豚草入侵湖南对植物多样性的影响

采用样方法调查了湖南省6个豚草入侵样地中4～10月杂草的种类和数量，分析了其物种丰富度指数、多样性指数和均匀度指数。结果表明，6个样地采得本地植物83种,其中常见本地植物41种，隶属19科。豚草入侵造成6种生境条件下物种丰富度指数、Simpson多样性指数和Shannon-Wiener多样性指数下降显著或极显著，均匀度指数变化小。豚草群落在不同季节物种丰富度指数变化小，多样性指数和均匀度指数在春夏季上升。表明豚草的入侵对生物多样性有不利影响。

Effect of Invasion of ragweed(Ambrosia artemisiifolia L.) on Plant Biodiversity in Hunan Province

Ragweed （Ambrosia artemisiifolia L.）, native to the southwest Americas, has become a major invasive wicked weed in China. Knowledge of effect on plant biodiversity is very useful in determining the invasive mechanism of ragweed and very helpful to controlling the spread of it. A survey was conducted with the square intercept method on species and quantity of weeds in 6 kinds of habitats where ragweed grew in Hunan Province,the species richness index, diversity index and evenness index were analyzed. Results showed that a total of 83 indigenous species were collected and among them, 41 species were common indigenous plants, belonging to 19 families. Invasion of ragweed caused significant （P0.05 or P0.01） decline of species richness index, Simpson index and Shannon-Wiener index and little change of Pielou evenness indexes in all the habitats involved. The variation in species richness index of ragweed invasion communities in the different season was small,diversity indexes and evenness indexes were increased, and the invasion communities were concentrated on ragweed in spring and summer. It was suggested that the invasion of ragweed is harmful to biodiversity of weed communities in Hunan Province.