近15年来长江源区土地利用变化及其生态环境效应

长江源区是我国重要的水源涵养区,也是高海拔地区生物多样性最集中的地区和生态变化最为敏感的地区。基于1986年TM和2000年ETM+卫星遥感数据和野外实地调查,采用GIS软件和景观生态空间分布格局分析方法,对长江源区近15年来土地利用类型的时空变化进行了研究。结果表明：1986～2000年,源区林地和湿地面积减少54.2 %和42.69 %,建设用地、耕地和未利用土地面积分别增加120 %、43.83 %和21.1 %。全区土地利用的空间位置转换面积大于其数量变化,土地利用类型总变化的面积大小依次是草地＞未利用土地＞湿地＞水域＞林地＞耕地＞建设用地。土地利用动态转化过程以草地转化为未利用土地、湿地转化为草地和未利用地逆转为草地为主要特征。15年里景观破碎化程度加剧,分维数和多样性指数增加,优势度降低,景观异质性增强。长江源区脆弱的生态体系对土地利用变化响应强烈,造成水土流失与沙漠化程度加剧,导致大范围高寒草甸、草原植被退化,湿地萎缩。气候变化和人类经济活动是导致研究区土地利用变化的主要因素。     

Estimated home ranges can misrepresent habitat relationships on patchy landscapes

Home ranges of animals are generally structured by the selective use of resource-bearing patches that comprise habitat. Based on this concept, home ranges of animals estimated from location data are commonly used to infer habitat relationships. Because home ranges estimated from animal locations are largely continuous in space, the resource-bearing patches selected by an animal from a fragmented distribution of patches would be difficult to discern; unselected patches included in the home range estimate would bias an understanding of important habitat relationships. To evaluate potential for this bias, we generated simulated home ranges based on optimal selection of resource-bearing patches across a series of simulated resource distributions that varied in the spatial continuity of resources. For simulated home ranges where selected patches were spatially disjunct, we included interstitial, unselected cells most likely to be traveled by an animal moving among selected patches. We compared characteristics of the simulated home ranges with and without interstitial patches to evaluate how insights derived from field estimates can differ from actual characteristics of home ranges, depending on patchiness of landscapes. Our results showed that contiguous home range estimates could lead to misleading insights on the quality, size, resource content, and efficiency of home ranges, proportional to the spatial discontinuity of resource-bearing patches. We conclude the potential bias of including unselected, largely irrelevant patches in the field estimates of home ranges of animals can be high, particularly for home range estimators that assume uniform use of space within home range boundaries. Thus, inferences about the habitat relationships that ultimately define an animal's home range can be misleading where animals occupy landscapes with patchily distributed resources.     

渝宜高速（重庆段）对土地利用变化驱动及景观格局的响应

为深入认识道路对土地利用/土地覆被变化的作用过程和机制,确定道路的影响范围和强度,论文选取渝宜高速（重庆段）两侧15 km缓冲带为研究区,基于1986、2000、2007和2013年4期遥感影像数据,利用ArcGIS技术和景观生态学方法,从4个分段、3个尺度探讨了高速公路驱动下土地利用和景观格局演变的梯度差异及其对道路演变的响应。结果表明,1986-2013年,研究区土地利用变化规律正在由“点”往“轴”向格局转变;2013年西段低山丘陵区、中段低山宽谷区、中段中低山峡谷区道路的影响范围分别是10、7、5 km,东段中山峡谷区道路效应不明显;总体来看,公路沿线3 km范围内土地利用开发强度高,并且4个分段的土地利用综合程度自西向东逐步降低;在道路的驱动下,全区景观格局的变化局限在一定范围内,对于西段低山丘陵区和中段低山宽谷区的景观格局显著变化在5 km内,中段中低山峡谷区、东段中山峡谷区的变化主要集中在4和3 km内,影响域内景观破碎化程度加剧,景观稳定性降低,生态景观风险增加;各分段土地利用和景观格局变化空间差异与其通车时间存在正相关关系,同时受区域经济和地形因素以及环境政策的影响。研究结论有助于丰富对生态脆弱区道路效应的理解,为区域交通规划及土地资源持续利用提供科学依据。     

我国山地城镇的景观生态学探讨

应用景观生态学的理论，与平原城镇相比较，分析了山地条件下的山地城镇的景观生态特性：景观自然生境要素多，廊道体系不发达，景观要素布局松散，生态系统抗干扰能力差。按照地形条件和结构形态对山地城镇的景观结构类型进行了详细分类，总结了山地城镇的主要生态问题，为山地城镇的景观规划与设计提供参考。     

