Analysis of Large-Scale Spatial Heterogeneity in Vegetation Indices among North American Landscapes

We analyzed the spatial heterogeneity in vegetation indices among 13 North American landscapes by using full Landsat Thematic Mapper images. Landscapes varied broadly in the statistical distribution of vegetation indices, but were successfully ordinated by using a measure of central tendency (the mean) and a measure of dispersion (the standard deviation or the coefficient of variation). Differences in heterogeneity among landscapes were explained by their topographic relief and their land cover. Landscape heterogeneity (standard deviation of the Normalized Difference Vegetation Index, NDVI) tended to increase linearly with topographic relief (standard deviation of elevation), but landscapes with low relief were much more heterogeneous than expected from this relationship. The latter were characterized by a large proportion of agricultural land. Percent agriculture, in turn, was inversely related to topographic relief. The strength of these relationships was evaluated against changes in image spatial resolution (grain size). Aggregation of NDVI images to coarser grain size resulted in steady decline of their standard deviation. Although the relationship between landscape heterogeneity and explanatory variables was generally preserved, rates of decrease in heterogeneity with grain size differed among landscapes. A spatial autocorrelation analysis showed that rates of decrease were related to the scale at which pattern is manifested. On one end of the spectrum are agricultural, low-relief landscapes with low spatial autocorrelation and small-scale heterogeneity associated with fields; their heterogeneity decreased sharply as grain size increased. At the other end, desert landscapes were characterized by low small-scale heterogeneity, high spatial autocorrelation, and almost no change in heterogeneity as grain sized was increased—their heterogeneity, associated with land forms, was present at a large scale. Received 1 October 1997; accepted 11 February 1998.     

Multiscale Characterization of Land-Use Patterns in China

This article explores the pattern of land use in China to understand the relationships between land use and factors that can be used to predict it. Such understanding is important for development of comprehensive models of land-use dynamics. Correlation and regression analyses are used to identify the most important explanatory variables from a large set of factors generally considered important in predicting the distribution of land use. We found that the spatial distribution of all land-use types in China is best described by an integrated set of biophysical and socioeconomic factors. Specific attention is given to the influence of the scale of analysis on study results. Both data resolution and the extent of the study area influence the discovered relationships. Relationships obtained at a certain scale of analysis therefore may not be directly applied at other scales or in other areas. The relevance of the systematic and quantitative characterization of the land-use patterns in China for the parameterization of spatially explicit land-use models is discussed. Received 20 July 1999; accepted 10 March 2000.     

Land-Use History as Long-Term Broad-Scale Disturbance: Regional Forest Dynamics in Central New England

Human land-use activities differ from natural disturbance processes and may elicit novel biotic responses and disrupt existing biotic-environmental relationships. The widespread prevalence of land use requires that human activity be addressed as a fundamental ecological process and that lessons from investigations of land-use history be applied to landscape conservation and management. Changes in the intensity of land use and extent of forest cover in New England over the past 3 centuries provide the opportunity to evaluate the nature of forest response and reorganization to such broad-scale disturbance. Using a range of archival data and modern studies, we assessed historical changes in forest vegetation and land use from the Colonial period (early 17th century) to the present across a 5000 km² area in central Massachusetts in order to evaluate the effects of this novel disturbance regime on the structure, composition, and pattern of vegetation and its relationship to regional climatic gradients. At the time of European settlement, the distribution of tree taxa and forest assemblages showed pronounced regional variation and corresponded strongly to climate gradients, especially variation in growing degree days. The dominance of hemlock and northern hardwoods (maple, beech, and birch) in the cooler Central Uplands and oak and hickory at lower elevations in the Connecticut Valley and Eastern Lowlands is consistent with the regional distribution of these taxa and suggests a strong climatic control over broad-scale vegetation patterns. We infer from historical and paleoecological data that intensive natural or aboriginal disturbance was minimal in the Uplands, whereas infrequent surface fires in the Lowlands may have helped to maintain the abundance of central hardwoods and to restrict the abundance of hemlock, beech, and sugar maple in these areas. The modern vegetation is compositionally distinct from Colonial vegetation, exhibits less regional variation in the distribution of tree taxa or forest assemblages defined by tree taxa, and shows little relationship to broad climatic gradients. The homogenization of the vegetation, disruption of vegetation-environment relationships, and formation of new assemblages appear to be the result of (a) a massive, novel disturbance regime; (b) ongoing low-intensity human and natural disturbance throughout the reforestation period to the present; (c) permanent changes in some aspects of the biotic and abiotic environment; and (d) a relatively short period for forest recovery (100–150 years). These factors have maintained the regional abundance of shade intolerant and moderately tolerant taxa (for example, birch, red maple, oak, and pine) and restricted the spread and increase of shade-tolerant, long-lived taxa such as hemlock and beech. These results raise the possibility that historical land use has similarly altered vegetation-environment relationships across broader geographic regions and should be considered in all contemporary studies of global change. Received 5 May 1997; accepted 5 August 1997.     

