【作者】 李毅；

【导师】 胡自治；

【作者基本信息】 甘肃农业大学 ， 草业科学， 2002， 博士

【摘要】 本论文以东祁连山高寒植被类型的主要组成成分——高寒柳灌丛及其优势种群为对象，在其分布连续且梯度明显、海拔3050m～3450m范围内设置18个面积为16m×16m调查样地。采用方格网法取样调查，对该群落的结构、组成、种间、种内关系、物种多样性水平及山生柳克隆种群在基株、分株两个水平上的结构特征与分布格局进行了较为系统的研究。研究方法上，本文以重要值表征优势度对群落的组成和结构进行描述，以物种多样性指数反映群落物种多样性水平，用联结系数和共同出现百分率来确定种间关系，以静态生命表和存活曲线说明种群的年龄分布，用方差／均值比、负二项参数(k)、格林指数(GI)、扩散型指数(Iδ)、Cassie指标、丛生指标(I)、平均拥挤度(m)、聚块性指数(m／m)以及等级方差分析法(HAOV)进行种群空间分布格局集聚强度与规模的测定。 研究结果表明，东祁连山高寒柳灌丛群落主要由30种植物构成，其中，灌木植物13种，草本植物17种。灌木层中，山生柳优势度为3.1032～2.848，是柳灌丛群落中的优势种群和建群种；金露梅优势度为2.0657～1.8827，高山绣线菊优势度为1.1292～0.943，头花杜鹃优势度为0.874～1.2002，它们构成了群落中的亚优势种；坡柳、川滇柳、杯腺柳、青海杜鹃、烈香杜鹃、千里香杜鹃、鬼箭锦鸡儿构成了群落的伴生种(0.1＜优势度＜0.5)：鲜黄小檗和刚毛忍冬为群落中偶遇种(优势度＜0.1)。草本层中，圆穗蓼(优势度分别为1.9517，1.8579)与珠芽蓼(优势度为1.7483～1.7042)构成群落的优势种；矮嵩草、黑褐苔草、早熟禾、藏异燕麦(0.5＜优势度＜1)组成群落的亚优势种；风毛菊、苔草、马先蒿(0.1＜优势度＜0.5)为伴生种；垂头菊、火绒草、毛莨、银莲花、龙胆、虎耳草、绿绒蒿、甘肃棘豆(优势度＜0.1)为偶遇种。 群落中柳属植物由山生柳、坡柳、川滇柳和杯腺柳4个种组成，在不同的海拔区间其优势程度不同。山生柳种群的重要值随海拔梯度的增加呈升趋势，在海拔3400m～3450m之间形成单优群落；金露梅种群优势度随海拔增高而减小，在海拔3050m～3250m范围内其重要值大于或与山生柳种群的重要值相当，与柳灌丛一起构成共优群落；头花杜鹃种群在3100m～3350m区间，为仅次于山生柳种群的优势种群。不同海拔高度高山绣线菊种群的优势度变化不大，在3050m～3250m区间其重要值超过了头花杜鹃种群。 高寒柳灌丛群落由高位芽植物层片、地面芽植物层片和地下芽植物层片组成。高位芽植物层片由山生柳、坡柳、川滇柳、杯腺柳、金露梅、高山绣线菊、杜鹃组成等组成；地面芽植物层片由圆穗蓼、珠芽蓼、龙胆、藏异燕麦、甘肃棘豆、风毛菊等组成；地下芽植物层片由矮嵩草、黑褐苔草、早熟禾、马先蒿、火绒草、绿绒蒿等植物组成。 柳灌丛群落物种多样性测度指标的比较分析表明，盖度和重要值作为测度指标时较为一致，而多度差异性较大。由于盖度计测的多样性值最大，因此选用它作为 物种多样性指数的测度指标较为合理可靠。 柳灌丛群落内物种多样性水平上，草本层在物种丰富度指数、Simpson指数和 Shannonwiener指数三个指标上均大于灌木层，但在latalo均匀度指数上则低于灌 木层。灌木层中，物种多样性指数最大值发生在海拔3150m～3250m之间，草本层中， 最大值均发生在海拔3100m处。uqllttaker指数和Routledge指数共同表明了灌木层 p多样性水平高于草本层的多样性水平，而 Cod3指数则没有提供这方面的表征。在 灌木层，6多样性随海拔增高而降低：草本层，在海拔3150mrp200m间，物种替代 的程度最高：在此海拔之上，物种的替代速率随海拔的增高而降低。． 干扰对物种多样性有一定影响，能提高群落物种多样性水平。割灌试验表明， 干扰前后的物种多样性指数则发生了变化：物种丰富度指数（d。；。）、Simpson指数 ＊）和趾。11．WCllCf指数（H”）均有一定程度增长．其中，又以 d。I值上升 幅度最大。 柳灌丛群落内灌木植物种间关系表现为三种。正联结：海拔3050mryl00m间金 露梅和高山绣线菊之间；315仇止刁250二金露梅、山生柳和高山绣线菊两两之间： 325小S400二间，金露梅、山生柳和头花杜鹃两两之间：3400皿工45（h间鬼箭锦鸡 儿与山生柳、头花杜鹃两两之间。负联结：31 00m处金露梅与高山绣线菊之问；海 拔3200m处山生柳和千里香杜鹃、鲜黄小案之间；鲜黄小粱和金露梅、高山绣线菊 之间：3250m处杯腺柳和山生柳、金露梅、高山绣线菊之间，刚毛忍冬和山生柳之 间；3350m金露梅和烈香杜鹃、鬼箭锦鸡儿之间，鬼箭锦鸡儿和山生柳、头花杜鹃 之间；3450m刚毛忍和山生柳、头花杜鹃之间。无联结：3450m处．烈香杜鹃、金 露梅、高山绣线菊、千里香杜鹃和其它种群之间。 山生柳基株种群中，！龄级个体均较缺乏，其平均数仅占总株数的4．更多还原