混凝剂特性对建筑景观水水质维护效果的影响

建筑景观水体的水质会直接影响居民身体健康和生活环境,采用简单、高效的水质维护技术具有较大实用价值。采用混凝-沉淀法对比研究了硫酸铝(Al2(SO4)3)、聚合氯化铝(PAC)、三氯化铁(Fe Cl3)和聚合硫酸铁(PFS)4种常用混凝剂对建筑景观水体中主要污染物的去除效果,对混凝剂的电性中和特性与絮体特性进行初步分析。结果表明:在投药量为10~30 mg/L条件下PAC、PFS和Fe Cl3的混凝除污染效果均明显好于Al2(SO4)3;在投药量达到35 mg/L时,4种混凝剂的混凝效果趋于相近,均可达到较好的除污效果。由Zeta电位和絮体特性的分析可知:PAC电荷密度最高,PAC和PFS形成的絮体粒径和密度最佳。     

Situational Waste in Landscape Watering: Residential and Business Water Use in an Urban Utah Community1

Abstract: Landscape water conservation is an important issue for municipalities throughout the Western United States, and especially in Utah as rapid growth strains existing water supplies. We conducted interdisciplinary research in Layton, Utah, that aimed at understanding patterns of landscape water use among households and businesses. The research project involved three basic tasks. First, a landscape “water budget” was developed by producing a calibrated and classified mosaic of landscape type and area from airborne multispectral digital imagery, integrating this information with Layton City parcel boundary data to determine landscape vegetated areas per lot, and estimating irrigation needs derived from reference evapotranspiration (ETo) obtained using weather data for the Salt Lake City metropolitan region. Second, utilizing Layton water billing data, water use for each household and business was identified and categorized as “conserving,”“acceptable” or “wasteful” by determining how much the water applied varied from actual landscape plant need. Third, surveys were administered to a random stratified sample of households and businesses in the study area to investigate various factors that were hypothesized to be predictive of wasteful watering practices. This paper primarily focuses on analysis of the household and business survey data, which explores factors affecting urban landscape water use from a human behavioral perspective. We found that the most significant factors predicting actual water use were the type of irrigation system and whether the location was a household or business. Attitudinal and motivational characteristics were not consistently associated with water use. We found that wasteful watering is the result of many factors embedded in the complex context of urban landscapes. This implies that water conservation programs should identify potential wasteful users through analyses of water billing data and direct water conservation measures at these users by focusing on site‐specific evaluations and recommendations. Water audits or water checks are one such tool that some communities have employed to help people understand and assess the quantity of water needed by and applied to their landscapes. This approach provides an opportunity to evaluate situational constraints at particular locations and design appropriate strategies for reducing water waste.     

洞庭湖的景观动态分析

景观元素分为三种：嵌块体、走廊、本底，在洞庭湖区，湖泊是洞庭湖的本底，洲滩是一种典型的嵌块体，在湖区分布广泛，数量众多，是现在洞庭湖区最为活跃的景观元素之一，研究湖泊的演变规律，洲滩的结构，动态变化，以及洲滩对洞庭湖功能的影响，对洞庭湖的治理有着重要参考价值，整个湖区洲滩面积呈增长趋势，从1961年到1985年面积增长了815km^2，由于人工因素和自然因素的差异，洲滩分布在不同湖区县市，不同时期，不同高程出现了不同规律：洲滩主要分布在岳阳、沅江和汉寿三地，不同类型洲滩的演化动态在不同湖区分布呈现异质性，洲滩（景观结构）的改变导致洞庭湖功能（调蓄功能，生态功能等）的退化，因而沿庭湖洲滩治理刻不容缓，此外，还论述了芦苇，人工林和洲滩演化的相互影响，论证了芦苇是洲滩扩张的一个重要因素，而人工林有利于开发和治理洲滩。     

张家口市万全区某种植区土壤重金属污染评价与来源分析

以张家口市万全区某蔬菜种植区土壤为研究对象,采集132件表层和80件深层土壤样品,测试分析As、 Cd、 Cr、 Hg、 Cu、 Ni、 Pb和Zn等8种重金属元素含量以及Cr和Ni赋存形态.综合应用地统计学分析和PMF受体模型,并结合3种重金属污染评价方法,摸清了研究区土壤重金属空间分布特征、重金属污染程度和垂向上Cr和Ni赋存形态的分布情况,探析了土壤重金属污染源和贡献率.结果表明,表层土壤重金属Cd和Pb含量平均值均高于河北省土壤背景值,表层土壤Cr、 Ni、 Cu, Cd、 Pb和Zn空间分布特征存在相似性.地累积指数法表明研究区以无污染为主,分布少量轻污染点位,以Cd污染点居多;富集因子法表明研究区主要以无-弱污染为主,各元素均存在中污染情况,背景区显著污染元素为As、 Pb和Hg,重点区中显著污染元素为Cd;潜在生态风险指数法表明研究区以轻污染为主,局部分布“中”和“强”风险点,背景区Hg存在“很强”风险点,重点区Cd存在“很强”风险点.这3种评价结果表明背景区以Cd和Hg污染为主,而重点区则以Cd污染为主.垂向土壤赋存形态研究表明Cr以残渣态(F4)为主,可氧化态(F3)...