基于遥感数据的晋陕蒙交汇区景观格局定量分析--以东胜幅1/25万TM影像分析为例

以1996年8月份东胜幅1/25万TM影像数据为例,借助Arc/Info和Arc/view软件,对其景观进行了分类,并形成景观分类图,共分为9类景观类型.用景观格局分析软件FRAGSTATS计算了各类景观参数,并从斑块、类型和景观3个水平上计算了相应的参数和景观指数,定量地揭示了整个景观格局与类型特征.并构建了反映景观破碎化程度的一个指数--斑块密度指数(PD2).     

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.     

景观指数之间的相关分析

应用辽宁省1997~1998年的TM 5影像数据,编制了景观类型图,以78个县市区为单位,分割成78个景观,共计算39个景观格局指数,对它们进行了相关分析。总面积是最基本的景观指数,它决定景观总边界长度、斑块数、类型密度等基本指数,同时与多个指数有显著的相关关系(相关系数绝对值大于0.75)。形状指数的独立性强,极少数指数与其它指数有显著的相关关系;多样性指数和蔓延度指数之间信息重复量最多,都表示景观的异质性,但多样性指数以面积百分比表示景观异质性,而蔓延度指数以类型之间相邻边界的百分比表示景观异质性。研究发现,如果两个指数之间存在显著的相关关系,而由它们两个构成的指数与它们之间没有显著的相关关系。如果指数平均值之间存在显著的相关关系,则它们的变异系数之间不存在显著的相关关系。景观指数间的相关系数不仅与景观格局本身有关,还与空间尺度,分类系统、计算公式及其参数、计算单元和生态学意义关系密切。指数之间影响因子的相同之处越多,它们之间存在显著相关关系的概率越大。     

河口湿地人为干扰度时空动态及景观响应——以大洋河口为例

以大洋河河口湿地作为研究对象,利用1958年、1970年、1984年航摄影像(空间分辨率:2.0 m)和2008年SPOT5影像(空间分辨率:5.0 m)作为数据源,借助人为干扰度指数(HI)、景观格局分析、GIS空间分析方法,探讨大洋河河口湿地人为干扰度时空动态分异及景观格局指数的响应机制。结论:1)全干扰类型面积从1958年的4.16 km2上升至9.16 km2;半干扰类型从115.82 km2上升至180.57 km2;而无干扰类型面积从1958年的291.23 km2下降至221.13 km2,人为干扰度在不同历史时期呈非均质化变化,人类活动干扰中心逐渐由陆向海过度;围海养殖是人类干扰度变化的主控景观因子;2)在时间上,人类干扰过程(全干扰、半干扰)会导致斑块数量(NP)、边缘密度指数(ED)、平均形状指数(MSI)和面积加权的平均斑块分形指数(AWMPFD)总体在1958年—2008年间呈下降趋势;3)空间上,人为干扰度指数与景观格局指数空间分布相关性大小依次为:斑块数量(NP)边缘密度指数(ED)面积加权的平均斑块分形指数(AWMPFD),呈正相关,平均形状指数(MSI)与人为干扰度相关性不显著。     

庙岛群岛北五岛景观格局特征及其生态效应

海岛由于自然特征的空间差异、人类活动的日益增强以及生态系统的脆弱性,其景观格局空间分异性明显且生态效应趋于复杂。以庙岛群岛北五岛为研究区,基于现场调查和3S技术,从景观尺度、海岛尺度和区块尺度分析海岛景观格局空间特征,进而探讨景观格局与净初级生产力(NPP)、植物多样性和土壤性质的关系。结果显示:(1)不同尺度景观格局均表现出了空间差异。景观尺度上,针叶林、阔叶林和草地3类植被景观面积最大,斑块密度、边缘密度和平均形状指数总体较高,建筑用地也具有较大规模,其斑块密度较高,平均形状指数处于最低值,裸地也具有一定规模,其各项景观指标处于中间位置;海岛尺度上,随着海岛面积、人口和GDP的增加,斑块密度和人为干扰指数均明显增大;区块尺度上,斑块密度、边缘密度和平均形状指数与海拔呈显著正相关,人为干扰指数与海拔和坡度均呈显著负相关。海岛面积、地形和人类活动分别是北五岛景观格局的基本因子、重要限制因子和直接驱动因子。(2)海岛景观格局的生态效应与尺度密切相关。景观尺度上,各项生态效应指标在不同景观类型上均具有显著差异,海岛尺度上的生态效应指标对景观格局的响应不甚灵敏;区块尺度上,生态效应指标与景观格局指数表现出了显著的简单相关性和偏相关性,但二者结果具有差异。NPP和土壤水分主要受到景观类型和植被生长状况的影响,多样性和土壤养分同时受到景观类型和景观格局破碎度、边缘效应的影响,人为活动强度的增大地带来了各项生态效应指标的降低。控制建设规模、优化景观布局与改进开发利用方式是维系海岛生态系统稳定性的重要措施。     

