Al-Ferron逐时络合比色法研究PACS中铝的水解聚合形态

制备了碱化度(B)及不同Al~(3+)/SO_4~(2-)摩尔比的系列PACS,用Al-Ferron逐时络合比色法研究了铝的形态分布,考察了碱化度(B)、Al~(3+)/SO_4~(2-)摩尔比、稀释作用及pH值对铝的形态分布的影响.实验结果表明,Al~(3+)/SO_4~(2-)摩尔比及溶液的pH值对铝的形态分布有较大的影响,稀释作用对铝的形态分布影响较小.Al~(3+)/SO_4~(2-)摩尔比愈小,pH值愈高,铝的水解聚合大分子及胶体粒子所占的比例就愈大.     

广西贵港市土地利用总体规划实施评价

目前沿用的土地利用总体规划实施评价的方法多为定性的直接描述法，缺乏科学的评价体系，难以对规划实施的效果作出客观、科学的评判。文章引入层次分析法（AHP），对贵港市土地利用总体规划实施效果进行量化研究。结果表明，虽然当地政府高度重视规划的实施，实施情况总体良好，但社会经济成效指标和完成性指标评价得分较低。建议该市今后加快“三农”政策的落实，以提高农民种粮的积极性和农民的收入水平；加大土地开发复垦、退耕还林资金投入，并制定有力的保障措施，促进完成性指标的实施。同时，提高社会意识度，是规划实施工作的重中之重，今后的规划要强化公众参与。     

对生态系统中分离获得的菌种进行优势种群测定的方法学探讨：一株优势纤维分解菌的确定

两年内７次从同一个以杨木木屑为原料的厌氧发酵罐的高稀释度发酵液中分离出一株中温纤维分解菌，即新种阿氏梭状芽孢杆菌（Ｃｌｏｓｔｒｉｄｉｕｍａｌｄｒｉｃｈｉｉ）。从细菌计数高且能反复分离获得这两个特点，可以断定阿氏梭状芽孢杆菌在该生态系统中曾是一个优势种群。经菌落及菌体形态学观察，以及用首次分离的菌株所作的多价抗血清酶联免疫吸附试验（ＥＬＩＳＡ），确定７次分离菌株为同一菌种，从而证实阿氏梭状芽孢杆菌在１９８６年９月至１９８８年８月间，曾是该厌氧发酵罐中每毫升含菌高达１０６─１０７的优势纤维分解菌。     

Maritime oil spills— Environmental lessons and experiences with special reference to low-risk coastlines

Oil spill contingency plans are available for most coastlines but the amount of useful environmental data is variable. The information should be held on a GIS base. High risk areas should be identified and the pre-existing store of environmental knowledge should be commensurately extensive and should be available in considerable spatial detail. Contingency plans still depend on basic lists of coastal types as defined by static, sediment based shoreline characteristics. There is a lack of dynamic, process information. TheBraer oil spill of 1993 provides a case study of the application of sound coastal geomorphological and ecological data to impact assessment. Monitoring of the ecological effects of this massive oil spill reinforces other research which indicates that most coastlines can recover naturally from oil spills, and that oil spill clean up techniques may not necessarily benefit rapid shoreline recovery. Although pre-existing environmental informations is important, the key decisions must be taken quickly and are frequently judgmental and, therefore, place a premium on gathering appropriate scientific expertise to the site of the spill as soon as possible and with sufficient powers to affect both the oil spill response, to initiate early surveys of damage and to facilitate the initial monitoring programme.     

Conservation Strategies for Endemic Fish Species Threatened by the Three Gorges Dam

Abstract:   The largest damming project to date, the Three Gorges Dam has been built along the Yangtze River (China), the most species-rich river in the Palearctic region. Among 162 species of fish inhabiting the main channel of the upper Yangtze, 44 are endemic and are therefore under serious threat of global extinction from the dam. Accordingly, it is urgently necessary to develop strategies to minimize the impacts of the drastic environmental changes associated with the dam. We sought to identify potential reserves for the endemic species among the 17 tributaries in the upper Yangtze, based on presence/absence data for the 44 endemic species. Potential reserves for the endemic species were identified by characterizing the distribution patterns of endemic species with an adaptive learning algorithm called a "self-organizing map" (SOM). Using this method, we also predicted occurrence probabilities of species in potential reserves based on the distribution patterns of communities. Considering both SOM model results and actual knowledge of the biology of the considered species, our results suggested that 24 species may survive in the tributaries, 14 have an uncertain future, and 6 have a high probability of becoming extinct after dam filling.     

Quadratic diversity: Its maximization can reduce the richness of species

In recent decades numerous diversity indices have been introduced. Among them the quadratic entropy index Q expresses the mean difference between two individuals chosen from the community at random. Differing from diversity indices habitually employed, Q does not satisfy a property postulated earlier for those measures. Namely, the uniform distribution of species does not necessarily yield the maximal index value. Q is based on the difference matrix of species. For a given matrix one can seek for the vector yielding the maximum quadratic entropy. This task leads to a quadratic programming problem. Using the appropriate program of a program package, we determined the maximum vector for a genetic difference matrix of crane species, as published in the literature. We discovered that some components (frequencies) in the maximum vector are equal to zero. That is, by maximizing the quadratic diversity some species can be eliminated. We discuss briefly the possible implications of this observation. Moreover, even if all elements in the maximum vector are positive, the elements can differ.     

International Trade Status and Crisis for Snake Species in China

Abstract:  In recent years, the purchase of snakes for leather, food, and traditional medicine has increased in China, which has greatly reduced certain snake populations. Trade records show that since the 1990s, with respect to some species of snakes, China is changing from a net export country to a net import country. We analyzed data on international trade in snake species, concentrating, in particular, on trade dynamics and species composition. The overall number of snakes exported appears to have decreased in the last 10 years. However, the number of snakes imported during this period has increased steadily. Many species of snakes that are traded in significant numbers are endangered or threatened species. To conserve snakes in China, we recommended that the Chinese government and the international conservation community take the following actions: enhance legislation and list several species in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) appendices; register all snake farms in China; carry out population and market surveys; monitor the dynamics of trade; encourage biological research; encourage change in food habits; and enhance cooperation between Hong Kong and mainland China.     

扁刺栲-华木荷群系次生林林下物种多样性分析

对四川中亚热带扁刺栲(Castanopsis platyacantha)—华木荷(Schima sinensis)群系人工杉木林、水杉林、日本落叶松林和天然次生林林下植物进行了群落调查和物种多样性分析。结果表明：(1)杉木林、水杉林、日本落叶松林和次生扁刺栲—华木荷林(20a)的物种丰富度分别为62，59，53和32；Simpson多样性指数分别为7．95，7．08，9．24和5．38；Shannon—Wiener多样性指数分别为3．67，3．3l，3．64和2．46。(2)人工林林下植物群落之间的群落系数和相似度系数分别为0．45～0．60和0．62～0．82；人工林林下植物群落与次生阔叶林林下植物群落之间的群落系数和相似度系数分别为0．19～0．53和0．55～0．77。(3)人工林林下物种多样性比次生林高的主要原因可能是风倒木和站干死木导致人工林乔木层郁闭度减小，增加了林下的光照，从而改蛮了林下的微生境。表6参19。