若尔盖郎川公路建设区有毒有害植物扩散及生态安全性评价

通过大量的野外考察和文献资料分析,研究了朗川公路建设区沿线天然草地有毒有害植物种类、分布、群落结构及安全性。结果表明,由于人为干扰改变了天然植物群落物种间的竞争格局,具有较强竞争力的有毒有害物种得以扩散,在群落中作用增强,在群落中优势度逐渐上升。在各等级样方中,Shannon-Wiener物种多样性指数和Pielou均匀度指数随着有毒有害物种分盖度的增加呈现出先增后减再回升的趋势,Simpson优势度指数则随着有毒有害物种的分盖度增加而逐渐降低。此外,工程建设中采取草皮移植措施在一定程度上取得了成效,已恢复的边坡群落比较稳定,根据不同研究结果表明割取草皮厚度及大小与草皮恢复后的植物群落结构密切相关。

Poisonous and Pernicious Species Dispersal and Its Ecological Risks Assessment in the Langchuan Road Construction Region of the Zoige Region

Species distribution patterns of poisonous and harmful plants,and their impacts on ecological safety community structure and functions of natural grassland along the Langchuan road construction region have been studied primarily based on field investigation and documents review.Poisonous and pernicious species with higher competitiveness could spread their distribution area or improve their population density in grassland community after external disturbance such as overgrazing and destruction.Moreover,some poisonous and pernicious species become the dominant species of the grassland,such as Stellera chamaejasme and Ligularia virgaurea in most of degraded grassland.The Shannon-Wiener indices of communities fluctuated with the increase of poisonous and pernicious species coverage,while Pielou indices decrease with the increase of poisonous and pernicious species coverage.Some measures for grassland restoration destructed during the road construction,such as transplantation of greensward pieces,have been achieved success to some extent.However,the new communities formed thru greensward transplantation are related with area and thickness of greensward pieces.