鹞落坪保护区植被景观特征与地理因子的相关分析

分析了敏感水平、景观重要值、物种多样性信息指数和伴人植物数目等旅游影响因子与鹞落坪保护区旅游植被景观特征的相关性,结果表明: 鹞落坪植被景观特征受自然环境的影响很小,而受人为活动影响较大,相对于自然地理因子而言,人文地理因子对植被景观特征具有更为显著的影响.     

豫北太行山旅游开发对生态环境的影响

以豫北太行山旅游开发的典型地—红旗渠青年洞和太行大峡谷桃花洞景区为研究对象,采用样地调查和现场提问的方法,以敏感水平、物种多样性指数、旅游影响系数和环境质量重要值等6项指标,同时对景区土壤理化性质进行了考察,分析评价了旅游开发对该区生态环境所产生的影响。结果表明,旅游开发对生态环境的影响具有一定的规律性,在考察的各项指标中,敏感水平与群落景观重要值及生物多样性信息指数两项指标基本上成反比关系。旅游活动对景区的植被、土壤和环境质量都已造成了一定的负面冲击。     

基于结构方程模型分析森林草原带草本物种丰富度对景观因子的响应

受损景观是由不同比例的植被斑块组成的镶嵌体,阐明植被斑块的景观结构特征对物种多样性的影响,有助于提高受损景观物种多样性保护。在塞罕坝自然保护区选取38个天然植被斑块,其中包括12个草地、11个灌木林和15个天然次生林。根据光合作用的不同途径将草本物种划分为C_3和C_4功能群。选取斑块面积、形状指数、隔离度指数及每个斑块500 m缓冲区内的森林和草地比例作为景观因子。通过结构方程模型探讨C_3、C_4草本物种丰富度与景观因子的相互关系。斑块面积(2.18—74.06 hm~2)与C_3、C_4草本及总物种丰富度分布格局均具有显著的正相关关系(P0.05),且对C_3草本的影响最大;形状指数(1.06—3.11)、隔离度指数(33.51—327.65)对C_3、C_4草本及总物种丰富度影响不显著(P0.05);C_3、C_4草本及总物种丰富度与毗邻斑块草地比例(4.20%—64.95%)呈正相关,而与森林比例(35.05%—95.80%)呈负相关。研究区斑块面积和毗邻斑块植被构成是影响C_3、C_4草本植物的主要因素。在破碎化景观中保存面积大的天然植被斑块及提高毗邻斑块草地比例是保护关键C_3、C_4草本植物物种的有效途径。     

北京百花山旅游活动与植被环境的关系

通过实地取样并选取植被景观特征指标,分析百花山旅游植被景观特征与环境因子的关系。结果表明,自然因子对植被景观特征的影响较小,但各植被景观特征值大都与其有一定的相关性。在人文因子中,游径宽度和伴人种比值与生态效应值形成显著负相关,说明植被景观受人为活动影响较大。由此可见,山岳型景区开展生态旅游时必须加强生态旅游的规划和管理,尽可能减少人为因素对植被景观的影响。     

旅游干扰对云丘山不同植被景观区物种多样性的影响

应用TWINSPAN 分类结合实地情况把景区内41 个样方划分为5 个景观区; 应用多样性指数从植物的科的区系特征和各个不同景观区物种多样性的差别分析了云丘山旅游干扰下不同植被景观区的物种多样性。结果表明: 1) 旅游干扰强烈的区域, 其科数变化不大但种数明显小于旅游干扰少的地区且菊科、蔷薇科等科的种类出现的频率最高,属于忍耐性的种类; 单型科、单型种出现的频率也较高。2) 在干扰强度适中的景观区物种的丰富度反而有所增加, 但物种的生活习性有明显差距, 中旱生物种种类增加。3) 随着旅游干扰程度的减弱, 乔木植物的比例略有增加, 群落接近原始状态, 其物种多样性趋于平稳。     

