漫湾水电开发对库区景观动态的影响

基于GIS、RS技术,以云南漫湾水电站为例,对电站建设前后库区景观格局及其变化特征进行了研究.结果表明:1974-2004年的30年中,林地与灌丛面积呈现减少趋势,草地、农田、水域和建设用地呈现增加的趋势;在景观总体呈现破碎化与离散分布的前提下,电站建设后景观多样性和均匀度指数均较电站建设前有所降低,景观破碎化程度和景观类型离散分布的趋势减缓;景观类型相互转化频繁,主要表现为林地、灌丛和草地之间的转化.水电站建设后库区综合景观动态度降低,景观类型动态度以建设用地、草地和农田较高.总之,漫湾水电站建设后库区景观格局发生了显著的变化,研究结果对科学认识水电开发的景观生态效应具有重要的意义.     

Deforestation in central Chile causes a rapid decline in landscape connectivity for a forest specialist bird species

The abundance of woodland birds in fragmented forest landscapes may depend on the properties of patch networks. Understanding the consequences of deforestation on woodland birds, therefore, necessarily requires determining which changes in landscape structure make a major contribution to the degradation and subdivision of patch networks. In this study, we addressed how accelerated deforestation in central Chile has modified the landscape structure and function for thorn-tailed rayaditos—a woodland specialist bird. Using a graphical approach based on the habitat use and movement patterns of rayaditos, we quantified the reduction of the internal connectivity of components (i.e., connected patch networks) in the last two decades and determined the main mechanisms responsible for this connectivity loss. Forest cover decreased 61.7 % between 1989 and 2009. The component size, the fraction of components with ≥1 occupied patches and the number of patches per component experienced a large decline during the study period. Over time, most forest cover (ca. 80 %) was contained in only two components. The connectivity of components decreased steeply by 90 %. Only the loss of large patches made a highly significant contribution to explaining changes in connectivity, while the removal of stepping stones was marginally significant. The conversion of forest both to shrubland and to peri-urban areas were the only land-use variables explaining connectivity change with effects that changed over time. Conservation measures to ensure persistence of rayaditos populations in central Chile should be focused on the retention of key elements for connectivity.     

汉江流域景观格局变化对土壤侵蚀的影响

在流域尺度上,景观格局变化是决定土壤侵蚀程度的重要因素。以汉江流域为研究区域,基于2000—2015年四期土地利用类型数据及环境气象数据,运用中国土壤流失方程和逐步回归法,探究景观格局变化对土壤侵蚀的影响。结果表明:(1)在2000—2015年间,汉江流域土壤侵蚀量下降,高值区分布在流域中部草地区,低值区分布在流域东西两侧的林地和耕地区。不同坡度下各等级土壤侵蚀量不同,侵蚀量最大值出现在10—30°的坡度范围内。(2)研究期间,汉江流域的景观破碎化程度加强,斑块形状趋于简单,各斑块自身连通性增强,景观类型空间分布均匀。(3)汉江流域土壤侵蚀量与斑块密度和平均邻接度指数呈正相关,与蔓延度指数和香农均匀度指数呈负相关,即景观破碎度越高、连通性越差,土壤越容易遭受侵蚀,反之则不易受到侵蚀;研究表明景观格局变化对土壤侵蚀有显著影响,结果可为流域尺度景观管理与水土保持研究提供参考。     

黑河中游生态用地景观连接性动态变化及距离阈值

景观连接度描述了景观组分在景观格局、过程和功能上的有机联系.本文利用1986、2000和2011年土地覆被数据,基于图论方法,研究了黑河中游生态用地(林地、草地、湿地)景观连接性动态变化,并通过分析不同阈值下景观连接度值的变化揭示了研究区景观的适宜阈值.结果表明: 黑河中游1986—2011年对景观连接度产生重要作用的生态斑块面积呈减少趋势.湿地斑块面积2000—2011年减少幅度较大;草地斑块数量先减少后增加,面积变化不大,但是有斑块破碎化的趋势.不同阈值下景观连接度值的变化验证了距离阈值的正向作用.400～800 m是研究黑河中游物种扩散和生态流运行的适宜距离阈值.选择600 m作为距离阈值时,大型斑块对区域总体景观连接水平影响最为显著,是区域生态系统稳定和健康的关键组成;小型生态斑块虽然占生态斑块总面积的比例不大,但对区域的生态安全格局的维持和改善有较大影响,亦需加强保护与管理.研究结果对干旱区生态系统管理具有重要的借鉴意义.     

