小浪底库区河岸带植物物种多样性与土壤因子的关系

以黄河中游末端地段小浪底库区河岸带为研究对象,采用典型对应分析法(CCA),对物种分布和多样性与土壤因子的关系进行研究。结果表明,小浪底库区河岸带共发现植物31种,17科28属,其中禾本科、菊科、蓼科和锦葵科植物最多,苍耳和狗牙根为优势种。随着河流流向小浪底库区南北两岸的有效磷和有机质呈下降趋势;速效钾、含水量和全氮无显著变化。从变异系数看,土壤含水量、有机质、速效钾、全氮及有效磷均属于中等变异程度(0.1≤C≤1),表明土壤养分分布总体上呈现中度不均匀的特征。在6个土壤环境因子中,含水量、pH与有机质含量对小浪底库区河岸带物种多样性的影响较大,土壤速效钾、有效磷及全氮对各种多样性指数影响均不明显。其中,香农-维纳指数与含水量和有机质具有显著相关性(P<0.05);均匀度指数和含水量之间具有显著的相关性;丰富度指数与pH之间具有显著的相关性(P<0.05)。CCA排序显示土壤全氮、pH、有机质和含水量是影响群落分布的主要因子。香附子、牵牛花和荔枝草的分布主要受到全氮的影响;春蓼、野菊等主要受到pH的影响;柳树、牛筋草、大狼杷草主要在含水量和全氮高的环境下分布较多;椿树、榆树等主要在有机质和pH相对较高的区域分布。苍耳、狗牙根、狗尾草等物种广泛分布在样地内,受土壤因子影响较小,对范围的适应较强。

The study focused on the riparian zone of the Xiaolangdi Reservoir area located at the terminal section of the middle reaches of the Yellow River.The Canonical Correspondence Analysis(CCA)was employed to investigate the relationship between species distribution and diversity with soil factors.The results indicated the following:A total of 31 plant species were found in the riparian zone of the Xiaolangdi Reservoir area,belonging to 28 genera across 17 families.The most abundant plants were from the families Poaceae,Asteraceae,Polygonaceae,and Malvaceae,with Xanthium sibiricum and Cynodon dactylon being the dominant species.Along the flow direction of the river towards the south and north banks of the Xiaolangdi Reservoir area,there was a decline in available phosphorus and organic matter;however,there were no significant changes observed in available potassium,water content,or total nitrogen.Variation coefficients indicated that soil water content,organic matter,available potassium,total nitrogen,and available phosphorus all exhibited moderate variability(0.1≤C≤1),suggesting an overall moderately uneven distribution of soil nutrients.Among the six soil environmental factors,water content,pH,and organic matter content had a greater impact on the species diversity in the riparian zone of the Xiaolangdi Reservoir area.Soil available potassium,available phosphorus,and total nitrogen did not significantly influence various diversity indices.Notably,the Shannon-Wiener index showed a significant correlation with water content and organic matter(P<0.05);the evenness index was significantly correlated with water content;and the richness index was significantly correlated with pH(P<0.05).CCA ordination revealed that total nitrogen,pH,organic matter,and water content were the main factors affecting community distribution.The distribution of Cyperus rotundus L.,Pharbitis nil(L.)Choisy,and Saluia plebeia R.Br.was mainly influenced by total nitrogen;Polygonum persicaria L.,Chrysanthemum indicum L.,Humulus scandens(Lour.)Merr.,and Lindernia angustifolia(Benth.)were primarily affected by pH;Salix babylonica L.,Eleusine indica(L.)Gaertn,Bidens frondosa Linn.were more abundant in environments with high water content and total nitrogen and others were mainly distributed in areas with relatively higher organic matter and pH.Xanthium sibiricum L.and other species were widely distributed within the sample plots,less affected by soil factors,demonstrating strong adaptability to their range.