芦芽山自然保护区旅游开发与植被环境的关系

采用敏感水平、群落景观重要值、物种多样性信息指数等一系列评价指标,探讨了芦芽山自然保护区旅游开发与植被生态环境的关系。通过一系列评价指标分析,结果表明：保护站-冰口凹段,敏感水平不断增大,景观重要值不断减小;冰口凹到2420m段,敏感水平开始逐步减小,景观重要值则不断上升;2420-2580m段,敏感水平又开始逐步回升,景观重要值又迅速下降。物种多样性信息指数随着海拔的不断上升,呈一条波动且渐趋上升的曲线。但阴生种比值不能很好地反映生态环境质量的优劣。这些指标的变化趋势和其相互关系相吻合,且与植被现状大体一致,反映了整个自然保护区植物群落的旅游价值及其生态环境质量。同时,距游径的水平距离对植物群落及其景观特征的影响也较为明显。研究结果较好地反映了芦芽山旅游开发现状,与实际状况大致吻合,说明这一方法是可行的。     

芦芽山自然保护区旅游开发与植被环境的关系Ⅰ.植被环境质量分析

采用敏感水平、群落景观重要值、物种多样性信息指数等一系列评价指标 ,探讨了芦芽山自然保护区旅游开发与植被生态环境的关系。通过一系列评价指标分析 ,结果表明 :保护站～冰口凹段 ,敏感水平不断增大 ,景观重要值不断减小 ;冰口凹到 2 4 2 0 m段 ,敏感水平开始逐步减小 ,景观重要值则不断上升 ;2 4 2 0～ 2 5 80 m段 ,敏感水平又开始逐步回升 ,景观重要值则又迅速下降。物种多样性信息指数随着海拔的不断上升 ,呈一条波动且渐趋上升的曲线。但阴生种比值不能很好地反映生态环境质量的优劣。这些指标的变化趋势和其相互关系相吻合 ,且与植被现状大体一致 ,反映了整个自然保护区植物群落的旅游价值及其生态环境质量。同时 ,距游径的水平距离对植物群落及其景观特征的影响也较为明显。研究结果较好地反映了芦芽山旅游开发现状 ,与实际状况大致吻合 ,说明这一方法是可行的     

河南典型草地碳氮库构成对植物多样性的响应

以河南4种典型草地类型(暖性草丛、暖性灌草丛、热性草丛与热性灌草丛)为研究对象,基于野外调查与室内测定,结合RDA冗余分析方法,分析了植物多样性与生态系统碳氮库构成之间的关系。结果表明:河南草地植物物种多样性整体上呈现出灌草丛类草地大于草丛类草地;河南草地具有符合地域特征的植物功能群类型,C3植物比例均远大于C4植物,杂类草占64%～73%,有性兼无性繁殖方式的植物类型多达49%～56%;而生活型组成较为复杂,暖性草地以多年生草本和灌木为主,热性草地以一或两年生草本以及多年生草本为主; RDA分析结果显示,暖性草丛、暖性灌草丛植被氮密度与Shannon和Pielou指数呈正相关,植被碳密度、土壤氮密度与Shannon和Pielou指数呈负相关;热性草丛植被碳氮密度与物种丰富度指数呈正相关,土壤氮密度与Shannon和Pielou指数呈正相关,植被氮密度与Shannon和Pielou指数呈负相关;热性灌草丛土壤碳氮密度与Shannon指数呈正相关,植被碳氮密度与物种丰富度和Shannon指数呈负相关,即物种多样性及不同草地类型植被的组成共同作用影响植被和土壤碳氮密度。总之,河南草地生态系统碳氮库构成是植物物种丰富程度和分布均匀程度综合作用的结果。     

