粤北八宝山森林群落的组成和结构特征

在线路调查和样方凋查材料的基础上分析了粤北八宝山自然保护区森林群落的组成和结构特征。八宝山森林群落外貌终年常绿,群落的区系组成以亚热带的科属为主,优势科为壳斗科、山茶科、樟科、木兰科、金缕梅科、安息香科、五列本科、杜英科、杜鹃花科、松科、冬青科以及交让本科。优势种亦大部分由这些科的种类组成。群落中胸径≥２ｃｍ的个体密度为３３７７株／ｈｍ２,平均距离为１．６２ｍ。群落的垂直分化比较明显,乔木层一般可分为２—３亚层。第１亚层高１６—２２ｍ;第２亚层高１０—１６ｍ;第３亚层高５—１０ｍ。群落缺乏板根现象和大型木质藤本,附生植物也不发达,表现出中亚热带森林的特色。     

三种干扰方式对西双版纳热带森林群落植物多样性的影响

研究了西双版纳热带森林的 3种人为干扰破坏 (择伐、皆伐和轮歇 )后形成的次生群落在物种和群落水平上植物多样性各个方面的变化规律 ,研究结果表明 :( 1 )择伐群落和皆伐群落乔木层物种数、Simpson指数、Shannon-Wiener指数在科、属、种 3个水平上无显著差异 ,但较轮歇群落物种更为丰富 ,多样指数更高。( 2 )轮歇群落林下灌草层的物种数在科、属、种 3个水平上高于择伐群落和皆伐群落 ,但 Simpson指数和Shannon-Wiener指数则分别在各个水平上低于择伐群落和皆伐群落。 ( 3)轮歇群落先锋种类占较大比重 ,达76 % ,其它二类群落比例约为 5 0 %。( 4 )择伐和皆伐群落乔木层都由几种植物形成共同优势 ,轮歇群落则形成单优群落。 ( 5 )在生活型构成上 ,皆伐群落乔木树种种类相对较多 ,轮歇群落藤本植物较多 ,草本植物种类较为丰富 ,尤其一年生草本植物种类远多于其它群落类型     

浙江天台山甜槠群落研究

以分布以浙江省天台山的甜槠群落为对象,分析了群落的特征和性质。甜槠群落中,甜槠的优势突出,呈单优势群落。群落垂直结构复杂,可分为乔木层、灌木层、草本层,变有一定数量的层间植物。乔木层的物种多样性指数偏低,这与特定生境所形成的单优势群落有关。各样地间的植物种类具有较高的相似性,群落内种类组成相对一致。群落内优势种群甜槠、木荷的年龄结构属稳定型或增长型,它们在各样地的分布格局均呈集群分布。     

浙江天台山甜槠群落研究

以分布在浙江省天台山的甜储群落为对象,分析了群落的特征和性质。甜储群落中,甜储的优势突出,呈单优势群落。群落垂直结构复杂,可分为乔木层、灌木层、草本层,亦有一定数量的层间植物。乔木层的物种多样性指数偏低,这与特定生境所形成的单优势群落有关。各样地间的植物种类具有较高的相似性,群落内种类组成相对一致。群落内优势种群甜储、木荷的年龄结构属稳定型或增长型,它们在各样地的分布格局均呈集群分布。     

南岳篦子三尖杉群落多样性分析

采用样方法,对南岳境内的野生篦子三尖杉株群结构及物种多样性进行了调查研究。结果表明:在1 500m2样地中,共有维管束植物123种,隶属于69科99属,群落优势科不明显,种类主要集中在单种的科属内。植物生活型谱以小高位芽为主的木本植物占优势,叶的生活期以夏绿叶为主,常绿叶次之,群落外貌较整齐,冠面颜色黄绿色,结构层次明显,群落中乔木种类稀少,个体数较多,优势种为毛竹,灌木层的种类和个体数最多,优势种为篦子三尖杉等。该群落植物区系地理成分较复杂,有13个分布区类型,温带性成分占52.53%,热带性成分占38.38%,说明该群落植物属具有较强的温带性质,并表现出该区域植物从热带向温带过渡的性质。物种多样性分析显示该群落多样性指数不高,各层次的丰富度格局为灌木层草本层藤本层乔木层,多样性格局、均匀度格局和生态优势度局均为藤本层灌木层草本层乔木层。     

