景观遗传学：概念与方法

全球变化下的物种栖息地丧失和破碎化给生物多样性保护带来了新的问题和挑战,生物多样性保护必须由单纯的物种保护上升到栖息地景观的保护。景观遗传学是定量确定栖息地景观特征对种群遗传结构影响的一门交叉学科,在生物保护及自然保护区管理方面有巨大的潜力。从生物多样性保护的角度评述了景观结构与遗传多样性的关系,介绍了景观遗传学的基本概念,研究尺度和方法,并对景观遗传学当前的研究焦点及面临的挑战做了总结。     

生态保护区外斑块对景观连接度的影响评价

快速的城市化过程带来的生境斑块破碎化及损失会影响物种迁移、捕食等生态活动,对生物多样性构成威胁。然而,现有生态保护区可能无法覆盖其内生物的必要活动范围。生态保护区外的生境斑块对于维持生态过程也具有重要作用,因此识别生态保护区外的关键斑块并加以保护非常重要。以北京市延庆区为研究区,划分两种生境斑块,即核心生境斑块和潜在生境斑块,并基于图论构建生境网络。考虑地表覆盖类型、坡度、人类活动等因素构建生境阻力面。结合未来土地利用类型变化的模拟,研究城市化过程对区域生境网络和景观连接度的影响,选用CLUE-S模型模拟土地利用类型变化的格局。结合生境斑块特征和未来城市土地利用变化情况设计了3种未来生境变化情景。利用连接概率指数(PC)和网络连接度变化率(dI)评价不同生境变化情景下生态保护区外潜在生境斑块的景观连接度重要性,判断保护优先顺序,并分析景观格局变化对不同迁移能力物种的影响。结果表明：生态保护区外的全部潜在生境斑块对维持生境整体景观连接度有最大2.15%的影响,单个潜在生境斑块对维持景观连接度有最大0.28%的影响。此外,景观格局及其变化对不同迁移能力物种的影响差异显著,因此需针对保护物种和城市生境特征设计保护方案,研究区需要优先保护大中型斑块和位于关键位置的小型斑块。为了满足对生物多样性保护的需求,建议在区分生境斑块保护优先顺序时考虑生境斑块对景观连接度的贡献和城市化扩展过程的压力。研究为城市生物多样性保护和生境管理提供了方法参考。     

基于物种分布的北京平原生态网络构建

高强度的城市化活动导致了生物栖息地破碎化、退化和消失,是生物多样性减少的主要原因。建立城市地区生态网络是保护生物多样性的重要途径。因其他物种数据可获得性差,以观测的典型鸟类群落为指示物种,探讨构建生态网络,可为城市生物多样性保护提供新思路。以北京市平原区为研究范围,重点基于86种鸟类分布大数据,通过Maxent模型掩膜生成栖息地源地并进行分级,在GIS技术的支撑下,以土地利用数据建立鸟类活动阻力面,采用最小累积阻力模型算法,模拟并形成了平原地区分级的生物多样性保护网络。研究结果表明,河湖湿地和城市公园组成了北京平原地区生态网络的优势景观类型,占平原区生态空间的81%。基于景观类型大小与物种数量的线性关系筛选出分级生物栖息地,其中一级生物栖息地58个,二级生物栖息地146个,通过模型模拟形成了平原地区生物多样性保护的一二级生态网络,共948条网络,长3760km。筛选出重要生态节点12处,关键生态廊道6条,是保护平原地区生物多样性的重要生态设施。该生态网络的实施对于提升首都平原区的生物多样性具有重要价值,研究结果可为国土生态空间优化提供重要科学依据和参考。     

基于过程视角的城市地区生物保护规划——以浙江台州为例

生境破碎化和生物过程的阻断是城市区域生物多样性面临的主要威胁。当前以物种为中心的生物保护规划对区域生境格局关注不足,而景观导向的思路缺乏生物过程考虑。随着保护生物学、景观生态学及景观规划的发展,将物种生物过程与生境格局相结合的综合方法日益得到认可。台州是中国东南沿海快速城市化区域,具备丰富的生物资源,但近年的分散城市化和大规模基础设施建设造成严重的生境破坏和物种丧失问题。本文以2种鸟类作为指示物种,将其生物过程信息与区域景观格局设计相结合:黑嘴鸥作为典型迁徙候鸟,季节性停留于当地泥质滩涂,其生物行为可视作一种垂直生境选择过程;白茎长尾雉作为本地重要留鸟,其生物过程兼有垂直生境选择和水平迁移。利用景观适宜性和景观安全格局方法从垂直和水平过程对指示物种适宜生境进行判别,并叠加构建城市区域综合生物保护基础结构,为类似地区提供参考。     

