塔里木河下游生态输水过程中荒漠河岸林活力恢复监测

Monitoring on vitality dynamics of tugai vegetation in the lower reaches of Tarim River by ecological water delivery

根据近5年来对塔里木河下游荒漠河岸林植被的监测数据,分析了生态输水后植物活力的恢复状况。结果显示:应急生态输水增加了塔里木河下游的生物多样性,使原本面临死亡的荒漠河岸植被重新复活,而且不同程度上促进了胡杨群落的自然更新;在近河道50m的范围内均出现了少量的胡杨、柽柳实生苗,并且在离河道150m的范围内已经有相当数量的胡杨次生苗,在离河道400m范围内大约有25%的胡杨均有不同程度的基部新枝萌蘖。通过生态输水后地下水位的逐步抬升,河道两岸的低阶地发育着一定面积的草甸植被,形成了由胡杨、柽柳和草本植物所组成的干旱区非地带性河岸稀疏植被群落,说明应急生态输水对于胡杨为建群种的荒漠河岸林植被的恢复和自然更新产生了积极的影响。

The Tarim River is about 1 320 km long and thus one of the longest continental inland waterways worldwide. The rising water consumption in the upper and middle reaches and massive hydrotechnical interventions during the development of uncultivated land use （cotton growing） in the past decades,led to the widespread destruction of the natural ecosystems,particularly in the lower reaches of the river where on 320 km the floodplain forests of Euphrat poplars （Populus euphratica Oliv.） are either highly degraded or dead. Since 2000 the Chinese government has made efforts to restore these ecosystems and conducted ecological water delivery. According to monitoring results after the ecological water delivery in the past five years,the paper analyses the vitality dynamics of the Tugai vegetation in the lower reaches of the Tarim River. The results show：Due to ecological water delivery,there are a lot of changes. The biological diversity in the lower reaches of theTarim River has increased,a lot of plants that disappeared for a long time have reappeared,and the P. euphratica community has regenerated naturally to different degrees. Within 50 metres from the river course,a few P. euphratica and Tamarix spp. seedlings appear. Within 150 metres from the river course,a considerable number of P. euphratica appeared. Within 400 metres from the river bank,approximately 25% of P. euphratica have formed new branches at the base after the ecological water delivery. With water levels gradually rising after the water delivery,non-zonal meadow vegetation has developed in the large areas of the low-level terraces on both sides of the river sparse Arid non-zonal riparian vegetation commu-nities composed of P. euphratica,shrubs and herbaceous plants （Tugai Vegetation） developed,showing that ecological emergency water delivery has had a positive impact on vegetation vitality restoration and natural recovery of desert riparian vegetation whose main species is P. euphratica.