三峡水库峡谷地貌区消落带主要植物种间关联性研究

Interspecific Association of Main Plants in the Water Level Fluctuation Zone of Canyon Landform Area of the Three Gorges Reservoir

根据三峡水库峡谷地貌区消落带560个植物样方调查数据,选取频度≥5%的18种主要植物,采用方差比率法、χ2检验、Jaccard指数、Spearman秩相关系数等数量分析方法,对经历多次水库水位涨落后消落带植被主要植物的种间关联性进行研究,以探讨消落带植物的生态适应性、种间的内在联系以及群落演替现状,为三峡水库峡谷地貌区消落带植被恢复和重建提供理论依据。结果表明:(1)三峡水库峡谷地貌区消落带18种主要植物间总体为显著正关联;经χ2检验,在153个种对中,正关联种对78个,负关联种对75个;Jaccard指数小于0.20的种对占种对总数的82%;经Spearman秩相关性检验,正相关种对74个,负相关种对79个。(2)植物的生态习性以及植物对生境要求的相似性、生态位重叠等是消落带18种主要植物总体表现为显著正关联的主要原因;种对间Jaccard指数较小,表明消落带大多数种对间的关联不紧密,植物种间关系容易受到外界因素的干扰而出现波动;χ2检验和Spearman秩相关性检验结果基本一致。(3)种对间负关联种对数所占的比例较大,表明消落带虽然经历了多次水库水位涨落,但其生境仍然不稳定,植物种间还存在较明显的资源性竞争,消落带植物群落仍处于不稳定阶段。

Based on the data of 560 quadrates, we studied the interspecific associations of 18 main plants with its frequency greater than or equal to 5 % and experienced many times of water-level fluctuation in the water-level fluctuation zone of canyon landform area of the Three Gorges Reservoir through quantitative a- nalysis method such as variance ratio test, Chi-square test, Jaccard index, Spearman rank correlation coef- ficient and so on. The ecological adaptability and the intrinsic association of different plants, and the stageof community succession were discussed to provide a scientific basis for vegetation restoration and recon- struction. （1） The significant positive association was found among overall main 18 plants because of simi- larities of ecological habit, ecological requirement and ecological niche overlap. Among 153 species pairs, 78 species pairs showed positive association and 75 species pairs showed negative association in the Chi- square test, while 74 species pairs showed positive correlation and 79 species pairs showed negative correla- tion in the Spearman rank correlation test. （2） A larger proportion of negative association in the Chi- square test and the Spearman rank correlation test indicated the habitat was not stable and obvious resource competition existed among different plants. （3） The species pair with Jaccard index of less than 0. 20 accounted for 82 % of the total, which suggested that most species pairs were not closely related and inter- specific association was susceptible to the interference of external factors. In the actual habitat conditions, plant community was still in the stage of instability.