【作者】 施济普；

【导师】 朱华； 曹敏； 刘文耀；

【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， 2007， 博士

【摘要】 以分布于云南老君山国家级自然保护区、分水岭国家级自然保护区、黄莲山国家级自然保护区、哀牢山国家级自然保护区、无量山国家级自然保护区、大雪山国家级自然保护区和盈江县苏典国有林中的山顶苔藓矮林为研究对象,研究云南山顶苔藓矮林的群落生态学和生物地理学特征以及云南山顶苔藓矮林的主要环境特征,探讨了云南山顶苔藓矮林在世界云雾林中的地位、云南山顶苔藓矮林分布区形成的主要环境因素。为云南山顶苔藓矮林的保护、研究提供理论依据。研究结果表明:1)云南山顶苔藓矮林多由乔木层、以竹类占绝对优势的灌木层和较稀疏的草本层三层组成。主要由壳斗科(Fagaceae)、杜鹃花科(Ericaceae)、越桔科(Vacciniaceae)、槭树科(Aceraceae)、木兰科(Magnoliaceae)、茶科(Theaceae)、冬青科(Aquifoliaceae)、八角科(Illicieae)、樟科(Lauraceae)和蔷薇科(Rosaceae)等植物组成,在各研究地点乔木层优势物种有较大的差异。2)在面积为2500 m2的样地范围内,各样地所记录的维管束植物种类最低的只有57种,最多的达110种。乔木层辛普森多样性指数普遍在0.7545–0.9544之间,香农–威纳多样性指数在1.825–3.2905之间,皮耶罗均匀度指数则在0.6583–0.8982之间。总体上老君山山顶苔藓矮林群落无论辛普森指数、香农–威纳多样性指数、皮耶罗均匀度指数和物种丰富度指数都表现出相对较低的特点。而黄莲山山顶苔藓矮林的这些多样性指数则表现为相对较高的特点。与其它森林类型相比,云南山顶苔藓矮林物种丰富度与多样性普遍不高。2)云南山顶苔藓矮林主要由高位芽植物组成,各研究地点高位芽分别占研究地所记录物种种数的64%–87%,高位芽植物平均占总植物种数的75%左右,与分布于海拔较低的热带森林相比,其高位芽植物比例明偏低。云南山顶苔藓矮林植物种类主要以小叶、中叶物种为主,与热带雨林和季风常绿阔叶林相比较,小叶物种所占比例较高。云南山顶苔藓矮林中全缘叶物种比例平均达59.11%,低于热带雨林和季风常绿阔叶林,但高于一些中亚热带森林。尽管山顶苔藓矮林生境较为潮湿,但反映潮湿生境特征的具滴水叶尖物种比例明显很少,林内往往缺乏热带雨林中那样典型的滴水叶尖植物;革质叶所占比例则较高,常绿植物树种较多,群落外貌整体表现为常绿阔叶特征。3)各群落内植株的胸径随群落植株密度增加而减小,林木胸径分布在各群落中有较大的差异。从各群落实际情况看,由于各研究地点土壤总体上较为潮湿,土层一般都比较浅薄,所以推测风可能是影响林木径级分布的主要物理因子之一:在风力较强的地方树干分枝低矮、进入起测胸径范围的植株较少,很多植株胸径小于5 cm,并且常呈灌木状分布。各群落大多数植株胸径普遍在35 cm以下。4)对七个研究样地群落乔木层树种组成相似性作聚类分析,结果显示各群落之间相似性比较低。5)在种子植物区系组成上,云南山顶苔藓矮林科的地理成分以泛热带分布及其变型、热带亚洲和热带南美间断分布、北温带分布为主体,其中热带性质的地理成份明显高于温带性质的地理成分。6)云南山顶苔藓矮林植物区系在属一级水平上,则以泛热带分布及其变型、热带亚洲分布及其变型、东亚分布及其变型为主体。热带分布属与温带分布属在组成比例上基本等量,具有明显的从热带向温带过渡特性。7)云南山顶苔藓矮林植物区系,在种一级水平上,热带亚洲分布及其变型是其区系的主体成分,这类植物种类在各研究样地内所占比例略超过总种数的一半,显示出与热带亚洲的紧密联系。北温带分布、东亚和北美洲间断分布、旧世界温带分布、东亚分布及其变型在各研究样地中比例很小或没有记录到。云南特有种和中国特有种,是仅次于热带亚洲分布的第二大分布类型,在各研究地点比例约在25%–42%之间,这些种类大部分分布在我国西南地区,分布到温带地区的种类很少。8)云南山顶苔藓矮林植被土壤一般属淋溶土、棕壤类、山地酸性棕壤亚类,土壤有机质、全氮、全磷、全钾、速效氮、速效磷含量都较高,土壤肥力较好。土壤有机质、全氮、全磷、全钾、速效氮、速效磷等土壤肥力指标不是山顶苔藓矮林林木生长的限制因子,但在不同地点的森林中,各种肥力指标含量彼此间差异较大。土壤pH值在各研究点中变异较小,大都在4.0左右,酸性较强。10)徐家坝地区山顶苔藓矮林的土壤含水量与本地区其它森林类型,如季风常绿阔叶林、中山湿性常绿阔叶林、中山湿性常绿阔叶林与山顶苔藓矮林过渡带森林、滇山杨林相比显得较高。山顶苔藓矮林各年间相同时段内土壤湿度的数值分布较为离散。说明天气变化很容易影响到山顶苔藓矮林的水分状况。同时也暗示了山顶苔藓矮林作为世界云雾林的一部分,对全球气候变化可能特别敏感。土壤含水量沿海拔梯度变化明显,由低海拔到高海拔呈递增趋势。11)哀牢山山顶苔藓矮林与本地区其它植被一样,水分变化表现为相同的变化周期,即在多雨季节土壤湿度相对较高,在旱季土壤湿度相对较低,与该地区总的降雨节律相一致。12)中山湿性常绿阔叶林与其破环后形成的滇山杨次生林各层土壤湿度变化规律及离散程度差异不明显。这一情况说明中山湿性常绿阔叶林破坏后经较长时间恢复形成的滇山杨次生林对土壤水分变化影响不大。13)除山顶苔鲜矮林外,大部分植被类型表现出多雨季节0–10 cm土层土壤含水量高于10–20 cm土层土壤含水量,并有沿海拔梯度增加,差别加大的趋热;旱季两土层差别不大。山顶苔藓矮林则在全年内0–10 cm土层土壤湿度明显高于0–20 cm土层湿度,并在雨季两层间土壤湿度差别增大。山顶苔藓矮林出现这一独特表现的原因在于:山顶苔藓矮林一年中大部分时间内由于雾的影响较多,通过植物拦截后形成的的水滴直接影响了土壤表层的含水量,使0–10 cm土层土壤经常处于一种比较湿润的状态。14)低温不可能构成云南山顶苔藓矮林(云雾林)存在的必然要素。各地区山顶苔藓矮林湿度都较大,年平均均在85%以上,较为潮湿的生境可能是云南山顶苔藓矮林(云雾林)存在最为关键的环境因素。15)由于云南山顶苔藓矮林在群落结构及外貌特征上完全符合热带山地云雾林的特征,并在物种组成上热带性质的成分比例较高,云南山顶苔藓矮林完全可以作为世界热带山地云雾林的一部分来对待。大致相当于国际上的“upper montane cloud forest”。更多还原

