封育柞蚕场蒙古栎林不同恢复阶段种群结构与群落多样性研究

采用空间代替时间的方法,以柞蚕场蒙古栎在平茬后经不同时间(9年、12年、57年)封育保护而形成的蒙古栎次生林及对照柞蚕场蒙古栎林(3年生)为研究对象,对辽东山区蒙古栎次生林不同恢复阶段的种群结构与群落多样性进行了深入分析。研究结果表明:随封育林龄的增长,乔木层蒙古栎种群所占的重要值比例在降低,蒙古栎林在恢复演替进程中不断向阔叶混交林的方向发展;灌木物种间的重要值差距在减小;草本层植物种类在不断减少;蒙古栎林优势种群径阶分布宽度增加,径阶分布趋向于正态分布。在封育不同恢复阶段,羊胡苔草重要值均表现为最大,是草本群落最主要的物种。不同恢复阶段林分乔木层、灌木层物种多样性表现为随封育林龄的增长而增大,草本层多样性表现为随封育林龄的增长而减小。     

封山育林效果调查初报

在桓仁县北甸子和沙尖子老烧柴场设置固定样地,经过10a封育试验,结果表明,封育效果良好.封山育林比人工更新造林节省营林投资;封育林分林木长势与是否抚育和抚育起始期有关,经过抚育的林分林木生长迅速,蓄积量较未抚育的林分大;林分郁闭后抚育较郁闭前抚育林木干形好,在林分郁闭后7～8a开始抚育为宜.     

辽东山区现有柞蚕场的生态效益分析及可持续经营对策

文章通过对现有柞蚕场及停蚕后封育的柞树林现状调查,结果表明,现有部分柞蚕场沙化严重,主要表现在植被群落组成单一,柞木灌丛稀疏,层次结构不明显,缺乏草本、灌木层植物,植被覆盖度低,沙石裸露,有机质含量很少。杂木林和封育蚕场枯枝落叶生物量比正在放蚕的柞蚕场提高85.0%、3.5%和182.4%;枯枝落叶的持水量提高118.0%、51.7%和90.5%;柞蚕场封育后的林分土壤自然含水量、毛管持水量、田间持水量及最大含水量均高于放蚕的柞蚕场;毛管孔隙度、总孔隙度柞蚕场封育后的林分土壤明显高于柞蚕场;柞蚕场封育后的林分0~20cm土层有机质、全氮、碱解氮平均含量比正在放蚕的柞蚕场提高49.6%~116.5%,25.0%~100.0%,2.7%~38.4%,对柞蚕场生态效益、柞蚕生产过程以及柞蚕场遭到破坏的原因等方面进行分析,提出实现柞蚕场的可持续经营对策及建议。     

火烧对落叶松白桦林物种多样性的影响

对大兴安岭松岭林业局所辖的古源林场和绿水林场不同年代落叶松白桦林火烧迹地的植被恢复情况进行了调查,用α多样性对火烧后乔木层、灌木层、草本层进行评价。结果表明:物种多样性指数在火烧后表现为先增加后减小,然后急速增加,在火烧20a后除草本层多样性指数继续增加外,乔木层和灌木层逐渐趋于稳定状态;在火烧后4a之内乔木层物种均匀度指数降低,灌木层和草本层均升高;草本层的丰富度指数在火烧后变化较大,乔木层和灌木层由于受物种基数低而变化较小。     

