西藏地区手掌参的生境条件及致危因素分析

Geographic Distribution, Habitat and Analysis on Endangered Cause of Gymnadenia R.Br. in Tibet

结合已有文献资料和实地调查结果,对西藏地区手掌参的地理分布和生境特点进行研究,分析探讨西藏地区手掌参濒危的原因,以期为野生手掌参资源的保护和可持续利用提供参考。结果表明,手掌参分布范围狭窄,种群规模小,多呈零星或零星小片分布于藏南和藏东南各县域的局部地区。手掌参生长于海拔2800~4600 m,具有一定坡度的林窗、林缘、草甸、草地生境中,生境土壤呈酸性至中性,有机质含量丰富,土壤类型以棕壤和高山草甸土为主,其分布区具有高原季风气候的特点。手掌参濒危最主要的内在因素是其繁殖能力和繁殖效率低,市场需求的掠夺性、采集方式的致死性、采集时间过早、人为滥采滥挖等干扰因素和生境的破碎化是主要的外部致危因素,手掌参濒危是多种因素共同作用的结果。

The geographic distribution and habitat of Gymnadenia R.Br. in Tibet were studied based on literature and on site investigations. According to field survey results,the endangering factors were analyzed to provide the basis for its rational use and protec tion. Results showed that geographic distribution of Gymnadenia R.Br. was relatively narrow, which mostly showed a scattered or fragmental distribution.The altitudinal distribution of the species ranges from 2800 to 4G00 m. Its habitat was forest gap and forest edge, alpine meadows, natural grassland, all with certain gradient. Gymnadenia R. Br. growed in the soils from acidic to neutral. The soils were rich in organic matter. The mountain brown and alpine meadow soils were the main types of soil in the whole range of the species distribution. Its distribution areas were characterized by typical plateau monsoon climate. The internal endangered factors were its weak fertility and low breeding efficiency while the external factors were due to the predatory nature of market de mand, the lethality of collection methods, early collection time and excessive mining and stripping of human activities. Various fac-tots all contributed to the extinction of Gymnadenia R.Br..