沈阳城区绿地生态系统景观结构与异质性分析

对沈阳城区绿地生态系统景观结构和异质性进行了分析。结果表明,沈阳城区绿地景观斑块以街头绿地斑块最多,占城区绿地块数的50％以上,但绿地面积只占4．45％,斑块大小以防护绿地和公园绿地斑块平均值最大,分别为66．97hm^2和59．21hm^2。而街头绿地和游园绿地斑块平均值最小,为0．71hm^2和0．38hm^2。景观多样性指数以街头绿地最高,而公园绿地最低,在沈阳城区的7个区中不同绿地类型中的优势度和均匀度都比较小,但斑块绿地优势度高于廊道绿地的10倍多,绿地分布不均衡,应增加绿地斑块数量,均匀配置公共绿地(公园绿地、道路绿地),增加绿色廊道,建立城区与城郊自然生态系统绿色通道和充分发挥沈阳城区3条人工运河带状绿地美化环境、泄洪排涝和调节气候功能作用。     

人为干扰强度对村级景观破碎度的影响

村落具有人类活动所造成的许多景观特征,是研究人为干扰对景观破碎度影响的良好场所;本文运用地表植被的改变状况和主要辅助能的投入为指标,按重度干扰强度、中度干扰强度和轻度干扰强度3个等级把村落分为中心区、过渡区和基质区,分别不同研究区的景观破碎度与人为干扰强度的相互关系,3个研究区域的斑块密度指数分别为0．3416、0．3109和0．0028;景观破碎度分别为0．0820、0．0746和0．0007,重度干扰和中度干扰比轻度干扰下景观具有明显高的斑块密度指数和破碎化指数,随着人为干扰强度的增加,景观破碎化程度相应增加,中度人为干扰使景观破碎度值较高。     

Regional productivity mediates the effects of grazing disturbance on plant cover and patch‐size distribution in arid and semi‐arid communities

Patch‐size distribution and plant cover are strongly associated to arid ecosystem functioning and may be a warning signal for the onset of desertification under changes in disturbance regimes. However, the interaction between regional productivity level and human‐induced disturbance regime as drivers for vegetation structure and dynamics remain poorly studied. We studied grazing disturbance effects on plant cover and patchiness in three plant communities located along a regional productivity gradient in Patagonia (Argentina): a semi‐desert (low‐productivity community), a shrub‐grass steppe (intermediate‐productivity community) and a grass steppe (high‐productivity community). We sampled paddocks with different sheep grazing pressure (continuous disturbance gradients) in all three communities. In each paddock, the presence or absence of perennial vegetation was recorded every 10 cm along a 50 m transect. Grazing effects on vegetation structure depended on the community and its association to the regional productivity. Grazing decreased total plant cover while increasing both the frequency of small patches and the inter‐patch distance in all communities. However, the size of these effects was the greatest in the high‐productivity community. Dominant species responses to grazing explained vegetation patch‐ and inter‐patch‐size distribution patterns. As productivity decreases, dominant species showed a higher degree of grazing resistance, probably because traits of species adapted to high aridity allow them to resist herbivore disturbance. In conclusion, our findings suggest that regional productivity mediates grazing disturbance impacts on vegetation mosaic. The changes within the same range of grazing pressure have higher effects on communities found in environments with higher productivity, markedly promoting their desertification. Understanding the complex interactions between environmental aridity and human‐induced disturbances is a key aspect for maintaining patchiness structure and dynamics, which has important implications for drylands management.     

Factors affecting bird richness in a fragmented cork oak forest in Morocco

The cork oak forest of Ma'amora in north-western Morocco was the largest cork oak forest in the world until the beginning of the 20th century. Due to growing land use for agriculture and urbanization, however, this forest has become fragmented into relatively small and isolated patches. The effects of this fragmentation on the diversity of wild animal communities have never been investigated despite the importance of such investigations in elaborating long-term conservation plans of the biodiversity of this forest system. In this study of a sample of 44 forest patches we assessed the relationships between species numbers of wintering, breeding and spring migrant birds and patch size, shape, isolation and vegetation structure. We found that species richnesses of the three studied bird assemblages were strongly related to local vegetation structure, namely to the diversity and abundance of trees and bushes. Patches with higher diversity and cover of trees and bushes support higher numbers of bird species. However, patch size, shape and isolation were not significant predictors of bird richness. These results suggest that bird communities in the studied forest patches were more likely shaped by local habitat suitability rather than the amount of habitat or patch isolation. The results also demonstrate negative effects of current human pressures, namely logging, grazing and disturbance, on the diversity of bird communities in this forest system. This emphasizes the need for urgent management efforts aiming at reducing the negative impacts of forest use by humans on bird diversity in this forest system.     

