黑河分水后额济纳绿洲柽柳(Tamarix spp.)和苦豆子(Sophora alopecuroides)群落的恢复

The Recovery of Tamarix spp.and Sophora alopecuroides Communites Responding to the Water Resupply in the Ejin Oasis

为探讨黑河下游额济纳绿洲在供水持续恶化和改善后植被退化与恢复状况,以及在绿洲特殊的供水模式下植被恢复的趋势,通过对额济纳绿洲1982年、2001年和2009年3期植被调查资料对比,分析了绿洲主要荒漠河岸植被———柽柳(Tamarixspp.)群落和苦豆子(Sophora alopecuroides)群落在黑河分水后的恢复状况,同时分析了分水后历年供水的季节分配。结果表明:分水后2类群落都有不同程度的恢复。恢复的主要表现是建群种的覆盖度、生物量、当年枝条比率增加,枝条枯死率降低。群落种类组成在近河道的苦豆子群落增加明显,而其他生境中则恢复缓慢,增加的种类以一年生植物为主。分水前形成的"冷季充足、暖季短缺"的黑河对额济纳供水模式在分水后并未根本改变,这是绿洲植被不能恢复到缺水前状态的主要原因。

In order to investigate the vegetation change responses to water resource supply regimes i.e.continuously insufficient,normally,and special water resource supplement based on yearly water supplement distribution analysis in the Ejin Oasis of Heihe river lower reaches,we employed the filed investigation data collected in1982,2001,and 2009 to comparatively analyze characteristics of Tamarixspp.and Sophora alopecuroides community,which were dominant communities in desert riverside vegetation.The results showed that the two dominant communities restored better after 2001 than before and vegetation characters i.e.constructive species coverage,biomass,and ratio of annual branch increased,and ratio of mortal branch decreased.S.alopecuroides community compositions obviously increased near riverside than other habitats,annuals increased most significant among the composition.Water sufficient in cold season and insufficient in warm season is an unchangeable regime of water resource supplement before and after 2001 in the Ejin Oasis,this is the major problem for the oasis vegetation restores to 1982 ago while water resource supplement was normal situation in this area.