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1.
栎类和阔叶混交林林分结构多样性的动态研究   总被引:1,自引:0,他引:1  
林分结构多样性是反映林分结构状况的指标,它对于生物多样性保护、森林生态系统经营,森林结构优化调整具有重要的指导意义。通过对河南西峡县栎类、阔叶混交林连续清查样地的研究表明,在10 a的间隔期内(1993-2003年),栎类物种多样性和均匀度指数差异显著,物种与大小多样性、大小多样性变化均不显著。在更短的时间间隔期(如5 a)内,则表现为1993-1998年栎类的物种多样性、均匀度差异显著;1998-2003年期间,物种均匀度与物种多样性表现均为不显著。阔叶混交林在1993-2003年期间除大小多样性差异显著外,物种多样性和均匀度均表现为差异不显著。  相似文献   

2.
林下植物多样性影响因素研究进展   总被引:7,自引:0,他引:7  
生物多样性是衡量森林质量的重要指标,生物多样化是生态系统稳定的基础.综述了影响林下植物多样性的因素,指出:1)混交林的生物多样性优于纯林;2)老龄林群落具有较为丰富的物种和复杂的垂直层次结构;3)林分密度越小,越有利于林下植物的多样化;4)适度的间伐强度可显著提高林分的生物多样性.  相似文献   

3.
天然林植物物种多样性及其保育策略   总被引:1,自引:0,他引:1  
物种多样性是物种水平上的生物多样性,反映了群落的本质结构特征。开展天然林物种多样性的研究对我国天然林保护有重要意义。文章概述了天然林不同林分类型及层次结构、不同生境、不同演替阶段、林窗和人为干扰群落物种多样性变化,并提出了保护天然林物种多样性的建议。  相似文献   

4.
在对雾灵山自然保护区9个代表林分物种多样性详细调查的基础上,运用多种群落多样性指数对其群落的物种多样性进行分析。结果表明:各群落在乔木层、灌木层和草本层的物种多样性指数均呈现出一定的差异。乔木层物种多样性、P ielou均匀度指数和丰富度指数变化趋势呈一致性。灌木层和草本层均出现不一致性,主要是因为各林分起源不同,天然林群落是由处于不同发育阶段、具有不同组成结构、大小不同的众多斑块镶嵌而成的,是一个健康的生态系统。人工林群落的生物多样性很低,使人工林群落无论在活力、组织结构和恢复能力等诸方面,均表现出系统的不健康特点。  相似文献   

5.
[目的]探究林分空间结构、物种多样性随尺度变化的规律及林分空间结构与物种多样性的相互关系,为鄂西南常绿落叶阔叶混交林可持续经营提供科学依据。[方法]以鄂西南七姊妹山自然保护区、木林子自然保护区和金子山国有林场3个研究区的典型植被——亚热带常绿落叶阔叶混交林为研究对象,基于各研究区大样地调查数据,分析从20 m×20 m到200 m×200 m不同尺度下,林分空间结构指标和物种多样性指数及其随尺度变化的规律,结合Pearson相关系数法解析尺度变化影响下的空间结构指标与物种多样性的相关性。[结果]鄂西南地区常绿落叶阔叶混交林中物种丰富,常见优势乔木树种为川陕鹅耳枥、多脉青冈和锥栗。林分空间结构特征在尺度≥120 m×120 m后变化趋于稳定,整体表现出微聚集分布、大小分化中庸且混交良好的状态。不同尺度上林分空间结构参数角尺度与林分物种多样性存在中度相关性(P <0.01),其他结构参数与林分多样性不存在相关性。[结论]鄂西南亚热带常绿落叶阔叶混交天然林,林分空间结构调查的最适尺度为120 m×120 m;不同研究尺度下,角尺度是林分空间结构影响物种多样性的一个关键因子。  相似文献   