封育对华北落叶松低效人工林林下植被的影响

以木兰围场国有林场40a左右生华北落叶松低效人工林为对象,采用样地、样方测定法研究了封育2a对不同抚育疏伐保留密度林分林下植物群落植物组成与结构的影响,结果是保留密度为825株·hm-2和500株·hm-2的低效人工林,经封育后林下植物种类及个体数量都增加,增加者主要为草本植物,增加量低密度林分高于高密度林分;灌木层平均高度和盖度增加,盖度增加幅度低密度林地大于高密度林地;高密度林地草本层优势种(批针薹草)不变,低密度林地原次优势种(小红菊)上升为优势种,而原先的优势种(金毛狗尾草)衰退为次优势;草本植物Margalef丰富度指数、Simpson指数、Shannon-Wiener指数、Pielou均匀度指数等4个物种多样性指数高密度样地和低密度样地都有相应提高,封育可以提高林分林下多样性,高密度林分提高幅度大于低密度林分;综合考虑,为改善林下植物群落结构,40a生左右华北落叶松低效人工林抚育改造适宜保留林分密度为500株·hm-2左右。     

封山育林对华北落叶松林枯落物层持水能力的影响

为了研究封山育林对华北落叶松枯落物层水源涵养能力的影响,选择未封育、封育2年与封育4年华北落叶松林作为研究对象,采用室内浸泡法来测定枯落物层各项指标,结果表明:(1)采取封育措施后华北落叶松人工林枯落物的厚度与蓄积量随时间增长而增加,大小排序为封育4年>封育2年>未封育;(2)采取封育措施后枯落物最大持水量都有所增加;(3)枯落物层有效拦蓄能力由大到小排序为封育4年(40.33thm^-2)>封育2年(37.40thm^-2)>未封育(34.97thm^-2)。封育措施对林分枯落物层有效拦蓄量有一定的影响,但是增加的幅度不大。在对林分进行封育措施的同时应结合其他经营措施,以更加有效地提高林分枯落物层对水分的拦蓄量。     

松栎混交林抚育对林下灌草多样性的影响

以中村林场大庙岭油松-辽东栎混交林为研究对象,采用典型样地调查法,运用Patric丰富度指数、Simpson和Shannon-Wiener多样性指数、Pielou均匀度指数研究目标树全林经营前后林下灌草多样性的变化。结果表明:1)抚育后林下灌木层、草本层物种多样性都有增加,说明目标树全林经营有利于增加林下物种多样性。2)灌木层物种各指数在经营前后差异极显著(P0.01),草本层丰富度指数、多样性指数差异不显著(P0.05),均匀度指数降低,差异极显著(P0.01),这说明目标树全林经营对灌木层多样性影响较大;经营后灌木层均匀度增加,草本层物种均匀度降低。3)林下结构多样性受灌木层和草本层的综合影响,不同层次的物种对林下物种多样性的贡献不同,松栎混交林下多样性主要由灌木层决定。     

白龙江林区天保工程实施后封山育林技术措施

对具有培育前途的疏林地和具有一定数量的母树、幼苗、幼树、萌蘖根株的无林地进行封育,同时将新造林地、飞播区、直播区纳入到封育区内,封育对象分为两大类型:即封山育灌和封山育林。封育方式采用全封、半封轮封3种;一般采用乔木型5～8 a,乔灌型3～6 a,灌木型3～5 a;封山育林的主要措施包括除草除蔓、破土整地、间苗移植、补植补播、平茬复壮和人工促进天然更新等内容。     

不同林龄桉树林下植被多样性分析

以广东省信宜市中部山区不同林龄（3 a 生和 5 a 生）桉树人工林为研究对象,通过样地调查, 统计和分析了桉树林下植被结构特征（种类组成、结构与分布）和物种多样性（Margale 丰富度指数、 Simpson 优势度指数、Shannon-Wiener 指数和 Pielou 均匀度指数）。结果表明：（1）3 a 生桉树林下植被共 记录维管束植物23 科 31 属 33 种,5 a 生桉树林林下植被共记录维管束植物 24 科 32 属 35 种,不同林龄 桉树林下植被结构与分布特征差异较大,乔木幼苗、灌木层和草本层的优势种均明显不同;（2）林龄对 桉树林下植被丰富度影响相对较小,但对优势度和均匀度影响较大;随着林龄的增加,桉树林下灌木层 和草本层植被物种多样性均明显下降,其中灌木层下降幅度大于草本层。总体而言,林龄对林下植被的 种类组成影响相对较小,但对林下植被的结构与分布以及物种多样性有显著影响。     