Landscape connectivity dynamics based on network analysis in the Xishuangbanna Nature Reserve,China

Lack of landscape connectivity and habitat loss is major threats to biodiversity and ecosystem integrity in nature reserves aimed at conservation. In this study, we used structural pattern and functional connectivity metrics to analyze the spatial patterns and landscape connectivity of habitat patches for the Shangyong sub-reserve of the Xishuangbanna Nature Reserve from 1970, 1990, and 2000. On the basis of vegetation and land cover data, we applied the equivalent connected area ECA(PC) indicator to analyze the changes in forest connectivity. Four distance thresholds (2, 4, 8, 12 km) were considered to compare the patch importance of connectivity by dECA values. The results showed the declining trends of landscape connectivity measured by ECA(PC) index from 1970 to 2000. The importance of connectivity in each forest patch varied with the increment of dispersal distances at the patch level, and some important habitat patches, which exhibit a potential to enhance landscape connectivity, should be given more attention. The least-cost pathways based on network structure were displayed under four dispersal distances in three periods. The results showed that the number of paths among the fragments of forest patches exhibited radical increases for larger dispersal distances. Further correlation analyses of AWF, ECA (IIC), and ECA (PC) showed the weakest and least-frequent correlations with the structural pattern indices, while H presented more significant correlations with the PD fragmentation metric. Furthermore, Kendall's rank correlations between the forest patch area and functional connectivity indicators showed that dECA (PC) and dAWF indicators should provided the area-based prioritization of habitat patches. Moreover, the low-rank correlations showed that dF and dLCP can be considered as effective and appropriate indicators for the evaluation of habitat features and network patterns.     

基于景观连接度的森林景观恢复研究——以巩义市为例

景观连接度是研究景观促进或阻碍生物体或某种生态过程在斑块间运动的程度。基于景观连接度原理,借用景观连接度指数,在地理信息系统支持下,探讨了巩义市丘陵和低山地区森林景观在不同景观距离阈值下连接度的变化,确定了分析森林景观连接度的合适距离阈值。在此基础上分析了要恢复为森林景观的农业斑块的重要值的大小,确定了对要恢复为森林景观的每一农业景观斑块对新形成的森林景观的连接度贡献大小,并结合区域地形特征,明确了森林恢复之初的重要斑块的选取及恢复的先后次序。结果显示,在不同的距离阈值下,低山地区森林景观的整体连通性指数值(IIC)都大于丘陵地区森林景观的IIC值;森林景观的适宜距离阈值,在丘陵地区可选择750 m,在低山地区可选择500 m,或者更小尺度;通过农业景观斑块重要值(dIIC)确定的对森林景观连接度作用起"非常高"和"高"的斑块的数量非常少,但对森林景观连接度的贡献作用却比较大。提出的基于景观连接来分析在森林恢复时重要斑块的选取的方法,具有一定的可操作性与实用性,对区域生态恢复和生态建设具有重要意义。     

千岛湖生态保护与建设对景观格局的影响研究

生态保护和生态建设过程对景观格局产生影响并使之发生变化,这种变化又会影响景观的生态过程。应用3s技术和景观指数分析了39年(1964-2003年)内千岛湖库区土地利用和土地覆盖格局的变化。结果显示,斑块总数和景观破碎度基本保持不变,但是各斑块类型的斑块数量、面积和优势度变化非常显著。最优势斑块类型由荒山(占陆地面积的47．44％)演变为马尾松( Pinus massoniana)林(占陆地面积的52．8l％),研究区域内森林植被覆盖率增加。研究还发现景观多样性指数略微下降。景观多样性是对土地利用和覆盖类型丰富度和均匀度的概要度量,并不一定总是和景观功能呈正相关关系。上述变化归因于多项生态保护措施的实施使得自然演替得以实现。景观格局的优化使生态系统的生态功能得到提高,包括生境恢复、生物多样性增加、水土流失减少。森林植被恢复以后,马尾松林斑块的单一化趋势应在今后的生物多样性保护、生态规划和可持续发展中得到重视。     