【Abstract】 Understanding the ecology and biogeography of the mossy dwarf forest (cloud forest)is of critical importance in protecting theses rare and endangered ecosystems. Plant diversity, physiognomy, species composition and environment of the less known mossy dwarf forest in Yunnan were studied, based on data collected from 35 sampling plots in 7 sites. The study sites are located in six national nature reserves, from east to west, which are named as Laojunshang National Nature Reserve, Fengshuilin National Nature Reserve, Huangliangshan National Nature Reserve, Wuliangshan National Nature Reserve, Ailaoshan National Nature Reserve, Daxueshan National Nature Reserve, and one well protected Sudian National Forest area. The results ofour studies are concluded as following:1) In floristic composition, the mossy dwarf forests are mainly dominated by Fgaceae, Ericaceae, Vacciniaceae, Aceraceae, Magnoliaceae, Theaceae, Aquifoliaceae, Illicieae, Lauraceae, Rosaceae etc. The dominant species vary from site to site.1) In a 2500 m~2 sampling area of each community, the total vascular species varies from 57 to 110 and the Simpson’s index varies from 0.7545 to 0.9544, Shannon–Winner’s diversity index from 1.8251 to 3.2905 and Pielou’s evenness index from 0.6583 to 0.8982 for trees. The species richness, Simpson’s index, Shannon–Winner’s diversity index and Pielou’s evenness of the community in Laojunshang National Nature Reserve are lower than those of other study sites. In general, the species richness and diversity of the mossy dwarf forests in Yunnan are relatively low in comparison with those forests in lower altitude in Yunnan.3) In physiognomy, the forests are dominated by phanerophyte plants, and lianas are rare. The plants with microphyllous plus nanophyllous leaves contribute to 44.32–63.46% of the total species, and the plants with an entire leaf margin account for more than 50% of the tree and shrub species. There are also less abundant tree and shrub species with drip tip leaf apex and papery leaves. In the mossy dwarf forests, evergreen species make up more than 75% of the total tree and shrub species. The forests are evergreen broad–leaved forests.4) In these forest communities, the DBH class distribution of the tree species decreases with the increase of the tree thickness, and vary obviously from one community to another community. Most trees have DBH less than 35cm.5) The cluster analysis shows that these communities have low similarity.6) At the family level, the mossy dwarf forests in Yunnan is mainly composed by Pantropic distribution, Tropical Asia & tropical America disjuncted distribution and North temperate distribution. The families of tropical distribution are more than those of temperate distributions.7) At the generic level, the flora of the forests is composed mainly by the genera of Pantropic and tropical Asian distributions. The ratio of tropical elements is almost equal to the one of temperate elements. These results indicate that the flora is a transitional one from the tropical to subtropica1.8) At the specific level, the elements of tropical Asian distribution contribute more than half of the total flora. The close relationship of the