Construction of 3D landscape indexes based on oblique photogrammetry and its application for islands

Landscape indexes are quantitative indicators that reflect the composition and spatial configuration of landscape structures. However, the current two-dimensional (2D) spatial analysis methods lack accuracy in assessing patch characteristics due to the lack of three-dimensional (3D) information. Following the “Patch-Class-Landscape” framework, eight 3D landscape indexes were built to quantitatively describe spatial landscape features and two sensitivity indexes were developed to identify the differences between 2D and 3D structures. Based on two types of oblique photogrammetry data, validation and comparison studies were conducted for Tianheng Island and Sichang Island. The results found the following: (1) At the patch level, the 3D shape index (TPSI) of vegetation was generally higher than that of buildings, with an R² of 0.634, and the classification index (TCI) showed remarkable performance in identifying patch type. The patch type was likely to be building or vegetation when TCI approached 33, respectively, with a classification accuracy of 90% after verification. (2) At the class level, the 3D percentage of landscape (TPLAND) of grassland and arbor types on the two islands were quite different, reflecting significant differences in the dimensionality of the vegetation landscapes, as influenced by different climatic zones. Moreover, the 3D landscape shape index (TLSI) and other shape-related indexes had higher exponential sensitivity coefficient (ESC) values, due to the higher amount of 3D shape information they carry. (3) At the landscape level, the two 3D Shannon indexes (TSHDI and TSHEI) did not significantly change compared with their 2D counterparts, implying that these two indexes, as larger-scale landscape indicators, had lower sensitivity when extra-dimensional information was added. Overall, the 3D landscape indexes can better present 3D information at different landscape levels. As a potential and effective assessment tool and it will be applied to improve existing spatial planning and landscape management.     

Plant species composition in relation to green cover configuration and function of urban parks in Beijing, China

Parks, as one specific type of urban open space, play important roles in the conservation of urban biodiversity and provision of recreational services for local residents. As there is a lack of specific insight into park plant species composition in relation to park features, 24 sample parks within the inner city of Beijing, the capital of China, were studied by stratified random plot sampling of their tree, shrub, and herbaceous communities, respectively, in order to investigate how human activities have influenced park green cover configuration and floristic characteristics. The quantitative correlation of species richness and the park green cover indices (patch size, shape, etc.) were studied. The importance value index for plant species (trees, shrubs, and herbaceous species) of each park was calculated. The two-way indicator species analysis approach (TWINSPAN) was applied to classify the 24 parks into different groups based on their species assemblages. Two-hundred and eighty-eight species were recorded within the 24 study parks, belonging to 184 genera and 72 families dominated by Gramineae, Compositae, and Leguminosae. Among all the recorded species, 41% are exotic. The species occurrence, abundance and diversity vary significantly among different parks. Besides the positive correlation (R=0.505, P<0.05) between herbaceous species abundance and the park green cover size, no other significant relations were found between the species abundance and other indices of park green cover configuration. Remarkably, the TWINSPAN classification resulted in a good discrimination between park functional types and the variation in their species assemblage. For the parks of similar age (development history) or landscape design, their species assemblages show more similarity. The methodology adopted and results can be employed to improve baseline information on urban plant ecology and support the setting of priorities for future park management and vegetation protection.     