澳门青洲山翻白叶树群落特征及物种多样性研究

根据样方调查结果,对澳门青洲山翻白叶树(Pterospermum heterophyllum)群落的种类组成、外貌、结构特征与动态及物种多样性进行分析.结果表明:(1)在1 600 m2样地中,有维管束植物47种,隶属于29科44属;对乔木层和灌木层主要物种的重要值以及频度分析结果显示,该群落是以翻白叶树为主的单优种群落,群落种类组成多样性和水平分布不均匀,其外貌终年常绿;对优势种种群的年龄结构分析显示,该种群处于增长状态;(2)整个群落的物种丰富度Margalef指数为13.72,Shannon-Wiener指数为1.15,Simpson指数为0.875,均匀度指数为0.34,该群落的层次格局为:灌木层>藤本层>乔木层>草本层;(3) 与其他5个不同类型地区森林群的物种多样性比较结果显示,澳门翻白叶树群落的物种多样性明显低于其他5个森林群落.     

衡山青冈栎群落结构及物种多样性研究

利用样方法进行野外群落调查,共设计了15个样方,每个样方大小为20m×5 m,对衡山青冈栎(Cyclobalanopsis glauca)群落的种类组成、外貌、结构特征及物种多样性进行了研究.结果表明:在1 500 m2样地中,共有维管束植物26科37属46种,其中优势科为壳斗科、山茶科和蔷薇科等;该群落主要是以青冈栎为主的单优种群落,生活型谱以高位芽植物占绝对优势,叶级谱以中、小型叶为优势的特点,群落季相不明显;群落分层较明显,乔木层树种很少,灌木层种类较丰富,对群落物种多样性具有较大影响;物种多样性分析显示该群落多样性指数偏低,其多样性复杂程度由高到低的顺序为灌木层、藤本层、乔木层、草本层.     

柘林湾-南澳岛潮间带冬夏两季大型底栖动物种类组成及优势种

依据柘林湾-南澳岛潮间带2011年8月、2012年2月、2013年2月和8月的大型底栖动物调查资料,对该海域潮间带的大型底栖动物种类组成和优势种进行研究。结果表明:4次调查共采集到大型底栖动物7门112种,主要由软体动物、节肢动物和环节动物3大类组成;总种类数夏季冬季;夏季2次调查的类群种类数组成存在显著性差异(P0.05),冬季2次调查不存在显著性差异(P0.05),冬夏两季不存在显著性差异(P0.05);冬季→夏季的种类更替率较高,该段时间内群落的变动相对较大,稳定性相对较低;4次调查出现优势种共有23种,优势种组成最多的为软体动物;柘林湾-南澳岛附近海域潮间带生物的种类和分布由底质类型决定,同时,人类活动对海域的生物生态也造成了一定的压力。     

广州增城叶迳背乐昌含笑林群落特征研究

对广州南亚热带低丘平地的乐昌含笑(Michelia chapensis Dandy)林的群落特征进行了研究。结果表明,广州的乐昌含笑林组成种类复杂,1600 m2样带内有维管束植物44科58属70种,种子植物属以热带亚热带区系成分为主,体现出由热带向亚热带过渡的性质。群落结构较复杂,灌层密集而优势种明显,大径级个体较多,群落的胸高断面积极大,达66.13 m2 hm-2;频度分析表明本群落不符合Raunkiaer的频度定律,具有最大频度的种群比例小;基于样带面积统计的优势种年龄结构分析表明,群落建群种均属衰退种群,但从区域角度结合优势种群生物学特性的分析表明,本群落属本地带顶级群落类型,具有较高的稳定性。     

