长江中游典型河段底栖动物的物理栖息地模型构建与应用

考虑水生生物生境需求的物理栖息地模型被认为是评估河流流量变化对水生态系统影响的最可信的方法之一。本研究选取长江干流含有河漫滩的监利江段为实例,建立底栖动物各类群的物理栖息地模型,计算变化流量下栖息地适宜面积的时间序列,并据此进行生态流量决策。结果显示长江中游底栖动物最敏感的环境参数是流速,适宜范围为0～0.2 m/s;其次是水深,适宜范围为0～6 m。在考虑敏感环境参数的前提下,得出监利江段底栖动物的最佳生态流量为20 000 m3/s。三峡大坝蓄水后枯水期和平水期底栖动物适宜面积的低值部分减小,丰水期适宜面积增加。为了保护底栖动物栖息地,建议三峡大坝在防洪蓄水的同时能兼顾底栖动物的生态流量需求,调节枯水期和平水期的流量,让监利江段接近4000 m3/s,丰水期接近20 000 m3/s。在枯水年增大枯水期和平水期的流量,平水年增大枯水期的流量,丰水年减少丰水期的流量。本研究方法可以供长江其他河段目标物种的生态流量决策和生态修复方案设计参考。     

白洋淀底栖动物群落影响因子研究

基于2016年春、夏、秋3季的调查采样,采用典范对应分析(canonical correspondence analysis,CCA)研究底栖动物群落结构和分布对水环境因子和底泥环境因子的响应,识别影响底栖动物群落分布的关键环境因子。CCA结果显示,水环境因子中透明度、叶绿素a、水深、水温、溶解氧、氨氮、硝氮和氧化还原电位是影响底栖动物分布的主要因子;底泥环境因子中底质中值粒径、沉水植物生物量和氨氮含量是影响底栖群落分布的主要因子。优势物种摇蚊科和颤蚓科对高污染物浓度环境适应性更好。水体中氮、磷对底栖动物影响显著,而底泥中氮、磷的影响较小,可以通过氮磷的吸附转移降低水体污染对底栖动物的胁迫。     

里下河地区典型湖泊大型底栖动物与环境因子的相关性分析

为揭示里下河地区湖泊大型底栖动物群落现状及其主要的环境影响因子,于2013年4月对里下河地区4个典型浅水湖泊的大型底栖动物群落进行了调查,并测定分析相关水质环境因子;对大型底栖动物群落与环境因子进行冗余分析,找出了对大型底栖动物群落影响较大的环境因子。结果表明:研究区域湖泊均处于富营养化状态,大型底栖动物群落分布趋向于单一化,铜锈环棱螺和霍甫水丝蚓是该地区典型湖泊的主要优势物种。冗余分析排序中,排序轴前两轴特征值较大,为0.168和0.115,合计0.283,分别解释了42.6%和31.8%的物种-环境变异,PO3-4-P、Chl-a和DO是对大型底栖动物密度影响较大的环境因子。     

底栖动物与水生栖息地面积耦合机制研究

底栖动物对河流的生态状况反应比较敏感、迅速,当河流水生态发生变化时,底栖动物能够首先感受到这种变化,并在短时间内作出反应。从水生栖息地面积着手,通过采集、鉴定、分析南水北调西线调水区底栖动物样本,研究底栖动物生物多样性与水生栖息地面积之间的耦合作用机制,并分析了调水对底栖动物的影响。结果表明:底栖动物与水生栖息地面积之间存在着密切的关系,其物种数随着水面面积的增加而增加,并趋于稳定;当水面面积减小至原水面面积的45%时,底栖动物物种数开始减少,但减少速度缓慢;当水面面积继续减小至原水面面积的10%时,底栖动物物种数开始急剧下降;为保持底栖动物生态系统的稳定性,调水不应使坝址下游水面面积减小至原水面面积的45%以下。     

用底栖动物评价水环境

用底栖动物评价水环境宋宪国（济宁市环境保护监测站）１前言水体受到污染，必然引起水生生物生态结构的改变。应用生物评价水质，目前多认为以底栖动物较优，因其有相对稳定的生活环境，本身移动能力差，能客观地反映环境的变化。我们于１９９４～１９５５年的枯水期（５...     

