南亚热带季风常绿阔叶林不同演替阶段物种-面积关系

通过对云南普洱地区季风常绿阔叶林演替15年、30年及原始林群落的调查,探讨了不同演替阶段群落的物种-面积关系.结果表明:不同演替阶段群落中,取样面积与总物种数,乔木、灌木和藤本物种数均具有极显著相关关系,其变化解释率均超过94%;演替30年群落中总物种和乔木的物种累积速率(Z)最低(0.334和0.394),演替15年群落中灌木和藤本的Z值最低(0.437和0.326);不同演替阶段中总物种、乔木、灌木和藤本的物种-面积曲线截距无显著变化,但原始林中总物种和藤本物种-面积曲线的决定系数(R2)显著高于演替15年和30年群落.演替15年群落中,初始乔木及灌木物种丰富度解释了Z值变化的99.9%,而其他演替阶段群落中初始乔木、灌木、藤本及总物种丰富度与Z值均无显著相关性.     

云南普洱季风常绿阔叶林演替系列植物和土壤C、N、P化学计量特征

通过测定中国西南季风常绿阔叶林不同演替阶段(演替15a,演替30a及原始林)群落中植物叶片与土壤中C、N、P含量,探索了季风常绿阔叶林不同演替阶段群落C、N、P化学计量特征及其与物种丰富度及多度的相关性。结果表明:土壤及植物中全N、全P含量及土壤中C含量均为演替30a群落中最低,而植物中C含量在不同演替阶段群落间无显著性差异。在不同演替阶段共有种中,40%的物种N含量原始林中最高,40%的物种P含量演替15a群落中最高,而80%的物种C含量无显著性差异。土壤中C:N比在不同演替阶段间无显著变化,而N:P及C:P比则随演替呈减小趋势。植物中C:N及C:P比均为演替30a群落最高,而N:P比则随演替呈增加趋势。不同演替阶段共有种的C:N比中,40%的物种原始林中最低,40%的物种无差异,而C:P与N:P比中则均有60%物种无显著性差异,但70%物种在演替15a群落中N:P小于14,演替30a群落中50%物种N:P在14—16,原始林中则有80%物种N:P大于16。群落物种丰富度及个体多度均与C:N、N:P、C:P无显著的相关性,但植物中的N、P与土壤的N、P分别具有显著的线性正相关,说明土壤中N、P供应量影响植物体中的N、P含量。     

普洱季风常绿阔叶林次生演替中木本植物幼苗更新特征

以时空替代的方法,将针阔混交林、季风常绿阔叶林的次生林与成熟林等3个处于同一空间下的群落作为次生演替进程中的3个阶段,研究云南普洱地区次生演替过程中的木本植物幼苗更新特征,分析了次生演替过程中木本植物幼苗的物种组成、密度、高度级及与环境因子的相关性。结果表明:在8个共144 m2的幼苗样地中调查木本植物幼苗101种2014株,其中乔木幼苗是主要组成。随着次生演替的进行,木本植物幼苗、乔木与藤本幼苗密度逐渐增加,灌木幼苗密度无显著变化;藤本植物幼苗的物种丰富度随着次生演替进行而增加,乔木与灌木幼苗则无显著变化,成熟季风常绿阔叶林中木本植物幼苗Shannon-Wiener指数要显著小于针阔混交林与次生季风常绿阔叶林。次生与成熟季风常绿阔叶林木本植物幼苗多度随高度级增加而减少,针阔混交林则呈现偏峰曲线,幼苗密度均集中分布在高度20 cm以内,3个群落演替阶段木本植物幼苗物种丰富度随高度级增加呈现偏锋曲线。相似性系数反映出乔木和藤本幼苗的更新来源与群落的物种组成存在着紧密的联系。乔木幼苗密度分布与样地坡度之间存在着显著的负相关,灌木幼苗密度与土壤pH值之间存在着显著正相关。     