生物多样性保护的景观规划途径

景观规划设计在生物多样性保护中起着决定性的作用。基于不同的保护哲学,生物多样性保护的景观规划途径主要可分为两种：一是以物种为核心的景观规划途径,另一种是以景观元素为核心和出发点的规划途径。前者首先确定物种,然后根据物种的生态特性来设计景观格局,后者则以各种尺度的景观元素作为保护对象,根据其空间位置和关系设计景观格局。多种空间战略被认为有利于生物多样性的保护,包括保护核心栖息地、建立缓冲区、构筑廊道、增加景观异质性和引入或恢复栖息地。落实这些空间战略必须首先回答选择什么和在什么地方设计上述景观元素的问题。对此,目前尚没有很好的答案。传统的生物保护战略被动地强调现存濒危物种和景观元素的保护,如果将物种运动和生态过程作为一个能动的景观控制过程来对待,我们将会有一种全新的景观规划途径。其中有三个方面的概念对这种新的景观规划途径有启发意义：即景观的空间构型对生态过程的作用,生物进化空间轨迹与景观格局设计及景观阻力与潜在的生态基础设施的设计。景观生态安全格局正是在这些方向上的一个新的探索。     

快速城市化过程中土地覆盖格局研究——以深圳市为例

研究一个以城市化过程为主的土地利用/覆盖变化可以从不同的角度出发。选择景观生态学中的景观格局的研究方法,对快速城市化地区——深圳市的城市化过程中的土地利用/覆盖的动态变化进行研究。具体选择景观格局指数中的破碎度指数、Shannon-Weaver多样性指数和聚集度指数,来表征斑块水平、景观水平、区域水平3个不同层次的土地覆盖格局。首先在区域水平上,分析了深圳全市,以及经济特区和特区外的宝安区、龙岗区的土地覆盖格局变化。在此基础上,以研究区的镇级行政单元为景观单元,计算了镇级行政区域以及镇级行政区海拔0～30m的区域的景观格局指数,在景观水平上分析了区域经济发展水平和速度,以及地形因素对土地覆盖格局变化的影响。随后分析了研究区各土地覆盖类型以及不同时期的斑块水平上的土地覆盖格局。最后以城镇用地比例表征城市化水平,讨论了城市化水平与土地覆盖格局变化的关系。在城市化初期,景观类型多样性和斑块破碎化程度出现上升趋势,空间聚集性下降,生态安全问题开始突现。在城市化水平20%～40%之间,其景观类型多样性和斑块破碎化程度达到较高水平,而空间聚集度水平较低,生态安全水平明显下降;随着城市化过程的不断深入,城市化水平不断提高,景观类型多样性和斑块破碎化程度又出现了较为明     

三江平原东北部湿地生态安全格局设计

以三江平原东北部为研究区域,采用"3S"技术和数学模型,根据景观尺度上生物多样性保护规划的景观生态安全格局方法,对三江平原湿地生物多样性保护进行规划设计.利用GAP分析方法预测湿地鸟类丰富度,并评价和计算了湿地鸟类干扰度,在此基础上构建物种运动阻力模型,并利用此模型计算物种运动阻力指数,建立物种运动等阻力面,在阻力面上识别战略点、辐射道和源间联接等景观组分.为了保护本区的湿地生物多样性,提出扩大保护区的面积、建立保护区与热点之间的廊道和设立微型保护地块的规划措施.提出的湿地鸟类多样性保护的景观生态安全格局技术与方法,不但为三江平原湿地及其生物多样性的保护和管理提供科学依据,而且丰富和发展了我国生物多样性保护的理论与方法.     

