景观破碎化及其对生物多样性的影响

景观破碎化是指景观中各生态系统之间的功能联系断裂或连接性减少的现象。景观破碎化引起生物生境的丧失或退化,从而造成生物多样性的丧失。景观破碎化造成的物种多样性变化主要表现为影响物种、遗传和生态系统的多样性。景观破碎化对物种多样性的影响研究是景观生态学的主要研究方向之一,但是目前的研究主要集中于动物种群,研究周期也比较短,而对于植物种群和生态系统受景观破碎化影响的研究开展较少,破碎化对生物多样性的影响机制研究应该更加深入。     

景观破碎化对物种多样性的影响探讨

指出了景观破碎化是当今世界一个突出的生态学问题,物种多样性的变化也是全球生态学的热点问题。重点阐述了破碎化斑块的面积、形状、密度等因素对斑块内部物种多样性影响程度,以及边缘效应、背景效应等对斑块边缘物种多样性的影响程度,探讨了景观破碎化对物种多样性的影响。     

我国蝶类昆虫生物多样性研究进展

从遗传多样性、物种多样性、生态系统多样性和景观多样性四个层次分析了我国蝶类昆虫生物多样性研究进展;指出我国蝴蝶生物多样性研究主要集中在物种多样性研究上,少数涉及遗传多样性、生态系统多样性和景观多样性方面的研究报道;今后应加大蝴蝶多样性研究力度,特别是热点地区濒危蝴蝶多样性研究,从而为蝴蝶多样性保护提供依据。     

景观破碎化对动物适合度的影响研究综述

景观破碎化是生物多样性下降的主要原因之一,景观破碎化已成为保护生物学和生态学的中心问题之一。通常以岛屿生物地理学、异质种群生物学和景观生态学的理论来解释景观破碎化的生态学效应。以往研究表明,生境破碎化对动物适合度造成严重影响。文章通过综合文献,论述景观破碎化对动物适合度的影响,分析影响动物适合度的各项指标,包括物种生存能力,繁殖能力和子代存活能力：同时探讨研究中存在的问题,为物种的保护提出建议,并指出今后研究的主要方法、亟待解决的问题和研究热点。     

南宁市青秀山风景名胜区景观多样性探析

景观多样性是生物多样性研究的主要内容之一,在生物多样性保护方面具有重要作用。本文运用景观生态学原理,借助地理信息系统技术,选取景观多样性、优势度、丰富度密度、均匀度、分离度、分维数等指数,分析了南宁市青秀山风景名胜区不同景观类型的空间分布特征。结果显示:整个研究区域的多样性丰富,各景观类型所占比例相对均匀,常绿阔叶林和马尾松林的破碎化程度较轻,经济林和农田等人工景观较破碎,表明人为干扰十分强烈。     

西洞庭湖区森林景观多样性研究

森林景观多样性是生物多样性的重要组成,具有十分重要的自然、生态、经济价值。人类活动的强烈干扰,对景观多样性产生了严重的威胁,一些有较高价值的景观正濒于退化、消失,保护景观多样性,已成为环境保护的紧迫任务。文章以西洞庭湖区为研究区域,在对森林景观及景观类型多样性的理论研究的基础上,以土地类型为依据,对西洞庭湖区的森林景观类型进行了划分,并选取景观多样性指数、景观优势度指数、景观破碎化指数这3个景观异质性参数,对西洞庭湖的森林景观异质性进行了研究。     

滇西北滇金丝猴栖息地景观格局分析及其破碎化评价

生境丧失及破碎化已成为生物多样性最主要的威胁之一,对物种栖息地的景观格局进行分析及对其破碎化进行评价显得十分必要.对滇金丝猴栖息地景观格局和破碎化进行分析评价,结果表明,包括滇金丝猴适宜生境在内的森林面积占整个研究区面积的2/3,是该地区的主导景观类型;研究区景观格局已表现出一定程度的景观破碎化.滇金丝猴适宜生境面积为308 212.44 hm2,占整个研究区面积的18.86%.目前滇金丝猴适宜生境的破碎化程度较低,但仍需控制适宜生境已出现的景观破碎化,并通过生境恢复及廊道重建等措施加强对滇金丝猴的保护.     