云南普洱季风常绿阔叶林不同林层非结构性碳水化合物特征

在聚类分析的基础上,研究云南普洱季风常绿阔叶林主要物种非结构性碳水化合物(NSC)及其组分浓度、分配和季节性动态在林冠层、亚冠层和林下层间的变化特征.结果表明:亚冠层中可溶性糖及NSC浓度最高,分别为3.9%和13.3%,可溶性糖淀粉比在林下层最低,为0.76,而淀粉浓度则在各林层间无显著性差异.3个林层的可溶性糖均主要分配在叶片中,淀粉和NSC主要分配在根中.亚冠层中叶片和树干的可溶性糖浓度显著高于林冠层和林下层,枝和根的可溶性糖浓度在3个林层间无显著性差异;叶片的淀粉浓度则随林层高度降低而增加,但根淀粉浓度则是在林下层最低,为10.7%,枝和树干的淀粉浓度在3个林层间无显著差异;叶片NSC浓度为林冠层(10.7%)显著低于亚冠层(12.3%)和林下层(12.0%),但根的NSC浓度在林下层中最低,为14.2%;林下层叶片、枝、树干中可溶性糖淀粉比值均最低,但根的可溶性糖淀粉比值最低值出现在林冠层(0.79).3个林层NSC及其组分均存在显著的季节性变化,可溶性糖及可溶性糖淀粉比均为雨季显著高于旱季,而淀粉和NSC浓度则均在旱季中较高.不同林层NSC及其组分浓度的差异反映了不同高度树种碳利用策略的差异,部分地解释了物种的共存机制.     

天童常绿阔叶林五个演替阶段凋落物中的土壤动物群落

为探讨森林凋落物中土壤动物群落的结构特征以及土壤动物群落随植被演替而发生的变化 ,于 2 0 0 3年冬季 ,对浙江天童常绿阔叶林 5个演替阶段凋落物中的土壤动物群落 ,按代表不同分解阶段的新鲜凋落物层、腐叶层和腐殖土层进行了调查研究。共获得土壤动物 13381只 ,分别隶属于 2门 8纲 2 0目。优势类群为蜱螨目 (Arcarina)和弹尾目 (Collem bola) ,二者共占总数的 94 .2 4 % ,A/ C为 7.6 6 ;常见类群为双翅目 (Diptera)。研究结果表明 :(1)凋落物中的土壤动物群落存在明显的有别于真土层的垂直分布 ,类群数和个体数总体表现为向下递增的趋势。共有 19类、5 9.0 3%的土壤动物分布在底部腐殖土层 ,仅 8类、5 .35 %的土壤动物分布在新鲜凋落物层 ,其余共 8类分布在中间腐叶层。而且 ,不同类群在各演替阶段的分布表现出一定的差异 ;(2 )凋落物中土壤动物群落随植物群落的演替而发生明显的变化 :个体总数和类群总数在演替顶极阶段最高 ,其次为中期阶段 ,演替初期最低。但是 ,在目这一分类等级上 ,各演替阶段凋落物中土壤动物群落的主要类群基本一致 ,均为蜱螨目、弹尾目、双翅目和鳞翅目 (L epidoptera) ;(3)相似性分析表明 ,演替中期凋落物中土壤动物群落与顶极阶段最为相似 ;但它们的Shannon- Wiener多样性     

云南普洱季风常绿阔叶林优势物种不同生长阶段叶片碳、氮、磷化学计量特征北大核心CSCD

为探索植物叶片氮(N)、磷(P)、碳(C)生态化学计量特征随植物生长发育的变化规律,在普洱季风常绿阔叶林中,选取6种优势植物种(红锥(Castanopsis hystrix)、短刺锥(Castanopsis echidnocarpa)、泥柯(Lithocarpus fenestratus)、截果柯(Lithocarpus truncatus)、西南木荷(Schima wallichii)、茶梨(Anneslea fragrans))采集叶片,分析其N、P、C含量及化学计量比随植物生长发育的变化。结果显示:6种植物在不同生长阶段的N含量变化范围为7.90–17.72 mg·g–1,P为0.34–1.39 mg·g–1,C为458.48–516.87 mg·g–1,C:N为28.04–65.70,N:P为11.41–63.50,C:P为355.23–1 878.17,且不同生长阶段6种植物及总体叶片N、P、C含量及其化学计量比变化趋势各异。在变异系数上,N:P比整体变异最大,为36.46%(变化范围19.19%–91.65%),其次为C:P,为34.80%(变化范围15.99%–91.60%),C的整体变异最小,为3.12%(变化范围1.61%–5.89%)。变异来源分析结果显示,N含量、C含量、C:N、N:P及C:P均主要受植物生长阶段的影响,而P含量主要受物种与生长阶段的交互作用影响。     