Fractal properties of forest spatial structure

The definition of fractal dimension of natural objects, which enables to deal with scale dependence of fractal dimension is discussed. Abrupt changes of fractal dimension of spatial structure of terrestrial ecosystems are considered in the context of hierarchical paradigm. On this ground the procedure is proposed for segmentation of a territory, which takes into account the scale dependence of spatial variability of ecological parameters. Using remotely sensed data — normalized difference vegetation index (NDVI) and thermal radiation in the infrared band — fractal dimensions and critical scales are evaluated for different forest types with the help of software, developed for this purpose. The results obtained corroborate the potentialities of fractal approach in ecology. These methods and results can be used for discrimination of remotely sensed data; but further investigations, including detailed comparison of fractal characteristics of remotely sensed forest images with results of on-site field studies are necessary to validate them.     

桂西北喀斯特区域景观结构特征与石漠化的关系

采用典范对应分析方法（CCA）,从景观类型和景观两个层次选取了16个景观格局指数来表征景观结构特征,分析了广西省环江县喀斯特区域的景观结构与石漠化强度的关系.结果表明,平均斑块面积、平均旱地斑块面积、景观形状指数和聚集度指数与CCA排序的前两个排序轴相关性强,对区域石漠化过程具有重要影响.研究区潜在石漠化主要与平均旱地斑块面积、平均旱地斑块分维数和平均灌木林地斑块分维数呈较强的正相关,与旱地斑块数呈负相关;轻度石漠化与分维数、平均未利用地斑块分维数和灌木林地斑块数的正相关性较强;中度石漠化和重度石漠化主要与平均未利用地斑块面积呈正相关、与平均灌木林地斑块分维数呈负相关,说明景观结构特征对土地石漠化程度具有一定的指示意义.排序分析结果较清晰地解释了研究区石漠化程度沿景观结构特征梯度的变化规律.     

川西丘陵区景观空间格局分析

采用分形维数、平均斑块面积、形状指数和伸张度分析了川西不同丘陵地貌区灌溉水田、一般旱地、果园、有林地和农村居民点斑块的空间格局特征,并用分形维数、平均斑块面积和Shannon-Weiner指数3种方法研究了浅丘、中丘和高丘的综合景观特征。结果表明,不同景观斑块在同一丘陵区内的格局特征不同,同一景观斑块在3种丘陵区的格局也有差异。浅丘、中丘和高丘的综合景观格局特点是随着地势起伏的增加、人类活动和土地利用强度的减弱,分形维数增加,从1.1865到1.3123;斑块平均面积则依次变小,从2.2204hm^2减少到1.2403hm^2。3种丘陵区的景观多样性指数分别为1.7199、1.9802和2.0898。     

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1～50 m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Shannon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.     

