豚草在次生演替植物群落中的频度分布特点

2012年春季，采用样方法对2011年夏季由红壤堆积形成的撂荒空地进行次生演替植物群落调查研究.研究结果表明：构成堆积性红壤次生演替植物群落的植物种类有54种，分属27科,51属,属于外来入侵种的有10种；54种植物中，频度属A级的植物种类占91%，属于B级者有3.4%，C级有3.4%，D级有0，E级有1.9%，五个频度级的关系是：A〉B=C〉E〉D；在10种外来入侵物种中，豚草的频度是92%，属于E级，是构成堆积性红壤次生演替植物群落的优势种和建群种，在群落次生演替中起到了先锋植物的作用，在防止水土流失方面有一定的生态意义；也说明堆积土壤种子库中豚草种子特别丰富和豚草种子发芽率高，这也是豚草能快速传播的因素.

The frequency distribution characteristics of ragweed on secondary succession plant community structure

In the Spring of 2012, with the method of quadrat sampling, a field survey was conducted in secondary succession plant community structure on abandoned naked red soil. 54 species were identified on vegetation type composition belonging to 51 genera , 27 families and 10 invasion of alien species. As the data showed, there were 5 classes of frequency and with the order of A〉B=C〉D〈E. Among all the samples, class A were 91%, class B and class C were both 3.4 %, class E were 1.9%, and class D were 0%.92% invasion of alien species consisting of ragweed, belonging to class E. Ragweed was also the dominant species and constructive species, and it played the pioneer role on secondary succession and had some ecological significance in soil erosion. It also suggested that Ragweed seeds were exceptionally rich and high germination rate in the seed bank of accumulative red soil, which contributed to its rapid seed dispersal.