三江源地区冬虫夏草采挖对草地植被的影响

在三江源地区冬虫夏草3个产区——青海省黄南藏族自治州泽库县、果洛藏族自治州玛沁县和玉树藏族自治州杂多县设置虫草采挖样地和对照样地,通过样方调查和统计分析,评价冬虫夏草采挖活动对草地植被的影响. 结果表明:冬虫夏草采挖使草地物种多样性、盖度和地上生物量降低,群落优势度升高.由于采挖活动,Shannon-Wiener多样性指数减少了10.3%~12.5%,群落盖度降低了10.6%~19.1%,地上生物量降低了20.7%~46.1%,Berger-Parker优势度指数增加了16.7%~31.8%. 采挖活动未使地下生物量产生显著变化. 植被状况的恶化将影响冬虫夏草的形成过程,因此,应加强冬虫夏草产区的植被保护,以实现资源的可持续利用. 地上生物量对冬虫夏草采挖活动最为敏感,可作为冬虫夏草产区植被保护过程中的首选评价指标. 采挖活动对地上生物量的影响程度与地理位置有关,表明采挖活动的效应具有区域分异特征,冬虫夏草资源保护策略应根据区域特点制订. 

The Impact of Cordyceps sinensis Excavation on Grassland Vegetation in the Sanjiangyuan Region

Cordyceps sinensis was an expensive medicinal fungus in the Tibet Plateau. The excavation of the C. sinensis seriously affected the ecological environment. The excavation plots and control plots were set in Zeku County, Maqin County and Zaduo County, where were high production areas of C. sinensis in the Sanjiangyuan region. Field sampling investigation and statistical analysis were applied to assess the impact of C. sinensis excavation on the grassland vegetation. The results showed that, since excavation of C. sinensis, species diversity expressed as Shannon-Wiener indexes decreased by 10.3%-12.5%, community dominance expressed as Berger-Parker indexes increased by 16.7%-31.8%, vegetation coverage decreased by 10.6%-19.1%, and aboveground biomass decreased by 20.7%-46.1%. However, underground biomass not significantly changed under excavation of C. sinensis. Grassland degradation would impede the formation of C. sinensis. Therefore, it was necessary to protect the vegetation in the production areas for the sustainable utilization of C, sinensis resource. Aboveground biomass was the most sensitive variable to C. sinensis excavation, which could be used as the evaluation indicator in vegetation protection. The impact of excavation on aboveground biomass significantly related with the geographical locations, which means a necessity to make the protection strategy distinctively. Thus, further studies considering the climatic characteristics and soil properties were needed.