川西高山典型自然植被土壤动物多样性

为了解川西高山不同自然植被类型下土壤动物的多样性差异,于2008年8月至2009年6月对该地区代表性植被--针叶林、灌木林和草甸下的土壤动物群落进行调查.从3种植被下共捕获土壤动物48343只,隶属于7门16纲31目117科.不同植被类型的大型土壤动物优势类群差异较大,其土壤动物类群数存在显著差异(P＜0.05).3种植被下土壤动物个体密度与类群数的垂直分布均具有明显表聚性.针叶林苔藓层的土壤动物个体密度与类群数极显著高于凋落物层和土壤层（P＜0.01）.不同植被下土壤动物密度 类群指数(DG)存在极显著差异(P＜0.01).大型土壤动物生物量在6月达到最大值.Jacard相似系数显示:受干扰草甸的土壤动物群落与其他植被相似程度最低.表明植被类型对土壤动物群落结构特征影响显著;坡向、海拔以及干扰等因素对土壤动物群落结构也有影响.     

淮南市重金属污染对土壤动物群落和多样性影响研究

通过对淮南煤矿和发电厂及灰场污染地的土壤动物群落结构进行分析。结果表明,土壤动物群落的组成与数量随着污染的加重而减少,土壤动物的密度也有同样的变化趋势;在重污染土壤中,优势类群与常见类群的种类明显减少。随着污染的加重使土壤动物的种类和数量逐渐减少。重金属污染对土壤动物群落结构的影响是随着污染的加重,多样性指数、均匀性指数、密度类群指数都有减少的趋势,优势度指数在灰场外围是先增加后减少。在群落指标的相关性中,多样性指数和均匀性指数呈密切正相关,多样性指数与优势性指数呈负相关,有机质含量与土壤动物个体数量关系不密切。     

淮南八公山区不同生境条件下的土壤动物类群比较

2010年3月—4月对淮南市八公山区4种生境土壤动物进行了调查,获得各类土壤动物1965只,隶属4门12纲27目。其中优势类群为膜翅目和近孔寡毛目,常见类群为等足目、鞘翅目幼虫、鞘翅目成虫、柄眼目、鳞翅目幼虫、蜘蛛目和山蛩目,其余类群为稀有类群。研究结果表明:植被类型对土壤动物群落的结构特征有一定影响,不同植被条件下土壤动物个体及群落类群数存在差异。土壤动物多样性与均匀度指数呈正相关,与优势度呈负相关。4种生境的土壤动物群落之间都达到了中等相似水平。从土壤动物群落数量的垂直分布来看,0 cm~5 cm土壤层数量最大,有明显的表聚现象。     

江苏常熟虞山土壤动物群落多样性研究

对江苏省常熟市虞山国家森林公园内的土壤动物进行了调查,共采得土壤动物样本 3916个,隶属于 5门 10纲,共26类群。蜱螨目、弹尾目和线虫纲是优势类群,占个体总数的88.22％,它们构成了该地区土壤动物的主体。对针阔混交林、竹林和茶园的土壤动物群落结构分析表明:土壤动物密度、类群数、多样性指数(H’)、密度-类群指数(DG)和多群落比较多样性指数(DIG)排序均为针阔混交林>茶园>竹林。茶园的均匀度指数最高。竹林的优势度指数最大。不同群落的相似性(q)分析表明,3种生境的土壤动物群落两两间的相似性指数q均大于0.5,都达到了中等相似水平。土壤动物的类群数垂直分布有明显差异,类群数向下逐渐减少。     