6.
不同强度人为干扰对马尾松林分结构及物种多样性的影响   总被引:7,自引:2,他引:5  
分析了不同强度人为干扰条件下马尾松林分结构特征及其物种多样性的差异。结果表明:随着人为干扰强度的减轻,马尾松林分的高度级及径级结构趋于完整,但由于轻度干扰林分郁闭度大、林内透光率较小而使得林下更新受到阻碍,应予以单株间伐利用;物种多样性的各测定指标也随着干扰强度的下降而增加,减少外界破坏因素有利于物种多样性的恢复,当封育林分达到郁闭时,可进行合理的保护性利用。  相似文献   

7.
小陇山不同灌木林地改造模式林分树种多样性研究   总被引:2,自引:0,他引:2  
生物多样性研究已经成为生态学研究的热点,而维持物种多样性是目前森林经营研究的一个主要内容。本文运用点抽样方法研究了甘肃小陇山5种不同的灌木林地改造模式的树种多样性。结果表明:带状割灌改造模式林分的树种较全面清理割灌模式丰富,Shannon-Wiener指数与Margalef指数较高,林分的树种多样性较高,林分内各树种分配较为均匀,带状割灌改造更有利于提高林分的树种多样性;在3种全面清理割灌改造模式中,改造日本落叶松模式虽然树种数与其它2种相同,但林分内树种分配均匀性差,集中性高。不同的改造模式对林分树种多样性的影响不同,这对提高和保持改造林分的物种多样性具有一定借鉴意义。  相似文献   

8.
在对玫瑰湖湿地物种现状进行统计分析的基础上,建立湿地生物多样性评价指标体系与赋值标准.从物种多样性和生态系统多样性两个指标对玫瑰湖’湿地生物多样性进行了评价。玫瑰湖湿地生物多样性总评分为68.5分,结果表明玫瑰湖湿地生物多样性处于一般水平。  相似文献   

9.
为了解华北落叶松人工林物种多样性随林分年龄的变化规律,对燕山北部地区不同年龄华北落叶松人工林的生物多样性进行调查和分析。研究结果表明:3种林龄的落叶松人工林在物种丰富度指数、Shannon-Wiener指数以及均匀度Pielou指数都以9 a生华北落叶松人工林为最高,其次为33 a生华北落叶松人工林,而18 a生华北落叶松人工林最低;林隙林隙地段物种多样性明显高于非林隙。随林分年龄的变化,华北落叶松人工林物种多样性没有表现出明显的规律性,与林分年龄相比,林分郁闭度以及林隙的数量对物种多样性的影响更大。  相似文献   

10.
采用固定样地和样方法调查了小陇山林区百花林场3个实施不同经营措施的锐齿栎天然林林分特征和物种组成,运用4种常用的物种多样性指数对调查林分的乔木层、灌木层和草本层的物种多样性进行对比分析,结果表明:3种类型锐齿天然林的灌木层相对于其乔木层和草本物种组成丰富,多样性高;长期封育后的锐齿栎天然林群落在3种天然林类型中物种组成最丰富,乔木层、灌木层和草本层的Shannon-Wiener指数、Pielou指数和Margalef指数值在3个林分中最高;近自然技术单株经营后的锐齿栎天然林各层次的物种组成相对较少,多样性较低,但其林分中保留的乔木树种个体较大;结构优化抚育后的锐齿栎天然林的物种组成和多样性介于二者之间.抚育经营措施对林分的影响与抚育经营强度密切相关,适当的抚育经营强度能够促进林分多样性提高,否则会带来不利的影响,结构化森林经营技术是一种有效的经营方法.  相似文献   

11.
Biodiversity conservation is one of the important ecosystem services that has been negatively impacted by anthropogenic activities. Natural forests (NF) harbor some of the highest species diversity around the world. However, deforestation and degradation have resulted in reduced forest land cover and loss of diversity. Homegarden agroforestry (AF) systems have been proven to be an intermediary for biodiversity conservation. In this study, we evaluate the effectiveness of home garden AF practices to conserve tree species diversity in Bangladesh and compare them with tree species diversity in NF. A total of nine locations were selected for this synthesis from published literature which comprised of five AF sites and four NFs. Shannon?CWeiner Diversity Index (H) was similar for home-garden AF (3.50) and NF (2.99), with no statistical difference between them. Based on non-metric multi-dimensional scaling (NMDS) ordination analysis, the AF and NF plots showed distinct separation. However, Bray?CCurtis dissimilarity index ranged from 0.95 to 0.70 indicating nearly no overlap in species composition to significant overlap between AF and NF. Based on our results, we conclude that AF can serve as an important ecological tool in conserving tree species diversity, particularly on landscapes where NF fragments represent only a small fraction of the total land area. Creating and maintaining AF habitats in such human dominated landscapes should be part of the biodiversity conservation strategy.  相似文献   

