基于鱼类栖息地需求的雅鲁藏布江中游环境流量计算

针对水利工程影响下,河道下游天然水文情势改变造成鱼类产卵场面积减小和质量降低等潜在生态问题,通过数值模拟与统计建立拉萨裸裂尻鱼产卵期栖息地适宜度模型,采用栖息地模拟法计算了雅鲁藏布江中游藏木水电站坝下米林—尼洋河汇口处38.9 km河段的环境流量。结果表明:拉萨裸裂尻鱼产卵期适宜水深为0.7～1.0 m,适宜流速为0.4～0.6 m/s;研究河段内拉萨裸裂尻鱼产卵期环境流量为432 m~3/s。     

水力学参数在资料缺乏区河流 生态保护中的应用

本文在总结不同尺度河流栖息地水力学表征参数的基础上,以南水北调西线工程水源区稚碧 江甘孜河段生态保护为例,从中观尺度栖息地保护角度,依据长系列流量资料和水文站断面资料,探 讨了少资料区生态水力学指标的获得方法,以及水利工程建设对该河段鱼类产卵的影响,本方法为资 料缺乏地区水生态环境保护提供了思路,为水利工程生态调度研究提供参考。     

滇中引水工程取水口下游金沙江生态流量研究

对拟建滇中引水工程大同取水口下游至虎跳峡前的43.5 km金沙江研究河段,采用流量历时曲线法和栖息地模拟法分别进行生态流量研究。栖息地模拟法选用目标鱼类长丝裂腹鱼,结合水动力学数值模拟与栖息地模型结合的方法,利用MIKE21建立研究河段的平面二维浅水水动力学模型。按长丝裂腹鱼对水深、流速的适宜度标准确定不同流量下的栖息地加权可利用面积(WUA),得到栖息地面积WUA随流量的变化趋势,最终确定目标鱼类产卵繁殖期适宜的生态流量值。比较2种方法的研究结果,取其中最大值作为最终生态流量值。     

汉江桥闸工程下游河段典型鱼种栖息地模拟研究

探究水利工程干扰下的鱼类生境变化特征是维护河流生态健康的基础性研究。以汉中平川段内汉江三桥桥闸下游10 km为研究河段,利用水文学法和栖息地模拟法计算了生态流量。建立了河段二维水动力学模型,选用宽鳍鱲为目标鱼种,依据其对水深和流速的适宜性曲线确定了流量变化下的生境面积,并采用生境质量分级分析了不同流量响应鱼类生境的变化特征。研究结果表明:两种方法计算出河流生态流量相近,分别为54.3和53.1m~3/s,最终适宜流量为47.8～54.3 m~3/s;在流量8.8～212.7 m~3/s时,相比中等和低质量生境,高质量生境面积随流量的波动更为显著,呈现先升后降的趋势,212.7 m~3/s以上流量的各级生境面积随流量变化较小;高质量生境多分布于两岸和冷水河交汇口,中等质量生境主要分布在河段下游;低质量生境位置相对不固定;研究成果可为桥闸运行和河流鱼类保护提供重要参考依据。     

三峡水库变动回水区蓄水期鱼群空间分布及生境特征

三峡水库蓄水后变动回水区水动力条件和泥沙运动发生了显著变化,鱼类栖息地也受到了不同程度的影响。为了掌握三峡变动回水区朝天门至涪陵河段蓄水期鱼类栖息地现状,研究采用Bisonics DT-X科学回声鱼测仪对朝天门至涪陵河段进行了鱼群空间分布及生境特征监测。结果表明:蓄水期该河段水环境因子空间分布变化不显著,表明水环境因子不是影响该河段鱼群分布的主要原因;水深与流速在该河段变化较大,是影响鱼类栖息的关键因子;监测到8个大型鱼群平均密度为(64.6±13.5) ind/(10³ m³),鱼类平均体长为(16.8±4.6 )cm,以中小型鱼为主;回水沱、深潭及分汊河道是鱼类喜居河段,是鱼类重要栖息地。研究结果可为三峡水库变动回水区鱼类保护和栖息地修复提供科学依据。     