北京昌平区景观复杂度和局地管理对苹果园传粉蜂多样性的影响

传粉蜂为作物生产和粮食安全提供重要的生态系统服务。随着农业经济的不断发展,土地利用强度加剧,大量自然或半自然生境已经转变为农业用地。景观均质化和集约化管理导致野生蜂多样性下降,从而威胁到农业可持续生产。本研究以北京市昌平区苹果园为对象,探究景观复杂度(半自然生境比例)、局地管理强度(地表开花植物多样性和土壤全氮)及其交互作用对传粉蜂多样性的影响。结果表明: 共捕获传粉蜂8642头,其中人工蜂5125头,野生蜂分属5科14属49种3517头。传粉蜂多样性对景观复杂度和局地管理强度响应的最优尺度在500 m。样点半径500 m范围内,总传粉蜂和野生蜂多度随周围半自然生境增加均呈显著上升趋势。景观复杂度与开花植物多样性的交互作用对总传粉蜂和野生蜂物种丰富度有显著影响。当景观复杂度较低时(≤29.9%),总传粉蜂和野生蜂物种丰富度与开花植物多样性呈显著正相关;而当景观复杂度较高时(>29.9%),总传粉蜂和野生蜂物种丰富度与开花植物多样性呈显著负相关。此外,人工蜂多度随果园内局地开花植物多样性和土壤全氮增加呈显著升高趋势。土壤全氮与开花植物多样性的交互作用对人工蜂多度有显著影响。当土壤全氮含量较低时(≤1.9 g·kg^-1),人工蜂多度与开花植物多样性呈显著正相关;而当土壤全氮含量较高时(>1.9 g·kg^-1),人工蜂多度与开花植物多样性呈显著负相关。农业景观中半自然生境比例的增加有利于提高野生蜂多度,而地表开花植物多样性可以促进传粉蜂多样性,但是受到景观尺度(半自然生境比例)和局地尺度(氮肥施用)的影响。因此,农业景观中野生蜂多样性的维持需要综合考虑多尺度因素来制定保护策略。尽可能保留更高比例的耕地仍然是生产的长期需求,而保持中等景观复杂度,增加地表开花植物多样性,减少氮肥施用量将是促进苹果园传粉蜂多样性的有效方式。     

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...     

Patterns of plant species richness in Alpine hay meadows: Local vs. landscape controls

Habitat type and quality are recognised as important local determinants of species richness, but other processes operating at the landscape scale can also affect diversity patterns. The evidence regarding the relative importance of landscape context on vascular plants is diverse, and little is known about the effects of this complex factor in Alpine environments. Hence, the primary purpose of the study was to elucidate the relative effects of the determinants of plant species richness by decomposing the variation into local and landscape components. We sampled 99 hay meadows in the Italian Alps, and recorded 14 explanatory variables ascribed to three sets: two sets of local variables, meadow management and abiotic environment, and a set of landscape variables. Plant diversity was affected primarily by local determinants. Species richness tended to increase in less fertilised meadows, confirming the detrimental effect of intensive meadow management on plant diversity. Site conditions such as steep slopes also enhanced plant species richness, showing a most pronounced positive effect in meadows that were cut less frequently. As to the landscape determinants, a high proportion of urban elements affected species richness negatively probably due to further eutrophication. In contrast, an increased length of meadow edges had a positive effect, particularly in meadows located on shallow soils. Partitioning analyses revealed that the three sets of variables showed relatively large shared effects with each other (over half of the total variation explained). In conclusion, the composition of the surrounding landscape had a lower impact on vascular plant species richness than did meadow management and local abiotic environment.     