云南绿汁江下游河谷季雨林群落学研究

基于1 ha样地的群落学调查,研究了云南绿汁江下游河谷两岸的季雨林植被。结果显示:该群落高15~20 m,乔木层分为明显的两层,由落叶的厚皮树和常绿的灰毛浆果楝等树种组成;样地内共记录维管植物116种,其中乔木层树种36种,灌木14种,草本43种,藤本21种,附生植物2种;综合1 ha样地计算所得乔木层树种Shannon-Wienner指数为2.2824,Simpson指数为0.8321;样地中共记录到胸径≥1 cm的树木1 764株,且以中、小径级占优势;该群落主要以高位芽植物为主,并且以单叶、纸质、全缘和非尾尖的植物种类和小叶植物为主;群落的种——面积曲线在取样面积为2 000 m2时趋于平缓,建议将2 000 m2作为其最小取样面积。根据乔木第一层与第二层的优势种,将该群落初步定为厚皮树——灰毛浆果楝林。     

滇南勐宋热带山地雨林的物种多样性与生态学特征

 研究了鲜为人知的滇南勐宋地区的原始山地雨林植被, 根据分布生境、群落结构和种类组成特征,可将该山地雨林区分为沟谷和山坡两个类型, 分别定义为八蕊单室茱萸(Mastixia euonymoides)-大萼楠(Phoebe megacalyx)林和云南拟单性木兰(Parachmeria yunnanensis)-云南裸花(Gymnanthes remota)林。该山地雨林的外貌仍以单叶、革质、全缘、中叶为主的常绿中、小高位芽植物组成为特征,层间木质藤本植物仍较丰富,草本高位芽植物和附生植物丰富,但板根和茎花现象少见,属于热带山地垂直带上低山雨林或山地雨林植被类型。与该地区的典型热带季节雨林和赤道热带雨林相比, 勐宋的山地雨林群落中的大、中高位芽植物和藤本高位芽植物比例相对减少, 小、矮高位芽植物和草本高位芽植物比例相对增加,单叶、革质、非全缘叶和小叶比例相对增加,板根现象少见。与中国热带北缘-南亚热带地区（季风）常绿阔叶林比较, 勐宋的山地雨林有较多的附生植物和草本高位芽植物,相对较少的小高位芽植物和矮高位芽植物,小叶比例亦较少,非全缘叶和革质叶比例相对较低。故勐宋山地雨林是滇南热带北缘山地的一种较湿润生境的植被类型, 与所谓的季风常绿阔叶林不同。在物种多样性上,勐宋热带山地雨林在单位面积植物种数上并不比该地区的热带季节雨林低, 物种多样性指数与低丘季节雨林相当,比沟谷季节雨林低, 明显高于季风常绿阔叶林。     

Geological History,Flora, and Vegetation of Xishuangbanna,Southern Yunnan,China1

Xishuangbanna of southern Yunnan is biogeographically located at a transitional zone from tropical Southeast (SE) Asia to subtropical East Asia, and is at the junction of the Indian and Burmese plates of Gondwana and the Eurasian plate of Laurasia. The flora of the region consists of a recorded 3336 native seed plant species, belonging to 1140 genera in 197 families, among which 83.5 percent are tropical genera and 32.8 percent are endemic to tropical Asia, suggesting a strong affinity to tropical Asian flora. The vegetation of Xishuangbanna is organized into four forest types: tropical rain forest, tropical seasonal moist forest, tropical montane evergreen broad‐leaved forest, and tropical monsoon forest. The tropical rain forest in Xishuangbanna has the same floristic composition of families and genera as some lowland equatorial rain forests in SE Asia, and is dominated (with a few exceptions) by the same families both in species richness and stem dominance. The exceptions include some deciduous trees in the canopy layer, fewer megaphanerophytes and epiphytes, and a higher abundance of lianas and microphyllic plants. We consider the tropical rain forest of Xishuangbanna as a type of tropical Asian rain forest, based on their conspicuous similarities in ecological and floristic characteristics.     

