黄河三角洲潮沟形态特征对湿地植物群落演替的影响

Effects of tidal creek morphology on succession of wetland plant communities in the Yellow River Delta

通过野外调查明确黄河三角洲潮上带、潮间带、潮下带内潮沟的形态特征及植物群落演替特征,并在此基础上探讨潮沟对植物群落的影响。结果表明:1)潮沟共包括4级,沿海到内陆方向,呈现出潮沟分叉增加、级别增多、曲率变大的发育趋势。潮上带和潮下带均出现较大的宽深比,潮间带的潮沟密度和分汊率较大;2)共统计到植物10科15属15种,大部分为草本植物。植物演替的方向为碱蓬—柽柳—芦苇和香蒲,物种生态位宽度最大值随着演替的进行,由碱蓬变为柽柳再到芦苇和香蒲;3)潮沟曲率、潮沟密度和潮沟宽度与群落演替方向呈正相关,而潮沟分汊率和潮沟深度与群落演替方向呈负相关。植物群落演替对潮沟分汊率的变化的反应最敏感,潮沟密度次之。

The morphological characteristics and the succession characteristics of plant communities in the three microfacies intratidal gullies of the Yellow River Delta,i.e.the supratidal,intertidal and subtidal zones,were clarified through field investigation.On this basis,the effects of the tidal creek on plant communities are discussed.The results showed that:1)The tidal creek in the study area was divided into 4 grades.From coastal to inland,the bifurcation,grade and curvature of tidal creek increased.The ratio of width to depth in both supratidal and subtidal zones was larger.And the density and branching rate of the intertidal zone were higher.2)There were 15 species of plants belonging to 15 genera and 10 families in the study area,and almost all of them were herbaceous plants.The direction of natural succession of plants in the study area was along the evolution of Suaeda glauca-Tamarix chinensis-Phragmites communis and Typha orientalis as dominant species.The maximum niche breadth of species changed from Suaeda glauca to Tamarix chinensis and then to Phragmites communis and Typha orientalis.3)The curvature,density and width of tidal creek were positively correlated with the direction of community succession,while the tide was positively correlated with the direction of community succession.Furrow branching rate and tidal creek depth were negatively correlated with community succession direction.The succession of plant communities was most sensitive to the change of tidal branching rate,and followed by the density of the tidal channel.