模糊数学方法模拟水库运行影响下鱼类栖息地的变化

水库调度改变了河流水文情势,从而使得水生动植物栖息地的空间分布发生明显的变化。针对水库运行对鱼类栖息地的影响,利用模糊数学方法建立栖息地模型,并与水环境模型耦合,分析不同水文情势下鱼类在不同生长期的栖息地变化情况。基于专家分析法建立模糊函数隶属度及规则集,计算栖息地适宜性指数(HSI),提出适宜栖息地宽度指数(HSWI)表征河道内栖息地连通性,并对栖息地变化的有效性进行分析。选取漓江下游的某个复式河道为对象,模拟特征鱼种光倒刺鲃(Spinibarbus hollandi)在典型水文年份中水库不同调节模式下的栖息地变化情况。结果表明,在丰水年及枯水年的产卵期,水库补水明显增加了鱼类适宜栖息地面积,其中高适应性区域面积增幅近50%,而平水年影响较小;水库补水对越冬场的影响则相对微弱,仅增加5%左右。

Application of fuzzy logic to model fish habitat in the downstream of Lijiang River under reservoir operations

Reservoir operations changed the river hydrological regimes, thus significantly altered the spatial distributions of species habitats. This research developed a fuzzy logic habitat model and combined it with a water quality model to investigate the impacts of reservoir operations on fish habitats, in particular during different life-stages. Ecologist's knowledge was involved in this model to link environmental conditions to the quantitative Habitat Suitable Index of aquatic species. Moreover, Habitat Suitable Width Index was introduced to quantitatively characterize habitat continuity and analyze the validity of habitat variation. The model was applied to a compound channel of the Lijiang River, and simulated the habitat variations of the special fish Spinibarbus hollandi for different reservoir operation schemes in three typical hydrological years. The results indicated that water recharge from the reservoir in dry season significantly improved the suitability for fish spawning, in particular for wet and dry years that the high suitability area was increased about 50%. The water recharge had relatively small effects for fish overwintering, and the increase was only 5% in average.