Generation of Spatial Patterns in Boreal Forest Landscapes

Boreal forests are composed of a few plant species with contrasting traits with respect to ecosystem functioning and spatial patterning. Early successional deciduous species, such as birch and aspen, disperse seeds widely, do not tolerate low light and nitrogen availabilities, have rapidly decaying litter, and are highly preferred by herbivores. These later succeed to conifers, such as spruce and fir, which disperse seeds locally, tolerate low light levels and low nitrogen availability, have litter that decays slowly, and are unpalatable to most mammalian herbivores. Although there are also early successional conifers, such as jack pine and Scots pine, the aspen-birch-spruce-fir successional sequence is the most common over much of North America, and (without fir) in Fennoscandia and Siberia. The course of succession in these forests is controlled partly by seed dispersal and selective foraging by mammalian herbivores. Both of these processes are spatially dynamic, but little is known about how their spatial dynamics may affect ecosystem processes, such as nitrogen cycling or productivity. We present spatially explicit models that demonstrate the following: (a) Spatially explicit seed dispersal results in more clumped distribution of tree species and persistence of greater paper birch biomass than uniform seed rain across the landscape. Such results are consistent with current spatially explicit population models of dispersal and coexistence. (b) With localized seed dispersal, the concentrations of available soil nitrogen are distributed in larger patches with sharp transitions from low to high nitrogen availability near patch edges. In contrast, with a uniform seed rain, the distribution of soil nitrogen availability was more uniform and “hotspots” were more localized. Thus, the spatial pattern of an ecosystem process (nitrogen cycling) is determined by seed dispersal and competition for light among competing populations. (c) A dispersing herbivore, such as moose, that selectively forages on early successional deciduous species with high quality litter, such as aspen or birch, and discriminates against late successional conifers, such as spruce or fir, imposes higher-order repeated patterns of plant species and biomass distribution on the landscape. Thus, seed dispersal and herbivore foraging correlate properties in adjacent patches but in different ways, and different spatial patterns emerge. Other processes, such as insect outbreaks, fire, and water flow, also may correlate properties between adjacent patches and result in additional patterns. Received 8 February 1999; accepted 28 May 1999.     

Land Reform and Land-Use Changes in the Lower Amazon: Implications for Agricultural Intensification

Land tenure has been considered one of the key factors that define patterns and change in land-use systems. This paper examines the implications of land reform for household decisions regarding patterns of land use, agricultural intensification, and forest conservation. We look at an Amazonian caboclo settlement in the Lower Amazon that had experienced land reform by the end of the 1980s. Results show that defined land tenure is not enough to guarantee agricultural intensification and forest conservation. In fact, several factors working at different scales are affecting land-use change in the region. At the settlement level, privatization of upland forest has led to an overall increase in cultivated land—pasture and annual crops—and increasing deforestation rates. However, at the farm-property level, different systems of agricultural production—intensive, extensive, or abandonment of land—occur according to availability of labor, and capital, and access to different natural resources.     

