditions of the karst regions in Guangxi and thetheory of regional sustainable development this paper estabishes an index system of comprehensiveevaluation, then takes twenty-eight representative cities and counties within the karst regions ofGuangxi as research objects to evaluate the level of sustainable development. It basically illustratesthe state of regional sustainable development of the karst regions in Guangxi.

Aging Characteristics and Influencing Factors of the Sheds of Composite Insulators in Karst Regions of China

In recent years,more and more high-voltage overhead transmission lines were built passing through the karst regions in southwestern China.This type of special landform seems to have an adverse effect on the aging of the sheds of the line suspension composite insulators,which may lead to unexpected flashover and line tripping.In order to find out the particularity of the aging characteristics of insulators operating in the karst regions,samples in operation were selected from both the karst regions and the flatlands.Hydrophobicity,amount of surface contamination,and contaminant composition of the sheds were studied,then a comparison of performance between the two was made,and the possible influencing factors that cause such differences were discussed.The results show that the overall aging of the sheds of the composite insulators operating at the karst regions is more aggravated,which is caused by the combined influence of factors including the special topography,climate,and pollution in the area.The strong wind crossing the col will bring about the mutual scraping on the edges and stress concentration at the root of the sheds,leaving scratches and root cracks;the infiltration from these rupture of acid liquid,if any,will accelerate the aging and corroding of the internal silicone rubber material;moreover,the carbonates enriched on the surface of the sheds will gradually transform into more corrosive sulfates in an acidic environment,leading to further deterioration and chalking of the sheds of the insulators.The research work in this paper can provide guidance for the current operation and maintenance of composite insulators in the karst areas,as well as having important reference values for the layout design and insulation configuration of transmission lines to be built across karst landforms in the future.

Genotype-Specific Microsatellite (SSR) Markers for the Sugarcane Germplasm from the Karst Region of Guizhou, China

Genetic variability among sugarcane genotypes from the Karst region of China was evaluated using genotype-specific microsatellite (SSR) markers. Eighteen sugarcane genotypes including 13 active cultivars and five elite QT-series clones bred locally were screened for genetic variability with 21 SSR primer pairs. All the primer pairs were highly polymorphic and amplified a total of 167 alleles with an average of eight alleles per primer pair. The average polymorphism information content (PIC) value was 0.86 with a range of 0.68 and 0.92. A UPGMA dendrogram categorized the 18 sugarcane genotypes into three major groups containing three, ten and five genotypes, respectively. No geographical affinity was observed among genotypes within the same group. Eight SSR primer pairs produced cultivar-specific alleles, of which five alleles were unique to the QT-series clones, namely, SMC334BS-165 and SMC851MS-145 in QT 08-558, mSSCIR43-229 in QT 4, SM597CS-182 in QT 08-536 and SMC7CUQ-168 in QT 06-212. The clone-specific SSR alleles will be useful in identifying elite QT-series clones for use in the sugarcane crossing programs in China.

Nitrous oxide emissions from different land use patterns in a typical karst region, Southwest China

Fluxes of nitrous oxide (N2O) from different land use patterns (matured forest, secondary forest, grassland and cropland) in a subtropical karst region of Guizhou Province, Southwest China, were measured for one year with a closed static chamber technique and by gas chromatography. The results showed that soil under different land uses was a source of atmospheric N2O. The cropland was a source with relatively high N2O as compared to forest and grassland, but no significant differences were observed. N2O emissions from soils varied with land use change and fertilizer application. There were two peaks of N2O flux occurred following the combination of two obvious precipitation and fertilizer events in the cultivated land. Converting from the matured forest to secondary forest tended to increase annual emissions of N2O (from 1.40 to 1.65 kg N ha -1 a -1 ), while changing land use from secondary forest to scattered grassland tended to decrease annual emissions of N2O slightly (from 1.65 to 1.45 kg N ha -1 a -1 ). Our range of cumulative annual N2O emission across different land uses (1.40-1.91 kg N ha -1 a -1 ) in a karst region is in general agreement with previously published data in a non-karst region. However, in the maize field, N2O emission factor (EF) was 0.34% for fertilizer application, which is about 71.2% lower than the IPCC default value. It is suggested that current IPCC (Intergovernmental Panel on Climate Change) EF methodology could overestimate N2O emission from the karstic cropland. Anyway, the N2O emission from cropland in the karst region would contribute significantly to the global N2O budget, so reducing fertilization frequency during the crop growing season could lead to a decrease in N2O emission in the whole year.