新疆阜康绿洲不同生境土壤动物群落多样性及其季节动态

为了查明阜康绿洲不同生境土壤动物群落多样性特征及其变化动态,2010年4、7、9及11月中旬分别以该绿洲的用材林、防护林、苗圃、耕地、盐碱地、灌木林及荒草地生境为研究对象,采用手捡法、改良干漏斗法和湿漏斗法分离0～20 cm土层中的土壤动物,并分析了不同生境土壤动物的群落结构、分布特征及季节动态.共获得土壤动物1 1098只,共35类,其中线虫类、轮虫类和弹尾类为优势类群.在7种不同生境土壤动物类群、个体数和多样性以及不同季节之间均存在显著差异(P＜0.05),其中Shannon多样性指数依次为用材林＞防护林＞灌木林＞耕地＞盐碱地＞苗圃＞荒草地;时空分布调查发现,不同生境土壤动物群落分布具有明显的表聚性特征,并在不同土层及季节间均有显著性差异(P＜0.05),季节动态变化依次为秋季最多、其次春季和冬季,夏季最少;不同生境土壤动物群落间的Jaccard相似性指数属于中等不相似(处于0.25～0.50).不同生境组间聚类和排序结果表明,将7种不同生境分为人工林生境型、人为干扰生境型、灌木生境型及荒漠生境型4大类型.结果表明,阜康绿洲不同生境土壤动物群落组成和多样性具有明显的生境和季节差异特征.     

高原鼢鼠干扰强度对祁连山东段高寒草甸大型土壤动物功能群特征及空间分布的影响

为明晰高原鼢鼠干扰对大型土壤动物类群分布和功能群特征影响,选取祁连山东段高原鼢鼠典型分布高寒草甸,依据鼠丘密度将研究区划分4个干扰梯度,调查各干扰区植物、群落结构、土壤理化性质和大型土壤动物功能群组成。采用冗余分析方法探讨植物土壤因子对土壤动物功能群组成和分布的影响。结果表明：研究区植食性土壤动物为优势功能群,极重度干扰区植食性功能群丰富度和Shannon多样性指数显著高于中度和重度干扰区(P<0.05);高原鼢鼠干扰对高寒草甸土壤动物群落稳定和相似性影响较小;冗余分析表明土壤温度、紧实度、全氮和全钾以及莎草科生物量和植物物种均匀度均显著影响高寒草甸土壤动物功能群的空间分布(P<0.05),其中土壤温度对土壤动物功能群分布影响最为显著。     

南昌城乡不同绿地中小型土壤动物群落多样性及其影响因素

城市化是导致生物多样性下降及生境破碎的重要因素,土壤动物群落作为城市生态系统的重要组成部分,在改善土壤结构及肥力、促进生态系统物质循环等方面起着关键作用。为探究城市化进程中绿地中小型土壤动物群落分布特征及其对环境因子的响应机制,本研究沿南昌市城区-郊区-乡村梯度27个绿地样方为对象,调查样方内植物信息、土壤理化性质和中小型土壤动物群落分布特征。结果表明：共捕获土壤动物1755头,隶属于2门11纲16目,其中,优势类群为弹尾纲、寄螨目和真螨目,个体数占比达81.9%;土壤动物密度、Shannon多样性指数和Simpson优势度指数均表现为郊区显著高于乡村。城乡梯度中绿地中小型土壤动物的不同营养级结构差异较大,植食者和大型捕食者在乡村占比最多,而在其他地区占比较小。冗余分析表明,冠幅、林分密度、土壤全磷是影响研究区绿地中小型土壤动物群落分布的主要环境因子,解释率分别为55.9%、14.0%、9.7%。非度量多维尺度分析说明,城乡梯度绿地中小型土壤动物群落特征呈现一定差异,地上植被因子是土壤动物群落特征差异的主导因素。本研究补充了南昌城市生态系统的研究体系,为维持土壤动物多样性和城市绿地建设...     

羊草草原土壤动物群落多样性的研究

对东北羊草草原不同生境土壤动物群落多样性研究表明 ,生境条件愈优越 ,土壤动物的多样性指数愈高 ,种类则愈丰富 .土壤动物群落的多样性与土壤有机质和全N含量呈正相关 ,与 pH呈负相关 ,与土壤自然含水量和全P含量关系不明显 .土壤动物群落多样性随土层深度的增加而减少 ,且表聚性明显 .     

