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作 者 ：卢志军;李连发;;黄汉东;陶敏;;张全发;江明喜;

期 刊 ：武汉植物学研究 2010年 28卷 3期 页码：303-314

关键词：河岸带；恢复生态学；群落演替；水淹；植被动态；

Keywords:Riparian zone, Restoration ecology, Community succession, Submergence, Vegetation dynamics,

摘 要 ：

三峡库区消涨带植被一直受到广泛关注.为了研究水库蓄水对175 m以下消涨带原有植被的潜在影响, 2008年8月在三峡大坝上游长江干流从巴南到秭归12个监测点, 设立68个5 m×5 m永久监测样方,比较被水淹过的156 m以下与当时尚未水淹的156～175 m地段植被物种组分、物种多样性和草本层生物量的差异.结果表明:被水淹过与尚未水淹的植被物种组分存在显著差异,DCA可以将二者明显分开,156 m以上尚未水淹的植被以灌丛为主;156 m以下被水淹过的植被以草丛为主,优势种包括多年生草本:狗牙根(Cynodon dactylon)、牛鞭草(Hemarthria altissima)和硬秆子草(Capillipedium assimile);一年生草本:狗尾草(Setaria viridis)、毛马唐(Digitaria ciliaris)和千金子(Leptochloa chinensis).木本植物基本死亡,只有枫杨(Pterocarya stenoptera)、牡荆(Vitex negundo)和地瓜(Ficus tikoua)存活.此外,被水淹过的植被中灌木物种数比例显著降低,而一年生草本物种数比例显著增加.被水淹过和尚未水淹植被的物种多样性也存在显著差异,被水淹过植被物种总数、灌木和多年生草本物种数显著低于尚未被水淹过的植被,但一年生草本物种数没有显著差异.被水淹过的植被草本层生物量与尚未水淹的植被没有显著差异.可见,水淹显著改变了消涨带原有植被物种组分和物种多样性,但一年生草本物种数和草本层生物量没有显著差异.未来175 m以下的植被中,草本尤其是一年生草本将占据优势.在消涨带植被恢复选择适应水淹生境物种过程中,应分别从植物的生活史、生理学和形态学等角度进行筛选,尤其应重视生活史适应策略植物的应用.被水淹过的156 m以下现有优势草本和存活的灌木可以作为三峡库区未来消涨带植被恢复的备选物种.

Abstract:Vegetation of the drawdown zone of the Three Gorges Reservoir is a hotspot for Chinese researchers and governments.Responses of the vegetation to the reservoir impounding are vital both for assessments on the Three Gorges Dam construction and for future drawdown zone vegetation restoration.To obtain information on local vegetation responses in already inundated zones(up to 156 m)and future water levels (up to 175 m)in 2009,we established sixtyeight 5 m×5 m permanent plots along the Yangtze River at 12 sites from Banan to Zigui upstream from the Three Gorges Dam in August 2008.We compared vegetation in zones already submerged (145-156 m A.S.L.) and vegetation in zones to be submerged (156-175 m A.S.L.) in terms of plant species composition,plant species diversity,and herbaceous layer aboveground biomass.Our results demonstrated that plant species composition of submerged vegetation,which were dominated by annuals and perennial forbs,were significantly different from vegetation to be submerged,which were mainly dominated by shrubs.The most dominant forbs/herbs in the submerged vegetation included perennials, Cynodon dactylon,Hemarthria altissima and Capillipedium assimile,and annuals Setaria viridis,Digitaria ciliaris, and Leptochloa chinensis.Most woody plants in the submerged zone were dead except for Ficus tikoua,Pterocarya stenoptera，and Vitex negundo.In addition,shrub species richness was significantly lower and annual species richness was significantly higher in the vegetation below 156 m A.S.L.than the vegetation distributed at elevations from 156 to 175 m.As for plant species diversity,the richness of vascular plants and ferns，and that of perennial forbs/herbs in the vegetation of the submerged zone were significantly lower than the vegetation to be submerged,which showed no significant difference for annual species richness.Based on aboveground biomass,no significant differences were detected in herbaceous layer biomass between the vegetation in the submerged zone and the zone to be submerged.We concluded that plant species composition of local vegetation was greatly altered by submergence and plant species diversity greatly decreased due to impounding of the reservoir.Annuals will dominate future vegetation below 175 m A.S.L.in the drawdown zone of the Three Gorges Reservoir Region.To select suitable plants to restore the vegetation in the drawdown zone,lifehistory,physiology,and morphology traits should be taken into account,and,in particular,lifehistory strategy should be thoroughly examined.Dominant annuals,perennial forbs,and shrubs found below 156 m have a potential value for future vegetation restoration in this region.

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