大花金鸡菊入侵对植物多样性的影响

Effects of invasion of Coreopsis grandiflora on vegetation diversity

采用样方法研究了青岛市5个不同生境下大花金鸡菊(Coreopsis grandiflora)入侵地植物的种类和数量,分析了其物种丰富度、多样性指数和均匀度指数,并计算出每种植物的重要值。5个样地共采集本地植物92种,隶属16科,以菊科和禾本科最多,其中出现频率较高或植株数量较多的植物共33种。大花金鸡菊入侵地物种丰富度、Simpson指数、Shannon-Wiener指数和Pielou指数较对照均有下降,最大下降幅度分别为34.75%、60.53%、58.22%和41.98%。大花金鸡菊的平均重要值高达56.92%,远大于群落中其他植物的重要值,并且和群落的物种丰富度有显著相关性(R2=0.907),当大花金鸡菊重要值高于20.25%时,样方内物种丰富度随着重要值的增加而减少,对入侵地的植物多样性产生不利的影响。

Five representative habitats invaded by Coreopsis grandiflora were investigated in Qingdao city. The variety and quantity of the indigenous vegetation were studied by using the square intercept method in five habitats. Ninety two indigenous species belonged to sixteen families were recorded, the number of Asteraceae and Poaceae were the most. The pattern of local community biodiversity was analyzed by spe- cies richness, diversity index and Pielou evenness index. The importance value of each species was calcu- lated. The results showed that the invasion of C. grandiflora reduced species richness, Simpson diversity index, Shannon-Wiener diversity index and Pielou evenness index of the sample plots. The most reductions of four indexes were 34.75%, 60.53%, 58.22% and 41.98%. By calculating, the average important value of C. grandiflora was 56.92%, which was more than other vegetations in communities. Analysis of rela- tionship between the average important value of C. grandiflora and the species richness of communities revealed that when the important value of C. grandiflora was 20.25%, with increase of the former, the latter was on the decrease. These results clearly showed that the invasion of C. grandiflora had a nega tive effect on biodiversity.