贵州典型坝子土地利用强度空间演变及景观格局响应

基于坝子(喀斯特山区受人类活动影响最明显的特殊地貌)尺度较小的特征,运用系统网格法,结合半方差变异函数修正模型,分析贵州省境内3种类型共15个坝子2005、2010、2015年土地利用强度的空间演变特征,揭示贵州岩溶山区典型坝子土地利用强度空间演变的一般规律及其与坝子内部景观格局变化的相互关系.结果表明: 贵州坝子土地利用强度空间动态演变和景观格局响应模式展现出明显的类型差异.总体上,土地利用强度随坝子经济水平由高到低呈梯度递减.微观演变上,市县中心坝子的土地利用强度围绕坝地中心外围呈同心带状先减后增,空间演变趋势为稳定-扩张型;市县周围坝子的土地利用强度以单一“极-轴”为高强度中心,变化兼具增减,演变趋势为波动型;偏远地区坝子的土地利用强度基本稳定不变,甚至小幅减弱,演变趋势为稳定-衰弱型;坝子景观格局与土地利用强度变化因坝区主导功能差异存在5种不同的响应关系模式.研究期间,3种类型坝子土地利用强度的空间演变受自然和人文因子双重控制,各因子之间相互作用形成其空间演变的典型特征.     

土地利用/覆被变化与景观服务:评估、制图与模拟

从景观尺度上探讨生态系统服务功能的研究越来越引起国内外学者的重视.相比生态系统尺度,景观尺度是探索人类活动对土地利用/覆被变化影响、探究可持续景观演变机理和过程的最佳尺度.基于对当前国际学界对景观服务研究进展的系统梳理与分析,本文探讨了景观服务的内涵与分类,并对景观服务价值评估、制图与模拟等研究方法进行归纳与分析,并对景观服务的未来研究趋势进行展望.景观服务研究的未来方向应进一步明确景观服务的内涵及其分类体系,不断完善和发展景观服务评估、制图与模型模拟方法,重点开展景观格局-过程-服务-尺度长期综合研究,继续加强景观生态学及景观经济学等理论与方法在景观服务研究领域中的应用.     

景观空间分析的特征和主要内容

在综合前人对景观空间格局与异质性,景观镶嵌动态,尺度,格局,过程相关等景观生态学基本原理的基础上,初步提出了景观空间分析的框架,认为景观空间分析主要包括景观空间形态分析,空间关系分析与空间构型分析,并对景观空间分析的特征及与一般空间分析之间的关系进行了探讨。     

北京市景观格局演变及其对多种生态系统服务的影响

景观格局是人与自然共同作用的结果,深刻影响着区域的生态系统服务及可持续发展。以高度城市化地区——北京市为案例,选取了粮食生产、水质净化、空气净化、气体调节、生境质量以及休闲娱乐6项重要生态系统服务,采用InVEST （Integrated Valuation of Ecosystem Services and Tradeoffs）、ROS （Recreation Opportunity Spectrum）等模型定量评估了1980-2018年生态系统服务时空分布。通过对北京市景观组成与景观配置指数进行定量分析,进一步探索了景观格局演变对生态系统服务的影响。结果表明：（1）北京市1980-2018年建设用地扩张了120%,建设用地扩张是耕地面积减少的主要原因。景观格局总体上趋于破碎化,斑块形状复杂化,斑块异质性增加;（2）时间上,北京市1980-2018年粮食生产、水质净化、气体调节、生境质量、休闲娱乐5项生态系统服务均呈现下降趋势;空间上,粮食生产呈现东南部较高,西北部较低的分布特征,其余生态系统服务均呈现西北部较高,东南部较低,市中心最低的分布特征;（3）景观水平上,林地、建设用地等景观组成变化对生态系统服务影响最为显著。破碎化指数、多样性指数等景观配置指数对生态系统服务影响最为显著;类型水平上,平均斑块面积、斑块聚集度对生态系统服务影响相对最为显著。总体来讲,通过分析景观格局演变如何影响生态系统服务,为如何通过设计和优化景观格局来提升生态系统服务提供了定量依据,从而为促进区域的景观可持续规划提供理论依据和案例参考。     