Impacts of land use on riparian forest along an urban – rural gradient in southern Manitoba

Extensive landscape modification by humans has led to the fragmentation of riparian forests across North America. We compared the vegetation of extant riparian forest along an urban-rural disturbance gradient. In 1999, twenty-five sites along Assiniboine River in Manitoba, Canada were categorized according to land use: urban, suburban, high intensity rural, low intensity rural, and relatively high quality reference forest. Differences in herbaceous, shrub, and tree species composition and diversity were related to the proportion of surrounding land use, forest patch size, connectivity, and area:perimeter ratio. Urban riparian forests were more disturbed and isolated. They were smaller and characterized by drier, more alkaline soils. Moreover, they had significantly lower native and overall understorey species diversity, and had a higher proportion of exotics including Solanum dulcamara and Hesperis matronalis. Suburban forests were less disturbed, faced greater development pressure, and had sandier soils. Although suburban understorey diversity was similar to that of rural forests, suburban sites had a higher proportion of exotic species, especially escaped horticultural and invasive species including Caragana arborescens and Rhamnus cathartica. Reference sites were relatively large and exhibited greater connectivity, but there was little difference in species composition and diversity among high intensity rural, low intensity rural, and reference sites. These site types were less disturbed than either urban or suburban forests, and reference sites were characterized by hydrophilic species including Scirpus fluviatilis and Carex aquatilis. Our results suggest that landscape measures of disturbance, and related changes in environment, may be confidently used to assess impacts of land use on vegetation along urban-rural gradients. This revised version was published online in June 2006 with corrections to the Cover Date.     

Response of wild bee diversity,abundance, and functional traits to vineyard inter‐row management intensity and landscape diversity across Europe

Agricultural intensification is a major driver of wild bee decline. Vineyards may be inhabited by plant and animal species, especially when the inter‐row space is vegetated with spontaneous vegetation or cover crops. Wild bees depend on floral resources and suitable nesting sites which may be found in vineyard inter‐rows or in viticultural landscapes. Inter‐row vegetation is managed by mulching, tillage, and/or herbicide application and results in habitat degradation when applied intensively. Here, we hypothesize that lower vegetation management intensities, higher floral resources, and landscape diversity affect wild bee diversity and abundance dependent on their functional traits. We sampled wild bees semi‐quantitatively in 63 vineyards representing different vegetation management intensities across Europe in 2016. A proxy for floral resource availability was based on visual flower cover estimations. Management intensity was assessed by vegetation cover (%) twice a year per vineyard. The Shannon Landscape Diversity Index was used as a proxy for landscape diversity within a 750 m radius around each vineyard center point. Wild bee communities were clustered by country. At the country level, between 20 and 64 wild bee species were identified. Increased floral resource availability and extensive vegetation management both affected wild bee diversity and abundance in vineyards strongly positively. Increased landscape diversity had a small positive effect on wild bee diversity but compensated for the negative effect of low floral resource availability by increasing eusocial bee abundance. We conclude that wild bee diversity and abundance in vineyards is efficiently promoted by increasing floral resources and reducing vegetation management frequency. High landscape diversity further compensates for low floral resources in vineyards and increases pollinating insect abundance in viticulture landscapes.     

Vegetation Components of a Subtropical Rural Landscape in China

To assess the overall vegetation changes and their ecological significance, following landscape evolution, plant composition and physical structures of the homegardens (woodlots and vegetation patches with hedgerow fence) and field boundaries were examined in the rural landscape of subtropical China in order to determine their ecological significance. Field surveys on landscape changes and plant composition were carried out in two typical villages in the Yangtze river plain. Analysis of landscape changes and plant composition showed that the rural landscape is diverse both in terms of types of elements and plant species. The vegetation types in the area have undergone frequent alterations by human beings following major changes of landscape management due to economic and social reforms. The plant diversity of the various vegetation types in the area is related to the duration of colonization of the vegetation type, the extent of disturbance by human beings, and the physical structure diversity of the vegetation type. In the discussion, the plant diversity and heterogeneity of the physical environment in any vegetation type is of importance for the ecological sustainability of the landscape.     