滇西北纳帕海湿地景观格局变化及其对土壤碳库的影响

采用3S技术和In-situ原状土就地取样技术,对滇西北纳帕海湿地26a来的景观格局变化及其驱动下的湿地土壤碳库变化研究表明:纳帕海景观格局变化显著,与1974年相比,景观破碎化程度增强、斑块形状趋于复杂、呈离散分布,湿地景观类型总面积比例呈略有增加(1994年)至大幅减小(2000年)的变化,非湿地景观类型总面积比例则呈略有减小(1994年)至大幅增加(2000年)的变化并取代湿地景观成为基质景观.响应景观类型面积变化,土壤碳储量由1974年的33.46×104 t增至1994年的36.91×l04 t,2000年降至32.92×104 t;随景观类型的转化,1974-1994年土壤碳库积累量为6.08×104 t,择放量为2.63×104 t,1994-2000年积累量为2.01×l04 t,但碳释放量为5.99× 104 t,是前20a的2.28倍.纳帕海湿地景观格局和土壤碳库的变化是自然和人为因素共同作用的结果,在地质、水文和气候等自然因素提供的变化背景上,排水、垦殖、过度放牧、无序旅游、汇水区植被破坏等强烈的人为活动干扰加剧了变化.     

黔中喀斯特山地城市景观稳定性评价与特征分析

城市景观稳定性是对城市生态环境进行分析和评价的基础,对城市景观生态安全格局和景观可持续性具有十分重要的意义。以典型喀斯特山地城市贵阳市为研究对象,以2008年、2013年和2017年景观类型为主要数据。运用蔓延度指数、斑块密度和总边缘对比度构建景观稳定性评价模型,在分析2008-2017年景观格局变化状况的基础上评价景观稳定性时空特征。并运用探索性空间数据分析方法揭示贵阳市景观稳定性时空演变规律和冷热点特征。结果表明:(1)2008-2017年贵阳市景观格局发生剧烈变化,耕地面积大幅减少,林地和建设用地面积持续增加,景观破碎化程度加剧,但破碎化趋势有所减缓。(2)10年间,贵阳市景观稳定性水平整体较低,以不稳定和较不稳定为主,表现出"先降低、后提高,总体略有降低"的趋势。(3)贵阳市景观稳定性的空间分布与演变具有明显空间聚集效应,全局Moran''s I指数介于0.2008-0.4005之间,但聚集趋势呈"总体减弱,小幅提高"的特征;此外,景观稳定性热点区主要集中在城镇建设用地或林地斑块相对集中连片、完整的区域。研究结果可为喀斯特山地城市景观空间格局优化、生态安全网络格局构建和生态文明城市建设提供重要的科学依据。     

长白山风灾景观30年格局变化过程分析

以长白山自然保护区内的由1986年台风形成的风灾景观为研究对象。选取1987年、1993年、1999年、2004年、2010年和2016年遥感影像进行解译。利用Fragstats 4.2软件对景观格局指数进行定量分析,并用主成分分析法与景观综合评价指数相结合的方法对景观格局变化做出综合评价,揭示风灾后30年景观格局变化过程。结果表明：(1)草本-灌木的优势度不断下降;阔叶林和针叶林在恢复过程中先以增加大斑块为主,后期面积增加主要是以小斑块为主;岳桦林恢复过程中先以增加小斑块为主,后期以大斑块连片生长。(2)小而分散的斑块在恢复过程中转换为大而集中的斑块,景观趋于均质化。(3)草本-灌木,阔叶林,针叶林,岳桦林四种斑块类型在恢复过程中呈现一种演替关系。(4)确定了分别与景观规模、形状和景观聚散度相关的两个主成分,作为表征景观恢复性的关键指标。(5)在30年的恢复期中,研究区整体景观格局质量得到提升,但恢复缓慢,与风灾前依然相差较大。(6)多次强风干扰可以形成长白山西、南坡非标准的垂直带谱。     