北京平原造林后景观格局与热场环境的耦合分析

在人类积极的土地利用调控下(植树造林),研究景观格局变化对城乡热场环境的影响,可为今后的城市造林工程建设与优化提供参考,并为未来景观格局与热场环境的相关研究提供新视角.本研究以北京平原区百万亩造林项目为背景,运用遥感技术和地理信息系统,利用矩阵转移及耦合分析,评估平原造林对城市热场环境的实际作用,探究因城市造林工程引起的景观格局变化与城市地表温度变化的相关关系.结果表明: 北京平原造林工程后,森林和公园的面积比例分别增加了7.6%和0.5%;平原区有19.2%区域热场强度降低,其中,城郊有23.3%区域的热场强度减弱,但仍有23.5%的城市区域存在热场增强的情况;在城乡尺度上,森林和公园面积比例、森林和湿地的平均斑块面积(MPS)与地表亮温(LST)变化呈显著负相关;在城市市区,森林的面积加权平均形状指数(AWMSI)与LST变化呈显著正相关;在城郊区域,森林的MPS和AWMST与LST变化均呈显著负相关,而公园则相反.北京实施平原造林工程后,增加的城市森林和公园对城市热场的缓解有一定作用,但范围有限,主要集中在城郊区的造林点周围,且森林与湿地越集中,越有利于热场的缓解;受研究粒度、时相、地形、人类活动等因素影响,土地利用结构调控引起的景观格局变化与地表温度变化之间存在非线性相关.     

近40年艾比湖湿地自然保护区生态干扰度时空动态及景观格局变化

以新疆艾比湖湿地为研究区,利用1972、1998、2007年及2013年4个时期的Landsat遥感影像作为数据源,并结合湿地的土地覆被状况,参考《全国土地利用分类》建立艾比湖湿地生态干扰类型分类系统。借助生态干扰度指数、景观格局指数以及GIS空间分析方法,探讨艾比湖湿地的生态干扰度的时空动态及景观响应机制。结果表明:(1)1972—2013年,研究区的生态干扰度总体呈现较为稳定的趋势,但其空间分布发生变化。生态干扰度类型之间的转化速率有加快的趋势。(2)1972—2013年,边缘密度指数(ED),平均形状指数(MSI),面积加权的平均斑块分形指数(AWMPFD)及景观分离度(DIVISION)4项景观格局指数大体呈上升的趋势,2013年区域的景观指数较为稳定。(3)景观格局指数与生态干扰程度有密切的一致性。生态干扰度与景观格局指数空间分布相关性大小依次为:边缘密度指数(ED)景观丰度密度(PRD)香农多样性指数(SHDI)平均形状指数(MSI)面积加权的平均斑块分形指数(AWMPFD)景观分离度(DIVISION)。客观系统的认识和评价艾比湖湿地的生态系统及环境,可为干旱区实现自然环境的保护,协调土地利用及环境保护之间的关系提供较为实用的参考。     

The Fractal Dimension as a Measure of the Quality of Habitats

Habitat fragmentation produces isolated patches characterized by increased edge effects from an originally continuous habitat. The shapes of these patches often show a high degree of irregularity: their shapes deviate significantly from regular geometrical shapes such as rectangular and elliptical ones. In fractal theory, the geometry of patches created by a common landscape transformation process should be statistically similar, i.e. their fractal dimensions and their form factors should be equal. In this paper, we analyze 49 woodlot fragments ( Pinus sylvestris L. ) in the Belgian Kempen region to study the direct relationship between a transformation process and the concomitant patch geometry. Although the fractal dimension of the woodlots is scattered (i.e. they are not statistically similar), the perimeter-area relation of the fragments is characterized by a single, 'dimension-like' exponent. This exponent suggests a certain shape homogeneity among the patches, which is confirmed by the absence of hierarchical levels associated with sharp increases of the fractal dimension at scale transitions. The interaction of different natural (soil factor, vegetation type) and anthropogenic (afforestation, urbanization) processes during patch development is assumed to have generated this feature. Comparison of the area and perimeter fractal dimension with an ecological index for habitat quality, the interior-to-edge ratio, shows that the fractal dimension is suitable for predicting interior habitat presence, which is more likely for patches with smooth perimeters and compact areas. The ratio of the area to the perimeter fractal dimension confirms this observation, with high values for high interior-to-edge ratios, characteristic for regularly shaped patches.     

