水文变异下淮河长吻鮠生境变化与适宜流量组合推荐

以淮河干流鱼类长吻鮠为保护目标,建立长吻鮠分时期生态需求与流量之间的概念性模型。对FLOWS法进行改进,加入水文变异前后长吻鮠生态环境对比分析,根据分析结果推荐一组适于长吻鮠生长繁殖的流量组合。结果表明,在环境流量成分的对比分析中,变异前的高脉冲流量历时长、发生时间合适,变异后发生洪水的频率增高,变异前的流量更适于长吻鮠的生长繁殖;在相关水力参数满足程度的对比分析中,在长吻鮠生长繁殖的各个时期,变异前的流量条件均优于变异后。选取变异前的平水年1970年的流量作为基础,推荐适宜流量组合,即产卵期的流量为545~1 212m~3/s,幼鱼索饵期应大于1 750 m~3/s,越冬期应大于等于74 m~3/s。该研究可为保护淮河珍稀物种,为淮河生态调度提供依据。

Definition of environmental flow components for Leiocassis Longirostris in the Huai River considering habitat change and hydrological change

Leiocassis longirostris (Chinese Longsnout Catfish) is classified by IUCN as data deficient, but population declines have been reported in China. Protection of the migration and overwintering habitats of L. longirostris was selected as the key environmental flow objectives for the main stream channel of the Huai River. First a conceptual model of the relationship between the ecological requirements of L. longirostris and the flow regime was established. Then the FLOWS method was extended by modelling the change in preferred physical habitat over time. Finally flow components suitable for survival and reproduction of this species were defined. Results of the analysis of environmental flows showed that high flow pulse occurred more frequently and with longer duration prior before the hydrological change, while the frequency of flooding increased after the change, so the environmental flows before change was more suitable for L. longirostris. Results of the analysis of satisfied degree of the assumed critical hydraulic parameters showed that the flow regime in the period prior to the hydrological change was more suitable for L. longirostris. So the mean water year before the change (1970 Year) was selected to characterize suitable environmental flow components. The suitable flow range for the spawning period was 545~1212 m³/s, the minimum flow for larvae feeding period was 1750 m³/s, and the minimum flow over the overwintering period was 74 m³/s. These research findings can assist in the protection of rare species and maintenance of ecosystem integrity in the Huai River.