广东顺德5种类型人工林群落物种的多样性

对顺德区5种人工林群落物种多样性进行了定量研究.结果表明:窿缘桉、台湾相思与湿地松群落物种多样性指数为灌木层>草本层>乔木层,针阔混交与阔叶混交群落物种多样性指数为灌木层>乔木层≥草本层,均匀度指数(E a除外)为灌木层>草本层>乔木层;群落间乔木层差异显著,灌木层与草本层变化趋势相对较复杂,但针阔混交林群落与阔叶混交林群落之间,窿缘桉、台湾相思与湿地松群落间无显著差异;7种多样性指数中,乔木层与灌木层采用的研究指数幅度更宽广,可采用SP、SW与P指数测度物种多样性,草本层采用Jsp、P指数较好;提出了基于物种多样性的人工林群落管理措施.     

Wildlife species associated with non-coniferous vegetation in Pacific Northwest conifer forests: A review

Non-coniferous vegetation, including herbs, shrubs, and broad-leaved trees, makes a vital contribution to ecosystem function and diversity in Pacific Northwest conifer forests. However, forest management has largely been indifferent or detrimental to shrubs and trees that have low commercial value, in spite of a paradigm shift towards more holistic management in recent decades. Forest management practices that are detrimental to broad-leaved trees and shrubs are likely to decrease habitat diversity for wildlife, but the number of species that may be affected has not previously been enumerated. I reviewed life history accounts for forest-dwelling vertebrate wildlife species and derived a list of 78 species in Oregon and Washington that are associated with non-coniferous vegetation. The diversity of direct and indirect food resources provided was the primary functional basis for associations of most species with non-coniferous vegetation. Thus, a diversity of herbs and broad-leaved trees and shrubs provides the foundation for food webs that contribute to diversity at multiple trophic levels in Pacific Northwest conifer forests. Given the number of species associated with non-coniferous vegetation in conifer-dominated forests, maintaining habitats that support diverse plant communities, particularly broad-leaved trees and shrubs, will be an important component of management strategies intended to foster biodiversity. Silvicultural practices such as modified planting densities, and pre-commercial and commercial thinning, can be used to control stand density in order to favor the development of understory herbs, shrubs, and a diversity of tree species within managed stands. Allowing shrubs and hardwood trees to develop and persist in early seral stands by curtailing vegetation control also would benefit many species associated with non-coniferous vegetation.     

次生林群落结构特性对红松幼树生长的影响

本研究以红松幼树及其周围最近4株相邻木组成的小环境结构单元为研究对象,研究了光照条件、土壤腐殖质层厚度、相邻木、直射光、上层树种、草本和灌木等6个环境因子对红松幼树生长的影响。本文对其中的直射光、上层树种、草本和灌木等3个群落结构特征因子进行研究。结果表明：(1)顶部透光对红松幼树生长最为有利,其次为东、西北、东南及中部等方向的直射光;(2)上层树种为叶片小或枝叶稀疏的树种时对红松幼树生长有利。(3)草本和灌木的盖度会影响红松幼树的生长,且在红松幼树的不同生长阶段,其影响作用不同。当红松幼树仍处于下木层时,草本和灌木会抑制红松幼树的生长,当红松幼树离开草灌丛后,草本、灌木影响作用将逐渐减弱。     

次生林火后演替过程中物种变化及相互关系

采用植被空间序列代替时间系列的研究方法,分析黑河地区近20 a来不同重度火烧迹地上植被的演替变化。研究表明：火后初期,草本、灌木迅速占据火烧迹地,灌木在数量和盖度上不及草本,随着火烧年度的推移,草本、灌木在数量和盖度上逐渐减少,物种结构也发生了很大的变化,乔木在数量和盖度上呈上升趋势。研究发现,灌木、草本高频物种所占比例较高且呈上升趋势,灌木高频物种高于草本的高频物种。另外还发现不同火烧迹地上灌木物种的相似度高于草本物种相似度,相似度范围波动较大,火烧迹地上相邻年份物种的相似度高于年份相差久远物种的相似度。     

