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采用CCA梯度排序和随机排列(random permutation)检验方法,分析了太白山牛皮桦-巴山冷杉混交林林隙内草本植物组成随林隙梯度变化的分布特征,以及个体数≥5的55种草本植物分布与凸度、坡度、土壤全N、全P、速效N、有效P、pH值和有机质8个林隙生境变量的关联性.结果表明:太白山牛皮桦-巴山冷杉混交林中,林隙面积占林分总面积的19.8%,林隙密度为20.7个.hm-2,其大小在25.6～279.1 m2,平均面积为93.7 m2.林隙面积扩大可以增加草本层物种丰富度,但林隙内69种草本植物中,大部分在所有林隙中都有分布,有8个物种仅出现在面积>120 m2的大林隙,即草本植物的分布未呈现出沿林隙大小梯度连续变化的规律.个体数≥5的55种草本植物中,27.3%的物种与生境变量显著相关.林隙面积对物种丰富度的增加作用具有随机性.
Using CCA gradient sorting and random permutation test methods, the distribution characteristics of herbaceous plants in the gaps of Betula albosinensis-Bassiana mixed forest gap in Taibai Mountain were analyzed, and the distribution characteristics of 55 herbaceous plants with individual number ≥5 Distribution and crown, slope, total N, total P, available N, available P, pH and organic matter in eight gaps.The results showed that: The area accounted for 19.8% of the total stand area, and the gap density was 20.7 ha-2, with a size of 25.6 ~ 279.1 m2 and an average area of 93.7 m2. Increasing the gap area increased the species richness of the herb layer, Among the 69 species of herbaceous plants, most of them distributed in all gaps, and 8 species only appeared in large gaps of> 120 m2. That is to say, the distribution of herbs did not show a continuous variation along the gap size gradient Among 55 herbaceous plants with individuals ≥5, 27.3% of the species had significant correlation with habitat variables, and the effect of gap area on species richness was random.