云南省维西县塔城镇土地利用/地表覆盖及其空间格局变化研究

利用遥感和地理信息系统,结合野外实地参与式调查,从土地利用类型和空间格局角度,对滇西北维西县塔城镇1990和1999年的土地利用变化进行综合分析。结果表明,塔城镇10年间土地利用类型和空间结构变化较小,仍以有林地为主。但高覆盖度林地、中覆盖度林地和低覆盖度林地的结构发生了变化,低覆盖度林地从9．93％增加到18．30％,增加8．37％;高覆盖度林地减少5．35％;中覆盖度林地减少5．15％,森林植被质量下降。土地利用／地表覆盖景观变化最大的区域在海拔3400m以上的塔城镇的东南角和西南角。景观多样性、优势度降低,景观破碎化程度加深,严重影响该地区滇金丝猴的栖息地。     

稳定与变革：德国景观规划在空间规划中的基础作用及社会变化下的挑战

中国的国土空间规划体系正在经历变革,规划编制和管控技术需要风景园林的视角。针对空间规划和风景园林的衔接问题,通过总结相关文献和报告,介绍德国景观规划的发展经验。德国作为实行空间规划体系的国家其景观规划对自然保护和景观多种功能的平衡做出了重要贡献。研究梳理德国景观规划的目标、层级、基础作用、模块设置以及对社会发展需求的灵敏反应。德国景观规划对中国风景园林衔接新的空间规划体系具有借鉴意义,特别是模块式的任务构建,在各尺度层级保持连贯的目标体系,以及系统地革新理论框架。     

Spatial Variation among Lakes within Landscapes: Ecological Organization along Lake Chains

Although limnologists have long been interested in regional patterns in lake attributes, only recently have they considered lakes connected and organized across the landscape, rather than as spatially independent entities. Here we explore the spatial organization of lake districts through the concept of landscape position, a concept that considers lakes longitudinally along gradients of geomorphology and hydrology. We analyzed long-term chemical and biological data from nine lake chains (lakes in a series connected through surface or groundwater flow) from seven lake districts of diverse hydrologic and geomorphic settings across North America. Spatial patterns in lake variables driven by landscape position were surprisingly common across lake districts and across a wide range of variables. On the other hand, temporal patterns of lake variables, quantified using synchrony, the degree to which pairs of lakes exhibit similar dynamics through time, related to landscape position only for lake chains with lake water residence times that spanned a wide range and were generally long (close to or greater than 1 year). Highest synchrony of lakes within a lake chain occurred when lakes had short water residence times. Our results from both the spatial and temporal analyses suggest that certain features of the landscape position concept are robust enough to span a wide range of seemingly disparate lake types. The strong spatial patterns observed in this analysis, and some unexplained patterns, suggest the need to further study these scales and to continue to view lake ecosystems spatially, longitudinally, and broadly across the landscape.     

中国土地利用格局及其影响因子分析

在遥感技术与 GIS技术的支持下 ,对中国土地利用空间格局及其影响因子进行了分析。首先通过 1∶1 0万中国土地利用数据库经过分层提取 ,生成中国土地利用类型空间分布格局数据库 ,在此基础上对中国土地利用空间格局进行了分析 ;而后在引入景观多样性指数、优势度指数、均匀度指数、破碎度指数的基础上 ,对中国土地利用景观格局进行了定量分析。研究结果表明 :中国土地利用景观多样性指数、优势度指数、均匀度指数、破碎度指数空间分布上具有明显的规律性 :随着人类活动的逐渐增强 ,景观的多样性指数逐渐增加 ,优势度指数逐渐减少 ,破碎度指数逐渐增加 ;而当人类已经彻底改变自然景观 ,多样性指数则逐渐减少 ,优势度指数增加 ,而破碎度指数逐渐减少。同时 ,针对中国土地利用景观格局及其生态背景的特点 ,选择北纬 40°、2 8°和 2 4°三条样带 ,东经 1 0 8°和 1 1 4°两条样带 ,对中国土地利用格局的影响因子进行了分析。     

