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１９９６年３月调查了南京地区１２个非农田旱地样点的早春杂草重要值，以此计测了它们的生态位宽度：以杂草群落梯度代替生态因子间隔，用生态因子间隔作为生态位重叠值计算中的加权因子，对该地区非农田生境杂草的生态位重叠值进行了计算；并用图论聚类中的最小生成树法，以生态位重叠值作为指标，作出了能直观反映该地区２１种主要杂草生态学相似程度的最小生成树。结果表明，波斯婆婆纳、猪殃殃、荠、宝盖草、野老鹳草、野燕麦、一年蓬、繁缕、泽漆等杂草生态位最宽，是本地区非农田生境的主要早春杂草；２１种杂草中，婆婆纳、波斯婆婆纳、睫毛婆婆纳、猪殃殃、繁缕、野燕麦、刺儿莱、卷耳、荠、臭荠等杂草的生态位重叠值比较大，说明它们对环境条件的要求比较接近。
In March 1996, the importance values of early spring weeds in 12 non-farmland dryland samples in Nanjing area were surveyed, and their niche breadths were measured: the weed community gradient replaced the ecological factor interval, the ecological factor interval used as the ecological niche The weighting factors in the calculation of overlapping values were used to calculate the niche overlap values of weeds in non-farmland habitats in this area. Based on the minimum spanning tree algorithm in graph theory clustering and the niche overlap value as index, The minimum spanning tree of ecological similarities among the 21 main weed species in the area. The results showed that weeds such as Persianaphori, Galium aparina, Chestnut, Pag grass, Geranium odoratum, Wild oats, Yearlings, Stellaria and Zechu had the widest niche and were the main early spring in non-farmland habitat in this region Weeds, 21 weed species, Veronica, Persian Verona, Eyelashes, Galium chinensis, chickweed, wild oats, thorns, ear, chestnut, water chestnut and other weeds niche overlap value Large, indicating that they are closer to environmental requirements.