Soil Ecosystem Degradation of Karst Regions in Southwestern China

Deeply influenced by karst geological environment, the structure of the soil ecosystem in the southwest karst area of China is characterized by strong vertical variation and space variation, structural feature of nonrenewable soil, and functional feature of poor circulation of nutrient elements and limited vegetation growth. On the basis of analyzing vulnerability in structure and function of soil ecosystem in China's southwestern karst regions, we discussed the degradation process and mechanism of soil structure, nutrient, water and microorganism in the course of soil erosion from the perspective of material and energy cycle. Finally, we put forward some recommendations for recovery of degraded soil, transformation and rational utilization of soil.

Evaluation of the Land Production Potential in the Context of Returning Farmland to Forest in Karst Region:A Case Study of Guizhou Province

In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test on the actual production capacity of land and the forecasted production capacity of land in 2007 and 2008, and then conduct comprehensive forecast of the land production potential in Guizhou Province in 2020. On this basis, considering the nutritional standards needed by three kinds of life type (dressing warmly and eating one's fill, well-off life, relatively affluent life), we evaluate the land production potential in Guizhou Province under the project of returning farmland to forest. Based on the evaluation results, we put forth the relevant recommendations for achieving sustainable land use in the context of returning farmland to forest in Guizhou Province.

Variability of Aquatic Chemistry in CentralGuizhou Karst Region,China

It is necessary to understand the aquatic chemical characteristics of natural surfacefresh water for water quality assessment. The chemical data from different kinds of water inthe central Guizhou karst area showed that spring water from carbonate rock cracks (crack-water) is of neutrality or meta-alkalinity and [C] Ca Ⅱ type. The amounts of all ions and theconcentrations of HCO3 and Ca2+ were higher in the autumn than in the spring. the crack-water was influenced by the infiltration of surface water in the process of erosion and/or transportation with decreasing HCO3- and increasing PH, SO, Cl, K+ and Na+ during runningin a certain distance on the land suffice. In particular, the chemical compeitions of the watersat Tianxingqiao (upper-stream), Shuiliandong (mid-waterfall) and Luoshuitan (down-pool)near the Huangguoshu Waterfall were much different from those of the crack-water. The concentrations of , Na+, Fe3+ and NO3- varied closely with seasons. The CaCO3 depositedviolently with CO2 release in the spring. In Lake Hongfeng the HCO3- /So- equivalent ratioswere only 2. 1 - 2. 4, but Ca2 + /Md+ up tO 2. 4 - 4. 2. The CI- concentration increased by afactor Of 1 and Na+ by order of magnitude relative to the spring water. These indicated the in-crease in artificial pollutant discharge in the Lake Hongfeng watershed. In addition, porewater in the soils coveing carbonate rocks belongs to strongly mineralized water. The obvious differences in water quality were controlled by carbonate despition, sulphate mineralization and nitrogen fixation as well as ammonification. It is indicated that the chemical compeitions in thewaters from the karst region were unstable and changeable.

Comprehensive Management Measures for Chicken Rearing in Tea Gardens in Karst Region

In karst region,industrial development is closely related to rocky desertification control. Using abundant natural resources in karst areas to develop chicken rearing in tea gardens can not only make full use of natural resources and alleviate the contradiction between development and governance in rocky desertification areas but also produce good quality chicken. In this paper,the comprehensive management measures related to chicken farming in tea gardens in karst region were elaborated,in order to provided certain guiding significance for practical production.

Performance of a deep excavation and the influence on adjacent piles:A case history in karst region covered by clay and sand

This paper presents a case study of deep excavation adjacent to an existing bridge in karst region of Guangzhou city,China.The movements of retaining structures,settlements of surrounding ground and pipelines,and the responses of bridge piles were measured and evaluated.A sudden surge of groundwater was recorded at the north pit when excavated halfway.Soil-cement columns using the Metro Jet System(MJS)method was employed along the outer perimeters of the diaphragm wall where water inflow occurred,for the sake of blocking the flow channels.The measured maximum wall deflection dhm in this case ranged from 0.13%H to 0.3%H,with a mean value of 0.2%H(H is the excavation depth),which agreed well with the empirical prediction in mixed ground.During the MJS treatment,the wall and surrounding soils experienced notable lateral deflection and settlement.The bridge piles experienced significant settlement since the excavation commenced,which might be attributed to the inherent deficiency in geological condition and pile length.The soil disturbance induced by the adjacent deep excavation accelerated bridge settlement.The finite element analysis revealed that the excessive settlement of the bridge piles and ground surface resulted from confined-water withdrawal in sand layers.