区域城市扩张对森林景观破碎化的影响——以粤港澳大湾区为例

森林生境丧失与景观破碎化是引起生物多样性下降,生态系统功能降低的重要原因。量化森林景观破碎化的时空特征及其与城市扩张格局的关系是开展区域生态修复与功能提升的重要基础。本文以快速城市化的典型区域——粤港澳大湾区为研究对象,基于遥感解译的1980年、1990年、2000年、2010年和2018年土地覆盖/利用专题图,通过多尺度的景观格局分析和统计分析,定量解析森林景观破碎化的时空演变特征及其与城市扩张格局间的关系。研究结果显示：1）1980-2018年,大湾区林地覆盖面积缩减1,274 km²,林地转变为建设用地的面积占林地丧失总面积的比例从1980-1990年的11%增长至2010-2018年的42%,表明城市扩张已成为林地丧失的主导因素;2）森林景观破碎化程度加剧,表现为林地斑块密度提高,平均斑块面积减小,但破碎类型与程度具有地域差异;3）城市扩张幅度与空间格局显著影响林地破碎化,其中,城市扩张幅度对林地破碎化的影响更为重要。基于森林景观破碎化与城市扩张的现状,落实城市增长边界划定、关键斑块-廊道识别与生态网络构建等措施,有助于保护与连通重要生态空间,保障和提升生态功能。     

北京市近二十年景观破碎化格局的时空变化

基于1993—2013年3期时间序列的遥感影像获得的一、二级景观类型的土地覆盖数据,利用移动窗口法和空间主成分分析法研究景观破碎度空间分布格局和破碎化过程。结果表明:北京市正处于快速城市化阶段,20年间其建设用地面积增加了1000.8 km~2,增长47.14%,而耕地面积减少21.86%;全市破碎化程度增加,其中,景观斑块总数增加了15.26%,而景观斑块的平均面积缩小了15.35%,景观形状指数(LSI)从88.426增加到98.897;北京市景观破碎化格局的空间异质性较大,但没有方向性偏好,却表现了"两极化"发展趋势,其中,高破碎化区域和低破碎化区域的面积增加,中等破碎化的区域面积减少,核心大城区和山区的景观破碎度降低,而新兴城区和郊区的景观破碎度增大;北京市景观破碎化格局的距离效应显著,呈现倒"U"型二次函数关系,其中,2013年的破碎度距离函数为:Y_3=0.1767+0.02898X_3-0.0005167X_3~2,距城市中心20—35 km处的城郊交错区景观破碎化程度最高。景观破碎化格局的分析有助于了解大城市快速发展阶段的景观格局演变规律,为城市生物多样性保护、绿地廊道维护和生态文明城市建设提供理论依据。     

基于MSPA与最小路径方法的巴中西部新城生态网络构建

目前快速城市化导致了生境斑块的日益破碎化,景观之间的连通性不断降低。构建生态网络可以连接破碎的生境斑块,增加绿地景观的连通性,对生物多样性保护具有重要意义。以高度景观破碎化的四川省巴中西部新城为研究区,采用形态学空间格局分析(MSPA)方法,提取出对研究区生态网络构建具有重要生态意义的核心区和桥接区两类景观要素,并选用整体连通性(IIC)、可能连通性(PC)和斑块重要性(d I)等景观指数,分别对核心区和桥接区进行景观连接度评价,遴选出对维持景观连通性贡献最大的10个核心区生境斑块作为生态网络的源地,并根据斑块对维持景观连通的重要性程度将其他核心区和桥接区进行类型划分,以此作为景观阻力的赋值依据,融入消费面模型中,最后采用最小路径方法构建了研究区潜在的生态网络,并基于重力模型对重要生态廊道进行了识别与提取,在此基础上有针对性地提出了生态网络优化的对策。研究结果表明,MSPA方法能够科学的辨识出研究区内对生态保护具有重要意义的结构性要素,例如作为物种栖息地的核心区和物种迁移通道的桥接区,这些要素是生态网络的重要组成部分;景观连通性的计算,明确了研究区景观要素的保护重点,为最小路径方法中的景观阻力赋值提供了重要的参考信息;基于MSPA与最小路径方法的生态网络分析框架综合了现有景观结构性要素识别、连通性分析以及物种潜在迁移路径分析等方法,将景观中潜在的生态源地和结构性廊道的连通性作为构建生态网络的重要基础和主要依据,从而使得生态网络的构建更科学。研究结果可为高度破碎化地区生态网络的构建提供重要的参考与依据,对其他地区生态网络的构建也具有一定的借鉴意义。     

Open Space Loss and Land Inequality in United States' Cities, 1990–2000

Urban growth reduces open space in and around cities, impacting biodiversity and ecosystem services. Using land-cover and population data, we examined land consumption and open space loss between 1990 and 2000 for all 274 metropolitan areas in the contiguous United States. Nationally, 1.4 million ha of open space was lost, and the amount lost in a given city was correlated with population growth (r(272) = 0.85, P<0.001). In 2000, cities varied in per capita land consumption by an order of magnitude, from 459 m²/person in New York to 5393 m²/person in Grand Forks, ND. The per capita land consumption (m²/person) of most cities decreased on average over the decade from 1,564 to 1,454 m ²/person, but there was substantial regional variation and some cities even increased. Cities with greater conservation funding or more reform-minded zoning tended to decrease in per capita land consumption more than other cities. The majority of developed area in cities is in low-density neighborhoods housing a small proportion of urban residents, with Gini coefficients that quantify this developed land inequality averaging 0.63. Our results suggest conservation funding and reform-minded zoning decrease per capita open space loss.     

