中国沙冬青属植物的地理分布及生境特征

沙冬青是我国珍稀濒危物种,掌握其地理分布范围及生境特征,有助于分析其所处境况以及展开相应的研究与保护工作。通过搜集历史文献资料与野外实地调查相结合的方法,对我国沙冬青属植物的地理分布范围、时空动态以及生境特征进行了研究,并从地形、气候、土壤三个方面探讨了限制沙冬青属植物生长分布的主要因子。结果表明：（1）新疆沙冬青分布范围为38°55'~40°09'N,74°42'~76°43'E;蒙古沙冬青分布范围为36°27'~42°01'N,102°36'~108°49'E,两种沙冬青在地理分布上不连续,以条带或块状方式呈现小聚集分布状态。（2）两种沙冬青的生境特征存在显著差异,其中限制新疆沙冬青分布的生态因子主要包括气候指标中的热量因子以及土壤指标中的pH、盐分和全磷,限制蒙古沙冬青分布的生态因子主要包括气候指标中的水分因子和土壤指标中的有机质、全氮。     

河口三角洲地区宜居人口容量估算 ——以广州原南沙区为例

近年来,不断有位于河口三角洲区域的县区升级为国家级新区,科学地估算这些县区的宜居人口容量是新区规划的前提。文章通过选取河口区人居自然环境主导因子、提取人口承载区和参考同类区域平均人口密度和相关国家标准等环节,构建了一种基于人居环境适宜性的河口三角洲地区人口承载力的估算方法,并估算了广州原南沙区宜居人口容量。结果显示：原南沙区宜居人口容量为87万人,宜居人口密度为2 776人/km²,其中,南沙街23万人,黄阁镇21万人,万顷沙镇为19万人,横沥镇为13万人,珠江街为11万人。考虑到地基和经济发展差异,南沙区宜居人口密度与上海浦东新区、天津滨海新区之间和美国首都华盛顿特区的人口密度有较好的可比性。文章所用方法突出了水文与地质条件的约束作用,可用于估算河口三角洲地区人口容量。     

利用粗糙集理论进行遥感分类信息提取

以辽宁省双台子河口湿地为研究对象,以Landsat 8和HJ-1-A/HJ-1-B的多时相遥感影像为数据源,根据研究区现状,将研究区分为旱地、芦苇、水田、碱蓬、混合植被、水面、滩涂、居民点、养殖塘九个类型.利用时间序列的归一化植被指数提取植被与非植被的分类阈值,采用粗糙集理论和多时相遥感影像,对植被和非植被分别进行分类规则的获取,建立了研究区决策树分类模型.为了进行精度评价,利用相同的训练点又进行了同样基于像元的最大似然法分类.最后利用混淆矩阵对上述两种方法进行了精度评估,基于粗糙集的决策树分类法与最大似然法总体分类精度分别为93.70%和91.62%,Kappa系数分别为0.92和0.90,两项指标值基于粗糙集理论法均比最大似然法有所提高.这为构建决策树分类模型进行湿地地表分类信息提取提供了一条新的研究思路.     

21世纪初中国生态退耕的空间格局及黄土高原典型区退耕的生态位适宜性分析(英文)

自1999年我国开始试行以"退耕还林"工程为主的生态退耕以来,到目前已历时十年。特别是进入21世纪,工程实施强度较大,因此从国家尺度上进行宏观生态退耕格局的分析对于评估生态退耕政策和确定未来政策导向具有重要意义。本研究以TM遥感监测的土地利用变化数据库为基础分析2000-2005年生态退耕的时空格局。在此基础上,以黄土高原典型地区陕西中北部为研究区,采用生态位适宜度评价模型探讨了生态退耕工程实施的合理性。研究结果表明:(1)2000-2005年间,生态退耕主要集中在中国中部地区,尤其是在黄河和长江的中上游地区,生态退耕面积与建设占用面积基本持平。在各生态类型区中,黄土高原土壤侵蚀区生态退耕面积最大,达到了1162.50km~2,主要用于还林;(2)整体看来,研究区内生态退耕的空间格局是合理的,即适宜性越差的耕地退耕比例越大。从退耕区域的适宜性水平来看,有77.35%的地区属于勉强适宜区,其中退为林地的面积为603.32km~2,退为草地的面积为528.94km~2。整个研究区内前者大于后者。然而,退耕地中仍有19.38%属于中度适宜区,原因可能来自于退耕指标分配等管理因素,另外,当地农民外出务工从而将中等适宜度的耕地退耕。结果表明,当前仍有大面积不适宜和勉强适宜的耕地存在,在未来工程实施过程区应该首先考虑该类地区。     

A framework for karst ecohydrology

Ecohydrology can be defined as the science of integrating hydrological and biological processes over varied spatial and temporal scales. There exists in karst a strong and direct interaction between the circulation and storage of groundwater and surface water. These fluxes in turn affect the spatial distribution of organisms in these habitats. Because of the fact that the appearance, storage and circulation of water in karstified areas is significantly different from other more homogenous and isotropic terrains, karst ecohydrology should develop original methods and approaches. At the same time, traditional approaches are also very useful. Large karst underground geomorphological patterns occur in many sizes and varieties, ranging from a few meters long or deep to very large, the deepest being deeper than 1 km and longer than hundreds of kilometres. In this article, special attention is paid to ecohydrological functions of karst underground features (caves, pits, conduits, etc.), which play a crucial dual role in (1) hydrology and hydrogeology of water circulation and storage and (2) ecology of many rare and endangered species. Differences in morphology, hydrology, hydrogeology and climate have resulted in a range of different environments, which provide the opportunity for the coexistence of different species. The role of the epikarst and vadose zones, as well as caves in ecohydrological processes, is discussed. The importance of the flood factor in karst ecology is analysed. The aim of this article is to move forward the discussion among different disciplines to promote and develop a conceptual framework for karst ecohydrology.     