Landscape connectivity and the role of small habitat patches as stepping stones: an assessment of the grassland biome in South America

Connectivity losses lead to a reduction of the amount of habitat resources that can be reached and used by species, and hence to a decline in the ranges and abundance of multiple taxa. Despite the recognized important role of small habitat patches for many species inhabiting fragmented landscapes, their potential contribution as stepping stones for maintaining overall landscape connectivity has received less attention. Using connectivity metrics based on a graph-theoretic approach we (i) quantified the connectivity of grassland patches in a sector of the Pampa region in Argentina, using a range of dispersal distances (from 100 to 10,000 m) representative of the scale of dispersal of different species; (ii) identified the most relevant patches for maintaining overall connectivity; and (iii) studied the importance of small patches (defined for different area thresholds of 5, 20, and 50 ha) as connectivity providers in the landscape. Although grassland patches were in general poorly connected at all distances, some of them were critical for overall connectivity and were found to play different crucial roles in the patch network. The location of small patches in the grassland network allowed them to function as stepping stones, yielding significant connectivity gains for species that move large distances (>5000 m) for the three area thresholds considered. Thus, under the spatial pattern of the studied landscape, species that move long distances would benefit from stepping stones, while less mobile organisms would benefit from, and mostly rely on the largest patches. We recommend that future management activities should (i) aim at preserving the grassland patches with the highest potential as stepping stones to promote landscape-level connectivity; and (ii) pay more attention to the conservation of key small patches, particularly given that usually they are those more vulnerable to land clearing for agriculture.     

沈阳城市森林景观连接度距离阈值选择

利用2006年沈阳市QuickBird遥感影像城市森林解译数据,借助地理信息系统,以沈阳市三环以内区域城市森林景观斑块为研究对象,基于生境可利用性和动植物的扩散能力,选取50、100、200、400、600、800、1000、1200 m 8个距离阈值,采用整体连通性指数、可能连通性指数和景观中各斑块的重要性对研究区城市森林景观连接度的距离阈值进行了分析和筛选.结果表明：2006年沈阳城市森林景观连接度的适宜距离阈值范围在100～400 m,以200 m尤为适宜.距离阈值的选择可因城市森林景观连通性的可执行性和不同层次需求而适当增大或减小.     

北京城市景观格局时空变化及驱动力

2004—2020年城市总体规划以来,北京经历了快速的城市化发展期,城市景观格局发生了很大变化。采用TM遥感影像为信息源,通过RS解译建立了2003、2007和2011年北京市土地利用覆盖空间数据,利用Fragstats对景观格局特征指数进行了计算和分析,分别从全市域和六环内城市化典型地区两个尺度研究了北京市城市景观格局时空变化特征,结合社会经济、城市总体规划和城市发展政策因素,分析了北京城市景观格局变化的驱动力因素。研究结果表明,过去近10年,市域景观特征发生了深刻变化,建设用地保持较快的增长速度,其比例由15.0%上升至18.0%,相反耕地面积比例由21.3%下降至18.8%。林地一直是市域的优势景观类型,比例维持在51%以上。而六环内城市化典型地区的景观变化更加明显,建设用地比例增加近10%,是六环地区的优势景观类型,耕地比例相应减少10%。建设用地的增长主要以耕地占用为主。景观格局指数的分析表明,大尺度和小尺度的景观格局变化表现出不同的特征,市域大尺度建设用地斑块破碎化程度高,景观蔓延度、聚合度下降,景观多样性增加;而小尺度六环内的建设用地斑块破碎化趋势降低,景观蔓延度和聚合度上升,但景观多样性下降迅速。大小两个尺度的景观空间形态均表现出复杂性增加的趋势。通过景观格局变化的驱动因素分析,人口规模的增加、产业结构调整、城市总体规划的实施以及城市发展政策的变化是导致景观格局变化的主要因素。     