Fine roots refilling process in an artificial gap in a Picea mongolica forest

Picea mongolica is an endemic but endangered species in China. The spruce forest is only found in sandy forest-steppe ecotones. In this study, we examined the initial response of the quantity and refilling process of fine roots in an artificial canopy gap with a diameter of 36 m in a P. mongolica forest. Under the canopy, the fine root length densities of trees, shrubs and herbs were 2,622, 864 and 3,086 m·m–2, respectively. The fine root biomass of trees, shrubs and herbs were 148, 62 and 65 g·m–2, respect...     

Diversity and regeneration status of Sarkot Van Panchyat in Garhwal Himalaya, India

We investigated the floristic composition, phytosociological and regeneration status of Sarkot Van Panchyat (community forest) in Chamoli district of Garhwal Himalaya. A total of 52 plant species of 46 genera and 26 families were recorded, which included 12 trees, 18 shrubs and 22 herb species. Quercus leucotrichophora was dominant tree species in sapling and seedling layers, followed by Lyonia ovalifolia and Rhododendron arboreum.Out of 12 tree species, 7 species in seedling stage and 8 species in sapling stage were recorded in the study area. The 44.41% species in the study area showed good regeneration status, 16.66% species were fairly regenerating,and 8.33% species showed poor regeneration status, while 33% species were not regenerating. Number of individuals from lower girth classes (0 10 cmand 10 30 cm) showed decreasing trend with the increase in size of girth class. Shannon index (H) for trees, shrubs and herbs was recorded as 1.82,2.24 and 2.41 respectively. Simpsons index (CD) was recorded as 0.21, 0.12and 0.12 for trees, shrubs and herbs respectively. The forest should be divided into compartments for better management purpose and each compartment should be closed for five years to assist regeneration and enrichment planting may also be carried out for sustainable management.     

城市近郊林土壤种子库研究

对沈阳、抚顺两城市交接的近郊林区不同林分类型土壤种子库进行研究.结果表明:不同林分类型土壤种子库均具有较好的储量和活力,其储量大小顺序为:乔木林地＞灌木林地＞宜林荒地,土壤种子库物种多样性指数大小顺序为:灌木林地＞乔木林地＞宜林荒地,种子种类以乡土树种为主;数量化分析表明坡位对乔木林地及灌木林地中土壤种子库储量和活力影响较大,而植被覆盖度对宜林荒地中土壤种子库储量和活力影响较大.     

八大公山国家重点保护野生植物繁殖特性

以八大公山国家级自然保护区35种国家重点保护野生植物为研究对象,对植物的科属、保护级别(I级、II级)、生活型(乔木、灌木、草本)、自然条件下繁殖属性(有性繁殖、无性繁殖)以及种子传播方式(脊椎动物传播、蚂蚁传播、鸟类传播、风传播)进行分类。结果表明:八大公山国家级自然保护区的35种国家重点保护植物隶属于22科27属,有国家I级保护植物6种,国家II级保护植物29种,乔木为28种,占80%,灌木与草本较少;自然条件下,35种保护野生植物均为有性繁殖,其中金毛狗为有性孢子繁殖,其余为种子繁殖;种子(孢子)传播方式中脊椎动物传播为18种,鸟类传播为14种,风传播为3种,分别占总物种数目的 51.43%、40.00%和8.57%。可见,八大公山国家自然保护区脊椎动物和鸟类的减少导致植物繁殖扩散困难可能是国家重点保护野生植物数量进一步减少的重要原因之一。     

Comparison of fractal characteristics of species richness patterns among different plant taxonomic groups along an altitudinal gradient

