澜沧江中游河段中国结鱼栖息地模拟

Habitat simulation of Tor sinensis in middle reaches of Langcang River

为了定量化评估和预测不同水库流量下泄情况对生物栖息地变化的影响,选取澜沧江特有的经济鱼类——中国结鱼作为指示物种,构建栖息地模型模拟其适宜的生境范围。根据成鱼生活习性和产卵行为等关键因子建立栖息地适宜度评价指标(HSI),通过耦合一维水动力模型和HSI建立中国结鱼栖息地模型。基于模型模拟结果,得到成鱼加权可用面积(WUA_d)和产卵加权可用面积(WUA_s),并运用Mann-Kendall测试分析漫湾大坝建设前后WUA_s和WUA_d的变化趋势。结果表明:漫湾大坝建设期和运行期WUA_s和WUA_d分别发生突变。对中国结鱼的产卵场(WUA_s)而言,大坝对最低和中等级别的栖息地有显著影响,对最优级别的栖息地影响较小;对中国结鱼的成鱼(WUA_d)而言,大坝降低了中等和最优的WUA_d。产卵所需的最佳流量(2 200~3 200 m^3/s)大于成鱼生存所要求的最佳流量(510~760 m^3/s),因此为了给不同时期的鱼类提供适宜的生境,应尽量保持流量的多样性。

In order to quantitatively evaluate and predict the change of habitat for different reservoir discharge,select the Tor sinensis as the indicator species,and establishethe habitat model tosimulate suitable habitat range of it.For the key habitat factors which affects fish adult and spawning behavior of Tor sinensis,the habitat suitability index(HSI)is established according to their living habits.Tor sinensis habitat model isdeveloped by coupling an one-dimensional(1-D)hydraulic model with habitat suitability index(HIS).Based on model simulation results,the Weighted Usable Areas for adult(WUA_d)and spawning(WUA_s)are obtained.The Mann-Kendall test isused to analyze the variation trend of WUA_s and WUA_dbefore and after the construction of the Manwan dam.The result shows that,abrupt respective changes in WUA_d and WUA_soccurreduring the dam construction and operation period.To the spawning site of Tor sinensis(WUA_s),the dam has a remarkable influence upon the minimal and medium level habitats,while less influence on the optimal habitats.And for the adult Tor sinensis(WUA_d),the dam reduced the medium and optimal WUA_d.The pawning required optimal discharge(2 200~3 200 m^3/s)is more than adult required discharge(510~760 m^3/s).So diversity discharges should be maintained to provide suitable habitat for fish of different age.