水位节律差异对三峡水库消落区不同物候类型1年生植物物种构成的影响  

Effect of water-level fluctuation discrepancy on the composition of different annuals in Three Gorges Reservoir drawdown zone

作　　者：袁慎鸿[1] 曾波[1] 苏晓磊[1] 许建平[1] 

机构地区：[1]三峡库区生态环境教育部重点实验室,重庆市三峡库区植物生态与资源重点实验室,西南大学生命科学学院,重庆400715

出　　处：《生态学报》2014年第22期6481-6488,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(31370443;31070474;30500041);教育部高校博士点基金课题(20100182110022);国家重点基础研究发展计划项目(2012CB723205);中央高校基本科研业务费专项资金项目(XDJK2013A003)

摘　　要：三峡水库蓄水后改变了原有长江自然的水位波动节律,并在三峡库区内形成了两种类型的消落区:蓄水前未经历过水淹的完全水库消落区,其水位节律夏低冬高;以及蓄水前属于自然消落区目前受蓄水和洪汛双重影响的消落区,其水位在冬季和夏季都存在高水位。这与自然消落区冬低夏高的水位节律均存在差别。1年生植物根据萌发结实特性可分为春萌秋实、冬萌夏实型植物和广适性植物3类。在不同消落区选取5个样地划分样带设置固定样方,涨水前和退水后调查发现:各消落区均存在3种1年生植物,但3种类型物种的比例和和优势度存在显著差异。只受夏季洪汛影响的自然消落区共发现1年生植物73种,冬萌夏实型植物以45种占优;而水位节律与之相反的完全水库消落区,1年生植物物种数为85种,其中春萌秋实型植物以45种以及较大的优势度成为该区域的优势1年生物种;双重影响消落区,1年生植物物种总数未明显下降,但是在蓄水和洪汛的双重影响下其种群大小相对较低。水位节律的巨大变化会引起1年生植物优势类型的显著改变,适合生长的1年生植物主要是因为其生长周期与淹没期不完全重叠而成为优势物种类型。After the Three Gorges Dam impoundment, the original water-level fluctuation rhythm of Yangtze River change dramatically. As a result, two new kinds of drawdown zones appear in Three Gorges Reservoir （TGR）： the preupland drawdown zone （PU-DZ） which never submerged before impoundment and the preriparian drawdown zone （PR-DZ） which is the former riparian zone of Yangtze River. The water-level fluctuation rhythm of PU-DZ is high in winter because of impoundment, and low in the summer because of flood discharged. Meanwhile, the PR-DZ is affected by both the impoundment in winter and the flood in summer, so the water-level can raise high in winter and summer. Apparently,they both have differences with the water-level fluctuation rhythm of natural riparian zone （NRZ）, which is only high in summer for the flood. Annuals can be divided into three types according to their germination and fructified characteristics： annuals germinating in winter fruitifying in summer（AGWFS）, annuals germinating in spring fruitifying in autunm （AGSFA） and the common annuals. In this study we chose five sample sites in each kind of habitat and survey them before the freshet and after the impoundment subsiding by fixed quadrats in different transects. All these three types annuals can be discovered in each drawdown zone, however, the proportion of the number of different type＇s species and their population size are significantly different. The major reason is discrepancy of occurred submergence time in different zones. There are 73 kinds of annuals found in NRZ. The number of AGWFS is 45, its proportion of species number are 52.26-67.46 as the elevations decrease, which is obviously dominant compared with the other two types, because they can avoid the disturbance of summer flood. The total number of annual in PU-DZ is 85, wherein the number of type of AGSFA is 45. The proportions of this type in the total species number are 59.42-82.44 as the elevations decrease. They are dominance in PU-DZ, for the water-level

关 键 词：三峡水库 水位节律 1年生植物 物候 

分 类 号：Q948[生物学—植物学]