【作者】 马文章；

【导师】 刘文耀； 张一平；

【作者基本信息】 中国科学院研究生院（西双版纳热带植物园） ， 生态学， 2009， 博士

【摘要】 生长借助有机生物体提供物理支撑,缺不从其宿主获取养分和水分的附生植物是热带、亚热带森林生态系统中重要的组成成分,对促进森林水分、养分循环、维系物种多样性等方面发挥着重要的生态功能。本论文对哀牢山徐家坝地区原生木果柯林、山顶苔藓矮林及因人为干扰形成的早冬瓜林、滇山杨林和栎类萌生林三类次生群落的附生植物进行了物种组成和多样性、生物量的空间分布特征调查；在林缘-林内梯度上调查了边缘效应对附生植物物种组成和生物量的影响；对附生植物组成分布与生态因子的关系进行了测定和分析；并定量探讨了不同生长基质对维系林冠附生苔藓植物多样性的贡献,研究结果显示：1、本区具有丰富的附生植物多样性。其中附生苔藓植物176种,隶属于38科83属,依分布频率的大小,优势种分别为：树平藓(Homaliodendron flabellatum)、树形羽苔(Plagiochila arbuscula)、刀叶树平藓(H. scalpellifolium)、疏叶丝带藓(Floribundaria walkeri)和齿叶平藓(Neckera crenulata);附生维管束植物共记录67种,分属26科41属,其中蕨类植物占据着整个附生维管束植物群落的绝对优势,如假友水龙骨(Polypodiodes subamoena)、棕鳞瓦韦(Lepisorus scolopendrium)、鳞轴小膜盖蕨(Araiostegia perdurans)和尖齿拟水龙骨(Polypodiastrum argutum)分别是出现频率居前的物种。2、原生林及不同次生林附生苔藓植物在组成与分布上存在明显的差异。次生林中扇型藓类和粗平铺型苔类的分布频度显著地减少,但丛集型藓类的频度相应地增加。次生林(尤其是演替初期的旱冬瓜林)中附生苔藓植物的β多样性指数显著低于原生林。尽管次生群落在具体的生态功能上不及原生植被,不同演替序列的各森林群落之间所组成的多样化生境组合,为维系附生苔藓植物在该地区的多样性稳定起到了重要的作用。树平藓(Homaliodendron flabellatum)和粗仰叶垂藓(Sinskea phaea)分别是原生木果柯林和苔藓矮林的指示种；齿叶平藓(Neckera crenulata)是滇山杨林的指示种；野口青藓(Brachythecium noguchii)、尖叶拟蕨藓(Pterobryopsis acuminata)、多褶苔(Spruceanthus semirepandus)、平滑小壶藓(Tayloria subglabra)和细茎耳叶苔(Frullania bolanderi)是指示早冬瓜林的物种。3、在林缘-林内梯度上,边缘效应对树干0-2m范围内单位面积附生植物生物量、附生苔藓植物盖度和附生蕨类植物密度均存在显著的影响。林内外相对一致的大气相对湿度是该梯度上各样带间物种丰富度无显著差异的主要原因,但边缘效应改变了附生植物的物种组成,10m样带(代表边缘生境)同80m样带(代表森林内部)之间的物种相似性系数仅为0.506。丛集型(P<0.001)和交织型(P<0.001)的附生苔藓植物在林缘各样带间存在着显著的频度差异,其中前者多分布于森林边缘生境,而后者多分布于森林内部。4、苔藓、维管束植物和林冠有机残留物是本区山地森林中附生物质的主要组分,其中附生维管束植物和苔藓植物对总生物量的贡献率最大,分别达47.0%和43.4%。林冠附生植物及其枯死残留物的生物量与宿主径级之间存在呈幂函数关系,通过拟合回归方程并结合样地宿主的实测信息,推算得到本区附生物质的生物量为10.33t·ha-1。林冠层距地面10-22m的区间上集中着附生物80.6%的生物量。宿主调查单元的水平上,附生维管束植物和苔藓植物的生物量呈现出与林冠有机残留物显著相关的格局。5、宿主树皮持水力、树皮粗糙程度、林地内木质残体的储量和林冠遮蔽度是解释附生苔藓植物分布格局的关键因子。树皮持水力影响生活型为悬垂型的苔藓植物分布；树皮的粗糙程度影响丛集型苔藓植物的分布；林地内木质残体的储量影响该区交织型苔藓植物的分布；林冠遮蔽度影响树型苔藓植物的分布。在针对附生维管束植物群落的CCA排序分析发现：大部分附生植物在林冠生境的分布并未受养分条件的限制：假友水龙骨、鳞轴小膜盖蕨、曲鳞书带蕨(Vittaria plurisulcata)和节肢蕨(Arthromeris lehmanni)在林冠不同位置的分布表现出与林冠有机残留物互惠互利的关系。6、本区林内木质残体的存在对维系附生苔藓植物的物种多样性具有重要的意义,其储量不仅与交织型附生苔藓植物的分布相关,且96.4%的腐木生苔藓植物都能以兼性(Facultative)附生的形式出现在林冠生境上。分析表明：腐木生苔藓群落与附生苔藓群落之间互为传播源。更多还原