广东揭阳东湖公园植被调查及景观格局分析

运用景观生态学原理,对广东揭阳东湖公园植被进行调查,同时在进行植被景观要素分类的基础上,选取景观多样性、斑块数目、斑块面积、破碎度、优势度等指标对东湖公园植物景观的异质性、多样性、均匀性等景观格局进行分析。结果表明,东湖公园植被较丰富,景观整体布局基本合理,景观结构相对稳定,但植物配置需要加强,尤其需要突出季相变化,同时适当增加灌丛和草地的斑块,丰富空间景观结构。     

Structure and function of wildfire and mountain pine beetle forest boundaries

Landscape boundaries, in particular those created by natural disturbances, are fundamental structures in landscape functioning. At the stand scale, forest boundaries show a wide range of characteristics varying from sharp to diffuse, wavy to straight, enclosed areas (patches) to open ones; all of these have different effects of forest vegetation. The objectives of this study were 1) to characterize the structure of forest boundaries (width, steepness, heterogeneity) and 2) to investigate forest vegetation functional response in the boundary zones created by wildfires and mountain pine beetle (MPB) outbreaks. We studied 11 mountain pine beetle and 7 wildfire boundary zones (4–7 y since disturbance) using field‐based two‐dimensional grids in southern central British Columbia (Canada). Boundary zone delineation was determined through spatially constrained clustering algorithms at three sampling unit resolutions (5×5 m, 10×10 m, and 20×20 m). Then, to characterize boundary width and shape, we developed two new boundary indexes (maximized and minimized boundary zones). The identified boundary widths ranged from 0 to 127 m with a mean width of 51 m at the 20×20 m resolution for both fire and MPB. Although the widths were comparable between disturbance types, fires generally had steeper boundaries (more pronounced) than MPB, largely due to higher peak tree mortality within the disturbances (89 vs 43%). Most of the forest vegetation response variables (understory vegetation diversity, plot‐level species richness, evenness, and multivariate community measures) in the boundary zones tended not to be intermediate in value between the intact forest and disturbance area, in spite of intermediate tree mortality. Tree mortality heterogeneity in the boundary zones was often highest in fires and was equal to the internal heterogeneity in MPB disturbances. Using historical natural disturbance patterns as a conservation strategy, this study proposes that forest management should create boundary complexity (width and shape), thereby creating landscape heterogeneity similar to landscapes influenced primarily by natural disturbances.     

Ecological indicators for protection impact assessment at two scales in the Bozin and Marakhil protected area,Iran

Official protection can play a major role in biodiversity conservation, but it may have unintended effects on habitats at multiple scales. We evaluated the effects of this protection designation on forest area and structure at two spatial scales in Bozin and Marakhil protected area. We classified Landsat-5 TM images from 2001 and 2009, covering protected and unprotected areas and used for broad scale analysis, and IKONOS and GeoEye images from 2001 and 2009 for fine scale analysis. We used landscape structure metrics and the models that fit patch size distribution as the ecological indicators of protection impact. The protection effect was scale dependent, with significant habitat loss and fragmentation at the fine scale but not at the broad scale. Protection increased the number of large patches inside the park, as indicated by a shift from a truncated power law to a power law distribution of patch sizes. The habitat structural maintenance and aggregation inside the park, and fragmentation outside the park boundaries, signal a potential shift of human pressure from inside to directly outside of the park. This study indicates the need for spatial analyses on both sides of protection boundaries at multiple scales using complementary indicators to understand the impacts of protection on habitat structure.     

黄土区农业景观空间格局分析

景观空间格局分析是景观生态学研究的核心问题之一。本文用地理信息系统,分维分析和统计分析相结合,以１∶１万土地利用现状图为基础,选取斑块大小、分维数、斑块伸长指数、多样性、优势度、相对丰富度、破碎度等指标,陕北米脂县泉家沟流域农业景观的空间格局。结果显示,乔木林地、坡耕地、果园、草地和梯田农地的分维数较低,坝地、水库、灌溉农田、居信用地和灌木林地的人维数较高,斑块形状较为复杂。随着斑块面积的增加,农     