云南普洱季风常绿阔叶林优势物种不同生长阶段叶片碳、氮、磷化学计量特征

为探索植物叶片氮(N)、磷(P)、碳(C)生态化学计量特征随植物生长发育的变化规律, 在普洱季风常绿阔叶林中, 选取6种优势植物种(红锥(Castanopsis hystrix)、短刺锥(Castanopsis echidnocarpa)、泥柯(Lithocarpus fenestratus)、截果柯(Lithocarpus truncatus)、西南木荷(Schima wallichii)、茶梨(Anneslea fragrans))采集叶片, 分析其N、P、C含量及化学计量比随植物生长发育的变化。结果显示: 6种植物在不同生长阶段的N含量变化范围为7.90-17.72 mg·g^-1, P为0.34-1.39 mg·g^-1, C为458.48-516.87 mg·g^-1, C:N为28.04-65.70, N:P为11.41-63.50, C:P为355.23-1878.17, 且不同生长阶段6种植物及总体叶片N、P、C含量及其化学计量比变化趋势各异。在变异系数上, N:P比整体变异最大, 为36.46% (变化范围19.19%-91.65%), 其次为C:P, 为34.80% (变化范围15.99%-91.60%), C的整体变异最小, 为3.12% (变化范围1.61%-5.89%)。变异来源分析结果显示, N含量、C含量、C:N、N:P及C:P均主要受植物生长阶段的影响, 而P含量主要受物种与生长阶段的交互作用影响。     

Soil animal communities at five succession stages in the litter of the evergreen broad-leaved forest in Tiantong,China

Soil animals are abundant in forest litter layer,but little attention has been Paid to the vertical distribution of community structure of soil animals in the layers at different plant community succession stages.The forest litter layer can be divided into fresh litter layer(L),fermentation layer(F)and humus layer(H),which may represent different litter decomposition stages.The aim of the study is to ascertain the vertical distribution features of soil animal communities among the three litter layers and the change in the succession process of the Evergreen Broad-Leaved Forest(EBLF)in Tiantong,Zhejiang Province,China.Soil animal communities in the five plant communities at different succession stages were investigated during the 2003 winter.Soil animals,which were collected by using Tullgren funnels,amounted to a total of 13381 individuals falling into 2 phyla,8 classes and 20 orders.The dominant groups were Acarina and Collembola,accounting for 94.24% of the total individuals,with the number of Acarina individuals 7.66 times than that of Collembola.The common group was Diptera.The results indicated that there was a distinctive vertical distribution of the soil animal communities in the forest litter laver,but it differed from that in soil below the litter layer.In contrast to those in the soil,the soil animals in the litter layer generally tended to increase in both group abundance and density from the top fresh litter layer to the bottom humus layer.Altogether 19 groups and 59.03% of total individuals were found in the bottom layer,while only 8 groups and 5.35% of the total individuals in the top.Moreover,there were some variations in the distribution of the soil animals at different plant succession stages.85.19% of Homoptera and 100% of Symphyla were found in the litter layer at the climax succession stage.while 75.61% of Thysanoptera at the intermediate succession stage.Therefore,these groups might be seen as indicative groups.The total numbers of soil animal groups and individuals in the litter layers greatly changed in the succession process of the EBLF.They both were greatest at the climax,moderate at the intermediate and smallest at the primary succession stage.However,the main soil animal groups in the litter at the different succession stages were essentially the same.They were Acarina,Collembola,Diptera and Lepidoptera.Although similarity analysis revealed that the soil animal communities in the litter at the intermediate succession stage were most similar to those at the climax succession stage,they differed greatly from each other in the Shannon-Wiener diversity index.The Shannon-Wiener index was highest at the climax succession stage and lowest at the intermediate succession stage.Finally,the paper discusses the following three questions:the role of soil animals as indicators for plant community succession;the role of different soil animal groups in the litter decomposition at different stages;and the major factors affecting the composition and distribution of soil animals in the litter.This paper provides a new perspective for the research on the succession mechanism of plant communities and the decomposition functions of soil animals.     