Ecological and biogeographical studies on the tropical rain forest of south Yunnan,SW China with a special reference to its relation with rain forests of tropical Asia

Abstract. Ecological and biogeographic analyses of the tropical rain forest in south Yunnan were made using data from seventeen sample plots and floristic inventories of about 1000 species of seed plants. The rain forest is shown to be a type of true tropical rain forest because it has almost the same profile, physiognomic characteristics, species richness per unit area, numbers of individuals in each tree species and diameter classes of trees as classic lowland tropical rain forests. As the area is at the northern margin of monsoonal tropics, the rain forest differs from equatorial lowland rain forests in having some deciduous trees in the canopy layer, fewer megaphanaerophytes and epiphytes but more species of lianas as well as more species of microphylls. In its floristic composition, about 80% of total families. 94% of total genera and more than 90% of total species are tropical, of which about 38% of genera and 74% of species are tropical Asian. Furthermore, the rain forest has not only almost the same families and genera, but also the same families rank in the top ten both in species richness and in dominance of stems, as lowland forests in southeast Asia. It is indisputable that the flora of the rain forest is part of the tropical Asian flora. However, most of the tropical families and genera have their northern limits in south Yunnan and most have their centre of species diversity in Malesia. More strictly tropical families and genera have relatively lower species richness and importance compared with lowland rain forests in tropical southeast Asia. Thus, the flora also shows characteristics of being at the margin of the tropics. Based mainly on physiognomy and floristic composition the tropical rain forest of Yunnan is classified into two types, i.e. seasonal rain forest and wet seasonal rain forest, the latter is further divided into two subtypes, i.e. mixed rain forest and dipterocarp rain forest. From analysis of geographic elements it is also shown that the tropical rain forest of Yunnan occurs at a geographical nexus with its flora coming mainly from four sources, i.e. Malesia, south Himalayas, Indochina and China.     

海南岛热带天然针叶林附生维管植物多样性和分布

作为热带林中一个重要的特征性组分, 附生维管植物对于维持热带森林的物种多样性及其生态系统功能均具有重要作用。该文首次系统地报道了热带天然针叶林中的附生维管植物多样性和分布特征。以海南岛霸王岭国家级自然保护区保存完好的热带天然针叶林(我国唯一较大面积分布的南亚松(Pinus latteri)天然林)中的附生维管植物为研究对象, 通过样带调查(共设置12个10 m × 50 m的样带, 记录每个样带内胸径(DBH) ≥ 5 cm树木上附生维管植物的物种名称、株数及附生高度), 分析附生维管植物的物种多样性和空间分布特征。结果表明: 1)热带针叶林0.6 hm ²面积内共有附生维管植物769株, 分属于7科17属27种, 附生兰科植物和萝摩科植物为优势类群; 2)附生维管植物在水平方向上呈现出聚集分布; 3)附生维管植物在垂直方向上, 在中等高度层次(10-20 m)分布最多, 在下层(0-5 m)也有较多的分布; 4)少数附生维管植物对南亚松表现出一定的选择性, 如华南马尾杉(Phlegmariurus fordii)、玫瑰毛兰(Eria rosea)、眼树莲(Dischidia chinensis)和铁草鞋(Hoya pottsii)等; 5)附生维管植物的物种丰富度及多度与宿主胸径均存在显著的正相关关系。     

Nitrogen fixation of epiphytic plants enwrapping trees in Ailao Mountain cloud forests, Yunnan, China

Epiphytic plants play an important role in the nutrient cycle of forest ecosystems. There had been fewer studies in subtropical regions than in other climate zones. Prior research showed that the canopy epiphyte could fix nitrogen combined with microorganism in tropical forest. The epiphytic plants enwrapping trees in canopy layer are very abundant in the subtropical mountainous cloud forest of Ailao Mountain (central and southern Yunnan Province, SW China). This forest lacks widespread nitrogen-fixing plants, and the nitrogen origin is elusive. Maybe there also exist such nitrogen-fixing systems in epiphyte community. Nitrogen-fixing potentials of canopy epiphytes increased greatly from dry season to wet season. There occurred an obvious difference on the epiphytic nitrogen fixation abilities between upper canopy layer and sub-canopy layer in alternant period between wet season and dry season. Epiphytic nitrogen-fixing potentials for the subtropical moist forest in Ailao Mountains ranged between 0.027 and 2.24 kg ha^?1?year^?1. Our results indicate that the canopy epiphytes in the subtropical moist forest of Ailao Mountains can fix a significant amount of atmospheric nitrogen. This finding suggests a new nitrogen source for the subtropical forest ecosystem, thus can have profound impact on the studies of nitrogen cycling.     