On the horns of a dilemma: molecular approaches refine ex situ conservation in crisis

Seven years into this new millennium, species and habitat loss continue at an accelerated rate. While there have been individual examples of conservation success, the trend towards catastrophic loss of biological diversity persists. If we are to be successful in saving even a handful of critically endangered species, it is clear that they will need to be intensively managed using a variety of in situ and ex situ approaches. The highest profile ex situ conservation strategy is captive breeding. Although its relative role in an overall conservation management plan varies, captive breeding may present the only viable option for propagating the future of a species once rendered extinct in the wild. The study of Iyengar et al. in this issue of Molecular Ecology on one such species, the scimitar-horned oryx (Oryx dammah), represents an important contribution to ex situ conservation, demonstrating how critical insights into demographic history and population genetic structure obtained using molecular approaches may significantly contribute to captive breeding and reintroduction strategies.     

Genetic diversity is overlooked in international conservation policy implementation

The importance of genetic variation for maintaining biological diversity and evolutionary processes has been recognized by researchers for decades. This realization has prompted agreements by world leaders to conserve genetic diversity, and this is an explicit goal of the Convention on Biological Diversity (CBD). Nevertheless, very limited action has been taken to protect genetic diversity on a global scale. International conservation efforts to halt biodiversity loss focus on habitats and species, whereas little or no attention is paid to gene level variation. By this year, 2010, world leaders have agreed that a significant reduction of the rate of biodiversity loss should have been achieved. However, gene level diversity is still not monitored, indicators that can help identify threats to genetic variation are missing, and there is no strategy for how genetic aspects can be included in biodiversity targets beyond 2010. Important findings and conclusions from decades of conservation genetic research are not translated into concrete conservation action in the arena of international policy development. There is an urgent need for conservation geneticists worldwide to become involved in policy and practical conservation work beyond the universities and research institutions.     

Safety in numbers? Supplanting data quality with fanciful models in wildlife monitoring and conservation

Ecologists and conservation biologists seem increasingly attracted to sophisticated modelling approaches, sometimes at the expense of attention to data quality and appropriateness of fieldwork design. This dissociation may lead to a loss of perspective promoting biological unrealities as conclusions, which may be used in conservation applications. We illustrate this concern by focusing on recent attempts to estimate population size of breeding birds at large scales without any explicit testing of the reliability of the predictions through comparison with direct counts. Disconnection of analysts from “nature” can lead to cases of biological unrealities such as that used here to illustrate such trends. To counter this risk, we encourage investment in well-rounded scientists or more collaborative, multi-disciplinary teams capable of integrating sophisticated analyses with in-depth knowledge of the natural history of their study subjects.     

IUCN and perspectives on biodiversity conservation in a changing world

Biodiversity conservation is not a clear-cut practice and there is no blueprint solution to the question how to best halt the loss of biological diversity. Various conservation approaches are surrounded by a variety of basic assumptions about the world, nature and the human-nature relationship. These assumptions are more often implicitly hidden in practices and discourse than purposefully produced and deployed at a conscious level. The aim of our paper is to contribute to the on-going discussion on how to halt the loss of biodiversity in a dynamic global socio-ecological system. We will present an analysis of the worldview(s) and management style(s) of the oldest and largest global conservation organization: the International Union of Nature Conservation (IUCN). Popular in many conservation organisations is the strategy of integrating conservation in policy, business and society. Our discourse analysis demonstrates that although IUCN employs a strongly pluralistic practice of conservation, it is difficult to speak of a truly integrative approach yet.     