Soil animal communities at five succession stages in the litter of the evergreen broad-leaved forest in Tiantong, China

Soil animals are abundant in forest litter layer, but little attention has been paid to the vertical distribution of community structure of soil animals in the layers at different plant community succession stages. The forest litter layer can be divided into fresh litter layer (L), fermentation layer (F) and humus layer (H), which may represent different litter decomposition stages. The aim of the study is to ascertain the vertical distribution features of soil animal communities among the three litter layers and the change in the succession process of the Evergreen Broad-Leaved Forest (EBLF) in Tiantong, Zhejiang Province, China. Soil animal communities in the five plant communities at different succession stages were investigated during the 2003 winter. Soil animals, which were collected by using Tullgren funnels, amounted to a total of 13 381 individuals falling into 2 phyla, 8 classes and 20 orders. The dominant groups were Acarina and Collembola, accounting for 94.24% of the total individuals, with the number of Acarina individuals 7.66 times than that of Collembola. The common group was Diptera. The results indicated that there was a distinctive vertical distribution of the soil animal communities in the forest litter layer, but it differed from that in soil below the litter layer. In contrast to those in the soil, the soil animals in the litter layer generally tended to increase in both group abundance and density from the top fresh litter layer to the bottom humus layer. Altogether 19 groups and 59.03% of total individuals were found in the bottom layer, while only 8 groups and 5.35% of the total individuals in the top. Moreover, there were some variations in the distribution of the soil animals at different plant succession stages. 85.19% of Homoptera and 100% of Symphyla were found in the litter layer at the climax succession stage, while 75.61% of Thysanoptera at the intermediate succession stage. Therefore, these groups might be seen as indicative groups. The total numbers of soil animal groups and individuals in the litter layers greatly changed in the succession process of the EBLF. They both were greatest at the climax, moderate at the intermediate and smallest at the primary succession stage. However, the main soil animal groups in the litter at the different succession stages were essentially the same. They were Acarina, Collembola, Diptera and Lepidoptera. Although similarity analysis revealed that the soil animal communities in the litter at the intermediate succession stage were most similar to those at the climax succession stage, they differed greatly from each other in the Shannon-Wiener diversity index. The Shannon-Wiener index was highest at the climax succession stage and lowest at the intermediate succession stage. Finally, the paper discusses the following three questions: the role of soil animals as indicators for plant community succession; the role of different soil animal groups in the litter decomposition at different stages; and the major factors affecting the composition and distribution of soil animals in the litter. This paper provides a new perspective for the research on the succession mechanism of plant communities and the decomposition functions of soil animals. __________ Translated from Acta Ecologica Sinica, 2005, 25 (3) [译自: 生态学报, 2005,25(3)]     

四川盆地亚热带常绿阔叶林凋落叶多酚类物质在不同降雨期间的降解特征

植物多酚类物质是森林凋落物中的重要组分,其含量的多寡在一定程度上决定了凋落物的分解速率。然而,凋落物分解过程中多酚类物质的降解动态仍不十分清楚。因此,以四川盆地亚热带常绿阔叶林最具代表性的3个针叶树种马尾松(Pinus massoniana)、柳杉(Cryptomeria fortunei)、杉木(Cunninghamia lanceolata)和3个阔叶树种香樟(Cinnamomum camphora)、红椿(Toona ciliata)、麻栎(Quercus acutissima)凋落叶为对象,采用凋落物分解袋法,研究了6种凋落叶多酚类物质在第一年不同降雨期间的降解特征。结果表明:自微量降雨期起至雨季前期止,6种凋落叶多酚类物质具有一致的降解动态,降解率均表现为随着降水量的增加而增加;自雨季后期之后,多酚类物质含量均处于稳定状态。第一个分解年,6种凋落叶多酚类物质降解率大小顺序依次为:红椿(100%)柳杉(97.81%)杉木(94.45%)麻栎(93.67%)马尾松(93.06%)香樟(91.64%)。分解初期旱季两时期(微量降雨期和春季少雨期),6种凋落叶多酚类物质均有较大的降解量,其降解率占全年降解率的42.16%—71.20%。并且,除香樟以外的5种凋落叶多酚类物质大量降解释放发生在雨季前期,占全年降解率的44.46%—55.72%。此外,凋落叶多酚类物质初始含量与其降解率呈显著的二次函数关系。可见,降雨是湿润亚热带常绿阔叶林区凋落物多酚类物质降解的关键驱动因子之一,树种组成是影响凋落物多酚类物质降解的内部因素。     

