黄河兰州段湿地植物多样性研究

兰州段黄河湿地在其城市生态系统中占有重要地位。采用样带和典型样方相结合的方法对黄河湿地3种生境系统进行实地调查,研究了兰州城市湿地的植物多样性。结果表明:(1)不同生境系统湿地植物群落以草本为主,乔木多以杨柳科的垂柳为主,灌木只调查到1科1种。过渡带湿地植物种类几乎涵盖了其他生境系统的所有物种。(2)近裸露湿地赖草、稗草、虎尾草的重要值分别达到16.336,14.112,11.723;过渡带湿地中芦苇的地位得到加强,近自然湿地中芦苇的重要值已达13.153,其常见伴生种如水芹、香蒲、罔草也具有一定的地位。(3)3种生境湿地丰富度指数,Simpson指数及Shannon—Wiener多样性指数大小依次为:过渡带>近裸露湿地>近自然湿地,均匀度指数与之变化趋势不一致。近裸露湿地与过渡带β多样性小于近自然湿地与过渡带,不同生境间的相异性也表现为近裸露湿地与过渡带小于近自然湿地与过渡带。

An Analyses of Plant Diversities for Yellow River Wetland in Lanzhou City

The Yellow River wetland plays an important role in the ecosystem of Lanzhou City.The plant diversities of Lanzhou urban wetland was studied by the field investigation of three habitats in the Yellow River wetland using belt transects and quadrats.Results show that:(1) Herb,particularly Salix babvlonica that belongs to Salicaceae,is the dominant species in various wetland plant communities,while only one species of one family shrub is found.Wetland plant species in transition zone nearly cover all the species in other habitat systems.(2) The importance values for Leymus secalinus,Echinochloa crusgalli and Chloris virgata are 16.336,14.112 and 11.723,respectively.Phragmites communis has been strengthened in transition zone and its importance value in nearly natural wetland is 13.153.Common companions,such as Oenanthe clecumbens,Typha angustifolia and Beckmannia syzigachne,also have certain positions in wet environment.(3) Simpson and Shannon—Wiener indexes of wetlands′ habitat follow the order of transition zone> nearly bare wetlands> nearly natural wetland,and however,evenness index does not have such a trend.β diversity for nearly bare wetland and transition zone is lower than that of nearly natural wetland and transition zone,which is consistent with the sequence of species dissimilarity among different habitats.