海南岛热带森林生物多样性研究进展

生物多样性是生态学研究中一个重要的领域,海南岛热带林有很高的生物多样性。阐述海南岛热带林生物多样性的意义和研究进展,介绍海南岛热带林物种多样性、遗传多样性、生态系统多样性和景观多样性特点,结合生物多样性锐减的现状提出了相应的保护建议。     

不同采伐方式对兴安落叶松林林下物种多样性的影响

在大兴安岭林区不同采伐区选择典型样地,采用Patrick丰富度指数、Simpson多样性指数、Shannon-Wiener多样性指数及Pielou均匀度指数,研究了不同采伐方式对兴安落叶松林林下物种多样性的影响。结果表明:适度的间伐干扰有利于生物多样性的提高,随着采伐干扰强度和频度的增大,生物多样性会下降;皆伐更新不利于生物多样性的保护,会降低物种多样性指数,改变生物多样性结构;渐伐符合森林更新及林下重要物种对外界环境变化适应的要求,有利于生物多样性和整个生态系统的稳定。     

城市鸟类群落与绿地关系研究进展

城市化进程的加快使城市生物多样性保护及发展面临严峻的考验。城市鸟类对环境变化敏感，与人类活动关系密切，是衡量城市生物多样性的重要指示物种。鸟类在城市化地区的分布和生活，与城市绿地关系密切。探究城市绿地与鸟类的关系对城市生物多样性提升、生态系统保护，以及动物景观环境改善等方面具有重要意义。文中从城市绿地的尺度、空间分布、破碎化、边缘效应、连通性、类型和结构等方面对城市鸟类群落的影响进行归纳评述，并提出今后的研究拓展方向，以期为保护城市绿地中鸟类的多样性提供参考。     

森林生物多样性保护原理概述

热点地区的分析,为我们确定生物多样性保护的策略和优先等级提供了依据;由于人类的剧烈干扰,现在地球上有许多物种和生态系统都处于濒危的境地,热带雨林的生物多样性丧失最为严重;热点地区虽然在地球上所占的面积很小,但却拥有大量的物种,这些地区的生物多样性丧失应特别引起我们注意;每个物种灭绝的难易程度不同,稀有种和长寿命种特别易于灭绝,而关键种一旦受到威胁,依赖于其生存的许多物种也会有灭绝的危险。遗传多样性的丧失也是生物多样性丧失的重要方面,种群内遗传多样性的丧失主要来源于奠基者效应、统计瓶颈效应、遗传漂变和近亲交配４种因素。物种的概念影响到对物种的保护,物种保护应包括物种内遗传多样性的保护;种群的动态调节机制和源—汇种群动态对于生物多样性保护具有重要的意义。种群生存力分析是了解物种濒危机制的崭新手段。群落中的种间关系和自然干扰体系是生物多样性保护中应考虑的重要方面。人为的生境破碎与自然景观的异质性不同,生境破碎会造成边缘效应和拥挤效应等一系列的生物学后果。     

Climate Change Effects on Mediterranean Forests and Preventive Measures

This paper synthesizes and reviews literature concerning climate change effects on Mediterranean forest ecology and management as well as the restorative techniques necessary to maintain forest health, forest yield and biodiversity. Climate change compounded with trends of rural abandonment are likely to diminish forested areas within the Mediterranean basin that will be replaced by fire prone shrub communities. This could be favoured by outbreaks of pathogens, fire and other large-scale disturbances. Landscape fragmentation is expected to impede species migration. Annual increments and subsequent income from forests are expected to decrease. Reafforestations are necessary to ensure the presence of propagules of forest species and their site-specific varieties best adapted to future climatic conditions even though they may be different from the present forest-plant community. Current challenges in biodiversity conservation can only be met by afforestations whose main objective is to maintain ecosystem functioning. A new silviculture must emerge encompassing these habitat displacement and economic concerns while maximizing carbon sequestration.     