Spatial Prioritization for Biodiversity Restoration: A Simple Framework Referencing Past Species Distributions

The spatial prioritization of biodiversity restoration sites on a national scale lags behind that of protected areas. We present a simple framework for spatial restoration prioritization using complementarity analysis based on the differences between past and present species distributions and restoration feasibility. In the framework, sites that were not only diverse or unique in the past (high restoration potential), but also have high restoration feasibility (e.g. low anthropogenic pressures) are ranked higher. We applied the framework to endangered bird species that breed in Japan for which distribution data were available from nationwide distribution censuses conducted in 1978 and 1998. The data were compiled in a 20‐km grid resolution across Japan. We incorporated the degree of urbanization and number of farmers as a cost to optimize the sets of cells with regard to restoration feasibility. We successfully identified candidate sets of restoration cells, in which at most six can be allocated for each species under the constraint that the total area selected does not exceed 15% of the degraded cells. At most, 11 cells were allocated for each species under the constraint that restoration cells were within 15% of all ecosystem types. Comparison with the distribution of existing nature restoration sites revealed that only 9.3 or 9.7% (depended on the constraint) of high‐priority cells overlapped cells including existing restoration sites. Our framework provides an objective, efficient method to obtain a testable plan for biodiversity restoration, which might contribute to the attainment of the 2020 target set by the Convention on Biological Diversity .     

景观生态学的核心:生态学系统的时空异质性

1　景观生态学与景观异质性景观生态学是研究在一个相当大的区域内 ,由许多不同生态系统所组成的整体 (即景观 )的空间结构、相互作用、协调功能以及动态变化的生态学新分支[1 ] 。它的出现促进了空间关系模型和理论、空间格局与动态的数据类型的获取以及经典生态学很少涉及的空间尺度检测等方面的发展[2 ] 。Ｒｉｓｓｅｒ等认为景观生态学研究就是异质性的研究[3] 。其实 ,“景观”本身就具有“变化的异质性整体”的含义[4] 。景观生态学集中关注于对生态系统空间关系的研究 ,它把景观视为空间上镶嵌出现和紧密联系的生态系统组合 ,景观可…     

Land-Use History and Forest Regeneration in the Cayey Mountains, Puerto Rico

Although deforestation continues to be a major threat to tropical biodiversity, abandonment of agricultural land in Puerto Rico provides an opportunity to study long-term patterns of secondary forest regeneration. Using aerial photographs from 1937, 1967, and 1995, we determined land-use history for 2443 ha in the Cayey Mountains. Pastures were the dominant land cover in 1937 and <20% of the area was classified as forest. Between 1937 and 1995, forest cover increased to 62% due to widespread abandonment of agriculture. To examine the effect of historic land use on current forest structure and species composition, we sampled secondary forests in 24 abandoned pastures, 9 abandoned coffee plantations and 4 old-growth forest sites. Sites were located on two soil types along an elevational gradient (125–710 m) and included a chronosequence from 4 to over 80 years old. After 25–30 years, basal area and species richness in secondary forest sites derived from abandoned pastures and coffee plantations were similar to old-growth forest sites. The species composition of secondary forests derived from abandoned pastures and coffee plantations remained distinct from old-growth forest. In addition to historic land use, age and elevation were important environmental variables explaining variation in secondary forest species composition. Non-indigenous species were common in recently abandoned pastures and coffee plantations, but their importance declined in the older sites. This study demonstrates that secondary forests on private land can be an important component of the conservation of tropical tree biodiversity. Received 16 June 1999; Accepted 8 October 1999.     