Groundwater quality and land use change in a typical karst agricultural region:a case study of Xiaojiang watershed,Yunnan

Taking the typical karst agricultural region, Xiaojiang watershed in Luxi of Yurman Province as a research unit, utilizing the groundwater quality data in 1982 and 2004, the aerial photos in 1982 and TM images in 2004, supported by the GIS, we probe into the law and the reason of its space-time change of the groundwater quality over the past 22 years in the paper. The results show： （1） There were obvious temporal and spatial changes of groundwater quality during the past 22 years. （2） Concentrations of NH4^＋, SO4^2- , NO3, NO2^-, Cl^- and the pH value, total hardness, total alkalinity increased significantly, in which NH4^2-, NO3, and NO2^- of groundwater exceeded the drinking water standards as a result of non-point pollution caused by the expansion of cultivated land and mass use of the fertilizer and pesticide. （3） Oppositely, Ca^2＋ and HCO3^- showed an obvious decline trend due to forest reduction and degradation and stony desertification. Meantime, there was a dynamic relation between the groundwater quality change and the land use change.

The impact of land use on soil properties in a karst agricultural region of Southwest China: a case study of Xiaojiang watershed, Yunnan

Supported by RS and GIS, the land use change from 1982 to 2003 were analyzed and the impacts of land use changes on pH value, organic matter, total N, total P, total K, available N, available P, and available K in soil of Xiaojiang watershed, a typical karst agricultural region of Yunnan Province, Southwest China were assessed. The following aspects are concluded. （1） The total land use converted during the past 20 years in Xiaojiang watershed covers an area of 610.12 km^2, of which 134.29 km^2 of forestland was converted into cultivated land, and 210 km^2 of.unused land was converted into cultivated land. （2） The rapid growth of population and the economic development were the main driving forces of land use change. （3） With the change in land use, the soil properties have been changed significantly. The pH, organic matter, total N, total P, total K, available N, available P and available K in soil in 1982 were 6.3, 38.02 g·kg^-1, 1.86 g·kg^-1, 1.63 g·kg^-1, 10.94 g·kg^-1, 114.42 g·kg^-1, 11.65 mg·kg^-1 and 64.69 mg·kg^-1g, respectively; and those in 2003 were 6.73, 25.26 g·kg^-1, 1.41 g·kg^-1, 0.99 g·kg^-1, 12.6 g·kg^-1, 113.43 mg·kg^-1, 11.11 mg·kg^-1 and 151.59 mg·kg^-1, respectively. Pared samples t-test of the tested indices of soil properties indicate that those indices have changed significantly during the last 20 years. But the soil properties changed differently, due to the differences in land use change. （4） Also, with the change in land use and management measures of soil, the modifications in soil properties which developed from carbonate rocks were more sensitive than those in the soil developed from sandstone.

Environmental Geochemistry of Fluorine in the Rock-Soil-Water System in the Karst Region of Central Guizhou Province

Systematic determination of and adsorption experiment on fluorine in the carbonate rock\|soil\|water system in the karst region studied in Guizhou Province, in conjunction with the mineral surface and soil chemistry data, have revealed the geochemical characteristics of F and the mechanisms of its transport and enrichment in the rock\|soil\|water system of the karst region, central Guizhou Province. Deep\|seated underground waters (-100m or lower) and soil layers in the karst region of central Guizhou are characterized by high\|F anomalies whereas shallow\|level underground and surface waters by low contents of F (mostly lower than 0.5 mg/L). Fluorine in soil and water in the region studied comes largely from Triassic marine strata dominated by gypsum\|bearing carbonate rocks. The special adsorption and desorption of F on the surface of geothite in soil layers are the important mechanisms of its transport and enrichment in the rock\|soil\|water system of the karst region studied.