薇甘菊入侵对中小型土壤动物群落 结构特征的影响

薇甘菊是菊科假泽兰属的恶性杂草,在我国华南地区已成功入侵并造成严重危害.为了解薇甘菊入侵对土壤动物的影响效应,采用野外样地试验法对广州市火炉山森林公园薇甘菊入侵群落的土壤动物进行了调查.2009年4次采样共获得中小型土壤动物5206头,隶属于4门10纲19类,其中线虫类为优势类群,蜱螨目、弹尾目和轮虫是常见类群.薇甘菊入侵地中小型土壤动物群落结构特征发生了改变,与其他样区相比,入侵区中小型土壤动物的总个体数以及线虫类、蜱螨目的个体数显著增加,但中小型土壤动物类群数的变化不明显;在群落多样性方面,薇甘菊入侵区土壤动物群落的密度-类群指数显著提高,物种丰富度、优势度指数亦有所上升,但差异不明显,而均匀度、Shannon指数趋于下降;在群落相似性方面,薇甘菊入侵区与群落交错区的相似程度较高,与土著植物区的相似程度较低.薇甘菊入侵所引起的局部气候环境、凋落物、根系分泌物与土壤理化性质的变化可能是造成中小型土壤动物群落结构特征改变的主要原因.     

薇甘菊入侵对中小型土壤动物群落结构特征的影响

薇甘菊是菊科假泽兰属的恶性杂草,在我国华南地区已成功入侵并造成严重危害.为了解薇甘菊入侵对土壤动物的影响效应,采用野外样地试验法对广州市火炉山森林公园薇甘菊入侵群落的土壤动物进行了调查.2009年4次采样共获得中小型土壤动物5206头,隶属于4门10纲19类,其中线虫类为优势类群,蜱螨目、弹尾目和轮虫是常见类群.薇甘菊入侵地中小型土壤动物群落结构特征发生了改变,与其他样区相比,入侵区中小型土壤动物的总个体数以及线虫类、蜱螨目的个体数显著增加,但中小型土壤动物类群数的变化不明显;在群落多样性方面,薇甘菊入侵区土壤动物群落的密度-类群指数显著提高,物种丰富度、优势度指数亦有所上升,但差异不明显,而均匀度、Shannon指数趋于下降;在群落相似性方面,薇甘菊入侵区与群落交错区的相似程度较高,与土著植物区的相似程度较低.薇甘菊入侵所引起的局部气候环境、凋落物、根系分泌物与土壤理化性质的变化可能是造成中小型土壤动物群落结构特征改变的主要原因.     

游动分割窗技术在生态交错带定量判定中的应用*-以四川巴郎山岷江冷杉林线为例

 以样带上样方间的距离系数为指标,采用游动分割窗技术辨析了岷江冷杉(Abies faxoniana)林线附近交错带的位置和宽度。结果表明,Bray-Curtis距离、相对欧氏距离、弦距离与平方欧氏距离的峰值和峰宽具有很好的重合性,上述距离系数均能作为判定林线交错带群落的边界和宽度的优良指标,其中,平方欧氏距离更能直观和准确地反映交错带植被的变异。样带上距离系数的峰值区和峰宽对生态交错带的位置和宽度有较为敏感的指示意义,游动分割窗技术是交错带判定和群落划分的有效方法。以样带上样方间的距离系数为指标,采用游动分割窗技术辨析了岷江冷杉(Abies faxoniana)林线附近交错带的位置和宽度。结果表明,Bray-Curtis距离、相对欧氏距离、弦距离与平方欧氏距离的峰值和峰宽具有很好的重合性,上述距离系数均能作为判定林线交错带群落的边界和宽度的优良指标,其中,平方欧氏距离更能直观和准确地反映交错带植被的变异。样带上距离系数的峰值区和峰宽对生态交错带的位置和宽度有较为敏感的指示意义,游动分割窗技术是交错带判定和群落划分的有效方法。     