Genetic diversity of the subterranean Gansu zokor in a semi-natural landscape

We studied the relationship between genetic diversity of the subterranean Gansu zokor Myospalax cansus and habitat variability in the Loess Plateau, Qinghai Province, China. We used a combination of geographic information systems and molecular techniques to assess the impact of habitat composition and human activities on the genetic diversity of zokor populations in this semi-natural landscape. Although they occurred relatively infrequently in the landscape, woodland and high-coverage grassland habitats were the main positive contributors to the genetic diversity of zokor populations. Rural residential land, plain agricultural land and low-coverage grassland had a negative effect on genetic diversity. Hilly agricultural land and middle-coverage grassland had little impact on zokor genetic diversity. There were also interactions between some habitat types, that is, habitat types with relatively better quality together promoted conservation of genetic diversity, while the interaction between (among) bad habitat types made situations worse. Finally, habitat diversity, measured as patch richness and Shannon's diversity index, was positively correlated with the genetic diversity. These results demonstrated that: (1) different habitat types had different effects on the genetic diversity of zokor populations and (2) habitat quality and habitat heterogeneity were important in maintaining genetic diversity. Habitat composition was closely related to land use thus emphasizing the importance of human activities on the genetic diversity of subterranean rodent populations in this semi-natural landscape. Although the Gansu zokor was considered to be a pest species in the Loess Plateau, our study provides insights for the management and conservation of other subterranean rodent species.     

浙江西天目山主要森林类型的苔藓多样性比较

苔藓是森林的重要组分, 是森林保护区的重要保护对象, 在物种资源和生态系统功能维护中有重要作用。该研究以浙江西天目山国家自然保护区内7种主要森林类型(落叶矮林、落叶阔叶林、常绿-落叶阔叶混交林、常绿阔叶林、针阔混交林、针叶林和竹林)内的苔藓植物为对象, 调查了32个10 m × 10 m的样地, 记录地面生苔藓植物盖度和树附生苔藓植物多度, 采用重要值、相似性系数、多样性指数分析了森林类型间的苔藓植物多样性差异。共采集969份标本, 隶属41科84属142种, 其中苔类植物13科18属33种, 藓类植物28科66属109种, 优势科为灰藓科、青藓科和羽藓科。2种混交林(常绿-落叶阔叶混交林和针阔混交林)的物种丰富度和多样性指数均高于其余5种森林, 其中物种丰富度以针阔混交林最高, 苔藓植物多样性则以常绿-落叶阔叶混交林最高, 竹林两者均为最低。海拔等环境因子较为接近的植被类型的苔藓植物多样性相似性较高, 常绿阔叶林与针叶林相似性最高, 而落叶矮林和竹林相似性最小。     

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.     

Spatial heterogeneity and habitat configuration overcome habitat composition influences on alpha and beta mammal diversity

The effects of habitat fragmentation on different taxa and ecosystems are subject to intense debate, and disentangling them is of utmost importance to support conservation and management strategies. We evaluated the importance of landscape composition and configuration, and spatial heterogeneity to explain α- and β-diversity of mammals across a gradient of percent woody cover and land use diversity. We expected species richness to be positively related to all predictive variables, with the strongest relationship with landscape composition and configuration, and spatial heterogeneity respectively. We also expected landscape to influence β-diversity in the same order of importance expected for species richness, with a stronger influence on nestedness due to deterministic loss of species more sensitive to habitat disturbance. We analyzed landscape structure using: (a) landscape metrics based on thematic maps and (b) image texture of a vegetation index. We compared a set of univariate explanatory models of species richness using AIC, and evaluated how dissimilarities in landscape composition and configuration and spatial heterogeneity affect β-diversity components using a Multiple Regression on distance Matrix. Contrary with our expectations, landscape configuration was the main driver of species richness, followed by spatial heterogeneity and last by landscape composition. Nestedness was explained, in order of importance, by spatial heterogeneity, landscape configuration, and landscape composition. Although conservation policies tend to focus mainly on habitat amount, we advocate that landscape management must include strategies to preserve and improve habitat quality and complexity in natural patches and the surrounding matrix, enabling landscapes to harbor high species diversity.