北京地区植被景观中斑块形状的指数分析

选取４个斑块形状指数（斑块的击长面积比ＳＩ１、斑块周长与等面积的圆周长之比ＳＩ２和身份个斑块分维ＳＩ３和ＳＩ４）并借助ＧＩＳ软件ＡＲＣ／ＩＮＦＯ对北京地区植被景观中的斑块形状进行分析,又地这四个形状指数进行 ｅａｒｓｏｎ相关分析和Ｓｐｅａｒｍａｎ秋相关分析,结果表明,ＳＩ１与ＳＩ４,ＳＩ２与ＳＩ３两两之间均呈显著的正的秩相关,ＳＩ１与ＳＩ２,ＳＩ２与ＳＩ４,ＳＩ３与ＳＩ４两两之间于垢负和秩相关。因     

不同尺度下城市景观综合指数的空间变异特征研究

在GIS与RS技术支持下,采用5 m分辨率的SPOT遥感图像数据,从城市土地利用角度,利用半变异函数对不同尺度的景观多样性、聚集度与分维数的空间变异进行了定量分析.结果表明,不同尺度下3种指数的空间变异具有相似特征,各个尺度上都具有空间依赖性,尺度越小,空间依赖性越大,空间变异的细节更显著,空间自相关性对总体变异的贡献逐渐增加,但尺度过小,有时会破坏景观内部结构.不同指数的半变异函数模型在相同尺度上差异显著,说明不同景观指数在不同尺度下的半变异函数模型不具可比性.就研究上海市内部土地利用结构而言,1 km的幅度是较合适的空间尺度.景观指数空间变异特征是尺度的函数,尺度对景观格局的影响不能忽视.景观综合指数对尺度响应的生态过程揭示了上海城市空间结构的规律性:在小尺度上的复杂无规律性,中尺度上的多中心性和大尺度上的圈层结构性,但各个尺度是相互依赖的,没有绝对界限.     

中国城市空间形态的环境效应

中国城市需要更为紧凑的空间形态,但是城市空间紧凑性的环境效应并不十分清晰。采集城市管网设施指标、城市道路、交通设施指标、生态协同指标等建立环境因子指标集,选择标准化紧凑度指数NCI、标准化离散度指数NDIS、最大斑块面积指数LPI、景观形状指数LSI、平均形状指数SHAPE_MEAN、周长-面积分形维数PAFRAC等形态指标,运用统计分析的方法探索中国146座城市的空间形态的单因子环境效应、综合环境效应及环境效应的差异性。研究结果表明:(1)人均城市道路面积、供水管密度、排水管密度、万人拥有公交车辆、万人拥有出租车辆、人均公园绿地面积等环境因子与城市空间形态密切相关。城市紧凑度越高,城市管网系统密度越低,公共交通设施越少,人均公园绿地面积越少。城市形状越复杂,城市管网系统密度越高,公共交通投入越大,人均公园绿地面积越大。(2)综合环境因子与LSI呈中等强度的正相关(r=0.43,P0.01)。城市空间形状越复杂,城市资源环境相关设施总体投入越多。(3)在不同的紧凑及形状复杂性水平下,万人拥有公交车辆、万人拥有出租车辆、供水管道密度及综合环境因子的显著性差异再次表明城市越紧凑,交通越发达;城市形状越复杂,环境投入越多。本文研究证明了城市空间形态越紧凑、资源越是节约,紧凑型城市空间形态能够用于中国城市建设。     

Fractal dimension as an indicator for quantifying the effects of changing spatial scales on landscape metrics

While geographers and ecologists are well aware of the scale effects of landscape patterns, there is still a need for quantifying these effects. This paper applies the fractal method to measure the scale (grain or cell size) sensitivity of landscape metrics at both landscape and class levels using the Gold Coast City in Southeast Queensland, Australia as a case study. By transforming the original land use polygon data into raster data at eleven aggregate scales, the fractal dimensions of 57 landscape metrics as defined in FRAGSTATS were assessed. A series of linear log–log regression models were constructed based on the power law to obtain the coefficient of determination (COD or R²) of the models and the fractal dimension (FD) of the landscape metrics. The results show that most landscape metrics in the area and edge, shape and the aggregation groups exhibit a fractal law that is consistent over a range of scales. The six variations of several landscape metrics that belong to both the area/edge and shape groups show different scale behaviours and effects. However, the metrics that belong to the diversity group are scale-independent and do not accord to fractal laws. In addition, the scale effects at the class level are more complex than those at the landscape level. The quantitative assessment of the scale effect using the fractal method provides a basis for investigating landscape patterns when upscaling or downscaling as well as creating any scale-free metric to understand landscape patterns.     