基于围垦特征的海滨地区景观格局变化研究——以盐城海岸为例

为探讨滩涂围垦对海滨地区景观格局带来的影响,选取1973—2013年Landsat1、4、5、7、8影像数据,利用GIS(Geographic Information System)、RS(Remote Sensing)和景观指数计算方法,对盐城国家级自然保护区(川东港-新洋港段)已围垦区和未围垦区,以及典型垦区(海丰、海北和金丰垦区)围垦前后景观变化情况进行对比分析。1973—2013年研究区围垦特征如下:以10a为间隔,围垦区域平行于海岸线呈条带状向海推进,且条带逐渐变窄;围垦难度逐渐加大,总体上围垦强度呈减小趋势,过程上围垦面积呈升降交替状态;围垦后垦区利用方式各异,主要以种植业和养殖业为主。受围垦影响该区景观格局变化如下:1973—2013年,未围区(Ⅰ区)自然植被面积增加4762 hm2,斑块形状日益复杂、自然,分维数由1.10上升到1.15,景观破碎化水平较低,在0.17—0.21之间,多样性指数由1.11上升至1.52;已围区(Ⅱ、Ⅲ、Ⅳ区)自然植被面积不断减少,分别减少了9873、13788 hm2和6890 hm2,斑块形状更加简单、规则,分维数分别下降了0.03、0.03和0.02,破碎化程度分别上升了0.21、0.23和0.17,多样性均先升后降,升幅约0.8,降幅约0.5。海北、海丰、金丰垦区自然景观不断向人工景观转移,海北和海丰垦区斑块形状不断趋于简单规则,形状指数分别下降0.8和0.5,而金丰垦区形状指数上升0.4,景观破碎度方面分别呈"升—降—升"、"降—升—降"和"升—降"趋势。围垦前,各垦区景观面积和斑块形状变化差异不大,而景观破碎度变化差异明显;围垦期间各垦区景观格局变化一致;围垦后,各垦区除非受新一轮人类活动干扰,其景观格局基本维持围垦末期状态。     

Landscape structure influences tree density patterns in fragmented woodlands in semi‐arid eastern Australia

Landscape and local‐scale influences are important drivers of plant community structure. However, their relative contribution and the degree to which they interact remain unclear. We quantified the extent to which landscape structure, within‐patch habitat and their confounding effects determine post‐clearing tree densities and composition in agricultural landscapes in eastern subtropical Australia. Landscape structure (incorporating habitat fragmentation and loss) and within‐patch (site) features were quantified for 60 remnant patches of Eucalyptus populnea (Myrtaceae) woodland. Tree density and species for three ecological maturity classes (regeneration, early maturity, late maturity) and local site features were assessed in one 100 × 10 m plot per patch. All but one landscape characteristic was determined within a 1.3‐km radius of plots; Euclidean nearest neighbour distance was measured inside a 5‐km radius. Variation in tree density and composition for each maturity class was partitioned into independent landscape, independent site and joint effects of landscape and site features using redundancy analysis. Independent site effects explained more variation in regeneration density and composition than pure landscape effects; significant predictors were the proportion of early and late maturity trees at a site, rainfall and the associated interaction. Conversely, landscape structure explained greater variation in early and late maturity tree density and composition than site predictors. Area of remnant native vegetation within a landscape and patch characteristics (area, shape, edge contrast) were significant predictors of early maturity tree density. However, 31% of the explained variation in early mature tree differences represented confounding influences of landscape and local variables. We suggest that within‐patch characteristics are important in influencing semi‐arid woodland tree regeneration. However, independent and confounding effects of landscape structure resulting from previous vegetation clearing may have exerted a greater historical influence on older cohorts and should be accounted for when examining woodland dynamics across a broader range of environments.     

不同斑块类型的景观指数粒度效应响应——以无锡市为例

斑块类型与景观格局粒度效应响应关系密切。以无锡市为研究区域,针对地区社会经济活动频繁、人为干扰强烈和生态脆弱等特性,以土地利用类型、热力等级和生态贡献为斑块类型划分依据,构建出对应的3种不同景观格局。在相同粒度变化情况下,选用了19个景观水平指数和Moran's I指数,分析了不同景观格局粒度效应的响应情况。结果表明,随粒度变粗:1)土地利用类型、热力等级和生态贡献斑块的部分景观指数响应曲线变化剧烈程度依次减弱;2)3类斑块的Moran's I指数均存在尺度效应。其中,土地利用类型和生态贡献斑块的Moran's I指数存在负相关,热力等级斑块没有。生态贡献斑块响应曲线在正相关区域内变化相对平缓,土地利用类型与热力等级斑块响应曲线变化趋势相反;3)指数反映的第一临界粒度基本一致,但景观指数响应曲线的临界现象更为明显。总体上,不同类型斑块在同一研究区构成的景观格局、指数响应曲线变化趋势和第一临界粒度都较为相似;斑块类型对景观指数粒度效应响应存在影响,但还有待深入探讨。     

