农业景观异质性对地表节肢动物多样性影响的最优尺度分析

农业景观均质化与破碎化是近代农田生物多样丧失的重要原因之一。为明确景观异质性对地表节肢动物多样性的影响,对下辽河平原典型农区——昌图县地表节肢动物多样性与不同尺度景观异质性进行相关性分析。结果表明：1000 m为研究景观指数对农田地表节肢动物多样性影响的最优尺度;地表节肢动物Simpson多样性指数与景观香农多样性指数呈极显著相关(P<0.01),与蔓延度指数、香农均匀度指数呈显著相关(P<0.05)。表明农业景观异质性强、斑块类型复杂且存在优势斑块时,农田中地表节肢动物多样性较高且分布均匀;地表节肢动物Shannon多样性指数与景观香农多样性指数呈极显著相关(P<0.01),地表节肢动物Margalef丰富度指数与景观香农多样性指数呈显著相关(P<0.05)。表明农业景观中景观破碎化程度低、斑块类型数较少、各斑块类型复杂性及变异性低时,农田地表节肢动物的物种数较高,群落较复杂。     

景观格局指数间相关关系对植被覆盖度等级分类数的响应

运用景观指数进行景观格局分析已成为景观生态学的主要研究方法。但是,由于景观本身的复杂性以及景观格局指数之间的相关性,其应用与发展受到制约。选用面积/周长/密度、形状和蔓延度等3类共28个指数,以广州市中心城区为研究区域,以TM遥感影像为数据源形成植被覆盖度等级图,在景观类型水平上探讨各类型内指数之间的相关性及其对景观分类数的敏感程度。相关性分析表明:景观格局指数间都存在一定的相关性,但是相关程度差异较大,其中面积/周长/密度类指数间的相关性最强,蔓延度类指数其次,形状类指数间独立性相对较强。敏感性分析结果显示:117个指数对的相关关系都随景观分类数发生变化,根据其变化类型和程度,可以分为简单型、分段型、复杂型等3种指数关系响应的类型,分别包括12、31和74对指数;敏感曲线还表明4或5是指数对之间相关关系最敏感的分类数;不仅如此,分类数对景观格局指数之间相关关系的影响程度因景观格局指数所属的类别而异,面积/周长/密度类型指数不敏感,其次是蔓延度类指数,最敏感的是形状类指数;最后,研究结果表明景观格局指数间的相关性对分类数的敏感性存在较大的空间变异。     

太湖流域典型入湖港口景观格局对河流水质的影响

以太湖流域宜兴段的3条主要入湖港口为研究对象,通过实地调查和数据分析,探讨了入湖港口景观格局对河流水质的影响。反映景观格局的指标有港口周边5 km缓冲区域内的"源-汇"景观空间负荷对比指数(LCI)、斑块数量(NP)、边界密度(ED)、蔓延度指数(CONT)、香浓多样性指数(SHDI)和聚集度指数(AI);反映水质变化的主要指标为总氮(TN)、总磷(TP)和化学需氧量(CODMn)。以水质指标为因变量,对二者做了相关性分析和通径分析,结果表明,LCI与TN、TP和CODMn关系显著,对它们的直接作用分别为0.266、1.512和0.979;ED对TN、CODMn和NH+4-N有显著影响,直接作用为0.740、-0.189和0.852;TN和NH+4-N与CONT相关性显著,与SHDI呈负的极显著相关;对TN和NH+4-N来说,两个景观格局指标(LCI与景观格局指数)对它们都呈直接负作用;其它指标之间关系不显著。这说明景观格局变化对区域内港口水质有一定影响,合理配置景观格局能够有效地治理面源污染,改善水质状况。     

