Nature Research Centre, Akademijos 2, 08412, Vilnius, Lithuania.
Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy.
Sci Rep. 2020 Dec 10;10(1):21687. doi: 10.1038/s41598-020-78701-8.
The meso-scale habitat simulation model MesoHABSIM was applied in three Lithuanian lowland rivers to study the effect of low-head hydropower plants (HPPs) on the fish habitats. Stream flow time series on a daily scale for the period 1970-2015 were used to describe flow regime downstream of HPPs for periods before and after their installation. Conditional habitat suitability criteria were developed for 4 species of cyprinid fish, schneider (Alburnoides bipunctatus), dace (Leuciscus leuciscus), roach (Rutilus rutilus) and vimba (Vimba vimba) to simulate their available habitat at different water discharges. Modelling results showed that HPPs have a significant impact on habitat availability in the low flow period in dry years below HPPs due to insufficient released flow. The environmental flow, as prescribed by the Lithuanian national law, is estimated between 80 and 95% exceedance probability of the mean minimum discharge of 30 days. This flow leads to a significant reduction in frequency and duration of available suitable habitats for vimba and schneider during low flow period. The roach habitat is the least affected. The results of habitat modelling are in line with the actual data on the occurrence and relative abundance of considered fish species in the studied river stretches. A general comparison of the relative abundance of modelled fish species in 42 natural river stretches and 20 stretches below the HPPs also showed that the relative abundance of roach is significantly higher, and that of schneider is significantly lower in river sections below the HPPs than the abundance in natural river sections. All results indicate that the current environmental flow does not secure survival of certain fish species. The applicability of the average low flow release during summer could be a plausible alternative to the current environmental flow in order to maintain ecosystem health and services.
中尺度栖息地模拟模型 MesoHABSIM 被应用于立陶宛的三条低地河流中，以研究低水头水电站 (HPP) 对鱼类栖息地的影响。使用 1970-2015 年逐日尺度的河川流量时间序列来描述 HPP 安装前后的下游水流状况。为 4 种鲤科鱼类（ Schneider (Alburnoides bipunctatus)、白条（Leuciscus leuciscus）、欧鲫（Rutilus rutilus）和 Vimba vimba）开发了条件适宜性栖息地标准，以模拟不同流量下它们的可用栖息地。建模结果表明，由于释放的流量不足，HPP 对低流量期和枯水年份下游的栖息地可用性有重大影响。立陶宛国家法律规定的环境流量，是根据 30 天平均最小流量 80-95%的超出概率来估计的。这种流量导致在低流量期，Vimba 和 Schneider 的可用适宜栖息地的频率和持续时间显著减少。而欧鲫的栖息地受影响最小。栖息地建模的结果与研究河段中所考虑鱼类物种的实际存在和相对丰度数据相符。对 42 个天然河段和 20 个 HPP 以下河段中模拟鱼类物种相对丰度的一般比较也表明，在 HPP 以下河段中，欧鲫的相对丰度明显更高，而 Schneider 的相对丰度明显更低，而在天然河段中则相反。所有结果都表明，目前的环境流量并不能确保某些鱼类物种的生存。在夏季平均低流量释放的适用性可能是替代当前环境流量的合理选择，以维持生态系统健康和服务。