This study was done using the non brown fractal model to quantify and compare the variations in the species richness of trees, shrubs, herbs and all plants along an altitudinal gradient and to characterize the dominating ecological processes that determine the variations. Two transects were sampled far away from any anthropogenic disturbances along the shady slopes of the Dongling mountains in Beijing, China. Both transects were continuous and 2 m wide, and every individual tree and shrub was recorded in each of them. Discrete quadrats of 1 m × 1 m were located along the transects A and B for estimation of the herb species richness along the altitudinal gradients. The level interval between the quadrats was 10 m and 25 m respectively. In this study, transects A and B were combined into one transect AB, and 40 m was selected as the optimal quadrat length along the altitudinal gradients for measuring the plant species richness patterns. Species richness in each quadrat was calculated using a program written in Matlab 6.0. Direct gradient analysis was used to describe the overall trends in the species richness of trees, shrubs, herbs and other plants with change in altitude, while the non-brown fractal model was used to detect more accurately their variations at various scales along the gradient. The model assumed that each class of ecological processes affecting the distribution of a variable could be represented by an independent spatial random function. Generally, ecological phenomena are determined not by a single ecological process but by multiple ones. These processes act on ecological patterns within their own spatial scales. In the non-brown fractal model, the spatial random functions are nested within a larger range of spatial scales. The relative contribution of the spatial random functions to the spatial variation of a variable is indicated by a weighting parameter that has to be greater than or equal to zero. In this paper, we reached the following results and conclusions. Firstly, the direct gradient method describes the general trends of trees, shrubs, herbs and all plants along the altitudinal gradient but is unable to provide further details on the altitudinal variations in the species richness. The non-brown fractal model brought out the altitudinal variations in the species richness of trees, shrubs and herbs at various scales and related them to the ecological processes. The sharp changes in the double-log variograms suggest that the non-brown fractal model is suitable for characterizing the altitudinal patterns in the species richness of trees, shrubs and herbs at various scales but is not appropriate for explaining the variations in the plant species richness, since no significant changes were found in the double-log variograms in this case. Secondly, for the trees, the double-log variogram was divided into two scale ranges (0–245 m and 245–570 m), with a fractal dimension of 1.83 and 1.10, respectively, implying that changes in the tree species richness were random at small scales (0–245 m) and almost linear at large scales (245–570 m) along the altitudinal gradients. This suggests that altitudinal variations in the tree species richness are dominated by short-range processes at small scales and by long-range processes at large scales. Thirdly, for shrubs and herbs, the double-log variograms exhibited three ranges (0–101 m, 125–298 m and 325–570 m), and the fractal dimensions were 1.78 and 1.97, 1.56 and 1.43, and 1.08 and 1.25, respectively. The results indicate that, as in the case of trees, species richness of shrubs and herbs are distributed randomly at small scales and change in a linear manner at large scales although variations in the herb species richness is less heterogeneous than shrub species richness at large scales. These results also indicate that species richness of shrubs and herbs change approximately like brown movement at middle scales. The results also suggest that altitudinal variations in the specie richness of shrubs and herbs are dominated by three ecological processes, short-range ecological processes at small scales, long-range ecological processes at large scales, and brown fractal processes at middle scales. Interestingly, comparisons of the variations in the species richness of shrubs and herbs reveal that shrubs and herbs present the same scale range in spatial variation in species richness but display different trends in species richness along the altitudinal gradient, i.e. the shrub species richness decreased with increasing elevation whereas the herb species richness peaked at the mid-high elevation. These patterns suggest that although the scales at which the main processes affect patterns in species richness are the same, the processes are completely different, or the processes are similar but the responses of the shrubs and herbs to the ecological processes are different. Finally, the plant species richness did not show any obvious pattern along the altitude gradient and maintained a constant fractal dimension across all scales, this is perhaps because the processes defining the patterns of plant species richness had similar weights and acted over closely related scales. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(6): 901–909 [译自: 植物生态学报]