Elevational distribution and zonation of tropical pteridophyte assemblages in Costa Rica

The use of species turnover rates to identify discontinuities in vegetation assemblages along environmental gradients is hampered by the difficulty of the application of significance tests. We used a simulation procedure to detect abrupt transitions in fern species assemblages along a tropical elevational gradient to detect elevational zonations between 100 and 3400 m in a species-rich tropical forest in Costa Rica. Significant species turnover values were only observed at 300, 1000, and 3200 m. These boundaries in vegetation assemblages were caused by different lifeforms within the pteridophyte species set: epiphytes attained high turnover values at low, terrestrials at high elevations. Accordingly, the mean elevational ranges of epiphytes and terrestrials differed clearly at high elevations, where those of terrestrial species showed a sharp decline above ca. 2500 m, but those of epiphytes kept more or less constant. The boundaries of significant range limit accumulations coincide with shifts in the environmental settings, namely humidity conditions and forest structure. The location of the observed boundaries in turn influences the elevational amplitudes of species restricted to the resulting elevational zones, determining the elevational distribution of range amplitudes. Between 1000 and 3200 m no significant boundaries were observed, although it has been argued that the lower cloud condensation layer and the frost line are the prime drivers of elevational zonations.     

Diversity of dry forest epiphytes along a gradient of human disturbance in the tropical Andes

Question: Disturbance effects on dry forest epiphytes are poorly known. How are epiphytic assemblages affected by different degrees of human disturbance, and what are the driving forces? Location: An inter‐Andean dry forest landscape at 2300 m elevation in northern Ecuador. Methods: We sampled epiphytic bryophytes and vascular plants on 100 trees of Acacia macracantha in five habitats: closed‐canopy mixed and pure acacia forest (old secondary), forest edge, young semi‐closed secondary woodland, and isolated trees in grassland. Results: Total species richness in forest edge habitats and on isolated trees was significantly lower than in closed forest types. Species density of vascular epiphytes (species per tree) did not differ significantly between habitat types. Species density of bryophytes, in contrast, was significantly lower in edge habitat and on isolated trees than in closed forest. Forest edge showed greater impoverishment than semi‐closed woodland and similar floristic affinity to isolated trees and to closed forest types. Assemblages were significantly nested; habitat types with major disturbance held only subsets of the closed forest assemblages, indicating a gradual reduction in niche availability. Distance to forest had no effect on species density of epiphytes on isolated trees, but species density was closely correlated with crown closure, a measure of canopy integrity. Main conclusions: Microclimatic changes but not dispersal constraints were key determinants of epiphyte assemblages following disturbance. Epiphytic cryptogams are sensitive indicators of microclimate and human disturbance in montane dry forests. The substantial impoverishment of edge habitat underlines the need for fragmentation studies on epiphytes elsewhere in the Tropics.     

Contribution of peeling host for epiphyte abundance in two tropical dry forests in the “El Cielo Biosphere Reserve”, Mexico

Host traits partly determine the abundance and species richness of epiphytes in tropical forests. It has been proposed that older trees with rough bark and evergreens often house more individuals and more epiphytic species than those with thin, smooth, and peeling bark, which harbor few epiphytes. We hypothesize (i) that epiphytes are more abundant and species-rich in the more shaded forest, which is related to bark roughness, and (ii) that epiphytes are distributed in the middle of the host, where microenvironmental conditions are more favorable to survival. We evaluated abundance, species richness, and vertical distribution of epiphytes in two tropical dry forests, according to the deciduousness and basal area of the trees. Moreover, we selected the most abundant epiphytes to test whether their distribution is related to a specific bark type and examine their vertical distribution in two dry forests. We distinguished a high abundance and species richness of epiphytes in the deciduous forest, although basal area and host species richness were higher in the semi-deciduous forest. In both forests, we found a positive relationship between epiphyte abundance and basal area. Higher abundance of epiphytes was related to the predominance of Tillandsia schiedeana, a drought-adapted species, in both forests. Unexpectedly, epiphytes abundantly colonized Bursera simaruba, a host with peeling bark and a very branched crown, where small individuals of T. schiedeana colonized abundantly toward the top of the crown. Our results show the importance of the tropical dry forest, particularly, B. simaruba, in maintaining epiphyte diversity in terms of T. schiedeana colonization.     

