梁子湖水生植被1955—2001年间的演替

On aquatic vegetation succession of Lake Liangzihu from 1955 to 2001

为建立自然保护区 ,保护湖北梁子湖丰富的生物多样性资源 ,并为梁子湖湿地生态系统的恢复与重建提供科学依据 ,对梁子湖主体湖 1955— 2 0 0 1年以来 45年间水生植被的演替进行了研究 .结果表明 :①水生植被覆盖率下降到 54 2 7% ,近 5年内保持稳定 ;植被分布差异极为显著 ,东梁子湖为草型湖 ,前江大湖植被较少 ,中湖基本上无水生植被 .②水生植被单位面积生物量和总生物量继续恢复 ,分别达到 3 4 96g m2 和 7942 0 3t ,但仍未恢复到历史最高水平 ;群落单位面积生物量迅速上升 ,并超过历史最高水平 ,达到 6443g m2 .③挺水植被中的芦苇群落已消亡 ;菰群落在经历了较大的破坏后 ,近年来分布面积有所扩大 ,群落总生物量有所增加 ,但单位面积生物量变化不大 .浮叶植被分布面积变小 ,但单位面积生物量和总生物量明显提高 .④水生植被的变化经历了“恢复—旺盛顶期—急剧衰退—逐步恢复”的过程 ,目前仍以沉水植被为优势生活型 ,但优势群落发生了变化 ,以微齿眼子菜和金鱼藻为优势群落类型 .⑤如果浮叶植物继续受到破坏或环境恶化的话 。

To establish nature reserve for conserving the rich biodiversity in Lake Liangzi hu of Hubei Province of China and providing scientific foundation for restoratio n and rehabilitation of the wetland ecosystem, the aquatic vegetation succession during 45 years from 1955 to 2001 was studied in this paper,based on the field data collected during May to Jun in 2001 and other data.The main results are as follows:①The covering rate of aquatic vegetation in the main body of Lake Lia ngzihu dec reases to 54 27%, and it has been stable in recent five years; vegetation distr ibutions vary in different regions of the lake: the eastern part (also named Ea stern Liangzihu) is still a macrophytic lake, the middle part (named Qianjiangda hu) is poor in aquatic vegetation and there is no aquatic vegetation in the west ern part (named Zhonghu).②Biomass in unit area and total biomass of aquatic veg etation continue to rise, and reach 3 496 g/m 2 and 794 203 t respectivel y, but has not recovered to the highest level yet; community biomass in unit ar ea rises quickly to 6 443 g/m 2 ,and overtakes its historical highest leve l.③Emergent community Phragmites communis has disappeared; the distribution area of Zizania caduciflora enlarges gradually, and its total community bio mass inc reases, but its community biomass in unit area rises slightly after serious dama ge in many years.Floating-leaved communities decrease, but their community biom ass in unit area and total community biomass increases remarkably.④During the p eriod from 1955 to 2001,the aquatic vegetation in the main body of Lake Liangzih u underwent four stages: recovery—luxuriance—degeneration—slow recovery and d eveloping, and the submerged vegetation is still the dominant type, but dominant community ty pes were Potamogeton maackianus and Ceratophyllum demersum.⑤Summer domi nant submerged community will likely be replaced by Ceratophyllum emersum i f the floating-leaved communities are damaged or the environment deteriorates c ontinuously.