不同干扰背景下农业景观异质性——以巩义市为例

景观异质性包括景观组成和构型的异质性,而人为干扰是形成异质性景观的主要影响因素。以河南省巩义市为例,在以建成区、农田、丘陵和山地为主体的景观中各选取一个4km×4km的样区,采用移动窗口算法,以100、250、500、1000、1250m和1500m为移动窗口半径,借用蔓延度(CONT)和均匀度(SHEI)指数,分析了不同干扰背景下景观异质性的空间变化特征。结果表明:随着移动窗口半径的增大,各景观类型的蔓延度和均匀度指数的最大值逐渐递减,最小值逐渐递增(建成区除外);建成区和农田景观蔓延度指数的平均值均大于丘陵和山地景观,均匀度指数的平均值则相反;4种类型景观的均匀度指数和蔓延度指数都呈显著相关关系,除建成区1000m及以上移动窗口半径外,R2都大于0.9;拟合曲线的β值基本呈递增趋势。文中对于人为干扰强度的差异性和景观异质性的尺度依赖性分析,为构建合理的景观格局提供了理论依据。     

黄土丘陵小流域景观格局指数的粒度效应

采用基于GIS的景观格局分析法,研究了1975—2007年黄土丘陵沟壑区大南沟小流域景观格局指数在1～50m粒度范围内的粒度效应.结果表明:研究区小流域景观格局指数的粒度效应明显,不同年份之间的差异显著;该区景观格局指数的粒度效应可分为5种类型,即稳定不变型、平稳降低型、波动降低型、波幅增强型和不规则变化型.研究区景观的斑块丰富度属于稳定不变型,即随着粒度增大保持不变;边界长度、边界密度、景观形状指数、聚合度指数和蔓延度指数属于平衡降低型,即随着粒度增大呈显著的线性降低趋势;分维数随粒度增大呈波动递减趋势,属于波动降低型粒度效应;景观总面积、Shannon多样性指数和Shan-non均匀度指数的波幅呈显著增大趋势,属于波幅增强型粒度效应;不规则变化型粒度效应的景观格局指数包括斑块数、斑块密度、平均斑块面积、最大斑块指数、破碎度指数和景观分离度指数.1975年研究区上述景观格局指数的粒度效应与其他年份之间的差异显著,甚至截然相反.     

二维与三维景观格局指数在山区县域景观格局分析中的应用

景观格局指数是景观格局分析中常用的定量分析工具,而传统二维景观格局指数却忽略了地形对景观的影响,在定量描述山区景观格局时可能存在一定局限.本文以典型山地丘陵区山东栖霞市为研究区,在地形结构分析的基础上,选择面积/密度(类型面积、平均斑块大小)、边缘/形状(边缘密度、景观形状指数、平均斑块分维数)、多样性(香农多样性指数、香农均匀度指数)、聚散性(聚集度)4个方面的8个景观格局指数,比较分析传统二维景观格局指数与三维景观格局指数对山区景观格局及其动态变化定量描述的差异.结果表明:三维类型面积、平均斑块大小和边缘密度与其相应二维指数差异显著,三维景观形状指数、平均斑块分维数、香农多样性指数和香农均匀度指数与其相应二维指数差异不显著,三维聚集度与二维聚集度无差别.由于采用斑块表面面积和表面周长计算三维景观格局指数,采用各斑块的投影面积和投影周长计算二维景观格局指数,所以在描述山区景观面积、密度、边界等指标时三维景观格局指数相对精确,但在测定景观形状、多样性和聚散性等指数时,则与传统的二维景观格局指数差异不显著.三维景观格局指数引入了地形特征,对景观格局及其动态变化的反映相对精确.     