淮河流域环境流变化及其对洪泽湖鱼类栖息地的生态影响

为分析淮河流域环境流要素的变化趋势及其对洪泽湖鱼类栖息地的生态影响,以淮河中下游河段为研究区,采用IHA法,将蚌埠水文站1950—2015年径流序列划分为2002年蚌埠闸扩建前后两个时期,采用5种流量事件筛选出32种环境流评价指标,分析了水文变异条件下5种环境事件的生态效应;以鳜鱼为洪泽湖指示鱼类,综合考虑栖息地限制因子,运用PHABSIM模型得到栖息地加权可利用面积-流量曲线,计算了鳜鱼产卵期的生态流量。结果表明:淮河中下游环境流组成趋于单一化,大洪水事件减少,枯水流量增大,高脉冲流量持续时间缩短,出现次数增加,对下游生态环境不利;洪泽湖鳜鱼4—6月产卵期的最小生态流量为300 m~3/s,适宜生态流量为550 m~3/s;需合理调控环境流,增加鱼类补充和物质循环,并采取湖泊生态修复等措施,维持洪泽湖的生态平衡。     

基于物理栖息地模拟的长江中游生态流量研究

将Delft3D水力学模型和栖息地模型组成物理栖息地模拟模型以研究鱼类的生态环境。以长江中游宜昌至枝江河段为研究区域,以长江的重要经济鱼类四大家鱼为目标物种,结合流速及水深两个栖息地限制因子计算研究区域内不同流量下四大家鱼4个产卵场的栖息地面积,得到了流量与栖息地面积关系曲线。分析该曲线,结果表明：长江中游四大家鱼4—6月份产卵期间的最小生态流量为4 570m3/s,适宜生态流量范围为12 000~15 500m3/s。计算结果在传统水文学法界定的生态流量范围之内,分析认为该计算结果更加合理,可为四大家鱼的保护和三峡及葛洲坝工程的生态调度提供参考建议。     

基于栖息地模拟的河道生态需水量多目标评价方法及其应用

本文提出基于栖息地模拟法的多目标评价法计算河道生态需水量,以加权可利用面积(WUA)最大和流量最小为目标,采用理想点法进行求解.该方法综合考虑了生态用水和经济用水,提供了一个栖息地保护和经济用水相协调的最优河流生态需水量.最后以鱼类作为指示物种,对新疆额尔齐斯河中游鱼类产卵期的河道生态需水量进行了计算.计算结果表明,其生态流量为78m3/s,占该河段多年平均流量的74%.该结果比直接采用栖息地模拟法计算的结果小,但该生态流量可以对河流栖息地提供足够的保护,且较好地协调了生态用水和经济用水的矛盾.     

向家坝蓄水前后长江上游珍稀特有鱼类国家级自然保护区物理完整性评价

采用流量过程变异程度、高流量频率、高流量历时偏差、岸坡稳定性、栖息地类型多样性、底质类型多样性、河岸植被覆盖度、垂向透水性等8项指标对向家坝蓄水前后长江上游珍稀特有鱼类国家级自然保护区部分关键河段的物理完整性进行了评价研究。结果表明:赤水河的物理完整性远高于长江干流,长江干流的3个河段中江津段的物理完整性较高,其次是宜宾和合江。向家坝蓄水前后,高流量频率、高流量历时偏差、栖息地类型多样性、垂向透水性等4项指标差异较大。向家坝蓄水对保护区关键河段水文过程,特别是脉冲流量及其持续时间、底质中值粒径和水深、流速的分布等具有一定程度的影响。研究结果可为长江上游干支流物理完整性评价提供借鉴。     

长江中下游不同分汊河段中国鲤鱼栖息地模拟与评估

水流条件改变以及河床变形会影响鱼类栖息地适宜性水平。为了定量评估和预测长江中下游不同分汊河段对鱼类栖息地的影响,我们选取中国鲤鱼作为目标鱼类构建相应的生态水力模型。通过模型模拟,得到该种鱼成鱼和幼鱼不同流量条件下的生境指标。结果表明：两段河流的成鱼栖息地适宜度随着流量的增加而增加,幼鱼栖息地适宜度随着流量的增加则先增加后减小。此外,从长期来看,鱼类栖息地适宜度会随着时间的延长而降低。在20年以后,由于河床变形而导致的水动力条件变化,使得两段河流可能不再适合中国鲤鱼生存。     

Downstream environmental effects of dam operations: Changes in habitat quality for native fish species

