葛洲坝枢纽建成后宜昌-城陵矶河段变化对白暨豚影响的调查

长江中游宜昌-城陵矶河段,受葛洲坝枢纽和下荆江系统裁弯工程的影响,水流速增大、河床下切、床面粗化,洲滩渚汊并流,破坏和恶化了白鱀豚赖以生存的生态环境,引起白鱀豚分布区向下游退缩。1986年作者调查时,白鱀豚分布区上限尚在离葛洲坝下50公里处的宜都河段;而1991年已下移至距坝下160公里处的沙市河段。同时,藕池口-城陵矶河段(158公里)内白鱀豚分布密度逐年变稀,已从 1986年时的 3.67公里/头锐减到 1991年的10.36公里/头。白鱀豚种群规模小,虽已被列为国家保护动物,但人类活动仍严重危及该物种的生存。随着人们进一步开发利用长江,新的水利工程还将兴建,亟待来取相应保护对策。

INVESTIGATON FOR IMPACTS OF CHANGES OF THE LOWER REACH OF GEZHOU DAM BETWEEN YICHANG AND CHENGLINGdI ON THE BAIJI,LIPOTES VEXILLIFER AFTER ITS KEY WATER CONTROL PRUdECT FDUNDED

Due to the impacts of Gezhou Dam key water--control project andlower Jingjiang curve--cutting project after they were completed in the middle reach of the Yangtze River. Its current velocity in the affected section increased,river bed coarsened, coming branch channels were blocked, the river bed are un-dergoing a rapid change,and the counter-current eddies disappeared, thus spoilingand ruining ecological environment for the rare animal, Baiji. Its distribution areais thereby shortened toward the lower reach of the Dam. When the field expedi-tions in river section under research in 1986 to study the impacts upon the Baijicaused by these projects were conducted,its distribution had reduced from Yichangdownward to Yidu only 50 kilometers away from the Gezhou Dam,but it again redu-ced from Yidu downward to Shashi, 160 kilometers away from the Dam The dis-tribution density of Baiji in the river section of Ouchikou-Chenglingji(158 kilome-ters) was gradually rarefied. Its distribution density in the section under researchrarefied from 3.67km/per dolphin in 1986 to 10.36km/per dolphin in 1991. The Baiji has been listed as first-class animal under the protection of ChineseGovernment, but its population size remains smaller and human activities still se-verely endanger its existence. With human exploitation of the Yangtze River fur-ther, new key water-control project will be built. Hence, a conservation strategymust be adopted to rescue this species.