传统景观格局指数在城市热岛效应评价中的适用性

以北京部分城区为研究对象,以QuickBird影像制作景观类型图,基于同年4个季节的Landsat ETM+数据反演地表温度;将120 m×120 m作为固定窗口,计算其中的景观格局指数,探寻传统景观格局指数解释地表温度的适用性.结果表明:在景观水平计算的24个景观格局指数中,只有景观组成百分比(PLAND)、斑块密度(PD)、最大斑块指数(LPI)、欧氏距离变异系数(ENN_CV)和分离度(DIVISION)与3月、5月、11月的地表温度具有稳定的显著相关.在类型水平计算的24个景观格局指数中,PLAND、LPI、DIVISION、相似邻接百分比、分散与并列指数与4个时相(3月、5月、7月和12月)的温度显著相关,且与7月温度的相关性最强;斑块密度、边界密度、聚簇度、凝聚度、有效MESH大小、分裂度、聚合度、归一化景观形状指数依据不同景观类型而与地表温度呈现相关性.传统景观格局指数可能并不适合评估河流对地表温度的影响.一些景观格局指数可以用来表征城市地表温度,辅助分析城市地表热岛效应,但需要对其进行筛选和甄别.     

三峡库区典型农林流域景观格局对径流和泥沙输出的影响

以三峡库区秭归县25个典型农林复合小流域作为研究对象,斑块类型水平上选取斑块面积比例指数(PLAND),景观水平上选取斑块丰富度密度(PRD)、双对数回归分维数(DLFD)、Shannon-Weaver多样性指数(SHDI)、聚集度(CONT)等5类景观指数,基于遥感和GIS技术,应用AnnAGNPS(Annualized AGricultural Non-Point Source)模型模拟流域径流和泥沙输出,FRAGSTATS软件计算流域景观格局指数,SPSS19.0分析景观指数和径流、泥沙的相关回归关系,从景观水平探讨景观格局特征对径流、泥沙输出的影响。结果表明：流域径流量与农坡地PLAND、农梯地PLAND、农林梯地PLAND、居民地PLAND、CONT等指数显著正相关,林地PLAND、灌木地PLAND与径流量显著负相关;农坡地PLAND、农林梯地PLAND、居民地PLAND、CONT等与泥沙输出量显著正相关,林地PLAND、灌木地PLAND、SHDI等与泥沙显著负相关。景观指数(因子)与径流和泥沙输出量复相关系数R为0.856和0.962(均高度相关),复相关系数R均大于相对应的单因子相关系数。流域景观水平上,景观格局对径流和泥沙输出影响均显著,景观空间格局是景观功能多样性的反馈,本文是景观格局影响生态过程(径流、泥沙输出)的又一例证。     

浑善达克沙地中部斑块格局影响植物多样性及功能性状

景观格局与植物多样性之间的关系已被广泛研究, 然而, 斑块格局如何影响植物多样性, 以及这些影响的边缘类型差异尚不清楚。为从植物功能性状角度揭示斑块格局影响植物多样性的机制, 该研究采用不同边缘类型的斑块, 利用两年调查的705个样方数据, 结合遥感卫星图像解译和空间信息分析, 根据植物群落的空间位置和斑块格局, 按照向内、向外、向内成核和向外成核4种边缘类型将浑善达克沙地中部的斑块进行分类, 采用Duncan新复极差法比较了4种边缘类型斑块格局与植物功能性状多样性关系的差异, 应用Pearson相关系数和冗余分析(RDA)法量化了斑块格局对植物多样性的影响。结果发现, 植物丰富度和多样性指数与斑块格局密切相关, 这些关系存在着边缘类型的显著差异, 表现出不同的功能性状。对于向内边缘, 边缘指数与丰富度负相关, 和C₄植物比例正相关; 对于向外边缘, 边缘指数与C₄植物比例正相关; 对于向内成核边缘, 边缘密度与多年生植物和虫媒植物比例正相关; 对于向外成核边缘, 边缘角度和指数与物种Shannon-Wiener指数和Simpson指数正相关, 与Pielou指数、丰富度和动物传播植物比例负相关。这些发现表明, 斑块格局通过边缘效应影响植物多样性, 这种影响可以通过植物功能性状进行一定的解释。在景观管理、植被恢复和生物多样性保护方面需要考虑这些因素。     