Neither host-specific nor random: vascular epiphytes on three tree species in a Panamanian lowland forest

BACKGROUND AND AIMS: A possible role of host tree identity in the structuring of vascular epiphyte communities has attracted scientific attention for decades. Specifically, it has been suggested that each host tree species has a specific subset of the local species pool according to its own set of properties, e.g. physicochemical characteristics of the bark, tree architecture, or leaf phenology patterns. METHODS: A novel, quantitative approach to this question is presented, taking advantage of a complete census of the vascular epiphyte community in 0.4 ha of undisturbed lowland forest in Panama. For three locally common host-tree species (Socratea exorrhiza, Marila laxiflora, Perebea xanthochyma) null models were created of the expected epiphyte assemblages assuming that epiphyte colonization reflected random distribution of epiphytes in the forest. KEY RESULTS: In all three tree species, abundances of the majority of epiphyte species (69-81 %) were indistinguishable from random, while the remaining species were about equally over- or under-represented compared with their occurrence in the entire forest plot. Permutations based on the number of colonized trees (reflecting observed spatial patchiness) yielded similar results. Finally, a third analysis (canonical correspondence analysis) also confirmed host-specific differences in epiphyte assemblages. In spite of pronounced preferences of some epiphytes for particular host trees, no epiphyte species was restricted to a single host. CONCLUSIONS: The epiphytes on a given tree species are not simply a random sample of the local species pool, but there are no indications of host specificity either.     

林冠附生植物生态学研究进展

林冠附生植物及其枯死存留物是构成山地湿性森林生态系统中生物区系、结构和功能的重要组分。由于在林冠攀爬技术上的限制,过去对林冠附生植物在生态系统结构和功能过程中的作用未能引起足够的重视。近20年来,随着对林冠生物多样性及其在生态系统功能过程影响的认识和研究技术上的提高,对林冠附生生物的研究已逐步从个体水平转移到系统水平上。有关林冠附生植物多样性、生物量及其生态学效应已成为近年来国际上新兴研究领域——“林冠学”的研究热点之一。许多研究表明,林冠附生植物在生态系统水平上的交互作用比它们的解剖、形态和生理特征更为重要。国外大量的研究结果表明,林冠是一个适合于许多生物种类生存的场所,其数量比想象的更为丰富。在全球范围内估计有29 500余种附生植物,其中维管束附生植物的种类高达24 000种,约占总维管束植物种类的10%。林冠附生物的生物量在世界各地森林中存在较大的差异,其范围在105~44 000 kg·hm^-2之间,其中在一些热带和温带天然老龄林中林冠附生物的生物量超过了宿主林木的叶生物量。林冠附生植物还具有较大的叶面积指数(LAI)。林冠附生物丰富的物种组成、较高的生物量、独特的生理形态特征以及它们分布于森林与大气相互作用的关键界面,使得它们在生态系统物种多样性形成及其维持机制、养分和水分循环、指示环境质量等方面具有重要的作用。林冠附生植物及其枯死残留物具有较强的能力吸收雨水和空气中的营养物质,在林冠层中形成一个潮湿的环境促进氮固定,林冠附生植物群落还能为生存于林冠的其它生物(如鸟类、哺乳动物、两栖动物、爬行动物和昆虫等)提供食物和栖息场所。林冠附生植物的生长发育与分布格局除与宿主有关外,还受到环境因素(气候、地形、微生境条件等)和人为干扰的影响。由于世界各地森林类型多样和环境条件各异,目前国际上有关附生物的研究仍十分活跃,建立了林冠研究网络,研究不同类型森林中附生植物及其枯死残留物的动态及其与群落特征、环境因子的数量关系,探讨、交流和发展有效的标准测量方法和技术是该领域研究的主要内容。国内对林冠附生植物生态学的研究刚刚起步,有待于今后加强该领域的研究。