flora with tropical Asian flora is observed. The species of Chinese endemic and Yunnan endemic distributions are the second large part of the flora, which contribute to 25–42 % of the total flora.9) The soils of the mossy dwarf forest in Yunnan belong to Argosols order, brown soil group,Acid brown forest soil subgroup. Soil nutrient contents, such as total N,P,K,available N,P, K, manifested remarkable variability under different study sites. Compared with other forests in Yunnan, the soil nutrient contents are higher, and the soil pH is lower. The common pH value is about 4.0. Soil nutrient contents are not a limiting factor to tree species growth.10) The soil moisture of the summit mossy dwarf forests in Xijiaba area are higher than that of the monsoonal evergreen broad–leaved forest, the mid–montane humid evergreen broad–leaved forest, the transitional forest between the mid–montane humid evergreen broad–leaved forest and the mossy dwarf forest and Populus bonatii forest. And the soil moisture of the mossy dwarf forests manifested remarkable variability under different study years at the same times. The soil moisture significantly increases with increasing altitude.11) Same as other vegetation types in Ailao Mountain, soil moisture of the summit mossy dwarf forests show the same cycle period. In rainy season soil moisture is high and in dry season soil moisture is low.12) The soil moisture of the Populus bonatii forest shows the same variability under different layers. This result indicates the second forests of the mid–montane humid evergreen broad–leaved forest have no significant impact on the dynamic of soil moisture after a long time recover.13) The soil moisture of the 0–10 cm soil layer is higher than that of the 10–20 cm soil layers. There is commonly big discrepancy between the 0–10 cm soil layer and the 10–20 cm soil layer in rainy season but in dry season, except the summit mossy dwarf forest. The discrepancy in rainy season increases with increasing altitude. Discrepancy happens in the summit mossy dwarf forest all the year round, and the big discrepancy happens during the rainy season. The key reason is that the summit mossy dwarf forest is frequently covered in cloud or mist, so it can intercept more cloud water, and condition the 0–10 cm soil layer under wet conditions.14) Low temperature is not the necessary element for the occurrence of the cloud forest (summit mossy dwarf forest). The environments of the summit mossy dwarf forests in Yunnan are very wet and the annual mean humidity is higher than 85%. So the wet environment may be the key fact for the occurrence of the summit mossy dwarf forest.15) The summit mossy dwarf forests bear all the characters of tropical montane cloud forest and possess high percentage of tropic elements species. They should be treated as one of the world tropical montane cloud forest. The term‘summit mossy dwarf forest’has the same meaning as‘upper montane cloud forest’.更多还原