中亚热带常绿阔叶林不同演替阶段碳储量与格局特征

研究了湖南鹰嘴界自然保护区内马尾松(Pinus massoniana)林、马尾松阔叶树混交林和常绿阔叶林这3种处于不同演替阶段森林类型的碳储量及时空分布格局.结果表明:3种类型森林生态系统碳储量分别为182.86、179.84和229.12 Mg C·hm-2,其中乔木层占59.57％ -67.88％,随森林进展演替增加,乔木层是生态系统碳储量主要贡献者,且各林分均以树干占乔术层碳储量比例最大;土壤层占31.05％～ 36.55％,碳储量随演替进展而增加,但对森林生态系统碳储量贡献率减小;林下植被和凋落物层分别占0.41％ ～3.04％和0.65％ ～2.53％,均随演替进展而减少,对生态系统碳储量贡献微弱;演替过程中生物量碳与土壤碳储量比为1.96、1.69和2.20,生物量碳在生态系统碳储量中所占比例呈增加趋势.可见在常绿阔叶林分布区,实施近自然林经营,模拟常绿阔叶林结构,是提升该区域森林碳汇能力的重要途径.     

人为干扰下南亚热带厚壳桂种群分布格局

南亚热带季风常绿阔叶林是华南地区典型代表植被类型。由于人为干扰,其现存面积日益减少。为加强保护,对这一植被类型中的演替顶级种厚壳桂(C ryp tocarya ch inensis)种群在人为干扰下的数量和分布格局进行了研究。研究地点设在广东省广州市萝岗长龙村村边。此林为南亚热带次生季风常绿阔叶林,受当地农民的干扰很大。样方面积是50×100 m2。研究结果表明,和较少受人为干扰的种群相比,这一种群趋于随机分布,特别是小树和幼苗阶段的个体。种群数量的调查研究表明这一种群幼苗库明显不足,表明人为干扰对这一种群的更新影响较大。认为在加强保护区等建设的同时,对分散在各地点的典型植被类型要进行保护,特别是加强对周围居民的保护意识教育。     

Spatial associations of tree species in a subtropical evergreen broad-leaved forest

Aims The spatial segregation hypothesis and the low-frequency hypothesis are two important proposed mechanisms that delay or prevent competitive exclusion in ecosystems. Because tree species interact with their neighbors, the importance of these potential processes can be investigated by analyzing the spatial structures of tree species.Methods The distribution of the adults of 27 common tree species in a fully mapped 5-ha subtropical forest plot in Baishanzu, eastern China, was analyzed to investigate the community-level intra- and interspecific spatial association patterns. We first tested for the overall spatial pattern in the 5- to 40-m neighborhoods and classified first-order bivariate associations with a diametric scheme based on Ripley's K and nearest-neighbor statistic (G -function). Then heterogeneous Poisson null models were used to distinguish second-order interactions from overall spatial associations (including first-order effects). Finally, we analyzed correlations between the existence of species interactions and some attributes of the species involved.Important findings Partial overlap and segregation increased with scale, whereas mixing decreased. Nearly 70% of the species pairs occurred less than expected at random, and only 3.4% of the species pairs were well mixed; 11.0% of all species pairs showed significant small-scale interactions, which was a greater frequency than expected by chance if species are abundant or prefer the same habitat, but less frequent than expected if species are highly aggregated. This suggests that both spatial segregation and low frequency of species facilitate species coexistence by reducing the opportunity that trees of two species encounter each other. The study also revealed that positive interactions were more prevalent than negative interactions in the forest, which indicates that positive interactions may have important effects on forest species assemblies.     