海南岛东北部土地利用与生态系统服务价值空间自相关格局分析

土地利用/覆被变化是全球环境变化的重要原因,对生态系统服务价值空间分布格局有直接影响。以海南岛东北部为研究对象,基于遥感影像数据,应用空间自相关理论定量探讨了土地利用与生态系统服务价值的空间自相关格局和分布特征,并运用双变量空间自相关分析两者之间的空间响应规律。结果表明:2016年海南岛东北部生态系统服务功能总价值为132.09亿元,其中林地构成生态系统服务功能价值的主体,而湿地的单位生态系统服务价值最高。土地利用类型具有显著的空间自相关性(P0.05),不同土地利用类型所表现的空间聚集或异常的区域及范围明显不同,以建设用地和林地的空间聚集性最强。研究区生态系统服务价值在空间上呈显著的正相关性(P0.05),高值区明显聚集于海岸带、东寨港和清澜港红树林一带,低值区集中在海口城区、文昌北部农耕区域;土地利用程度与生态系统服务价值呈空间负相关关系(P0.05),且具有明显的空间溢出效应。根据研究结论建议继续实施生态修复与保护政策,优化土地利用结构,提升生态核心的服务价值,实现区域可持续发展和维护生态安全。     

南方红壤水土流失区土地利用动态变化——以长汀河田盆地区为例

福建省长汀县曾是我国南方红壤地区水土流失最严重的县份之一,经过20多年的艰辛努力,长汀已成为中国水土流失治理的典范.采用遥感技术和景观格局分析技术,基于1988、1998、2004、2009和2011年的遥感影像,对长汀县水土流失最为严重的河田盆地区进行土地利用动态变化检测与景观格局变化分析.结果表明,研究区在这23a间的土地利用发生了很大变化,其中最主要的特征就是以针叶林为主的林地面积的快速增长和地表裸土面积的大幅下降.景观分析表明,水土流失治理新增的小块林地正逐渐形成连片分布,而裸土面积在大幅减少的同时,其斑块也趋于破碎.总的看来,这23a间的水土流失治理已使得研究区的生态明显趋于好转.     

流溪河流域景观空间特征与河流水质的关联分析

人类活动影响或改变流域景观空间结构,并有可能对河流水质产生不同程度的影响,以流溪河流域为研究区,分析流域景观空间格局特征与水质指数之间的相关关系。将流域划分为27个子流域,采集水样分析水质状况,所选用的水质指标有氨氮(NH3-N)、硝态氮-亚硝态氮(NO3-N+NO2-N)、总磷(TP)、化学需氧量(CODCr)。结果表明:1)该流域土地利用结构与水质具有显著相关性,其中居住用地对水质的影响作用最强,林地对河流水质具有净化功能,与水质指标之间的关系表现为负相关,园地与水质指标关系具有不确定性;2)流域景观特征从上游到下游之间表现为城市化增强的梯度,水质状况响应这个梯度变化表现为上游优于下游,人类活动及城市化发展引起的土地利用变化及土地管理方式对水质变化有显著影响;(3)景观破碎度与水质呈现显著正相关性,是影响水质的重要指标,景观聚集程度和斑块形状复杂程度与水质有负相关关系;子流域尺度和河岸带尺度景观空间特征对水质的影响差异不明显。     

基于分形理论的乡村聚落景观空间特征及演变——以厦门市为例

空间结构和空间形态共同构成乡村聚落景观空间特征,对二者的科学分析是乡村土地利用格局优化的基础.本研究采用分形理论,从全市与分乡镇两个尺度上对厦门市乡村聚落景观空间结构的特征和演变进行定量分析,并提出空间格局优化的相应对策.结果表明: 厦门市乡村聚落景观空间结构与形态的分形特征明显.在全市尺度上,聚集维数、交通网络直通度和空间形态维数随时间变化而增大,而空间关联维数持续减少;乡村聚落景观空间结构呈多中心聚集态分布,交通网络通达性变好,空间结构自组织不断优化,而乡村聚落景观空间形态日趋复杂,空间呈扩展的趋势.在分乡镇尺度上,乡村聚落景观空间特征差异显著,空间结构松散、通达性较弱等问题存在于部分乡镇.未来需加强交通等基础设施投入和中心村建设,提高乡村聚落内部各要素的关联度,促使其空间结构优化.本研究结果为优化乡村聚落空间布局、科学编制乡村土地利用规划提供了有力的技术手段和理论支撑.