基于鱼类生境需求的生态流量过程研究

选用日涨水率和日落水率两个生态水文因子,构建裂腹鱼栖息地生态水文学特征指标。结果表明,产卵期日涨水率的适宜范围为0.005~0.015,日落水率的适宜范围为0.005~0.015;非产卵期(5~10月)日涨水率的适宜范围为0.01~0.05,日落水率的适宜范围为0.02~0.04。采用文献法和专家法得出裂腹鱼产卵期偏好水深范围为0.5~1.5 m、偏好流速范围为0.5~2.0 m/s。用不同方法计算了苏洼龙水电站坝下河段生态需水量,并结合金沙江上游天然河流的水文情势及裂腹鱼栖息地生态水文学特征,以生态水力学法的计算结果作为基流量,确定了苏洼龙水电站坝下河段的生态流量过程。     

中小河流鱼类生境适宜性评估模型与等级分区

以浙江省龙游县社阳溪厚唇光唇鱼为代表性鱼类,通过2017—2020 年现场鱼类群落与生境影响因子调查,采用广义可加(GAM)模型和栖息地适宜性指数(HSI)模型,构建了社阳溪厚唇光唇鱼生境适宜性评估模型,并分析其生境适宜性阈值范围及分区。结果表明:采用GAM 赋权的算术平均算法(AMM)具有最好的模型拟合度,流速、水深及叶绿素a 的质量浓度是生境适宜性指数模型的关键解释变量,其偏差贡献率分别为61. 5%、21. 0% 和12.5%。厚唇光唇鱼最适宜流速为37 ~58 cm/ s,最适宜水深为40 ~63 cm,最适宜叶绿素a 质量浓度为0. 10 ~0. 35 mg/ m3。厚唇光唇鱼生境分区具有较强的时空差异性,在空间上,最适宜生境主要分布在中下游河段;在时间上,2019—2020 年生境适宜度明显变差。     

齐口裂腹鱼幼鱼在竖缝式鱼道模型中的上溯行为研究

为了解齐口裂腹鱼在鱼道中的上溯情况,在大比尺竖缝式鱼道物理模型中开展了以齐口裂腹鱼幼鱼为过鱼对象的过鱼试验研究。试验中对通过时间、通过率和上溯轨迹进行了记录,并运用Spearman秩相关分析对齐口裂腹鱼的上溯轨迹和池室结构的水力因子(流速、紊动能、总水力应变)进行了分析。研究发现,试验用鱼通过时间平均值为132.7s,多数鱼倾向于快速通过鱼道完成上溯。试验鱼道通过率为71.9%,过鱼效果良好。多数齐口裂腹鱼上溯过程中会避开高流速区、高紊动能区和高水力应变区,在池室内齐口裂腹鱼上溯轨迹主要分布于上述参数较低的右侧回流区和隔板背水面,竖缝断面处多数齐口裂腹鱼选择上述参数相对较低的隔板侧区域通过。研究结果可为相关竖缝式鱼道设计和实践提供参考。     

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。     

水温对竖缝式鱼道中齐口裂腹鱼上溯行为影响试验研究

水温是影响鱼类上溯行为不可忽视的因素之一,本研究在竖缝式鱼道水工模型中进行了齐口裂腹鱼幼鱼的过鱼试验,研究的水温变化范围为13～21℃,通过提取通过率与通过时间参数对齐口裂腹鱼的上溯行为进行了定量分析,并采用统计分析软件SPSS进行了检验.研究发现在开展试验的水温范围内,水温对齐口裂腹鱼上溯行有显著影响(P=0.032...     

栖息地模拟中指示物种的选取方法研究

指示物种的选取是栖息地模拟中的关键一环,为了选取澜沧江流域的指示物种,以澜沧江中游漫湾大坝为例,通过调查大坝建设前后的水生生态系统和鱼类资源,建立ESHIPPO-PPm模型,评估澜沧江流域四种特有鱼类(中国结鱼Tor sinensis、红鳍方口鲃Cosmochiluscardinalis、宽头华鲮Sinilabeolaticeps、云南裂腹鱼Schizothoraxyunnanensis)的灭绝风险,并根据调查和风险分析结果选取该地区的指示鱼种。结果表明:根据生态适宜(ES)与HIPPO系统因子的得分,中国结鱼和红鳍方口鲃的生态适宜性最好,宽头华鲮和云南裂腹鱼的生态适宜性居中;宽头华鲮和云南裂腹鱼的灭绝风险适中,中国结鱼和红鳍方口鲃处于灭绝风险临界值。按照保护优先级(PP)物种得分高低依次为:红鳍方口鲃(76)中国结鱼(74,风险水平显著)宽头华鲮(62)云南裂腹鱼(60)。中国结鱼是澜沧江流域特有的经济鱼类,种群数量大,易捕获,养殖成本低,对环境的敏感性较高,是该区域生境质量变化较好的鱼类指示物种。     

