Abstract:

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.

Key words: mountainous banana fields, weeds, niche breadth, niche overlap