基于缓冲带的贵港市城市景观格局梯度分析

运用景观格局指数与城市建成区缓冲带划分相结合的方法,分析了广西贵港市近20a来城市建成区整体景观与主要城市景观类型（公共设施用地、工业用地、居住用地及农田）的圈层梯度变化特征.分析结果表明：贵港市城市建成区可以看作是居住用地与公共设施用地的镶嵌景观,但这种镶嵌景观随着城市化的发展,存在日趋不明显的特征;整个景观层面的指数20a来在31个梯度带内,表现出相似的变化趋势,斑块面积指数显示出贵港市城市建成区存在两个较为明显的商业金融中心;各梯度带内景观的平均面积增大,景观的形状日臻规则,景观多样性随景观类型及均匀度的增加显著上升.2004年主要城市景观类型在缓冲区中间各带能够很好的反映出格局的变化特征,其中工业用地和农田用地的斑块数和斑块密度随缓冲区梯度表现出较为一致的变化特征,而公共设施用地和居住用地的梯度变化趋势相似.各个梯度带中工业用地形状最为复杂,所占比重最低,平均斑块面积最大;公共设施和居住用地形状较为简单,在各带中所占比重较高,平均斑块面积较小;农田景观在各带中所占比例变化不大,近似连续分布,对城市生态环境的调节起到一定作用.     

The taste of nectar – a neglected area of pollination ecology

We investigated the impact of landscape structure on landscape connectivity using a combination of simulation and empirical experiments. In a previous study we documented the movement behaviour of a specialized goldenrod beetle ( Trirhabda borealis Blake) in three kinds of patches: habitat (goldenrod) patches and two types of matrix patch (cut vegetation and cut vegetation containing camouflage netting as an impediment to movement). In the current study, we used this information to construct simulation and experimental landscapes consisting of mosaics of these three patch types, to study the effect of landscape structure on landscape connectivity, using the T. borealis beetle as a model system. In the simulation studies, landscape connectivity was based on movements of individual beetles, and was measured in six different ways. The simulations revealed that the six measures of landscape connectivity were influenced by different aspects of landscape structure, suggesting that: (1) landscape connectivity is a poorly defined concept, and (2) the same landscape may have different landscape connectivity values when different measures of landscape connectivity are used. There were two general predictions that held over all measures of landscape connectivity: (1) increasing interpatch distance significantly decreased landscape connectivity and (2) the influence of matrix elements on landscape connectivity was small in comparison to the influence of habitat elements. Empirical mark-release-resight experiments using Trirhabda beetles in experimental landscapes supported the simulation results.     

Change in Vegetation Patterns Over a Large Forested Landscape Based on Historical and Contemporary Aerial Photography

Changes to vegetation structure and composition in forests adapted to frequent fire have been well documented. However, little is known about changes to the spatial characteristics of vegetation in these forests. Specifically, patch sizes and detailed information linking vegetation type to specific locations and growing conditions on the landscape are lacking. We used historical and recent aerial imagery to characterize historical vegetation patterns and assess contemporary change from those patterns. We created an orthorectified mosaic of aerial photographs from 1941 covering approximately 100,000 ha in the northern Sierra Nevada. The historical imagery, along with contemporary aerial imagery from 2005, was segmented into homogenous vegetation patches and classified into four relative cover classes using random forests analysis. A generalized linear mixed model was used to compare topographic associations of dense forest cover on the historical and contemporary landscapes. The amount of dense forest cover increased from 30 to 43% from 1941 to 2005, replacing moderate forest cover as the most dominant class. Concurrent with the increase in extent, the area-weighted mean patch size of dense forest cover increased tenfold, indicating greater continuity of dense forest cover and more homogenous vegetation patterns across the contemporary landscape. Historically, dense forest cover was rare on southwesterly aspects, but in the contemporary forest, it was common across a broad range of aspects. Despite the challenges of processing historical air photographs, the unique information they provide on landscape vegetation patterns makes them a valuable source of reference information for forests impacted by past management practices.     

