云南山地香蕉园主要杂草生态位

运用Levins和Shannon-Wiener生态位宽度以及Pianka生态位重叠指数,研究河口山地蕉园主要杂草的生态位动态,分析其香蕉园内优势杂草生态位对旱季、雨季的动态响应特征,为云南山地蕉园杂草生态防控提供指导依据。结果表明：雨季和旱季的杂草在生态位宽度和重叠上均有着显著的变化。雨季的马唐（Digitaria sanguinalis）、光头稗（Echinochloa colona）、香附子（Cyperus rotundus）的生态位宽度最大,旱季的白花鬼针草（Bidens pilosa）、小飞蓬（Conyza canadensis）、鹅肠菜（Myosoton aquaticum）的生态位宽度最大;雨季和旱季杂草间的生态位重叠普遍较大,分别占66.7%和 44.4%,相似性比例较高,重叠值均大于0.50,其均值分别为0.54和0.40。以上结果表明,河口山地香蕉园杂草无明显的单优势种,杂草间对资源的利用存在较高的竞争或互补。其生态位宽度和重叠值较大的杂草会随着群落演替的延续,在资源配置不足的情况下加剧竞争而排挤掉其他杂草。

Ecological Niche of Dominant Weeds in Mountainous Banana Fields of Hekou,Yunnan, China

Using the Levins and Shannon-Wiener niche breadth, Pianka niche overlap index, we researched the niche dynamics of the dominant weeds in the banana fields in the mountainous regions of Hekou to analyze the dynamic response characteristics on the niche of the dominant weeds in dry and rainy seasons, and to provide guidance for the ecological control of the weeds in the mountainous banana fields. The niche breadth and overlap of the weeds in rainy season and dry season had significant changes. Digitaria sanguinalis, Echinochloa colona, Cyperus rotundus had the widest niche breadth in rainy seasons, and Bidens pilosa, Conyza canadensis, Myosoton aquaticum had the widest niche breadth in dry seasons. The niche overlap among weeds was generally large, the value more than 0.50 for the two seasons accounted for 66.7% and 44.4% respectively. The similarity ratio was high, and the mean value was 0.54 and 0.40 correspondingly for the two seasons. It indicated that there was no obvious single dominant species, there was a high competition or complementarity in the utilization of resources among weeds. The weeds with larger niche breadth and overlap value will intensify the competition and exclude other weeds in the process of community succession under the condition of insufficient resource allocation.