新疆叶尔羌河流域胡杨林时空格局特征

叶尔羌河流域胡杨林对保障我国新疆南疆地区生态安全有着重要的功能,到目前对该区胡杨林时空格局特征规律的研究极少。基于1995—2015年Landsat TM/OLI长时间序列遥感监测数据,通过土地利用程度变化指数、转移矩阵以及景观指数对叶尔羌河流域胡杨林时空格局变化进行动态监测与分析。结果表明:(1)胡杨林面积从1995年的1916.15 km~2减少到2015年的1652.25 km~2,面积减少了263.90 km~2。永安坝至夏河林场段,耕地向河道扩张,胡杨林转为耕地;而夏河林场至三河口段,水资源匮乏,胡杨林被迫向河道收缩,转为未利用地。(2)胡杨林动态度和空间动态度降低,而胡杨林变化状态指数、斑块密度、最大斑块指数和散布与并列指数增加,斑块结合度指数高,胡杨林空间分布逐渐集中、破碎度降低、连通性增加。流域景观要素连接性逐渐减弱,破碎化程度较高,优势度斑块类型比例逐渐下降,景观类型向复杂化方向发展。(3)1995—2005年胡杨林受气候变化和人类活动的干扰,胡杨林面积减少较快,景观格局变化剧烈,而2005—2015年胡杨林保护措施的实施、区域产业结构的调整以及生态安全输水区域的扩大等,胡杨林面积减少速度减缓,但形势仍较为严峻。在叶尔羌河流域合理利用水资源,统筹协调生活、生产和生态用水、强化水资源管理力度,以及调整产业结构、控制人口增长速度等是该区胡杨林生态系统恢复的有效手段和途径。研究可以为叶尔羌河流域生态系统恢复以及胡杨林保护提供参考。     

Importance assessment and conservation strategy for rural landscape patches in Huang-Huai plain based on network robustness analysis

With increasing landscape fragmentation, forest-dominated landscape patches between villages play a highly important role in connecting important urban habitats. Unlike urban environments, these rural landscape patches lack targeted protection strategies and face a significant risk of destruction. This study investigates the philosophy of green infrastructure while considering the rural ecological landscape. Specifically, the connectivity of the rural landscape patches was chosen as the research focus. Taking Xuzhou as a case study, potential ecological corridors and stepping stones were identified through the circuit theoretical model and a multi-level green infrastructure network was constructed. Two important stepping-stone networks were selected from the multi-level green infrastructure network and robustness analysis was performed under three scenarios (centrality destruction, risk destruction, random destruction). By comparing the changes in network indices (connectivity robustness, global efficiency, articulation vertices, assortativity), the more important landscape patches in villages were screened out and corresponding protection strategies were developed. The results revealed that forest landscape patches near rivers had high centrality and were at risk of destruction; accordingly, in the process of village construction and development, the protection of these patches should be prioritised. The results also reflect the importance of forest patches in some villages. This result provides support for rural planning and site selection in concentrated residential areas.     

岷江上游景观边界网络格局分析

格局与过程是景观生态学研究的核心内容,与基于斑块的研究相比,基于边界的研究是格局与过程研究的一个新的切入点.以岷江上游地区为例,基于TM影像数据,应用RS、GIS、Fragstats等软件,选用边界长度、边界密度、边界海拔、结点数量、网眼大小、网络连接度等指数,研究了景观边界网络格局的变化,并分析了与之相关的生态过程.结果表明,在1974～2000年期间,由于人为干扰强度的加剧,岷江上游景观边界网络结构变得更加复杂,在早期以边界长度增加为主,网络连接度变大,在后期以边界数量和结点数量增加为主,网络连接度变小;森林景观与低坡位景观类型间的边界减少,森林下线上移;农田与林地的边界在早期增加,1986年后减少,而与灌木林地的边界持续增加;随着林地的蚀退,森林结构变得简单化,而农田、灌木林地、草地等景观类型的结构变得更加复杂.     