【Abstract】 Epiphytes are organism that grows non-parasitically on its hosts, which constituent important component in tropical and subtropical forest ecosystems, and they perform many irreplaceable ecological functions such as facilitating water and nutrient cycling and sustaining biodiversity. The present study examined:1) epiphytic bryophytes’ species composition and biodiversity among forests under different successional stages;2) the edge effect on epiphytes;3) the distribution of vascular epiphytes and their biomass along the canopy gradient; 4) the influence of ecological factors, including atmospheric relative humidity, host bark traits and etc, on the species composition and distribution pattern of epiphytes;5) how bryophytes from other substrate contribute to the biodiversity of epiphytic bryophyte community. The major results are as follows:1. This region habored rich flora of epiphytes. There were altogether 176 epiphytic bryophytes recored from 38 families and 83 genera, in which Homaliodendron flabellatum (Sm.) Fleisch, Plagiochila arbuscula (Brid. ex Lehm.) Lindenb., H. scalpellifolium (Mitt.) Fleisch., Floribundaria walkeri (Ren. et Card.) Broth, and Neckera crenulata Hedw. appeared to be dominante species in terms of number of quadrats occuppied. Totally 67 species of vascular epiphytes coming from 26 families and 41 genera were listed from the whole canopy, among which Polypodiodes subamoena (Clarke) Ching, Lepisorus scolopendrium (Ham. ex D. Don) Menhra et Bir, Araiostegia perdurans (Christ) Cop. and Polypodiastrum argutum (Wall. ex Hook.) Ching were dominant species by frequencies.2. The epiphytic bryophyte species composition between old-growth and secondary forests were rather different. Several life forms showed pronounced habitat preferences:the frequencies of fan [moss] and rough mat [liverwort] had decreased significantly in secondary forests, while the frequencies of turf [moss] had increased accordingly. Theβdiversity indices were dramatically reduced in secondary forests, especially in Secondary Alnus Forest, which is during the early stage of succession. Althought secondary forests were less capable of performing certain ecological functions as compared to old-growth ones, forests consisted from patches under different successional stages had created a combination of diversified habitats, which turned out to be rather crucial in sustaining epiphyte biodiversity. Sinskea phaea (Mitt.) Buck and Homaliodendron flabellatum were identified as indicator species for Old-growth dwarf mossy forest (ODMF) and Old-growth Lithocarpus forest (OLF) respectively. In addition, Neckera crenulata were indicative of Secondary Populus forest (SPF), while Brachythecium noguchii Tak., Pterobryopsis acuminate (Hook.) Fleisch., Spruceanthus semirepandus (Nees) Verd., Tayloria subglabra (Griff.) Mitt. and Frullania bolanderi Aust. were detected as indicator species for SAF.3. Edge effects had significantly influenced the biomass of epiphytes, coverage of epiphytic bryophytes, and density of epiphytic ferns along the edge-interior gradient. But edge effect had not affected the species richness of epiphytes across edge transects mainly due to uniformed atmospheric humidity in this region. However, edge effect had shaped the species compositon of epiphytes in transects near forest edge. The overall similarity coefficient between 10m and 80m transects were merely 0.506. Turf-life-formed (P<0.001) and weft-life-formed epiphyic bryophytes exhibited significant differences, where weft preferred habitats in forest interior and turf appeared more in transects near forest edge..4. Bryophytes, dead organic matter (DOM) and vascular plants were the major component of epiphytic material in the present study area, in which vascular plants (ca.47.0%) and bryophytes (ca.43.4%) contributed the largest proportion of the epiphytic biomass composition. There were "power function" relationships between epiphytes and their associated DOM with host DBH. It is then deduced the total biomass of epiphyte in OLF were 10.33 t·ha-1 from empirical regression functions. 80.6% of the total biomass was spatially aggregated in the section between 10m and 22m above ground. There were significant correlations between the biomass of DOM and the biomass of vascular plant and bryophytes, which well illustrated the significance of DOM in maintaining epiphyte biodiversity.5. The water-holding capacity influenced pendant in epiphytic bryophytes;the roughness of host barks affected the distribution pattern of turf; the the mass of woody debris (WD) positively correlated with the distribution of weft; and "canopy illumination index" regulated the distribution of dendroid. CCA ordination on the distribution of vascular epiphytes suggested that the majority epiphytes were not "nutrient-limited", and there were mutual benefical relationships between DOM and Polypodiodes subamoena, Araiostegia perdurans (Christ) Cop., Vitlaria plurisulcata Ching and Arthromeris lehmanni (Mett.) Ching.6) WD was especially important in sustaining the biodiversity of epiphytic bryophytes. The mass of WD clearly affected the distribution pattern of weft-life-fromed species in epiphytic bryophytes as whole, and nearly all epixylic species (ca.96.4%) were capable of transforming into facultative epiphytes, by dwelling on nearby host trees. Further quantitative analysis implied that the direction of bryophyte dispersal between these two substrate (WD and host trunk) was mutual.更多还原