游动分割窗技术在生态交错带定量判定中的应用:以四川巴郎山岷江冷杉林线为例

以样带上样方间的距离系数为指标 ,采用游动分割窗技术辨析了岷江冷杉 (Abiesfaxoniana)林线附近交错带的位置和宽度。结果表明 ,Bray_Curtis距离、相对欧氏距离、弦距离与平方欧氏距离的峰值和峰宽具有很好的重合性 ,上述距离系数均能作为判定林线交错带群落的边界和宽度的优良指标 ,其中 ,平方欧氏距离更能直观和准确地反映交错带植被的变异。样带上距离系数的峰值区和峰宽对生态交错带的位置和宽度有较为敏感的指示意义 ,游动分割窗技术是交错带判定和群落划分的有效方法。     

Distribution and dynamics of surface-dwelling spiders across a pasture-plantation ecotone

The influence of the interface between different vegetation types on the surface active spider fauna within a grass pasture-coniferous plantation ecotone was sampled by pitfall trapping Species abundance, richness and diversity relative to pitfall traps were measured along a transect across the ecotone Spider species were classified into six categories based on their habitat preference and the influence of the non-preferred habitat The number of individuals trapped progressively decreased from the pasture across the interface to the plantation habitat Species richness increased by some 12 and diversity by some 141% at the interface These increases were attributable to both the overlap of pasture and plantation species invading the non-preferred habitat across the interface and to the presence of species with a preference for the ecotone The overlap of pasture and plantation species was found to be the larger part of the spider community at the interface, species classed as ecotone accounting for only 25% of the catch at the interface Distinct spider species assemblages were found in the pasture and plantation habitats, and the interface species composition was more similar to the plantation than to the pasture The variation in physical and biological characteristics which the interface induces, and their influence on the spider assemblages found, are discussed in relation to other ecotone studies     

Promoting survival prospects of rare plants

Many hypotheses have been put forward to explain the structure and position of alpine treelines. The spatial complexity of the ecotone, ranging from sharp boundaries to networks of tree patches within a heath matrix, may explain why no consensus has been reached. In this paper, we discuss factors from abiotic disturbances to herbivory that may help understand the spatial structure of the alpine treeline ecotone in Fennoscandia. The ecotone is dominated by mountain birch (Betula pubescens ssp. tortuosa), and may show a wide range of spatial structures. We discuss the influence of topography, seed limitations, seedling establishment, growth limitations, abiotic disturbances and herbivory as structuring factors. All of these factors may operate, but their relative importance in space and time is unknown. There is a basic difference between factors that prevent the establishment of trees, and thus act on early life history stages, and factors that thin out a previously dense forest, and thus act on adult trees. Mortality caused directly or indirectly by geometrid moths may belong to the latter category. We suggest that seedling and sapling mortality is more important than seed limitation for the establishment of new individuals in the treeline ecotone. Important mortality factors may be abiotic disturbances, competition (or allelopathy) from field layer plants and herbivory. The relative role of these factors needs to be examined further.     

Properties of ecotones: Evidence from five ecotones objectively determined from a coastal vegetation gradient