三峡库区典型流域“源”“汇”景观格局时空变化对侵蚀产沙的影响

以三峡库区王家桥流域为研究对象,基于五期遥感影像(1995、2000、2005、2010和2015)提取流域景观格局,采用马尔科夫模型研究"源""汇"景观格局时空变化,并结合野外多年实测数据建立景观格局指数与产沙量之间的关系,分析景观格局对流域侵蚀产沙的影响。结果表明:1995—2015年,王家桥流域景观格局时空变化明显,呈破碎化发展趋势。"源"景观面积持续下降,"汇"景观面积持续增长。在降雨量时序曲线相似的条件下,斑块类型尺度的景观指数对侵蚀产沙量的解释能力高于景观尺度。斑块类型尺度,"源""汇"景观指数与径流输沙量的复相关系数分别为0.946和0.903,均显著相关。对于"源"景观而言,相似邻近百分比(PLADJ)与斑块结合度(COHESION)是影响流域侵蚀产沙的重要指标。径流输沙量与PLADJ和COHESION指数呈正相关关系,输沙量随指数的增大而增大。对于"汇"景观而言,斑块密度(PD)、边界密度(ED)、景观形状指数(LSI)是影响流域侵蚀产沙的重要指标,径流输沙量与PD和LSI呈负相关关系,输沙量随着指数的增大而减小。斑块类型尺度上,流域景观格局时空变化对泥沙输出影响显著。研究结果可为建立其他流域景观格局变化与土壤侵蚀响应关系提供参考。     

The Role of Landscape Patterns of Habitat Types on Plant Species Diversity of a Tropical Forest in Mexico

The relationships among landscape characteristics and plant diversity in tropical forests may be used to predict biodiversity. To identify and characterize them, the number of species, as well as Shannon and Simpson diversity indices were calculated from 157 sampling quadrats (17,941 individuals sampled) while the vegetation classes were obtained from multi-spectral satellite image classification in four landscapes located in the southeast of Quintana Roo, Mexico. The mean number of species of trees, shrubs and vines as well as the mean value of the total number of species and the other two diversity indices were calculated for four vegetation classes in every one of the four landscapes. In addition, the relationships between landscape patterns metrics of patch types and diversity indices were explored. The multiple statistical analyses revealed significant predictor variables for the three diversity indices. Moreover, the shape, similarity and edge contrast metrics of patch types might serve as useful indicators for the number of species and the other two diversity variables at the landscape scale. Although the association between the three diversity indices and patch types metrics showed similar behavior, some differences were appreciated. The Shannon diversity index, with its greater sensitivity to rare species, should be considered as having a greater importance in interpretation analysis than Simpson index.     

Entropy increase of fragmented habitats: A sign of human impact?

Analysis of a recently validated fragmentation index, named ‘coherence’, shows a direct relationship with the Simpson and Shannon indices. Since these diversity metrics are also denoted as ‘entropy metrics’, it can be accepted that patch size heterogeneity can adequately be described by an entropy metric. Since both indices are used to determine the entropy of a sample, the Brillouin index should be applied instead to correctly determine the entropy of a landscape pattern, this because this latter index is developed for fully censused data sets, such as landscapes when a complete coverage by cartographic data or imagery is available. Calculation of the Brillouin entropy index for three specific sites located in Cadiz Township (USA), the Poole Basin (Dorset, UK) and Sao Paulo State (Brazil), respectively, and using long-term data of patch size diversity, reveals increasing entropy levels associated with anthropogenic land cover dynamics (fragmentation). The observed entropy trends defy the laws of thermodynamics and signal the impact of human action on landscape integrity.     

Landscape pattern and eco-hydrological charactedstics at the upstream of Minjiang River,China