鱼道进口水流对草鱼幼鱼上溯行为的影响研究

为使鱼类能够快速发现和顺利进入鱼道进口并成功过坝,设计了鱼道进口概化模型。以草鱼幼鱼为研究对象,在18±1℃的条件下研究了鱼道进口流速对鱼类上溯行为的影响。研究发现:鱼道进口水流存在一个最佳流速,在该流速下,鱼类进入鱼道进口的效率最高。利用诱鱼流道补水有助于进一步提高鱼道进鱼效率,诱鱼流道水流与鱼道进口水流之间存在一个最优流速比。针对草鱼幼鱼的鱼道进口最佳流速约为0.3 m/s,诱鱼流道水流与鱼道进口水流的最佳流速比约为2.3。通过对洄游区鱼类游泳轨迹以及流场耦合,可知草鱼幼鱼上溯的喜好流速范围是0.20~0.30 m/s。研究成果对于鱼道进口水力设计具有重要意义。     

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。     

Quantitative evaluation of fish alternative habitats in the Luosuo RiverEI北大核心CSCD

针对罗梭江替代生境适宜度及影响因素尚缺乏定量分析的问题,选取澜沧江干流特有经济鱼类中国结鱼(Tor sinensis)为目标物种,基于河流内流量增加法(IFIM),结合二维水动力模型和鱼类栖息地适宜性曲线,建立了罗梭江典型鱼类的栖息地评价模型,分析了替代生境适宜度及其影响因子。结果表明:罗梭江作为澜沧江最大支流,能为中国结鱼提供良好产卵场,产卵场在丰水期(7—9月)数量和质量较优,高质量产卵场主要分布于河流蜿蜒处;罗梭江不适宜成鱼全年栖息,尤其在枯水期(2—4月),成鱼产卵及育肥适宜度最差。在罗梭江替代生境后期管理中,建议优先加强对河流弯道处的生境保护及捕捞管理,同时重视其关联干流的生态保护。     

泥沙浓度对齐口裂腹鱼生存的影响试验研究

为探究泥沙浓度对齐口裂腹鱼生存的影响,选取中值粒径为0. 1 mm的悬沙进行了6种不同含沙浓度的室内水槽试验研究。试验记录了不同试验组水中溶解氧的浓度与幼鱼死亡时间,并分析了含沙浓度与溶解氧浓度、死亡率、死亡时间的关系。试验成果表明,随着含沙浓度的增加,幼鱼致死时间不断缩短。观察发现,含沙试验组死亡幼鱼鱼鳃淤堵明显,且含沙浓度高于5. 0 g/L时,死亡幼鱼鱼鳃出现出血现象,在含沙浓度为10. 0 g/L的试验组中,死亡幼鱼鱼鳃及口腔中还会出现粒径为0. 3 mm的较粗泥沙颗粒。由此可见,细颗粒泥沙淤堵、磨损鱼鳃,以及通过口腔进入其呼吸道和消化道,是泥沙颗粒影响鱼类生存的主要原因。     

水生生物栖息地适宜性指标的模糊综合评判

针对河流水生生物栖息地数学模型PHABSIM,分析现有确定栖息地适宜性指标方法的不足之处,在此基础上给出用模糊综合评判方法,确定水生生物栖息地适宜性指标。模糊综合评判方法考虑了栖息地质量因素之间的相互作用,得到的栖息地适宜性指标准确度较高。     

Linking SVM based habitat model and evolutionary optimisation for managing environmental impacts of hydropower plants

The present study proposes a support vector machine (SVM)-based habitat model linked with evolutionary optimisation to balance the impacts of generating hydropower on the downstream river habitats. This method was applied in the Rajaei reservoir and Tajan River basin in Iran to mitigate the environmental impacts of hydropower plants. SVM model classified the habitat suitability at downstream river in which a sigmoid function considering different slopes was applied. The Nash–Sutcliffe efficiency coefficient as the evaluation index of the habitat model is 0.8, which implies the SVM model is robust to simulate physical habitats. Hydraulic simulation demonstrated that depth and velocity change from zero to 1.79 m and zero to 1.82 m/s, respectively. Most suitable river flow is 7 m³/s downstream of Rajaei reservoir. Five evolutionary algorithms were used to balance environmental impacts with generating hydropower. Finally, a fuzzy technique for order of preference by similarity to ideal solution (FTOPSIS) selected the best optimal solution in the Rajaei reservoir. Based on optimisation results, The simulated annealing (SA) algorithm was the best optimisation method to balance generating hydropower and downstream ecological impacts, in which average habitat suitability is more than 90% of average habitat suitability in the natural flow, while reliability of generating hydropower is 38%. Moreover, SA is able to minimise the average difference between habitat suitability in the optimal release and the natural flow properly. Using the proposed method is recommendable to mitigate the potential impacts of generating hydropower on the downstream river habitats.     