自然保护区布局监测和生境破碎化监测——以海南铜鼓岭自然保护区为例

建立自然保护区是保护生物多样性的主要方法和手段。我国的自然保护区建设发展得很快,但是仍存在许多困难和问题,当务之急是建立一套完整的自然保护区管理体系、监测体系,组织自然保护区开展资源、生态等方面的监测工作。应用GAP对自然保护区的布局和现状进行分析表明,目前尚未得到有效保护的优先生态系统有27类。并以海南铜鼓岭自然保护区为例,利用RS和GIS技术对自然保护区的生境破碎化进行了监测研究。结果表明研究区生境破碎化程度增加,致使斑块内部物种向外迁移,生物多样性降低。     

Impact of urbanization on plant diversity: A case study in built-up areas of Beijing

Urbanization is developing rapidly in the world, which seriously changes the habitat of organisms and has clearly a negative effect on biodiversity. Preservation of biodiversity is crucial in urban planning and management, which is also an important symbol for the level of greening. Problems such as scarcity of urban green space and plant species have become obstacles to the establishment of ecological friendly cities. However, coexistence of nature and modernization, as well the coordination of economic development and biodiversity, are goals that people are seeking. We have taken the builtup areas of Beijing as a study case and discussed the impacts of urbanization on plant diversity, with the support of fieldwork and SPOT remote sensing data. The results are as follows： 1） in the process of urbanization, exotic plants have been widely introduced, which has affected species composition and the proportion of native plants; it is clear that artificial green spaces always will have a lower level of plant diversity than natural green spaces; 2） functional differences of green space types partially decide their species abundance, so that plant diversity in greenbelts and streets is generally lower than in parks; 3） the spatial variety of plant diversity contributes much to the imbalance of district de- velopment and the planning of different functional zones; this variation is embodied in different ring-belts and directions; 4） habitat fragmentation also affects plant diversity to a great extent; there is a significant positive correlation between high fragmentation and low plant diversity. According our results, some suggestions are proposed, which would be suitable for the preservation of plant di- versity and ecological improvement during urbanization.     

Decomposition of stumps in a chronosequence after clear-felling vs. clear-felling with prescribed burning in a southern boreal forest in Finland

The wood bulk density, bark mass and decomposition rate constants of cut stumps of the main European boreal tree species were assessed along a 40-year chronosequence of clear-felled sites with and without prescribed burning. Using the single exponential model, the annual decomposition rate constants k of above-ground stumps were calculated as 0.048, 0.052 and 0.068 year⁻¹ for Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and birch (Betula sp.), respectively. Bark decomposed faster than wood and bark fragmentation increased the rate of decomposition. There was a significant negative effect of burning on decomposition rate for pine wood, and for pine and spruce bark but not for spruce and birch wood or for birch bark. The decomposition of bark of all species was slower with larger diameter stumps but only slightly slower in the case of birch wood. Our results suggest (i) using different decomposition rate constants for wood and bark, (ii) taking into account fragmentation as it greatly increases the volume loss, and (iii) adjusting of k in carbon dynamics studies on burned sites. Such refinements to estimates of coarse woody debris decomposition constants could aid in identification of ecosystems and management scenarios necessary to maximize carbon storage and conserve biodiversity. Prescribed burning for restoration purposes decreases decomposition rates and consequently ensures longer persistence of stumps for maintaining biodiversity in intensively managed forests.     

Sustainability and Biodiversity

Abstract

The implementation of the Rio protocol and the preservation of biodiversity at the national and regional levels is an important step in achieving sustainable forestry. This is indeed a challenging task since our knowledge of the ecology and habitat demands for but a few species is severely restricted. Research in the last years shows that forest species have very different qualitative and spatial demands on their environment, which require complex and broad solutions. This poses a great problem for conservation and often forces societies/decision-makers to make decisions based on assumptions rather than on empirical data. With assumptions follow uncertainty, a factor that is necessary to control. We identify and discuss the uncertainties of steps that are considered to be important for preserving biodiversity on a regional level and exemplify this with cases from southern Sweden. We argue that there is no universal solution for the conservation of biodiversity. In strongly fragmented and transformed regions like southern Sweden, a mix of species approaches and ecosystem approaches is necessary for biodiversity conservation. Programs for preserving biodiversity should be flexible, not rigid, allowing for modifications due to a constantly increasing body of knowledge and environmental changes. Prominent gaps in our knowledge include species dispersal ability and propensity, extinction rates and the species dependence on fragmentation and landscape history. It is possible that the question of responsibility species (a species for which a region has an explicit conservational responsibility) may gain in importance, an issue with far-reaching implications for economy and inter-regional compensatory systems.