川东平行岭谷区野生春剑伴生植物群落特征研究

DISTRIBUTION STATUS OF WILD CYMBIDIUM TORTISEPALUM VAR. LONGIBRACTEATUM RESOURCES AND ASSOCIATED PLANTS IN PARALLEL RIDGE-VALLEY REGION IN THE EASTERN SICHUAN OF CHINA

为了对春剑野生种群生物多样性保护和再引入生态重建提供理论和技术基础，采用典型样地调查法，对JlI东平行岭谷区野生春剑伴生植物群落特征进行了研究。结果表明：野生春剑主要分布在松科与壳斗科针阔混交林、壳斗科常绿一落叶阔叶混交林和松树林植物群落，伴生植物有40科58属70种，优势种主要是乔木层的马尾松、青冈、巴山松、油松等，灌木层的杜鹃花、马桑、山茶花等，草本层的蕨类和地被层的苔藓。其中，马尾松、杜鹃花、蕨类、苔藓具有较高的重要值，可作为野生春剑栖息地的指示植物。春剑伴生植物种类具有相对的特异性和选择性，与其它群落相比，群落3、群落4和群落6物种多样性指数H1和均匀度指数E都相对较低，松科和壳斗科植物个体数量较多并占有突出地位，春剑种群的生态密度也相对较高。虽然川东平行岭谷区野生春剑的适生生境条件依然存在，但春剑种群数量总体较小，种群的生态密度在11～60株／hm2，人为破坏性的滥采，是其濒危的直接原因。加强野生春剑资源的就地保护和生境保护，突破春剑种子野生环境共生萌发技术瓶颈，积极开展春剑的“再引入”工作，是春剑保育策略的重要方向。

Wild Cymbidium tortisepalum var. longibracteatum （Orchidaceae） plants in Sichuan Province of China have become endangered due to over-harvesting in recent years. In order to provide theoretical and technical basis on wild C. tortisepalum var. longibracteatum biodiversity conservation and re-introduction in a larger scale, a systematic investigation on the main habitats of populations was conducted based on representative plot survey in Parallel Ridge-valley Region of the Eastern Sichuan in 2010. The results showed that the wild C. tortisepalum var. longibracteatum distributed mainly under the mixed forest of Pinoideae and Fagaceae,Mixed Fagaceae forest and Pinus forest where the altitude was about 680--1 900 m, and its main associated plants were composed of 34 species belonging to 15 families,28 genera in tree layer, 18 species belonging to 12 families, 15 genera in shrub layer and 17 species belonging to 12 families, 14 genera in field layer. Among associated plants, the shade density of tree layer was from 0.2 to 0.4, and the dominant species were Pinus massoniana , Fagus longipetiolata , Pinus henryi , Pinus tabuli formis, Fagus pashanica,Lithocarpus cleistocarpus and Quercus acutissima etc. The coverage of shrub layer was from 30% to 50~, and the dominant species were Rhododendron, Coriaria sinica, Camellia japomica, Rubus orchorifolius and Pyracantha fortuneana etc. The coverage of field layer was about 40~ to 80~,and its dominant species were Bryophyta, lichen, Pteridophyta. Among these plants, Pinus massoniana, Rhododendron, Bryophyta and Pteridophyta can be used as indicative plants for its high important value. Species diversity of plant community in different populations was investigated. Plants in the populations associated with suitable habitats of C. tortisepalum var. longibracteatum were prosperity and lush. Species abundance index of D was between 1. 915 to 3. 572 in 10 populations. Compared with others,the population of lst,3rd and 6th had relatively low index of H＇（Shannon-wiener index） and E （Pielou index）,and had high ecological density of C. tortisepalum var. longibracteatum, which indicated that individuals oft Pinaceae and Fagaceae were more than some other species and prominent in those populations. The individual quantity of every population of wild C. tortisepalum var. longibracteatum were only from 11 to 60 individual plants per ha, which revealed that this species in Parallel Ridge-valley Region in the Eastern Sichuan had become endangered due to over-harvesting. Although C. tortisepalum var. longibracteatum is rather rare, the habitat of wild C. tortisepalum var. longibracteatum were still protected well. These results, combined with other information about C. tortisepalum var. longibracteatum, may provide an important basis for proposing conservation strategies. In situ conservation will be suitable for in Parallel Ridge-valley Region of the Eastern Sichuan,especially in Tongjiang（the 1st population and 3rd population） and Nanjiang（the 6th population）, while the researches about seed physiology and symbiotic germination to raise germination rate of C. tortisepalum var. longibracteatum in wild environment and the application of re-introduction in the conservation of endangered orchid should be taken into consideration to expand the population to save the endangered status.