南湾水库底栖动物调查报告

2001年4月起对信阳南湾水库的底栖动物进行了周年定量采样调查。结果表明该水库底栖动物主要由水生昆虫和寡毛类组成，共检出底栖动物3种，年均生物量为0．6032克／平方米；密度为263．83个／m^2，每年提供的鱼产潜力为20034公斤。     

西南水电站建成后底栖动物与环境因子的灰关联分析

底栖动物作为河流生态系统的组成部分,在物质与能量转换中发挥着重要的作用,水库的修建对底栖动物的影响日益受到关注。本文通过收集水电站建成后的底栖动物及其环境因子的数据,采用灰关联方法确定底栖动物的关键环境制约因子,计算分析得到总磷与底栖动物关联度最高,关联度0．6828。通过有效控制关键环境因子,促进底栖动物群落多样性的维持,对于维系河流生态系统的健康具有重要的现实意义。     

白洋淀浮游生物群落动态变化与生物量模拟研究

为探究白洋淀浮游生物群落结构动态特征及其关键影响因子,基于2017年秋,2018年春、夏3个季节的水环境因子与浮游生物野外采样调查结果,采用冗余分析(ＲDA)、广义可加模型(GAMs)等方法探究了白洋淀不同季节的浮游生物群落动态变化,建立了浮游植物生物量与环境因子的非线性关系并进行了率定验证。结果表明:与1992年白洋淀干淀后重新蓄水时相比,浮游植物与浮游动物物种数分别下降了59%与37%,优势群落从绿藻门转化为蓝藻门。根据ＲDA排序结果可知,温度、透明度是影响浮游生物丰度的关键环境因子。运用GAMs构建了环境因子与浮游植物生物量的定量模型,最优模型结构为Biomass-phy～s(T)+s(TN)+s(Cond)+s(Biomass-zoo)+s(Biomass-pro)+te(Biomass-pro_TN)+te(Biomass-pro_Cond)+te(Biomass-pro_Biomass-zoo)。将2019年6月采样数据进行模型验证,计算模拟效果良好,实现了对浮游植物生物量的定量模拟,能够为白洋淀生态恢复与保护提供决策支持。     

潮白河流域底栖动物调查分析与水质评价

在生态监测和调查的基础上论述了北京市潮白河流域内底栖动物的种类组成与分布,并对其水质进行分析.结果表明:潮白河流域底栖动物物种较少,上游区域底栖动物物种数多于中下游区域;潮白河中下游区域底栖动物密度高于上游区域,主要物种为一些环节动物耐污种类;白河干流最清洁点位占80％,水体最好;白河支流清洁点位占33％,是仅次于白河干流的第二好水体.研究结果对河流的生态保护与生态恢复具有指导作用.     

乌梁素海浅水湖泊沼泽化现状及成因分析

为揭示乌梁素海面临的湖泊沼泽化问题与其驱动因素,针对2013年8月乌梁素海浅水湖泊沼泽化现状及成因,进行了实地勘查和采样,利用基于植物生物量与沉积速率、植物种类和泥深的2种评价方法进行分析。结果表明:乌梁素海沼泽化程度存在空间差异,部分区域属于沼泽化后期,分别分布在总排干入湖口处和湖区的中东部,其中,沼泽化综合指数在近入湖口处各点最大,沼泽化综合指数处于3~4,向湖区中东部逐渐减小,但仍然大于湖区中南部的下游区,该区域的沼泽化综合指标数为2~3,仍属于沼泽化盛期,直至湖区下游的最南端,属湖泊沼泽化不显著区。造成乌梁素海浅水湖泊沼泽化的主要原因很可能是在湖水流速缓慢和富营养化的综合作用下,外源物质淤积和水生植物蔓延,淤积物质和植物残体逐年累积形成底泥泥炭,随着泥炭的增厚和湖水变浅,从而演化为沼泽。     

城市浅水湖泊生态系统健康与保护研究

针对我国东部平原地区淡水湖泊资源丰富,且多为中小型浅水湖,受到社会经济快速发展的影响,城市化率高,人类干扰强烈,境内湖泊面临着富营养化、服务功能丧失等生态环境问题,以太湖流域东南部苏州市吴江区的湖泊群为例,在分析浅水湖泊特征的基础上,提出这一类型湖泊生态健康的概念框架,构建湖泊水生态健康评价体系,选择生态因子、环境因子、人类活动干扰与生态建设4个要素共12个指标描述湖泊健康水平,并分析其原因。结果表明:水环境质量的恶化与人类对湖泊资源的粗放式开发是造成湖泊生态功能失衡的主要原因。以评价结果为指导,制定典型湖泊三白荡的生态修复与建设的措施与方法,旨在为湖泊生态系统管理与修复提供科学依据。     

城市人工浅水湖泊群水系连通方案研究

城市大规模小型人工湖泊湿地群的建设,改变了水系水动力特性及污染物质迁移、扩散和转化过程。构建了包含状态变量、常数、作用力、进程、辅助变量和衍生变量等的一维河网和二维浅水湖泊水生态模型,确定敏感参数值,采用清潩河流域实测数据验证模型的准确性。模拟得到不同换水频率、不同恒定流量和不同波动流量等换水方式下人工湖泊的流场和水质浓度场,揭示了多种河湖水系连通方案下湖泊水动力特性和污染物质迁移转化规律。进一步结合多种方案下湖泊污染物质削减量和出水水质,组合优化水系连通方案。研究结果表明:彩用循环+换水的调控模式,控制清潩河流域湖泊群循环流量在0.03～0.20 m~3/s,换水次数选择每年的3,7月和11月统一换水3次,此时水系连通效果最优。     