景观格局视角下晋西三川河流域径流变化归因分析

黄土高原大规模人类活动造成下垫面剧烈变化,流域景观格局改变,影响产汇流过程。学科融合视角下,基于Budyko水热耦合方程、景观指数计算以及回归分析等多学科方法,以晋西黄土丘陵沟壑区三川河流域为例,分析不同尺度景观格局变化造成流域径流量变化的原因,判别地理景观空间对产汇流过程的影响。结果表明：(1)1980年至今是研究区径流锐减阶段,其中下垫面变化对径流贡献率为60.81%;(2)1980年至今的下垫面变化造成流域景观斑块破碎、形状趋于规整,景观格局分割度、蔓延度提高;(3)利用逐步线性回归模型可将径流减少的景观格局变化定位到具体地理空间,流域东部、北部主要支流上游与两条支流汇流处的林地核心斑块面积减少以及城市建设区域对于水体连通性的破坏。通过跨学科方法探究景观格局与径流变化之间的潜在空间关联,揭示径流对景观格局变化的响应,可为黄土高原水资源管理与生态规划提供决策依据。     

闽三角林地景观结构与功能连接度的空间耦合关系

以闽三角地区为例,为探讨景观连接度不同评价方法的科学性,提出一种基于最小耗费距离模型的成本距离指数表征景观功能连接度,并与传统的基于景观格局指数的景观结构连接度度量指标进行比较,揭示两者的空间耦合关系,为景观连接度的有效评价提供支持。结果表明：(1)2000—2020年,林地与其他土地利用类型之间发生不同程度的转化,林地转为建设用地370.72km²,占总转出面积的77.28%;草地和耕地转为林地80.45km²,占总转入面积的90.53%。(2)20年间,林地景观结构与功能连接度总体呈减小趋势,其中,湖里区林地景观结构与功能连接度降幅均最大,斑块密度、最大斑块指数、聚合度指数和斑块结合度指数分别下降了76.47%、51.33%、68.13%和68.40%,成本距离指数增加了178.56%。(3)成本距离指数与斑块密度、最大斑块指数、聚合度指数、斑块结合度指数和景观结构连接度综合指数均为负相关。(4)在研究期间,双变量局部空间自相关聚集类型由低-高转化为高-高,结构连接度无变化时,景观功能连接度降低;由高-高转化为低-高,结构连接度无变化时,...     

Landscape-level comparison of genetic diversity and differentiation in a small mammal inhabiting different fragmented landscapes of the Brazilian Atlantic Forest

Habitat loss and fragmentation can have detrimental effects on all levels of biodiversity, including genetic variation. Most studies that investigate genetic effects of habitat loss and fragmentation focus on analysing genetic data from a single landscape. However, our understanding of habitat loss effects on landscape-wide patterns of biodiversity would benefit from studies that are based on quantitative comparisons among multiple study landscapes. Here, we use such a landscape-level study design to compare genetic variation in the forest-specialist marsupial Marmosops incanus from four 10,000-hectare Atlantic forest landscapes which differ in the amount of their remaining native forest cover (86, 49, 31, 11 %). Additionally, we used a model selection framework to evaluate the influence of patch characteristics on genetic variation within each landscape. We genotyped 529 individuals with 12 microsatellites to statistically compare estimates of genetic diversity and genetic differentiation in populations inhabiting different forest patches within the landscapes. Our study indicates that before the extinction of the specialist species (here in the 11 % landscape) genetic diversity is significantly reduced in the 31 % landscape, while genetic differentiation is significantly higher in the 49 and 31 % landscapes compared to the 86 % landscape. Results further provide evidence for non-proportional responses of genetic diversity and differentiation to increasing habitat loss, and suggest that local patch isolation impacts gene flow and genetic connectivity only in the 31 % landscape. These results have high relevance for analysing landscape genetic relationships and emphasize the importance of landscape-level study designs for understanding habitat loss effects on all levels of biodiversity.     

道路对林地景观连接度的影响——以巩义市为例

基于景观连接度原理,借用景观连接度指数,在地理信息系统支持下,探讨了巩义市山区林地景观在不同距离阈值下连接度的变化,定量分析了道路对林地景观连接度的影响。结果显示,随着景观距离阈值的增大,无论是否有道路,林地景观整体可能连通性指数值都表现为逐渐增大;对林地景观连接度起"非常高"和"高"作用的林地斑块数量都比较少,但占林地总面积比例较大,面积大的林地斑块在提高景观连接度中起的作用较大;道路的分割使得林地斑块重要值降低,就单一斑块而言,随着景观距离阈值的增大,分割成的小斑块的重要值降低程度在逐渐减小。