Evaluation of fish habitat suitability using a coupled ecohydraulic model: Habitat model selection and prediction

The selection of an approach to evaluate habitat suitability for a specific fish or life stage has been a matter of concern in habitat quality modelling studies. This study has taken Jinshaia sinensis, a commercially valuable fish endemic to the Jinsha River, China, as the target fish species. One‐ and two‐dimensional hydrodynamic models were coupled and combined with fish habitat models for a middle reach of the Jinsha River. The resulting ecohydraulic model was used to predict the changes in hydrodynamics and spawning habitat suitability that resulted from the operation of an under‐construction reservoir downstream of the study area. The preference function (product, arithmetic mean, geometric mean, and minimum value) and fuzzy logic habitat evaluation methods were compared to predict the spawning habitat suitability of the fish. The model was validated using the numbers of spawning eggs, and the results show that both the arithmetic mean and fuzzy logic method can be used to predict spawning habitat suitability. The model predictions show that the hydrodynamics of the study area would be altered if the impoundment water level exceeded 969 m. During the spawning season, the spawning habitat suitability would increase from April to early June and has little change from early June to July under the impact of the reservoir impoundment. The optimal river discharge rate for fish spawning is ~3,500 m³/s, and this would not change after the reservoir begins operation. This research can benefit other regions that will be affected by planned dams by predicting the impacts of reservoir operation on fish habitat quality, and the results will help decision makers protect the health of rivers and the overall ecosystem.     

Instream flow determination using a multiple input fuzzy‐based rule system: a case study

The attempts made to manage water to meet human requirements should also consider the needs of freshwater species and ecosystems. There are many tools available to assess instream flow needs, one of which is the use of habitat preference models. In this study, a fuzzy approach was used for modelling habitat preferences for two life stages of Atlantic salmon (Salmo salar). Experienced fish biologists and technicians contributed to the development of fuzzy sets and fuzzy preference rules for spawning and parr habitat. Fuzzy sets were defined for water depth, velocity and substrate composition. Fuzzy preference rules for the two life stages were then defined as sets of IF–THEN rules relating the physical attributes to habitat suitability. The fuzzy suitability indices are then used to obtain weighted usable area (WUA) at different discharges and to estimate the ecologic flow required to preserve habitat. Different methods are applied to combine the membership function and rules defined by the experts. A sensitivity analysis of rules of the combined system indicated that a limited number of rules are determinant and results are highly dependent on the consequences of these rules. A modification in the consequence of these rules can significantly alter WUA estimations. It is therefore recommended to combine the knowledge of many experts in the elicitation process and to quantify the uncertainty associated with the combination of expert knowledge. Copyright © 2007 John Wiley & Sons, Ltd.     

Development of transient habitat modeling for stream Macrozoobenthos

In addition to the hydromorphological pressure on the ecological conditions of free-flowing river courses, increasing water temperature is affecting the water bodies, particularly by changing freshwater community compositions. The low discharge of numerous European rivers in the dry and hot hydrological year 2022 proves this relevance. Therefore, ecological assessment tools such as habitat modeling should take these factors into account when assessing the quantity and quality of habitats. In this paper, the habitat modeling tool “Transient River Habitat Modeling for Macrozoobenthos” (TRiMM) is improved by incorporating a fuzzy logic approach and adding water temperature to the set of parameters determining habitat suitability for macrozoobenthos. Habitat-relevant parameters, including hydromorphological factors (depth, velocity, mineral and organic substrate) and a water quality factor (temperature), are combined in the habitat model so that it can more broadly characterize river physical conditions and their interactions with biological indicators. Habitat modeling employed the mentioned parameters to simulate suitability for the macrozoobenthos in a small river in central Saxony, Germany. Due to its deteriorated condition, this river was selected as a representative for thousands of kilometers of small rivers across the region, which have been restored. The model simulated the status quo of river conditions from spring to summer for three macrozoobenthos species (Ancylus fluviatilis, Ephemera danica and Gammarus fossarum). The results showed that the natural flow resulted in dynamic habitat suitability both spatially and temporally, which differs for each species. Remarkably, the five-parameter model (depth, velocity, temperature, mineral, and organic substrate) generally performed better compared to a similar model without temperature.     