【Abstract】 The thesis, through sampling and investigating within eighteen plots with contiguous grid quadrat method whose size was 16mX 16m and distributed where plants spred continuously and altitude graduate was obvious from 3050m to 3450m, analysed the main constituent part of alpine vegetation - alpine Salix shrub community and its dominant populations in alpine area of east Qilian mountain. It was studied systematically for the community and the populations on the structure, component, intraspecies relationship, interspecies relationship, the level of species diversity, age structure and distribution patter at the genet and the ramet level. Importance value (IV) had been used to describe community’ component and construction, index of species diversity to indicate species diversity level of the community1, associate coefficient and the percentage of the simultaneous emergence to determine the interspecies relationship, static life stable and survival curve to express age distribution, ratio of variance to mean value(v/m). negative binominal parameter(k). Green’s index (GI). Index of dispersion(I f,), Cassie indexs (Ca), index of clumping(I) , index of mean crowding(m ), index of patchiness( m*/m) and HAOV to measure the crowding and the scale of the distribution pattern of the population.The results showed that Salix shrub community was mainly consisted of 13 shrub plants and 17 herbs. In the shrub layer, Salix oritrepha is a dominant community- and constructive species whose IV was 3.1012~2.848. Dasiphora fmticosa. Spiraea alpina. Rhododendron capitatum were subdominant species constituting the community and IV of them were 2.0657 ~ 1.8827, 1.1292- 0.943 and 0.847-1.2002 respectively. Salix myrtillacea, S. rehderiana, R. przewalskii. R. anthogonoides, R. thymifolium. Caragana jubata were companion species constituting the community (0.1< IV <0.5). Berberis diaphana and Lonicera hispida were rare species in the community (IV<0.1). In the herb layer, Polygonum sphaerostachyum with 7Fof 1.9517- 1.8579, and P. viviparum with IV of 1.7483-1.7042 were dominant species constituting the community. Subdonminant species was consisted of Kobresia humilis. Carex atrofusca, Poa spp. and Helictotrichon tibeticum (0.5<IV<1). Saussiirea spp.. Koeleria cristata. Pedicularis spp. (0.1< IV<0.5) were companion species. Cremanthodium humil, Leontopodium leontopodioies. Ranunculus spp., Anemone cathayensis, Gentiana spp., Saxifraga spp., Meconopsis spp. and Oxytropis kansuensis were rare species in the community.The species of Salix genus in the community were composed of 4 specieses -salix oritrepha, Salix myrtillacea, S. rehderiana and S.cupularis, whose dominance were different with different altitude graduate. The importance value of salix oritrepha, which formed monodominant community from 3400m to 3450m, had upward trend as altitude increasing. The dominance of Dasiphore fniticosa had downward trend as altitude increasing and it constituded co-dominant populations with salix oritrepha from 3050m to 3250m because the W was more than or equal to that of Salix oritrepha. Rhododendron capitatum is the second dominant population whose value only followed Salix oritrepha community from 3100m to 3350m. The dominance of Spiraea alpina in the different altitude was almost the same and IV of it was more than that of Rhododendron capitatum from 3050m to 3250m.Alpine Salix shrub community was consisted of phanerophyte synusia. hernircyptophyte synusia and geoph>1e synusia in which Salix oritrepha. Salix myrtillacea, S. rehderiana and S.ciipularis, Dasiphore fniticosa, Spiraea alpina, Rhododendron capitatum were phanerophytes , Polygonum sphaerostachyim. P. viviparum, Helictotrichon tibeticum , Gentiana spp., Oxytropis kansiiensis and Saiissnrea spp. were hemircyptoph\tes and Kobresia humilis, Carex atrofiisca. Poa spp., Pedicularis spp., Leontopodium leontopodioie.Meconopsis spp. were geophytessynusias.It was approvided that the diversity indices based on cover value had more ecological significance than that based on important valu更多还原