Temporal and spatial changes in a mountainous area of central Italy

Abstract. In this paper we present an application of aerial remote sensing to the analysis of spatial information in a mountainous area of central Italy by applying texture measures and landscape indices. Land cover data acquired in different time periods are used to calculate measures of landscape pattern and structure at pixel level (tone and texture variables) and patch‐level (landscape indices). Images of the patches from the 1950s, 1980s and 1990s have been derived from the tone‐texture classification of scanned black‐and‐white photographs. Multitemporal analysis of landscape indices has been performed to detect changes of landscape elements and related effects on vegetation dynamics due to the reduction of human impact.     

Capturing landscape changes and ecological processes in Nikko National Park (Japan) by integrated use of remote sensing images

Landscape change is of crucial ecological importance because of its impacts on biodiversity and the sustainability of habitats and landscapes. The ability to infer ecological processes from landscape changes provides a powerful new tool for large-scale and regional ecological research. Accordingly, we investigated landscape changes in Nikko National Park (Japan) from 1981 to 2006 using an integration of remote sensing images to track ecological processes in the park. We showed that natural succession and anthropogenic disturbance have caused an enormous expansion of coniferous forest (mostly Larix kaempferi and Tsuga diverifolia), which has resulted in an alteration of sika deer (Cervus nippon) habitat structure. The deer population has vastly increased in size, with concomitantly negative effects on the biodiversity of forest-floor vegetation. All changes that we detected have degraded landscape and ecosystem sustainability. Our integrated use of remote sensing images in 2006 accurately identified and classified landscape pattern in the study area. We achieved an overall accuracy of 96.48%, demonstrating that the procedure has an enormous potential for synthetic processing of multitemporal and multiresource remote sensing images.     

Factors influencing herpetofauna abundance and diversity in a tropical agricultural landscape mosaic

Agricultural intensification and the associated factors, including land transformation, are among the major global threats affecting biodiversity especially herpetofauna. However, little information is available about how different factors shape herpetofauna species assemblages in agricultural landscape at different spatial scales from patch (125 – 250m) to the landscape (500 – 1000m). We assessed the diversity of amphibians and reptiles in areas under low and high degrees of agricultural intensification and explored different factors regulating diversity at different spatial scales using four sampling methods. Diversity and abundance of amphibians varied significantly between the two zones, but not for reptiles. Agricultural intensification index (AII), calculated based on agrochemical use and area under agriculture at 250m scale, seemed to affect amphibians both at patch as well as at 500m and 1000m landscape scales. The AII influenced reptilian diversity only at patch and 500m scales. Vicinity of natural forest had a stronger influence on reptilian abundance. Seminatural vegetation impacted herpetofauna diversities at larger spatial scales. The extent of water bodies influenced the reptilian abundance at 250m patch scale and amphibian abundance both at 250m and 1000m scale. Fallow lands affected only reptilian diversity at all spatial scales. Plantation affected amphibian at all scales but reptiles only at the landscape scale. Habitat heterogeneity regulated only amphibian diversity. These results highlight the fact that different patch and landscape-scale factors regulate the diversity of reptiles and amphibians differentially. Such scale-specific information will crucially inform future conservation action for the herpetofauna in the agricultural landscape.     

A tool set for description and mapping vegetation on protected natural areas: an example from the Canary Islands

The Canary Islands belong to Mediterranean basin hotspot, especially because their rich endemic flora. Nearly 40% of the total archipelago area is protected through protected natural area network. However, some plant communities show high degree of disturbance or they develop in unprotected zones. So, multivariate analysis combined with vegetation mapping can be useful for identify, describe and protect the main plant communities. These tools have been applied in Caldera de Taburiente national park (La Palma. Canary Islands). An actual vegetation map of this park is showed and its major natural vegetation units are described. These tools could be applied to other protected and unprotected areas, especially for planning, management and conservation purposes.