Using a sub-pixel mapping model to improve the accuracy of landscape pattern indices

The assessment of landscape spatial patterns is a key issue in landscape management. Landscape pattern indices (LPIs) are tools appropriate for analyzing landscape spatial patterns. LPIs are often derived from raster land cover maps that are extracted from remotely sensed data through hard classification. However, pixel-based hard classification methods suffer from the mixed pixel problem (in which pixels contain more than one land cover class), making for inaccurate classification maps and LPIs. In addition, LPIs generated by hard classification methods are characterized by grain sizes (the sampling unit sizes) that limit the derived landscape pattern to a certain scale. Sub-pixel mapping (SPM) models can enable fine-scale estimation of the spatial patterns of land cover classes without requiring additional data; hence, this is an appropriate downscaling method for land cover mapping. The fraction images generated by soft classification estimate the area proportion of each land cover class within each pixel, and using these images as input enables SPM models to alleviate the mixed pixel problem. At the same time, by transforming fraction images into a finer-scaled hard classification map, SPM models can minimize the influence of grain size on LPIs calculation. In this research, simulated landscape thematic patterns that can provide different landscape spatial patterns, eight commonly used LPIs and a SPM model that maximizes the spatial dependence between neighbouring sub-pixels were applied to assess the efficiency of deriving LPIs from sub-pixel model maps. Results showed that the SPM model can more precisely characterize landscape patterns than hard classification methods can. Landscape fragmentation, class abundance, the uncertainty in SPM, and the spatial resolution of the remotely sensed data influenced LPIs derived from sub-pixel maps. The largest patch index, landscape division, and patch cohesion derived from remotely sensed data with different spatial resolutions through the SPM model were suitable for inter-comparison, whereas the patch density, mean patch area, edge density, landscape shape index, and area-weighted mean shape index derived from the sub-pixel maps were sensitive to the spatial resolution of the remotely sensed data.     

Fractal approach to the description of the auroral region

The plasma of the auroral region, where energetic particles precipitate from the magnetosphere into the ionosphere, is highly inhomogeneous and nonstationary. In this case, traditional methods of classical plasma physics turn out to be inapplicable. In order to correctly describe the dynamic regimes, transition processes, fluctuations, and self-similar scalings in this region, nonlinear dynamics methods based of the concepts of fractal geometry and percolation theory can be used. In this work, the fractal geometry and percolation theory are used to describe the spatial structure of the ionospheric conductivity. The topological properties, fractal dimensions, and connective indices characterizing the structure of the Pedersen and Hall conductivities on the nightside auroral zone are investigated theoretically. The restrictions imposed on the fractal estimates by the condition of ionospheric current percolation are analyzed. It is shown that the fluctuation scalings of the electric fields and auroral glow observed in the auroral zone fit well the restrictions imposed by the critical condition on the percolation of the Pedersen current. Thus, it is demonstrated that the fractal approach is a promising and convenient method for studying the properties of the ionosphere.     

Variation of folded polypeptide surface area with probe size

Three types of polypeptide surface area (contact, accessible, and molecular) have been studied as a function of the radius of a probe sphere used to map the surface. The surfaces are: (1) three alpha-helices, the H-helix of myoglobin, the E-helix of leghemoglobin, and an artificial polyalanine helix, each with 26 residues; (2) two globins, myoglobin and leghemoglobin, each with 153 residues; and (3) a two-center model system for which the three types of surface area have been calculated analytically. The two globin helices have almost identical surface areas as a function of probe size as do the two globins. The polyalanine helix surface area is smaller but similar in shape to the globin helix areas. All three helix contact areas tend to the same limit as the probe size increases, and the globin contact areas behave similarly. Fractal dimensions were calculated for the helix and globin contact and molecular surfaces. All fractal dimensions showed strong dependence on probe size. The contact fractal dimension peaks at larger values for both the helices and globins. Most residues do not make contact with large probes (15 A).