Hydropeaking dam operation and water extractions for irrigation have been broadly stated as alterations to natural flow regimes, which have also been noticed in the Biobío Watershed, in Central Chile, since 1996. In the Biobío River, most of native fish species are endemic and very little is known about them. Their ecological and social values have never been estimated, and there is lack of information about their habitat preferences. Furthermore, changes on fish habitat availability due to natural and/or man‐made causes have not been evaluated. In this study, eight native fish species, in a representative reach of the Biobío River, were studied and their preferred habitats were surveyed and characterized. A hydrodynamic model was built and linked to the fish habitat simulation model CASiMiR. Fuzzy rules and fuzzy sets were developed for describing habitat preference of the native fish species. CASiMiR was then used to simulate how physical habitat conditions vary due to flow control (i.e. upstream dams). Results show how overall habitat quality, expressed as weighted usable area (WUA) and hydraulic habitat suitability (HHS), changes and fluctuates due to the dam operation and how the daily hydropeaking is influencing quantity, quality and location of different habitats. The study suggests that the analysed fish are highly susceptible to flow control, as dams are currently operated, and fish habitat improvement suggestions are proposed. Copyright © 2010 John Wiley & Sons, Ltd.     

Exploring functional flow heterogeneity in regulated flow regime: Fish species turnover along hydraulic gradients in an artificial waterway network

Humans have altered river flows leading to a loss of connection with floodplain habitats. The expansion of agriculture in floodplains has resulted in landscapes dominated by irrigated farmland. A key challenge in water management is to conserve existing ecological communities and habitat heterogeneity, while simultaneously maintaining engineered infrastructure for agriculture. In this study, we focused on an artificial channel network for irrigation with a regulated flow regime and its function as habitat for various fish species. Differences in hydraulic conditions among channels and compositional changes in fish species were examined to clarify functional flow heterogeneity. Analyzed using pairwise Simpson dissimilarity among sampling reaches, species turnover was positively associated with Froude number (flow intensity) differences at intermediate discharges, and with differences in cross-sectional areas (flow magnitude) at low discharges. Drastic changes in inflows should be considered for the effective conservation of flow heterogeneity, even under a regulated flow regime. Improved engineering design to manage the hydraulic environment is one option for maintaining the ecological value of lateral waterbodies in human-dominated landscapes. Our findings provide insights into the importance of functional flow heterogeneity to conserve fish species diversity.     

计算河段最小生态需水的生态水力学法

水文学法与水力学法对河道生态需水量采用的方法都比较宏观，没有仔细考虑水生生物水力生境需求。本文提出了计算河道最小生态基流量的生态水力学法，该法是通过目标水生生物适宜的水力生境确定河段最小生态需水量，文章对河道水力模拟，水生物生境描述等理论进行了研究，同时结合目标水生生物对水力生境的需求，重点研究水深、流速、湿周、水面宽、过水断面的面积、水面面积、水温等水力生境参数；急流、缓流、浅滩及深潭等水力形态的指标表现形式。本文提出的生态水力学法具有直观、定量的特点，为河道确定生态基流量提供了一套较具体、可行的方法。     

Habitat fragmentation has interactive effects on the population genetic diversity and individual behaviour of a freshwater salmonid fish

Sufficient genetic diversity can aid populations to persist in dynamic and fragmented environments. Understanding which mechanisms regulate genetic diversity of riverine fish can therefore advance current conservation strategies. The aim of this study was to investigate how habitat fragmentation interacted with population genetic diversity and individual behaviour of freshwater fish in large river systems. We studied a population of the long‐distance migratory, iteroparous freshwater salmonid European grayling (Thymallus thymallus) in south‐eastern Norway. Genotyping (n = 527) and radio‐tracking (n = 54) of adult fish throughout a 169‐km river section revealed three major migration barriers limiting gene flow and depleting genetic diversity upstream. Individuals from upstream areas that had dispersed downstream of barriers showed different movement behaviour than local genotypes. No natal philopatry was found in a large unfragmented river section, in contrast to strong fidelity to spawning tributaries known for individuals overwintering in lakes. We conclude that (a) upstream sub‐populations in fragmented rivers show less genetic variation, making it less likely for them to adapt to environmental changes; (b) fish with distinct genotypes in the same habitat can differ in their behaviour; (c) spawning site selection (natal philopatry) can differ between fish of the same species living in different habitats. Together this implies that habitat loss and fragmentation may differently affect individual fish of the same species if they live in different types or sections of habitat. Studying behaviour and genetic diversity of fish can unravel their complex ecology and help minimize human impact.     