Ecosystem‐based environmental flow assessment in a Greek regulated river with the use of 2D hydrodynamic habitat modelling

Despite the long‐term research on the use of hydraulic‐hydrodynamic habitat models (HHMs) for predicting the response of aquatic biota to habitat alteration, their practical application in model‐based environmental flow assessments (EFAs) has been limited due to reasons mainly associated with cost‐effectiveness, time‐efficiency, required expertise, and availability of hydroecological information. In this study, we demonstrate a cost‐effective and time‐efficient application of a benthic‐invertebrate, two‐dimensional, fuzzy rule‐based EFA in a 277‐m long reach in the downstream route of a regulated river in western Greece. Apart from developing ecosystem‐based environmental flow (eflow) scenarios, we highlight the valuable features of HHMs, comment on their disadvantages, and propose working solutions to overcome them. The results of the study show that the hydrology‐based eflow of 0.2 m³/s, initially proposed by the managing authorities, is not sufficient to ensure the long‐term functionality of the downstream benthic communities, as the ecosystem‐based eflow ranged between 0.6 and 2 m³/s. As social resilience relies heavily on ecological resilience, ecosystem‐based approaches can ensure the sustainability of aquatic ecosystems. This study demonstrates, inter alia, that HHMs‐based EFAs can be implemented cost‐effectively and time‐efficiently to serve as an accurate scientific basis for water managers and stakeholders, in search of the fine balance between anthropogenic water demand and long‐term ecosystem integrity and functionality.     

The influences of typhoon‐induced mixing in a shallow lake

Vertical mixing affects the vertical transport of biochemical materials and modifies the characteristics of basin‐scale internal waves in subtropical, subalpine Yang Yuan Lake (YYL), in the north central region of Taiwan. Vertical mixing in YYL is generally caused by typhoons (strong winds and heavy rainfalls) during the spring, summer and early fall, or by cooling of the water column during late fall and winter. Vertical mixing caused by typhoons significantly affects internal thermal dynamics and biochemical processes, with basin‐scale internal waves enhanced before complete mixing occurs, and temporal variations of water temperature dramatically changing after typhoon events. This study quantitatively determines when the complete mixing (defined as homogenous temperature in a water column) occurs on the basis of the balance between kinetic energy and potential energy and also shows what meteorological conditions contribute to the vertical mixing. Data on water column thermal profiles and meteorological variables were collected by a wireless, instrumented buoy in the deepest location of YYL and from a nearby meteorological station, from spring 2004 to summer 2006. This study also investigated how a physical process (internal waves) is affected by the mixing associated with typhoons. Signal processing and a two‐layer model of the water column are used to understand the characteristics of basin‐scale internal waves.     

Long-term effect of tourism on the recent upward trend of phosphorus in a shallow alpine lake, Japan

The trend of total phosphorus (TP) concentrations in May-October of the tourist season was analyzed to examine the effect of more than 30 years of tourism on a shallow oligo-mesotrophic lake, Lake Oze-Numa. Annual mean TP concentrations increased rapidly at the rate of 11.6%/yr, from 7.5mg/m³ to 14.4 mg/m³ in 1982-90, and a mesotrophic condition of 23.1 mg/m³ is predicted for the year 2000. TP concentrations at the end of the tourist season were higher than at the beginning due to autumn circulation of the bottom sediment, and correlated with the current year TP loadings from tourists. TP concentrations in May were the lowest for the season, and showed good correlation with previous year concentrations. The recent upward trend of phosphorus concentration was mainly brought about by long-term tourism because 10% of the TP loading by tourists was estimated to accumulate annually in the water column. Phosphorus reduction measures should be taken urgently in such a shallow lake which now shows an accelerated rate of eutrophication.     

模糊评估法在湖泊综合开发利用评估中的应用

针对区域湖泊资源开发利用中适应性评估问题,本文在结合层次分析以及模糊评估法基础上,从景观适宜性、可达性、土地利用程度以及自然度等四个方面,探究开展区域湖泊资源开发利用适宜性综合评估。应用实例表明:模糊评估原理在区域湖泊资源综合开发利用评估中具有较强的适用性,有助于实现湖泊划定生态保护空间与合理功能定位。本研究可为科学有序开发湖泊资源提供有益借鉴。     

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.