青藏高原野生濒危药用植物掌裂兰的生境及濒危因素分析

Habitat and factors of endangerment of wild and endangered medicinal herb Dactylorhiza hatagirea in Qinghai-Tibet Plateau

关键词:  掌裂兰, 濒危植物, 藏药野生资源, 生境特征, 濒危因素

Key words:  Dactylorhiza hatagirea, endangered plant, Tibetan wild medicinal resources, habitat, factors of endangerment

摘要:

该研究通过对青藏高原珍稀濒危药用植物掌裂兰(Dactylorhiza hatagirea)的气候、地理、土壤和群落等生境方面的研究,分析了导致其濒危的主要因素。结果表明:(1)掌裂兰喜湿润的高寒草甸土壤,在青藏高原主要分布于青海省北部、东南部、南部和四川省西部,西藏东南部的湿生草甸或沼泽化草甸、嵩草草甸、滩地(台地)、河滩岸上,覆盖区域范围为94°15'49″—102°46' 27″ E、 29°14'15″—36°59'7″ N,海拔在2 960～4 150 m之间。(2)掌裂兰分布区的气候特点为累年年均风速为2.1 m·s^-1、累年年均气温为3.5 ℃、累年年均降水量在339.4～680.2 m之间、累年年均相对湿度为58%。(3)掌裂兰群落与共生植物种类多样,不同区域共生植物种类不同。调查样地内共有维管束植物58种,隶属于22科45属。群落1中优势种为黄帚橐吾(Ligularia virgaurea)和甘肃棘豆(Oxytropis kansuensis); 群落2中优势种为马蔺(Iris lactea),其次为鹅绒委陵菜(Potentilla anserina)等喜阳耐阴的植物种; 群落3中优势种为问荆(Equisetum arvense)及斑唇马先蒿(Pedicularis longiflora var. tubiformis)。(4)采用主成分分析法,找出影响掌裂兰濒危的主要生态因子有土壤有机质、总氮、总磷含量及降雨量和湿度,其载荷系数均在0.9以上,其次为风速、温度、pH值,载荷系数在0.8以上。实地调研发现,青藏高原掌裂兰分布区生境脆弱,遗传多样性低,风媒传播效率低,种子萌发率低,种群天然更新能力弱,分布区狭窄等因素是导致该植物稀少濒危的主要原因。建议对掌裂兰典型适生生境建立保护区,加强个体繁育和野生抚育研究,增加个体数量和生长量。

Abstract:

Through investigating of the habitat such as climatic characteristics, geographical distribution, soil factors and the community structure, main factors for endangerment of the herb were analyzed. The results were as follows:(1)Dactylorhiza hatagirea prefered the damp soil of alpine meadow soils which mainly distributed in the northern, southeas-tern, southern parts Qinghai Province and western part Sichuan Province of Qinghai-Tibet Plateau, as well as the wet meadows or swampy meadows, weedy meadows, shoals, and on river banks, covering the area between 94°15'49″-102°46'27″ E, 29°14'15″-36°59'7″ N, with the altitude between 2 960-4 150 m.(2)The climate in the distribution area of D. hatagirea had the average annual wind speed of 2.1 m·s^-1, the annual average temperature of 3.5 ℃, the annual average precipitation of 339.4-680.2 m, and the annual relative average humidity of 58%.(3)There were diverse species of D. hatagirea and symbiotic plants, with different symbiosis in each D. hatagirea in habitats. A total of 58 species of vascular plants were found in the survey site, belonging to 22 families and 45 genera. The dominant species in Community 1 were Ligularia virgaurea and Oxytropis kansuensis; The dominant species in Community 2 was Iris lactea var. chinensis, followed by the plant of sun-tolerate and shade-tolerate species, like Potentilla anserina; The dominant species in Community 3 was Equisetum arvense and Pedicularis longiflora var. tubiformis.(4)Principal component analysis found that the main ecological factors affecting Dactylorhiza hatagirea were soil organic matter, total nitrogen content, total phosphorus content content, rainfall and humidity, with the load coefficient of above 0.9, followed by wind speed, temperature and pH value, the load coefficient of above 0.8. Fragile habitats, low genetic diversity, low wind-borne transmission efficiency, low seed germination rate, weak natural regeneration ability and narrow distribution area were the main causes for the rare and endangered plant. It is proposed to establish the protected area at the herbal habitat, while the research of individual breeding and wild tending should be strengthened to increase the number and growth of individual plants.