12.
Woody plants diversity and possession in small-scale tree and shrub growing practices among farmers of central highland Ethiopia were assessed by using a complete census of the trees and shrubs existing on farmers’ lands. The future prospects of diversity and possession of woody plants in the agricultural landscapes were also investigated by using the farmers’ species preferences and seedling demands as indicators. Comparisons were made across wealth classes, proximity clusters to a nearby state forest and land uses. It was found that 27 tree and 21 shrub species exist on lands of the studied households. With increasing wealth status of the households, the tree and shrub species richnesses increased. Tree and shrub species richnesses were highest in boundary plantings and homesteads respectively. Small-scale woodlots had the highest number of tree stems while homesteads contained the highest number of shrub stems. The number of tree stems a household possesses is strongly influenced by distance from the state forest, family size, educational level of the household head and number of iron-roofed houses owned. And, the shrub stems possession is significantly influenced by wealth status, distance from the state forest, land holding size, family size, livestock holding, age of wife and possession of off-farm income sources. The species preference analysis and seedling demand computations indicated that the woody species diversity is less likely to change in the future because there is no difference between the currently existing species and the preferred ones. Nonetheless, the number of tree and shrub stems on the farmers’ holdings could increase if the seedling demands of the preferred woody species are met.  相似文献   

13.
Biodiversity is declining throughout southern African miombo woodlands due to poor land use practices that are detrimental to soil, vegetation and habitat. We aimed at examining tree and shrub species diversity and distribution in Uapaca kirkiana-dominated woodlands under three land tenure types; forest reserves, customary and leasehold land. The study was conducted at different forest sites within similar agroecological zone in southern Malawi. Study sites were located at a range of altitudes between 900 and 1,200 m a.s.l. Three circular plots each with 32.60 m radius were established at each study site to sample tree and shrub species composition, structure and distribution under three land tenure types. We found that forest reserves had higher species diversity with an average of 16 tree families, 27 genera and 34 species as compared to only 10 tree families, 6 genera and 6 species on customary forest lands. Comparisons of diameter at breast height size class distributions showed that customary land had significantly low numbers of small (5.0–10.0 cm) and very large (≥30 cm) diameter classes suggesting lower levels of regeneration and high rate of anthropogenic activities. The high species diversity and richness in forest reserves and leasehold land indicate high potential for protected lands to restore tree species diversity. It is concluded that levels of human activities as influenced by land tenure type reduce tree species diversity, composition and distribution at the different sites, and this confirms the hypothesis that open access lands are not compatible with conservation of tree and shrub species diversity because of high anthropogenic activities.  相似文献   

14.
川中丘陵区防护林群落多样性研究   总被引:3,自引:1,他引:2  
本文对川中丘陵地区主要防护林群落的物种多样性进行研究,结果表明:①该流域共有维管束植物55科,82属,88种,其科、属、种数与四川省乃至全国比较,官司河流域植物区系具有组成简单的特点;②物种丰富度,物种多样性和均匀度指数都是人工林低于天然次生林,纯林林分低于混交林分;③土壤pH值、土壤有机质、土层厚度和人为干扰是影响防护林群落多样性发育的重要制约因子,其中土壤pH值是主导因子,制约着本区防护林群浇的空间分布格局;④林木高度、郁闭度和灌、草层盖度与物种丰富度、物种多样性指数和均匀度指数相关密切,对群落多样性发育的影响较大;而林木胸径与群落多样性指数相关不明显,对群落多样发育的影响不大。  相似文献   