季风常绿阔叶林不同恢复阶段藤本植物的物种多样性比较

藤本植物是森林生态系统的重要组成部分,影响群落的恢复与演替。通过对云南普洱地区不同恢复阶段(恢复15a、恢复30a和原始林群落)季风常绿阔叶林群落的野外调查,分析了不同恢复阶段藤本植物的物种丰富度、密度、多度、径级分布、多样性指数及攀援方式,并探讨藤本植物与支持木的关系。结果表明:在0.81hm²的调查样地中,共发现DBH≥0.1cm的藤本植物1292株(分属34科51属64种)。原始林群落的藤本物种丰富度、密度(DBH＜1cm)、胸高断面积和平均胸高断面积都显著高于恢复阶段,原始林和恢复15a群落的密度(DBH≥1cm)、平均胸径和平均长度之间无显著差异,但都显著高于恢复30a。3种群落类型中藤本植物的物种组成和径级分布有显著差异,原始林中藤本植物物种更多,而且大径级(DBH≥10cm)的藤本植物仅出现在原始林及恢复30a的群落。单株藤本攀援的支持木在3种群落类型中均占多数,藤本植物与支持木的胸径存在显著的正相关(P＜0.001),原始林群落中DBH≥15cm的支持木更易被攀援,而恢复阶段则相反。茎缠绕藤本植物对原始林的负面影响要显著少于恢复15a及30a群落,而卷须类藤本植物也反映出原始林正处于一个动态变化的阶段,同时根攀缘和搭靠类藤本植物物种组成和多度变化可以反映出干扰后季风常绿阔叶林的恢复程度。森林砍伐是影响不同恢复阶段藤本植物的物种组成和分布的主要因素。     

基于枝条木材密度分级的鼎湖山南亚热带常绿阔叶林树高曲线模型

如何便捷准确地测量树高一直是林学及群落生态学所关心的问题。由于木材密度与树木生长密切相关, 因此基于木材密度建立树高曲线模型能够为测量树高提供新的方法。本文以鼎湖山南亚热带常绿阔叶林1.44 ha塔吊样地内119个物种的4,032个个体为研究对象, 利用树高、胸径和木材密度数据来探究基于枝条木材密度分级的树高曲线模型。首先, 对个体进行随机抽样, 将其划分为建模样本(占总样本量的70%)和检验样本(占总样本量的30%), 并通过聚类分析将所有个体的木材密度划分为4级。其次, 基于建模样本利用常见的5种理论生长方程(Richards、Korf、Logistic、Gompertz和Weibull方程)对不同分级建立树高-胸径模型; 基于检验样本检验模型精度, 并确定各分级的最适模型。最后, 构建基于物种分类的树高曲线模型, 并比较其与木材密度分级模型的差异。结果表明: 基于木材密度分级的模型, 各分级小组检验样本的平均绝对误差(MAE)和均方根误差(RMSE)最小值所对应的模型类型与建模样本结果一致, 确定Gompertz模型和Weibull模型为鼎湖山南亚热带常绿阔叶林最适树高模型类型。比较基于木材密度分级的模型与基于物种分类的模型, 发现二者的MAE、RMSE指数差异小。综上, 基于木材密度分级的树高曲线模型对树高估测精度高, 使用方便, 为树高预测提供了新方法, 可以更好服务森林调查等生产实践。     

季风常绿阔叶林不同恢复阶段乔木优势种群生态位和种间联结

生态位和种间联结是群落动态研究的重要内容之一,物种间相互作用影响着群落的恢复和演替。本文在对云南普洱地区不同恢复阶段(恢复15年、恢复30年和原始林群落)季风常绿阔叶林群落的野外调查基础上,采用生态位宽度、生态位重叠、方差比率(VR)和基于2×2联列表的χ2检验、联结系数(AC)等方法,分析了不同恢复阶段各种群的变化趋势。结果表明:3种群落类型中物种的重要值与相对应的生态位宽度之间存在着显著的正相关,恢复15年群落有78.22%的种对之间的生态位重叠值在0.4～0.8,说明其群落优势物种存在较强的资源利用性竞争,而恢复30年和原始林群落结构则具有一定的稳定性,多数生态位宽度较大的物种之间的生态位重叠要大于生态位较小的物种,反映出优势物种具有较强的竞争能力;恢复15年和恢复30年群落物种间总体呈不显著正联结,原始林群落则呈不显著负联结;3种群落231种对中,绝大多数种对联结系数未达显著水平,种对间的独立性相对较强,群落中物种间正负联结对数占总种的比例随恢复进程而出现下降趋势。不同恢复阶段群落中联结系数与生态位重叠值之间存在显著正相关,生态位重叠值越大,其联结系数也越大。     