Abstract. Several properties have been suggested to be characteristic of ecotones, but their prevalence has rarely been tested. We sampled five ecotones to seek evidence on seven generalizations that are commonly made about ecotones: vegetational sharpness, physiognomic change, occurrence of a spatial community mosaic, many exotic species, ecotonal species, spatial mass effect, and species richness higher or lower than either side of the ecotone. The ecotones were in a sequence from scattered mangroves, through salt marsh, rush‐marsh, scrub, woodland, to pasture. We developed a method to objectively define, by rapid vegetational change, the position and depth of an ecotone, identifying five ecotones. Their positions were consistent across three sampling schemes and two spatial grain sizes. One ecotone is a switch ecotone, produced by positive feedback between community and environment. Another is anthropogenic, due to clearing for agriculture. Two others are probably environmental in cause, and one may be largely a relict environmental ecotone. Sharp changes in species composition occurred. Three ecotones were associated with a change in plant physiognomy. In two, the ecotone was located just outside a woodland canopy, in the zone influenced by the canopy. Community mosaicity was evident at only one ecotone. There were few strictly ecotonal species; many species occurred more frequently within ecotones than in adjacent vegetation, but there were never significantly more ecotonal species than expected at random. There was little evidence for the spatial mass effect reducing ecotonal sharpness, or leading to higher species richness within ecotones. Species richness was higher than in the adjacent habitat in only one ecotone. It seems that supposedly characteristic ecotone features depend on the particular ecological situation, and the ecology of the species present, rather than being intrinsic properties of ecotones.     

大兴安岭森林草原过渡带典型植物群落动态变化特征

大兴安岭森林草原过渡带是大兴安岭森林与呼伦贝尔草原接壤的关键区域。由于过渡带本身的脆弱性,气候变化和过度放牧等人为因素的干扰导致区域内植物群落结构和功能发生剧烈变化。然而,气候变化和放牧双重作用对森林草原过渡带草地植物群落动态影响的研究还鲜有报道。以内蒙古陈巴尔虎旗森林草原过渡带为研究对象,分别于2008、2009、2010和2019年沿着草甸草原-森林草原过渡区域-林间草地-森林的梯度进行野外调查,对比分析11年间受气候变化和过度放牧的双重干扰下,该区域植物物种丰富度、Raunkiear生活型功能群、牧草饲用价值以及群落生物量随时间的变化动态。结果表明：从总体上看,与2008-2010年均值相比,2019年植物物种数量明显下降,其中禾本科牧草减少10余种;植物Raunkiear生活型功能群组成发生显著变化,其中一、二年生植物物种数增加4%,地面芽植物降低8%;牧草饲用价值中优等牧草所占比例下降5%,劣等牧草比例增加7%;总地上生物量显著下降35%。在过渡带各区段中,草甸草原群落结构和功能受气候和过度放牧影响更加明显。与2008-2010年均值相比,2019年草甸草原群落物种丰富度降低12%,优等牧草比例降低4%,劣等牧草比例增加7%,植物地上生物量更是显著降低62%。对区域气候和放牧因素分析可得,年降水量和年均温与过渡带地上生物量均显著相关,其中降水是导致过渡带整体上生产力下降的主要因素;而过度放牧是导致草甸草原群落生产力下降的主要因素。     

边缘效应的空间尺度与测度

综述了边缘效应的空间尺度类型以及在不同尺度上的测度方法.基于大量的研究整合,认为边缘效应空间尺度的划分,可以根据空间尺度的不同以及边缘效应形成和维持因素,分为大中小3个尺度类型,即大尺度的生物群区交错带、中尺度的景观类型之间的生态交错带和小尺度的斑块(生态系统)之间的群落交错区.大尺度主要是以植被气候带为标志的生物群区间的边缘效应,这种地带性的交错区主要受大气环境条件的影响.中尺度类型主要包括城乡交错带、林草交错带、农牧交错带等类型,是不同生态系统要素的空间交接地带,在物质能量等相互流动的作用下变得更为复杂.小尺度水平上是指斑块之间的交错所形成的边缘效应,受小地形等微环境条件及生物非生物等因子的制约,研究主要集中在群落边缘、林窗边缘和林线交错带等方面.对边缘效应测度的定量化研究有助于更加深入理解边缘效应.在大尺度水平上,边缘效应测度的研究主要是应用数量生态学等方法,研究不同气候带之间界线的划分及其物种分布的梯度规律性.中尺度水平上应用景观生态学的3S技术等方法,侧重于研究交错带的动态变化趋势及位置宽度的判定.小尺度水平上通过对距离边缘的长度,各群落中种群的数量、结构、多样性等定量指标的测定来构建测度公式,从而对边缘效应的强度进行量化,并反映边缘对群落的正负效应.总体上看,主要集中于中小尺度上,未来应该强化大尺度边缘效应测度的研究.     

