长江三峡淹没区与移民安置区植物多样性及其保护策略

随着三峡大坝的修建,三峡地区淹没区和移民安置区的植物多样性调查与保护工作相继展开。从多年考察采集到的标本及历史资料补充确定,两区高等植物为170科,762属,1784种。分别占到三峡地区高等植物科、属、种数的85.85%,75.30%和59.19%。其中特有植物27种。而三峡地区的灌木和草丛群落基本分布在沿江两岸的低海拔地区,受水库蓄水影响较大。对两区内21个马尾松(Pinus massoniana)群落物种多样性进行的Shannon-Wiener指数及Pielou均匀度指数的测定结果表明,马尾松群落的多样性变化总体趋势为:灌木层>草本层>乔木层;对该地区具有代表性的11种灌丛类型进行的物种多样性指数的测定结果表明:盐肤木(Rhus chinensis)、毛黄栌(Cotinus coggygriavar.pubescens)、荆条(Vitex negundo)、马桑(Coriaria sinic)等4种群落的灌木层丰富度较高,分别为16,26,20和15。多样性指数分别为1.791,3.427,2.949和1.718;对沿江分布的9种主要草丛群落进行的物种多样性指数的测定结果表明:芒萁(Dicranopteris dichotoma)、五节芒(Miscanthus floridutus)、白茅(Imperatacylindricavar.major)、荩草(Arthraxon hispidus)等4种海拔分布较高的群落物种多样性指数较高,分别达到1.697,1.354,1.144和1.018。另外,对淹没区及移民安置区的物种调查结果显示:受淹的自然植被类型共有22种。其中木本群落4种,灌丛9种,草丛9种。小鞍叶羊蹄甲(Bauhinia brachycarpavar.microphylla)、中华蚊母树(Distylium chinensis)、水杨梅(Geum aleppicum)、小叶黄杨(Buxus sinica var.parvifolia)、铁仔(Myrsine africana)、疏花水柏枝(Myricaria laxiflora)等灌丛被全部淹没;巫溪叶底珠(Securinega wuxiensis)、宜昌黄杨(Buxus ichangensis)和荷叶铁线蕨(Adiantum reniformevar.sinense)大部分被淹没。目前,已建立了库区植物物种保护站及监测站,200多种植物已得到迁地保护,包括已列入中国植物红皮书的37种珍濒物种和11种三峡库区建群种。

The plant biodiversity and its conservation in the submersion district and the immigration district of the Three-Gorges, China

The investigation and conservation project of plant biodiversity in the submersion district and the immigration district of the Three-Gorges region was carried out,accompanying the ongoing construction of dam.Based on the first-hand specimens collected for last many years and historical records,we found that there were about 1784 higher plant species,belonging to 762 genera,170 families,which accounted for 59.19%,75.30% and 85.85% of total amount of species,genera and families of the Three-Gorges region,including 27 species specific to these two districts.The shrub and grass communities were mostly distributed along the low altitude riparian zone of Yangzi River,largely influenced by dynamic water level of the Three-Gorges reservoir.The measurement of Shannon-Wiener and Pielou evenness indices on 21 Masson Pine communities distributed in the Three-Gorges reservoir area was carried out,and results showed that the biodiversity of shrub layer was the most higher,the grass layer middle,and the tree layer the lowest.Among the 11 typical shrub communities in this region,the abundance of shrub layers of Form.Rhus chinensis,Form.Cotinus coggygria var.cinerea,Form.Vitex negundo var.cannabifoliaand and Form.Coriaria sinica were relatively higher,which were 16,26,29 and 15,respectively.These four shrubs also showed high biodiversity index(H'),which were 1.791,3.427,2.949 and 1.718,respectively.While among the 9 grasslands mainly distributed along riparian zone,4 grassland communities with higher altitude(Form.Dicranopteris dichotoma,Form.Miscanthus floridutus,Form.Imperata cylindrica var.major and Form.Arthraxon hispidus)showed higher abundance and biodiversity,which were 1.697,1.354,1.144 and 1.018,respectively.Considering the submersion district and the immigration district,there were 22 vegetation types threatened by submersion,including 4 woody plant communities,9 shrub communities and 9 grassland communities.The 6 shrub communities of Form.Securinega wuxiensis,Form.Bauhinia brachycarpa,Form.Geum aleppicum,Form.Distylium chinense,Form.Buxus henryi and Form.Myrsine africana would be fully submerged.and part of Adianthum reniforme var.sinensis and Buxus ichangensis would be submerged.At present,plant species conservation and monitoring stations in the Three-Gorges region have been constructed,and more than 200 plant species have already been transplanted and conserved,including 37 threatened species listed in the China Plant Red Data Book and 11 dominant species of local communities.