九寨沟核心景区外来植物的分布格局与影响

Distribution pattern of the alien plants and their impacts on the scenic corezone of the Jiuzhaigou Nature Reserve

自然保护区是就地保护生物多样性最为经济有效的措施,而生物入侵已对全球生物多样性造成严重威胁.采用野外踏查和样方调查的方法,对著名的国家级自然保护区和风景名胜区九寨沟核心景区的外来植物的种类和分布格局进行研究.结果如下:(1)共发现13种外来植物,来自6科11属,以豆科、菊科植物最多.(2)引入方式主要是有意引入(绿化)和无意的旅游活动引入,人为因素起着主导作用,外来植物出现的概率与受人为干扰程度成正相关.(3)根据重要值(Important value)和外来入侵植物危害等级计算得出危害系数,小蓬草(50.2439)、红车轴草(41.1528)、野胡萝卜值(40.6883)较高,但目前外来植物在研究区域还未形成大规模的入侵现象.(4)影响外来植物分布和扩散的因素有生境适合性、路距、群落盖度,路距具有重要影响(P<0.05).(5)随着栈道距离的增加,外来植物(以草木犀为例)的重要值呈显著下降趋势.综上所述,九寨沟核心景区的外来植物分布主要受人为影响,豆科、菊科植物种类多且危害系数较高.

The Jiuzhaigou Nature Reserve is both a nature reserve and a tourist destination. While Jiuzhaigou becomes more and more popular at home and abroad, it is at ever higher risk of alien plants invasion. This paper is to characterize the distribution pattern of the alien plants and their impacts on the scenic core-zone of the Jiuzhaigou Nature Reserve, and to recommend management tactics in controlling the pest alien-plants. We set up sampling plots along the road of the core scenic Jiuzhaigou to investigate the species composition and distribution patterns of alien plants. The survey recorded 13 alien plants, which belonged to 11 genera and 6 families, with the majority being classified as Leguminosae and Compositae. The alien plants were mainly introduced by afforesting （intentional） or tourism （unintentional）; the anthropogenic factors played a leading role in the invasion of alien plants. Hazard coefficient were calculated for four typical alien plants; the values of Erigeron canadensis, Trifolium pretense and Daucus carom were high, but the study area was not massively invaded by them. The suitability of habitat, distance from road and community coverage impacted the distribution and spread of alien plants, among them the distance from the road playing an important role. The importance value of alien plants （Melilotus officinalis as a case study） significantly decreased with the distance from road. It was probably because the weakening human disturbance in the far distance from the road decreased the survival chance of alien plant species. The investigation showed 13 alien species of alien plants in Jiuzhaigou belonging to 11 genera and 6 families. Though they have not yet formed a massive invasion, some alien plants have already showed a trend of diffusion.