洱海沉水植物群落结构特征及最大生物量估算

Community Structure Characteristics and the Maximum Biomass Estimation of Submerged Macrophytes in Erhai Lake

以云南省洱海为研究对象,在生长季(2017年9月)对该湖泊沉水植物种类组成及生物量等群落特征进行了调查,根据频度及生物量评判物种优势度并分析沉水植物分布与水位梯度的关系。结果表明:①洱海沉水植物现有种类有13种,隶属6科8属,其中眼子菜科5种,水鳖科3种,茨藻科2种,其余种类占沉水植物总种类数的23.1%;②洱海绝对优势物种为金鱼藻(Ceratophyllum demersum)、微齿眼子菜(Potamogeton maackianus)和苦草(Vallisneria natans),其优势度分别为37.74%、21.87%和16.70%;③不同水深梯度沉水植物种类变化:2.0~4.0m(12种)>0.0~2.0m(11种)>4.0~6.1m(8种);④沉水植物生物量最大值出现在2.0~4.0m;⑤根据优势种及组成特征,沉水植物群落主要为3个类型:金鱼藻+竹叶眼子菜+黑藻群丛、金鱼藻+微齿眼子菜群丛和金鱼藻群丛;⑥计算结果显示,洱海生物量鲜重总值约为16.09万t。本研究结果表明,洱海沉水植物种类较为丰富,生物量总量也相对较高,不同水深下优势物种组成略有区别,说明洱海沉水植物群落状况较好,但也需要加强保护。

In this study,Erhai Lake in Yunnan province was chosen as the research object to evaluate the biodiversity,biomass,and vertical distribution pattern of submerged macrophytes in the growing season(September,2017).The results showed that there were 13 submerged macrophytes species in Erhai Lake,belonging to 8 genera,6 families,including Potamogetonaceae(5 species),Hydrocharitaceae(3 species),Najadaceae(2 species),other species accounted for 23.1%of submerged macrophyte species.The absolute dominant species in the lake wereCeratophyllumdemersum(37.74%),Potamogetonmaackianus(21.87%)and Vallisnerianatans(16.70%).The biodiversity of submerged macrophyte species varied with water depth,which was 2.0~4.0 m(12 species)>0.0~2.0 m(11 species)>4.0~6.1 m(8 species).The biomass of submerged macrophtyes reached its maximum value in water depth between 2.0 and 4.0 m.There are 3 submerged macrophyte communities according to the dominant species and their community,which are communities of Ceratophyllumdemersum+Potamogetonmalaianus+Hydrillaverticillata,C.demersum+P.maackianusand C.demersum.The total biomass(fresh weight)of the whole lake was about 160,900 tons.This research showed that the species abundance of submerged macrophyte in the lake was relatively abundant with relatively higher biomass.However,in order to prevent its degradation in the further,the change dynamic of submerged macrophytes in this lake should be paid more attention to.