苏州人居环境建设中创业文化氛围的培育

文章通过分析苏州近代历史,探讨了苏州人居环境中优越的物质和自然环境与创业精神缺失的矛盾及其产生根源,并对新经济时代苏州人居环境建设中创业文化氛围培育的需求和具体的做法进行了深入的探讨。     

乌鲁木齐河源区不同海拔的火绒草叶片结构特征的比较研究

采用PEG和Epon-812二次包埋方法, 利用光学显微镜和扫描电子显微镜对乌鲁木齐河源区海拔4 000 m、 3 400 m、 2 500 m三种不同高度的火绒草(Leontopodium leontopodiodes(Willd.) Beauv.)叶片剖面及表面结构进行了观察. 结果表明: 火绒草叶片既具有中生植物又兼有旱生和湿生植物的部分结构特征; 其叶片厚度、表皮细胞外壁角质层表面、外角质层蜡质分泌物的有无、表皮细胞形状、气孔器分布特征、保卫细胞极区"T"型角质加厚程度、气孔开口(长/宽)、气孔密度、维管束形态、 CTR值、叶肉细胞叶绿体含量等性状特征,在不同海拔的火绒草间呈现出明显差异; 而表皮的气孔水平位置类型、毛状附属器等性状则差异较小. 数值分析火绒草叶结构各类性状以及不同性状状态的组合, 显示出个体形态的多样性及其对高山环境和海拔高度的适宜性特征.     

九龙江河口平原晚第四纪硅藻及海平面变化初探

将福建九龙江河口平原ＺＫ５孔剖面细分为４个硅藻段、２４个硅藻带,并结合其他钻孔的微体生物组合特权和年代测定结果等进行分析。研究表明,晚玉木冰期本区海面升降频繁,但大多处于河口港湾环境,这主要是构造沉降所造成的;其间出现３次低海面,均为河流沉积环境。全新世冰后期海水大规模入侵,鼎盛期本区相对海面高出现代海面达５－１０ｍ。     

Keeping things in order: multivariate direct gradient analysis of a strongly fluctuating benthic community

Two spatial surveys of the macrobenthos of an estuarine intertidal area, the Oosterschelde in the southwestern part of The Netherlands, were conducted in different years. In the period between the surveys changes in the hydrodynamics of the estuary took place as a result of the construction of a storm-surge barrier. The works reduced the tidal volume in the basin and as a consequence the altitude of the tidal flats decreased by approximately 0.1 to 0.2 m. Considerable differences in species densities were found between the two surveys, but these large differences could not be explained by changes in the ‘spatial' environmental variables (such as altitude) that were taken into account in a direct gradient analysis. Unknown and ‘only-to-time-related' (e.g. weather-related) factors had considerably influenced species abundance. This implies that the impact of the works on the macrobenthos could not be evaluated on the basis of observed species densities in the before- and after-the-works surveys. Generally, it implies that even if the levels of future ‘spatial' environmental variables are known, direct gradient analysis based on a single survey cannot be used for prediction of future densities in absolute terms in such strongly fluctuating communities. Yet, the gradient analyses for the two years revealed rather similar estimates of the major environmental gradients. The same was true for the parameters that described the relative change in species densities in response to a change in the environmental gradient levels. Hence the most appropriate way of evaluating the changes that have occurred in the benthic community as a result of the works was in terms of the observed changes in the ‘spatial' environmental gradient levels. The levels of the first environmental gradient, which was strongly related to the sediment structure, did not change between years. Levels of the second gradient, which could be interpreted as a tidal zone gradient, decreased. This suggests that the works particularly affected taxa that are strongly related to this second gradient, such as Corophium living in the upper tidal areas and Nephthys living in the lower tidal zone.     

东台条子泥候鸟栖息地与毗邻潮间带表层沉积物重金属含量及其生态风险评价

为了解世界自然遗产地生态修复的“中国样本”和“鸟类保护的国际地标” ——江苏东台条子泥“720”高潮位候鸟栖息地的生态环境质量,本研究采用电感耦合等离子体发射光谱法和原子荧光光谱法测定了高潮位候鸟栖息地5个样点及与之毗邻的堤外潮间带4个样点表层沉积物中8种常见重金属元素（Hg、Cd、Cr、As、Pb、Cu、Ni和Zn）的含量,基于地累积指数法和潜在生态风险指数法对两个区域表层沉积物中重金属含量特征和生态风险进行了比较研究。结果表明,候鸟栖息地和堤外潮间带表层沉积物中8种重金属的平均含量均未超过国家海洋沉积物质量一类标准,两个区域表层沉积物的重金属含量具有显著的差异（P<0.05）,候鸟栖息地沉积物各重金属平均含量均高于堤外区,两个区域潜在生态风险指数也具有显著差异,候鸟栖息地沉积物重金属潜在生态风险大于堤外区,可能与栖息地建设前的水产养殖活动、候鸟栖息活动、周边农业活动和水动力条件有关;两个区域各采样点的重金属地累积指数均小于0,无明显重金属累积风险;两个区域综合潜在生态风险指数均小于150.00,各采样点单项潜在生态风险指数均小于40.00,均属于低潜在生态风险等级。通过研究区与其他滨海自然湿地中重金属特征对比研究发现,本研究区域中的主要生态风险因子是Hg,其次是Cd,后续需要更多的关注。