Research on soil multi-media environmental pollution around a Pb-Zn mining and smelting plant in the karst area of Guangxi Zhuang Autonomous Region,Southwest China

The method of principal component analysis was applied to systematical research on the soil multi-media environment, including soil, surface water, ground water, waterbody sediment and agricultural crops, as well as pollution-inducing wastewater, mullock (or waste ore) and slag in the periphery of a large-sized Pb-Zn mining and smelting plant in a karst area of Guangxi Zhuang Autonomous Region. The results revealed that soils in the area studied have been heavily polluted by Cd, Zn, Pb and Hg, and the levels of these metals in the samples of agricultural crop greatly exceed the standards. The above-mentioned pollutants exist in all soil-multi-media environments. The mullock, slag, wastewater, surface water, ground water, soil, and agricultural crops constitute a composite ecological chain. Therefore, the improper disposal of mullock and slag, and the use of polluted wastewater for agricultural irrigation are the main causes of soil pollution. Heavy metals in the soil have three transition progresses: point (improved soil with slag, ground water inflow plot), linear (river transition) and non-point transition (regional pollution by slag) patterns, and the tailing yard is the most important locus for heavy metals to release into the environment.

Karst Cave Tourism System in Zhejiang Province Based on Resource Regional Analysis

Karst cave tourism plays an important role in the overall tourism of Zhejiang Province,China.In analyzing the current status of karst cave tourism resources,it is crucial to develop a scientific system for optimizing resource exploitation and tourism development in the future.This study conducted an analysis of resource characteristics and regional structure in Zhejiang Province.Nearest neighbor index(NNI) method and accessibility index method were used for a comprehensive understanding of the effects of scale,strength,combination,and accessibility of karst cave tourism resources.Results indicated that karst cave tourism resources in Zhejiang Province have a significant regional influence,and that resource quality and exploitation are diverse in different regions.Among the regions,Jinhua had the highest exploitation proportion of over 60% and the lowest NNI value of 0.098.Furthermore,regional analysis inferred that different karst caves demonstrate diversity in accessibility to tourism markets,among which the Lingshan Cave,Fengshui Cave,and Xianqiao Cave reveal the highest accessibility index of 2.41.Finally,we put forward a karst cave tourism system in Zhejiang Province based on the Growth Pole Theory and set up an overall scheme for karst cave tourism development.From a regional perspective analysis,the study refined the methods for regional resource research and provided a strategic proposal for karst cave tourism in Zhejiang Province.

宜昌地区灯影组深层丘滩相碳酸盐岩储层特征

宜昌地区灯影组顶部发育微生物碳酸盐岩沉积,由藻叠层石、藻球粒、凝块石等微生物丘建造,以及藻砂屑、滑塌角砾等颗粒云岩组成,属于典型台缘浅滩—台缘斜坡相沉积。顶部高能颗粒滩相带发育大量蜂窝状溶蚀孔洞,深层碳酸盐岩孔隙度平均9.81%,为优质中孔中渗碳酸盐岩储层,是鄂西地区油气勘探开发的重要层系。

贵州北盘江喀斯特地区6种兰科植物结构及其生态适应性

【目的】分析兰科植物营养器官结构对喀斯特生境的适应特性和不同兰科植物响应生境异质的生存策略,为兰科植物研究、保护与发展提供理论支持和参考依据。【方法】以贵州北盘江喀斯特地区6种不同生活型兰科植物的叶、假鳞茎、根为研究对象,采用石蜡切片法进行结构观察并测量相关指标,数据分析采用描述性和方差分析、相关性分析和主成分分析。【结果】(1)不同兰科植物结构特征间存在显著差异,丘北冬蕙兰、莎叶兰、兔耳兰和单叶石仙桃均为等面叶,叶片较薄;栗鳞贝母兰与梳帽卷瓣兰叶片为异面叶,有栅栏组织和海绵组织的分化,叶片较厚。(2)假鳞茎主要由表皮、基本组织和维管束组成,地生兰基本组织细胞较小,维管束密度大;附生兰基本组织细胞较大,储水结构较发达。(3)地生兰根被和皮层较厚,根被细胞排列紧密,皮层细胞小层数多;附生兰根被与皮层较薄,皮层细胞较大。(4)叶片下表皮厚度与叶片厚度、叶维管束直径、叶肉厚度、叶脉厚度呈极显著(P<0.01)正相关,叶肉厚度与下角质层厚度、假鳞茎维管束直径呈显著(P<0.05)负相关;假鳞茎直径和表皮厚度、假鳞茎维管束数量、假鳞茎横截面积呈极显著正相关,假鳞茎维管束直径占比与假鳞茎直径、表皮厚度、假鳞茎维管束数量、假鳞茎横截面积均呈极显著负相关;根的各指标间呈极显著正相关,根直径、根被厚度和皮层厚度与根维管束直径占比呈极显著负相关。【结论】兰科植物根部结构具有相对稳定的趋同适应性,叶片和假鳞茎结构间相互促进协调,是兰科植物响应干旱喀斯特环境的重要结构。