Arthropod biodiversity loss and the transformation of a tropical agro-ecosystem

The coffee (Coffea arabica) agro-ecosystem in the Central Valley of Costa Rica was formerly characterized by a high vegetational diversity. This complex system has been undergoing a major transformation to capital-intensive monocultural plantations where all shade trees are eliminated. In this study we examined the pattern of arthropod biodiversity loss associated with this transformation. Canopy arthropods were sampled in three coffee farms: a traditional plantation with many species of shade trees, a moderately shaded plantation with only Erythrina poeppigeana and coffee, and a coffee monoculture. An insecticidal fogging technique was used to sample both canopy and coffee arthropods. Data are presented on three major taxonomic groups: Coleoptera, non-formicid Hymenoptera, and Formicidae. Data demonstrate that the transformation of the coffee agro-ecosystem results in a significant loss of biological diversity of both canopy arthropods as well as arthropods living in coffee bushes. Percentage of species overlap was very small for all comparisons. Furthermore, species' richness on a per tree basis was found to be within the same order of magnitude as that reported for trees in tropical forests. If results presented here are generalizable, this means that conservation efforts to preserve biological diversity should also include traditional agro-ecosystems as conservation units.     

A conceptual framework for urban ecological restoration and rehabilitation

Urban greenspace has gained considerable attention during the last decades because of its relevance to wildlife conservation, human welfare, and climate change adaptation. Biodiversity loss and ecosystem degradation worldwide require the formation of new concepts of ecological restoration and rehabilitation aimed at improving ecosystem functions, services, and biodiversity conservation in cities. Although relict sites of natural and semi-natural ecosystems can be found in urban areas, environmental conditions and species composition of most urban ecosystems are highly modified, inducing the development of novel and hybrid ecosystems. A consequence of this ecological novelty is the lack of (semi-) natural reference systems available for defining restoration targets and assessing restoration success in urban areas. This hampers the implementation of ecological restoration in cities. In consideration of these challenges, we present a new conceptual framework that provides guidance and support for urban ecological restoration and rehabilitation by formulating restoration targets for different levels of ecological novelty (i.e., historic, hybrid, and novel ecosystems). To facilitate the restoration and rehabilitation of novel urban ecosystems, we recommend using established species-rich and well-functioning urban ecosystems as reference. Such urban reference systems are likely to be present in many cities. Highlighting their value in comparison to degraded ecosystems can stimulate and guide restoration initiatives. As urban restoration approaches must consider local history and site conditions, as well as citizens’ needs, it may also be advisable to focus the restoration of strongly altered urban ecosystems on selected ecosystem functions, services and/or biodiversity values. Ecosystem restoration and rehabilitation in cities can be either relatively inexpensive or costly, but even expensive measures can pay off when they effectively improve ecosystem services such as climate change mitigation or recreation. Successful re‐shaping and re-thinking of urban greenspace by involving citizens and other stakeholders will help to make our cities more sustainable in the future.     

广西水土保持植物材料试验研究初报

植物措施能有效地防止水土流失。本文根据水土保持植物措施的新思路和新模式,选用和配置水土保持植物材料,研究其生态经济效益。     

Psychological benefits of greenspace increase with biodiversity

The world's human population is becoming concentrated into cities, giving rise to concerns that it is becoming increasingly isolated from nature. Urban public greenspaces form the arena of many people's daily contact with nature and such contact has measurable physical and psychological benefits. Here we show that these psychological benefits increase with the species richness of urban greenspaces. Moreover, we demonstrate that greenspace users can more or less accurately perceive species richness depending on the taxonomic group in question. These results indicate that successful management of urban greenspaces should emphasize biological complexity to enhance human well-being in addition to biodiversity conservation.     

Establishing the evidence base for maintaining biodiversity and ecosystem function in the oil palm landscapes of South East Asia

The conversion of natural forest to oil palm plantation is a major current threat to the conservation of biodiversity in South East Asia. Most animal taxa decrease in both species richness and abundance on conversion of forest to oil palm, and there is usually a severe loss of forest species. The extent of loss varies significantly across both different taxa and different microhabitats within the oil palm habitat. The principal driver of this loss in diversity is probably the biological and physical simplification of the habitat, but there is little direct evidence for this. The conservation of forest species requires the preservation of large reserves of intact forest, but we must not lose sight of the importance of conserving biodiversity and ecosystem processes within the oil palm habitat itself. We urgently need to carry out research that will establish whether maintaining diversity supports economically and ecologically important processes. There is some evidence that both landscape and local complexity can have positive impacts on biodiversity in the oil palm habitat. By intelligent manipulation of habitat complexity, it could be possible to enhance not only the number of species that can live in oil palm plantations but also their contribution to the healthy functioning of this exceptionally important and widespread landscape.