亚热带常绿阔叶林林窗物种丰富度的影响因素

林窗是森林群落物种多样性维持中十分重要的结构,但其本身物种多样性的维持机制尚不清楚,可能与相邻群落的物种丰富度、林窗面积以及土壤和地形因子等有关。本文选取浙江天童20 ha森林动态监测样地内的84个冠林窗作为研究对象,分析了林窗内部以及不同距离邻域内的物种组成,选取包含大部分林窗内物种(≥75%),并且对林窗内物种丰富度影响最大的邻域作为相关邻域(林窗周围成熟植株通过种子传播影响林窗物种丰富度,把距离冠林窗边缘5 m范围内的区域作为种源效应邻域;由于距离林窗较近,物种组成与林窗形成时仍存活个体的物种组成相似,故把距离冠林窗边缘4 m范围内的区域作为距离效应邻域),然后计算种源效应邻域内成熟植株的物种丰富度、距离效应邻域内所有植株的物种丰富度、冠林窗的面积、地形因子(海拔、坡度、坡向、凸度)和土壤因子(p H值、全氮、全碳、全磷),最后对11个潜在的影响因素进行随机组合,构建广义线性回归模型,筛选最优模型(AICc最小)进行分析。结果显示:种源效应邻域内成熟植株的物种丰富度和冠林窗面积显著影响林窗内物种丰富度,其他因素并未对冠林窗内物种丰富度产生显著影响。上述结果说明,冠林窗面积的大小以及外部种源的丰富程度是决定冠林窗内物种丰富度的主要因素,其他因素可能只产生间接影响。     

黄山亚热带常绿阔叶林的群落特征

黄山是我国东部高山之一, 处于亚热带季风气候区, 属南北植物区系交替的过渡带, 是第四纪冰期动植物的避难所。其地带性植被为常绿阔叶林, 植被垂直分布明显, 是中国生物多样性保护优先区域, 也是世界文化与自然遗产地以及享誉全球的风景名胜区。2014年, 我们在黄山建立了10.24 ha的森林动态监测样地, 并完成了首次调查。本文从物种组成、区系特征、径级结构和空间分布格局等方面分析了样地中植物的群落特征。结果表明: 样地内有维管植物59科129属191种, 其中乔木层内胸径≥ 1 cm的木本植物46科97属153种; 热带性质的科、属分别占总科、属数的65.79%和45.36%, 温带性质的科、属分别占34.21%和51.55%。样地内珍稀濒危物种较多, 其中国家II级重点保护野生植物6种、《中国生物多样性红色名录——高等植物卷》中的近危物种7种、《濒危野生动植物种国际贸易公约》(CITES)附录II物种1种以及64种中国特有种, 这些物种具有较高的保护和研究价值。当取样面积小于2,150 m²时, 物种数随着面积的增加而急剧增加; 其后增加速率明显降低; 但大于57,950 m²时, 增加速率又略变大。稀有种69种, 占总树种数的45.10%。壳斗科和杜鹃花科的重要值占一半以上。建群种甜槠(Castanopsis eyrei)的重要值达26.25%, 其次分别为细齿叶柃(Eurya nitida) (7.63%)、马银花(Rhododendron ovatum) (7.60%)、马尾松(Pinus massoniana) (6.29%)和檵木(Loropetalum chinense) (4.83%)。样地平均胸径为4.10 cm, 小径木的数量占较大优势。乔木层可分为两个亚层, 甜槠在两个亚层的个体数量均最多, 马尾松数量也比较多。甜槠、细齿叶柃、马银花、马尾松等均呈较显著的聚集分布。     

长白山红松阔叶林不同演替阶段优势种的变化

以皆伐后长白山红松阔叶林4个不同演替阶段的林分为对象,分析其群落和优势树种的变化特征.结果表明:在长白山红松阔叶林不同演替阶段中,乔木树种的丰富度、Shannon多样性和Simpson优势度变化较小,多度和均匀度变化较大.随着演替的进程,群落的优势树种组成发生变化,种数逐渐减少,优势种的胸高断面积加和和最大重要值逐渐增加,说明不同演替阶段群落的优势种地位不断提高.长白山红松阔叶林的演替过程是白桦、山杨、黄檗、春榆等阳性或半阴性树种不断减少,而紫椴、水曲柳、红松、色木槭等阴性树种不断增加的过程.