二维水力模拟在河流生态需水湿周法中的应用

湿周法是河流生态需水量计算中使用较为常见的一种水力学方法,通常采用一维的水力分析结果作为计算依据。二维水力模拟能提供更为细致全面的河道水力参数分布,通过对某水电站坝下13.3 km河道进行平面二维水力模拟,对其在湿周法中的应用进行了探讨。采用弗汝德数(Fr)作为浅滩生境划分标准,把浅滩生境较为集中的河段作为湿周法分析的浅滩河段。随后根据平面二维水力模拟结果,给出了浅滩断面相对湿周-流量关系曲线,采用斜率为1的斜率法计算得到了各浅滩断面的生态需水量。结果表明,采用二维水力模拟结果给出的曲线更为合理。     

Do Management Actions to Restore Rare Habitat Benefit Native Fish Conservation? Distribution of Juvenile Native Fish Among Shoreline Habitats of the Colorado River

Many management actions in aquatic ecosystems are directed at restoring or improving specific habitats to benefit fish populations. In the Grand Canyon reach of the Colorado River, experimental flow operations as part of the Glen Canyon Dam Adaptive Management Program have been designed to restore sandbars and associated backwater habitats. Backwaters can have warmer water temperatures than other habitats, and native fish, including the federally endangered humpback chub Gila cypha, are frequently observed in backwaters, leading to a common perception that this habitat is critical for juvenile native fish conservation. However, it is unknown how fish densities in backwaters compare with that in other habitats or what proportion of juvenile fish populations reside in backwaters. Here, we develop and fit multi‐species hierarchical models to estimate habitat‐specific abundances and densities of juvenile humpback chub, bluehead sucker Catostomus discobolus, flannelmouth sucker Catostomus latipinnis and speckled dace Rhinichthys osculus in a portion of the Colorado River. Densities of all four native fish were greatest in backwater habitats in 2009 and 2010. However, backwaters are rare and ephemeral habitats, so they contain only a small portion of the overall population. For example, the total abundance of juvenile humpback chub in this study was much higher in talus than in backwater habitats. Moreover, when we extrapolated relative densities based on estimates of backwater prevalence directly after a controlled flood, the majority of juvenile humpback chub were still found outside of backwaters. This suggests that the role of controlled floods in influencing native fish population trends may be limited in this section of the Colorado River. Copyright © 2014 John Wiley & Sons, Ltd.     

Applying instream flow incremental method for the spawning habitat protection of Chinese sturgeon (Acipenser sinensis)

The Chinese sturgeon, Acipenser sinensis, is an anadromous species that spawns in the Yangtze River and Pearl River of China. Its population has declined dramatically since the construction of the Gezhouba Dam (GD) in 1981 and then with the impoundment of the Three Gorges Dam (TGD) upstream of the GD in 2003. This paper presents a quantitative method based on the instream flow incremental method to explore the relationship between the fish spawning habitat and the operations of the GD and TGD, aiming to find a solution for conservation of the species. A two‐dimensional hydrodynamic model was built with the River2D to simulate the hydraulic behaviour of the stream below the GD. Habitat suitability index was determined by the biological data of the fish collected in the field. The two parts were then integrated through a geographical information system developed via ArcGIS to outline the fish habitat area variation with flows. The decision support system is applied to set up a habitat time series for validating the assumption that more habitats have the potential to support more fish. The fish habitat results for alternative instream flow schemes are then compared with one another for defining the optimal flow requirements and evaluating effects of reservoir operation alternatives in order to improve the operation management for the GD and TGD projects. The results show that the optimal flow for spawning of the fish is about 7000–13000 m³/s and the optimal inlets combination is where the inflow comes from two power plants. Copyright © 2009 John Wiley & Sons, Ltd.     

澜沧江中游河段中国结鱼栖息地模拟

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。     

基于物理栖息地模拟的长江中游生态流量研究

利用Delft3D水力学模型和栖息地模型组成物理栖息地模拟模型，以长江中游宜昌至枝江河段为研究区域，以长江的重要经济鱼类四大家鱼为目标物种，结合流速及水深两个栖息地限制因子推求研究区域内不同流量下四大家鱼四个产卵场的栖息地面积。研究结果表明：长江中游四大家鱼4—6月份产卵期间的最小生态流量为4570m3/s，适宜生态流量范围为12000~15500m3/s。计算结果在传统水文学法界定的生态流量范围之内，而且比传统水文学法的计算结果更加合理，可为四大家鱼的保护和三峡及葛洲坝工程的生态调度提供参考建议。