Based on three scenes of Landsat 5 Thematic Mapper (TM) satellite images acquired on June 26,1994,12 land cover types were identified by the supervised classification techniques.The precipitation,runoff,and normalized difference vegetation index (NDVI) data of six catchments were accumulated from April to September in 1992,1993,and 1995.A new eco-hydrological index,expressed by the difference between precipitation and runoff divided by the product of precipitation and NDVI,was used in this study to represent the eco-hydrological functions of different catchments.The results were:(1) The selected six catchments at the upstream of Minjiang River,China were different in landscape patterns in terms of landscape type and cover.There were higher contagion,lower edge density and diversity index in the Shouxi catchments and lower contagion,higher edge density and diversity index in the Zagunao catchments.(2)Eco-hydrological indexes had remarkable differences among different catchments.The highest eco-hydrological index was found in the Shouxi catchments,which indicated higher precipitation holding capacity of vegetation therein.While the lower eco-hydrological index was found in the Zagunao catchments,which indicated its lower precipitation holding capacity of vegetation.(3) High correlation was detected between the landscape indexes and eco-hydrological indexes.Eco-hydrological index was positively correlated with landscape contagion in contrast with the negative correlation with landscape diversity and edge density.     

广州地区森林景观多样性分析

景观多样性是生物多样性的重要研究内容和组成部分 ,它是对景观水平上生物组成多样性的表征[1～ 3 ] 。由于生物多样性是人类赖以生存的物质基础 ,生物多样性保护已成为现代生态学和环境科学的研究热点。但是 ,以往的研究主要集中在物种多样性和生态系统多样性方面 ,对景观多样性的研究相对较少[1～ 4 ,12 ] 。森林是陆地生态系统的主体和重要的可再生资源 ,森林的类型、空间分布及斑块的数目和形状对区域的生态平衡有较大影响。广州是我国人口稠密、经济高速增长的区域。研究广州地区森林景观多样性有利于了解人类活动严重干扰下的森林景观…     

土地整理项目区的景观格局及其生态效应

目前项目角度的土地整理生态效应评价较少,受到研究幅度的制约,而且已有研究中对景观格局优化目标和生态效应的系统分析较少.选择典型的土地整理项目作为研究案例,以GIS和景观指数为研究手段,结合景观格局优化目标建立相应的指标体系,对土地整理的生态效应进行评价.研究表明,土地整理项目的生态效应指标体系包括提升生物多样性、维持物质和能量流通、维持景观格局稳定、提升生活环境品质、提高生态服务价值等5个方面.研究区土地整理具有正效应和负效应,最大斑块面积提高、斑块密度减少、聚集度提高、廊道宽度和连通度提高、缓冲区宽度增加、植被覆盖增加、合理功能分区是土地整理的正效应,而景观多样性降低、分维数减少和生态服务价值降低是其负效应.因此,在土地整理规划和设计时应融入景观设计和生态保育思想.     

Landscape pattern and eco-hydrological characteristics at the upstream of Minjiang River, China

Based on three scenes of Landsat 5 Thematic Mapper (TM) satellite images acquired on June 26, 1994, 12 land cover types were identified by the supervised classification techniques. The precipitation, runoff, and normalized difference vegetation index (NDVI) data of six catchments were accumulated from April to September in 1992, 1993, and 1995. A new eco-hydrological index, expressed by the difference between precipitation and runoff divided by the product of precipitation and NDVI, was used in this study to represent the eco-hydrological functions of different catchments. The results were: (1) The selected six catchments at the upstream of Minjiang River, China were different in landscape patterns in terms of landscape type and cover. There were higher contagion, lower edge density and diversity index in the Shouxi catchments and lower contagion, higher edge density and diversity index in the Zagunao catchments. (2) Eco-hydrological indexes had remarkable differences among different catchments. The highest eco-hydrological index was found in the Shouxi catchments, which indicated higher precipitation holding capacity of vegetation therein. While the lower eco-hydrological index was found in the Zagunao catchments, which indicated its lower precipitation holding capacity of vegetation. (3) High correlation was detected between the landscape indexes and eco-hydrological indexes. Eco-hydrological index was positively correlated with landscape contagion in contrast with the negative correlation with landscape diversity and edge density. __________ Translated from Acta Ecologica Sinica, 2005, 25(4): 691–698 [译自: 生态学报, 2005, 25(4): 691–698]     

Spatio‐temporal analysis of the relationship between landscape structure and the olive fruit fly Bactrocera oleae (Diptera: Tephritidae)

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