Seasonal variation in the diversity and species richness of phytoplankton in a tropical eutrophic reservoir

The water chemistry, structure of sediment grain size, algal biomass, and patterns of nine bacteria physiological groups were studied monthly from May to October 1991 in an adjacent stream, ecotone, and reservoir zones (southern Poland). The distribution of five particulate organic carbon fractions was significantly different among the zones. Biomass of benthic algae demonstrated a maximum in the ecotone (22.74 g C m^–2). Most of the bacterial groups were more numerous in the stream sediments where aerobic heterotrophs prevailed (1.2–6.5 × 10¹¹ cells m^–2). The significant differences in density were found for anaerobic heterotrophs, anaerobic nitrogen fixing, amylolytic, and cellulolytic bacteria among the zones. The small density of bacteria in the ecotone was probably an effect of the rapid water fluctuations, accompanied by movement of fine sediments or/and an inhibitory effect of compounds secreted by the periphyton. The principal component analysis showed that the ecotone zone was more similar to the reservoir open water than to the stream.     

Variation in phytoplankton composition and limnological features in a water–water ecotone of the Lower Paraná Basin (Argentina)

1. Structure and dynamics of phytoplankton were studied at six sites in a reach of the Lower Paraná River floodplain, from the main course to a marginal shallow lake, connected through a stream. This system is defined as a water–water ecotone and thus, the aim of this work is to analyse the spatial changes of phytoplankton along the transitional system.
2. Temporal fluctuations in number of species and phytoplankton density were more pronounced in the river than in the shallow lake. Even though most species were ubiquitous, there was a clear segregation of the most abundant populations across the ecotone. Aulacoseira granulata var. granulata and other centric diatoms decreased towards the lentic system.
3. Transparency varied according to river discharge, being higher in the lake during high water phases, while the opposite behaviour was observed during dry periods. These fluctuations were related to precipitation and resuspension processes.
4. Nitrate concentration diminished towards the lake while soluble reactive phosphorus remained fairly homogeneous across the ecotone.     

Spatial scale types and measurement of edge effects in ecology

Classification of spatial scales and measurement of edge effects in ecology were reviewed. The spatial scales can be classified into large scale (biome ecotone), meso-scale (ecological ecotone) and small scale (community ecotone) through the formation and maintenance of edge effects in ecology based on the synthetic analysis of published literatures. The biome ecotone is influenced by climate, regional dominant vegetation and terrain environment. The ecological ecotone is usually distributed in the transitional region with remarkable habitat heterogeneity. It connects adjacent ecosystems and affects the flow of energy and nutrient. Nowadays, study on edge effects in ecology mainly focuses on boundary sensitivity which associates with urban-rural ecotone, forest-grassland ecotone, agro-pastoral ecotone, forest-farmland ecotone, water-land ecotone and forest-swamp ecotone. As to the community ecotone which links with different patches to the interior of the community, previous studies focused on community edge, gap edge and treelines. The borderlines of different biome ecotones and the gradients of species distribution in the biome ecotones have been investigated through the method of quantitative ecology. The dynamic change, location and width of the ecological ecotone have been studied using the Geographic Information System (GIS), Remote Sensing (RS) and Global Positioning System (GPS) technologies and the landscape ecology theory. As important indicators, distance from edge, population, structure and diversity determined for establishing models can be applied to measure the intensity of edge effects and decide the positive or negative impact on communities. Although study on the edge effects in ecology was mostly reported at the meso-scale and small scale, study at large scale should be paid more attention as it is the potential value in ecology and global change fields.