A MODEL INCORPORATING DISTURBANCE AND RECOVERY PROCESSES IN BENTHIC INVERTEBRATE HABITAT—FLOW TIME SERIES

We describe and demonstrate a model (Benthic Invertebrate Time Series Habitat Simulation) for calculating the effect of changes to flow regimes on benthic invertebrate habitat and population dynamics. The following inputs are required: a hydrograph (discharge time series), habitat–discharge relationship, disturbance–discharge relationship, wetted width–discharge relationship and a recolonization time series. Habitat–discharge, disturbance–discharge and wetted width–discharge relationships are common outputs from instream hydraulic habitat models (e.g. Physical Habitat Simulation, River Hydraulic Habitat Simulation and River2D). Hydraulic habitat models calculate a combined habitat suitability index from physical habitat suitability curves for water depth, velocity and substrate composition and weight this by area to give a weighted usable area (WUA). Because conventional invertebrate habitat suitability curves are based on density estimates, the combined habitat suitability index can be treated as an index of density and WUA treated as an index of potential relative abundance (at the reach scale) in the absence of disturbance due to flow variation (flooding and drying) and biotic processes. Our approach begins with WUA and calculates realizable suitable habitat (i.e. relative abundance) by taking into account the resetting of benthic invertebrate densities by floods and drying and recovery (or accrual) rates and times. The approach is intended mainly to compare the relative amounts of productive invertebrate habitat sustained by natural and modified flow regimes, but it also has the potential for investigating the influence of flow variation on invertebrate population dynamics. We anticipate that the model will be particularly useful for assessing effects of changes in flow regimes caused by diversions, abstractions or water storage on annual benthic invertebrate productivity. Copyright © 2013 John Wiley & Sons, Ltd.     

基于模糊数学理论的湛江组黏土触变性强弱分级

为了准确地对湛江组黏土的触变性强弱进行评判,基于模糊数学理论,根据黏土触变性的影响因素,构建以黏粒含量、含水率、孔隙比、灵敏度为指标体系的黏土触变性强弱模糊综合评判因素集,建立黏土触变性强弱综合评判的评语集及触变性强弱评价指标的等级标准,运用模糊数学综合评判的方法计算各指标的隶属度和权重,建立黏土触变性强弱的分级标准,并运用此标准对湛江组结构性黏土触变性强弱进行分级。结果表明:各个沉积相下的湛江组强结构性黏土均具有强触变性,且触变性强弱排序为:雷南河流相、浅海相、河口相和雷北河流相。     

混凝土坝健康模糊综合诊断方法研究

影响混凝土坝健康状况的因素众多,建立的混凝土坝健康综合诊断指标体系,既包含有定量指标,又包含有定性指标,同时,定性指标指标值的确定带有模糊性,并且混凝土坝健康等级之间的界限也难以准确的界定。模糊综合诊断模型通过确定各个诊断指标的权重及其隶属度向量获得模糊评判矩阵,然后把模糊评判矩阵与诊断指标的权重集进行模糊运算并进行归一化,得到诊断指标健康值,确定被诊断对象的等级层次,最终对混凝土坝健康进行评价,工程实例计算结果表明:模糊综合诊断模型计算结果与实际运行情况相符。本文利用模糊综合诊断模型解决了大坝健康综合诊断指标体系中的模糊性问题。     

Assessing habitat for lake sturgeon (Acipenser fulvescens) reintroduction to the Maumee River,Ohio using habitat suitability index models

Lake sturgeon (Acipenser fulvescens) were a candidate for reintroduction in the Maumee River, Ohio, where they were historically abundant, but are now functionally extirpated. Our objective was to determine if current habitat quality and quantity could support reintroduction efforts. We developed a spatially explicit habitat suitability index model for two lake sturgeon life stages: spawning adult and age-0 fish. To estimate habitat quality, substrate, water depth, and water velocity were assessed and integrated into suitability index values to delineate good, moderate, and poor areas for each life stage. Each habitat characteristic was mapped and combined to provide an overall assessment of habitat suitability, quantity, and location. Model results indicated 208 ha (10.2% of all habitat) of good adult spawning habitat (e.g., coarse substrates, depths between 0.3 and 8 m, and velocity between 0.5 and 1 m/s) and 529 ha (28.2% of all habitat) of good age-0 habitat (e.g., fine substrates, depths between 0.2 and 6 m, and velocity between 0.1 and 0.7 m/s). Good age-0 habitat was located mostly downstream of good spawning habitat, which will provide nursery areas for age-0 fish after hatch. Our models suggested habitat is not limiting for lake sturgeon and efforts to reintroduce this species into the Maumee River, and for the first time in the Lake Erie basin, were supported. The results of this work supported reintroduction efforts that began in 2018.