广州地区四季叶菜田杂草群落组成及其生态位

Weed Community Composition and Niches of Leaf-vegetable Plots in Guangzhou Region in Four Seasons

为明确南亚热带地区四季叶菜田杂草群落组成及其生态位,利用倒置"W"九点取样法,对广州地区4个市区16个规模化菜场杂草群落进行季节动态调查。结果表明:春季杂草群落结构以腋花蓼(Polygonum plebeium)+马齿苋(Portulaca oleracea)+光头稗(Echinochloa colonum)为主;夏季以马齿苋+碎米莎草(Cyperus iria)+凹头苋(Amaranthus lividus)为主;秋季以马齿苋+酸模叶蓼(Polygonum lapathifolium)+凹头苋为主;冬季以腋花蓼+碎米荠(Cardamine hirsuta)+酸模叶蓼为主。运用改进的Levins生态位宽度指数和Pianka生态位重叠指数对四季优势杂草生态位进行分析,结果表明,15种优势杂草生态位总宽度大部分在0.50以上,其中生态位总宽度大于1.00的有马齿苋(1.22)、腋花蓼(1.15)、酸模叶蓼(1.08)。夏季生态位重叠指数达到0.50的最多,秋季则最少。生态位重叠指数最大的3组杂草分别为春季的马唐(Digitaria sanguinalis)和牛筋草(Eleusine indica)(0.87),夏季的马齿苋和凹头苋(0.82)以及马齿苋和牛筋草(0.80)。

The seasonal dynamics of weed community in 16 large-scale vegetable plots of 4 cities and districts in Guangzhou region were surveyed by using inverted＂W＂sampling method to study weed community composition and niches of leaf-vegetable plots of south subtropical region in four seasons.The weed community was mainly consisted of（Polygonum plebeium）＋（Portulaca oleracea）＋（Echinochloa colonum） in spring,（Portulaca oleracea）＋（Cyperus iria）＋（Amaranthus lividus） in summer,Portulaca oleracea＋（Polygonum lapathifolium）＋（Amaranthus lividus） in autumn,and （Polygonum plebeium）＋（Cardamine hirsute）＋（Polygonum lapathifolium） in winter.The analysis of weed niches in different seasons based on improved Levins niche breadth index and Pianka niche overlap index showed that most weeds had a niche breadth of0.50,and the weeds having a total niche breadth of1.00 included Portulaca oleracea（1.22）,Polygonum plebeium（1.15）,Polygonum lapathifolium（1.08）.For the dominant weeds,their niche overlap indices0.50 were appeared most in spring and least in autumn,and the 3 maximum groups were between Digitaria sanguinalis and Eleusine indica（0.87）in spring,Portulaca oleracea and Amaranthus lividus（0.82）,Portulaca oleracea and Eleusine indica（0.80）.