15.
In Europe, the English yew species (Taxus baccata L.) is endangered. Intensive human land-use, including forest management, has caused a decrease of the yew populations all over Europe. In Austria, gene conservation forests are used for the in situ conservation of populations of this rare tree species by silvicultural treatments. In order to improve the conservation management in these gene conservation forests, this study addresses the relation between competition and viability of yew populations through the use of structural diversity indices. The structural indices, which include mingling, tree–tree distance, diameter, and tree height differentiation, were determined for a structural group of four trees as well as the neighbouring trees of the male and female yews at the monitoring plots on a regular grid in three gene conservation forests. Although the three study sites provided quite different environmental conditions for English yew, the vitality of each individual yew was influenced by the inter-specific competition of the neighbouring tree species at all sites. Low vitality was associated with a small mean distance to neighbours and large tree height differentiation. In conclusion, we suggest that a combination of different structural indicators is needed for an integrative assessment of conservation status in the gene conservation forests. This would help improve the evaluation of the impact management has on yew population viability.  相似文献   

16.
生物多样性研究现状与保护   总被引:4,自引:1,他引:3  
生物多样性已成为生物学、生态学等学科最为热门的研究领域之一。生物多样性内涵丰富,虽然学者对其描述不同,但核心内容相差不大。生物多样性具有巨大的价值,且某些价值尚未被人类发现或利用。生物多样性包含遗传多样性、物种多样性和生态系统多样性,也有学者建议加入景观多样性。针对各个层次的研究均取得了较大的进展。由于自然或人为原因,生物多样性在世界范围内遭到了严重破坏,世界各国对此都采取了相应的措施。  相似文献   

17.
通过对汉江集团不同性质园林绿地面积等指标的详细调查,并统计各绿地乔灌物种的株数,按单位的性质进行园林绿地性质分析和物种多样性的比较,得出不同性质的单位绿地所占面积、绿地性质、物种多样性指数是不同的。这一研究结果可为企业的园林绿地建设提供一定的科学依据。  相似文献   

18.
杨凌乔灌草型绿地植物群落空间结构特征   总被引:1,自引:0,他引:1  
对杨凌示范区绿地密度、间距、覆盖度3项水平结构指标,乔灌草比例、林层比2项垂直指标,树种丰富度、多样性等树种组成结构指标等进行测定。树种丰富度、多样性、均匀度和单调度分别采用Margalef指数(R)、Shannon-Wiener指数(H)、Pielou指数(J)和Simpson指数(M),从整个样地,样地乔木层和灌木层3个方面分别计算。结果表明:10个样地的植株密度较为合理;聚集指数R表明各样地植株都属于均匀分布;西北农林科技大学南校区和教嫁园的覆盖度较好;各样地乔灌草比例不尽合理;西北农林科技大学北校区和水保所的林层比较好;各样地的R值为0.985 4~3.40 29,H值为1.054 9~2.231 6,J值为0.693 1~0.968 8,M值为0.125 0~0.413 6。  相似文献   

19.
树种组成指数及其应用   总被引:3,自引:1,他引:2  
树种组成式仅为一个文字表达式,不便于林分间进行树种多样性的定量分析与比较。本文引入Shannon物种多样性指数,提出树种组成指数的概念,用树种组成指数可以定量描述林分树种多样性。用树种组成指数表,可迅速查出树种组成指数,应用十分方便。  相似文献   

20.
北京八达岭植物群落多样性特征分析   总被引:5,自引:0,他引:5  
根据34个样地的调查资料,分析了该地区森林植物群落物种多样性的特征:群落内各层物种丰富度指数的大小为草本层>灌木层>乔木层;多样性指数的大小为乔木层<灌木层和草本层。灌木层与草本层的多样性指数随林分郁闭度变化而变化,在林分郁闭度为25%的侧柏黄栌混交林中,灌木层的多样性指数和丰富度指数小于草本层;在郁闭度53%的杂木林中,灌木层和草本层的多样性指数接近;在郁闭度53%以上的各个群落内,草本层的多样性指数和丰富度指数基本上都大于灌木层。人工林中的物种多样性变化多样,明显低于天然林,林分层次单一,更新不良,缺乏灌木层和地被植物,生态系统很不稳定。  相似文献   

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