澜沧江西双版纳段鱼类组成和物种多样性

根据2018-2020年澜沧江西双版纳段5次鱼类资源调查数据,结合相关文献资料,对该流域鱼类组成及物种多样性进行了分析。结果显示：澜沧江西双版纳段此次共调查到鱼类119种,隶属于11目28科79属,而历史记录鱼类共179种,隶属于12目34科106属。随着调查的不断深入,土著鱼类种数逐渐增多,但占比却逐渐下降,外来鱼类种数逐渐增多,占比也逐渐升高;本次调查到土著鱼类92种,占鱼类种数的77.31%,占比进一步下降;外来鱼类27种,占鱼类种数的22.69%,占比进一步升高。该区域鱼类优势种为云南吻孔鲃Poropuntius huangchuchieni和少鳞舟齿鱼Scaphiodonichthys acanthopterus,常见种为长臀鲃Mystacoleucus marginatus和宽额鳢Channa gachua。有《国家重点保护野生动物名录》（2021年）鱼类5种,《中国生物多样性红色名录脊椎动物卷》（2015年）受威胁鱼类8种。相对于我国其他江河,澜沧江西双版纳段有极高水平的鱼类物种多样性,其中澜沧江干流鱼类物种多样性相对于左、右岸支流较低,左岸支流鱼类多样性高于右岸,罗梭江鱼类多样性高于其他一级支流。虽然澜沧江西双版纳段鱼类物种多样性维持在较高水平,但土著鱼类占比下降趋势明显,仍面临着严重威胁,本文分析了受威胁因素,并提出了保护建议。     

海南尖峰岭国家级自然保护区雨季鱼类群落结构特征研究

为了了解海南尖峰岭国家级自然保护区雨季鱼类群落结构和多样性特征,于2018年8月采用地笼、手抄网等网具对该区域内溪流的鱼类资源进行了调查。结果表明:本次调查共采集到鱼类样本310尾,隶属于6目13科21属23种。新记录鱼类共有14种,其中9种为外来物种。鱼类香农-威纳多样性指数(H')为2. 41,物种丰富度(D)为3. 84,均匀度指数(J')为0. 77,优势度为(λ)为0. 14。与历史资料相比,群落多样性显著升高,同时外来物种入侵生态风险也在升高。该研究结果丰富了尖峰岭国家自然保护区鱼类多样性基础资料,为海南热带雨林国家公园生物多样性保护策略制定提供科学依据。     

新疆阿勒泰地区额尔齐斯河和乌伦古河流域鱼类多样性演变和流域健康评价

为了解阿勒泰地区额尔齐斯河和乌伦古河流域的鱼类多样性现状和历史演变, 本研究于2013-2016年间在该流域的鱼类多样性进行了连续调查, 并结合历史资料和标本, 以Margalef丰富度指数、Shannon-Wiener多样性指数、Pielou均匀度指数分析评估了流域内鱼类的多样性水平和时空变化。该流域历史上分布有土著鱼类23种, 当前记录到19种, 流域内还有外来鱼类15种。阿勒泰鱼类的区系组成以鲤科种类为主, 其中特有和珍稀濒危物种占比高, 具有重要的保护价值。多样性指数计算结果显示, 2013-2016年鱼类多样性情况整体稳定, 额尔齐斯河鱼类物种数多于乌伦古河。研究还基于鱼类生物完整性指数(Fish Index of Biological Integrity, F-IBI)对34个采集点的河流健康状况进行了评价, 结果显示额尔齐斯河流域大多数调查点的健康状况处于“亚健康”或“一般”水平, 乌伦古河流域多数调查点的健康状况处于“健康”水平。水利工程、外来物种、过度捕捞是影响阿勒泰地区鱼类多样性的重要因素。未来应通过水利工程的联合调度、下泄合理生态流量、布设鱼类通道、规范养殖渔业、严控外来物种、本地土著鱼类的人工增殖放流, 以及合理的就地保护措施对阿勒泰地区的鱼类多样性加以保护, 提升水体健康程度。     

滇西南四个自然保护区鱼类多样性及评价指标探究

为了解滇西南怒江水系的南滚河自然保护区、南捧河自然保护区、永德大雪山自然保护区及澜沧江水系的澜沧江自然保护区鱼类多样性和变化趋势, 探讨其差异和变化的原因, 本文采用β多样性指数分析了4个保护区的鱼类多样性, 并比较了鱼类分类阶元的特有性、单型性和古老成分的有无等多项指标。结果显示, 4个自然保护区共有土著鱼类85种, 隶属于6目13科45属。在中国仅见于怒江水系的4个特有属有异鲴属(Aspidoparia)和新条鳅属(Neonoemacheilus)分布于这3个保护区中; 18种特有种中, 仅分布在这3个保护区的狭域特有种5种。在中国仅分布于澜沧江水系的属有31个, 但仅安巴沙鳅属(Ambastaia)分布于澜沧江保护区; 在澜沧江保护区分布着中国仅见于澜沧江水系的特有种20种, 其中狭域特有种3种。怒江水系的3个保护区分布有1个单型属, 即鳗鲡属(Anguilla), 但没有单型种; 澜沧江自然保护区无单型属与单型种分布。4个保护区中的鱼类均系晚第三纪和第四纪形成的种类或类群, 没有古老或孑遗种类。β多样性结果显示, 在4个保护区中澜沧江自然保护区的鱼类多样性最丰富, 而南滚河自然保护区的丰富程度最低, 但是怒江水系3个自然保护区鱼类多样性的代表性及保护地位比澜沧江自然保护区的要高。而特有阶元和单型性阶元的存在体现出怒江水系3个自然保护区的保护价值及保护意义比澜沧江保护区高。地理范围跨度大小、生境空间异质性高低、保护区面积大小及支流多少等是影响鱼类多样性的主要因素。因此, 规划和设计保护区时, 如果能在水系的上、中、下游分别规划1条一级支流作为保护区, 可使该水系的绝大多数鱼类得到保护。     

赣江鱼类物种更新名录

赣江是长江的主要支流之一, 淡水鱼类多样性极其丰富, 但是目前对于该河流的鱼类多样性还未有充分的了解。本研究于2016年9月至2017年8月对赣江鱼类进行了实地调查, 结合历史文献资料并参考最新的分类学成果, 更新了赣江淡水鱼类名录。结果表明, 赣江共有淡水鱼类180种, 隶属于12目31科93属。其中, 土著鱼类174种, 外来鱼类6种。赣江鱼类以鲤形目为主; 鲤科种类最多, 其次是鲿科。更新的物种名录中, 包含23个新记录土著种, 其中有5个未被描述的新种; 有36个历史资料记载的种类被剔除出物种名录; 25个物种发生了分类地位的变更。此外, 本次调查有28种鱼类未采集到, 说明这些鱼类的种群数量正在急剧下降, 而这些鱼类分别属于洄游性、流水性和产漂流性卵等独特生态类型, 说明赣江鱼类多样性受到了严重的人为干扰。本研究所给出的赣江鱼类的更新物种名录, 可为今后的赣江鱼类多样性保护提供理论基础。     

上海大莲湖鱼类群落组成及生物多样性

于2009年4月11—19日、4月27—5月8日和5月20—29日3个时间段对大莲湖的鱼类群落特征及其多样性组成进行了调查,共收集鱼类样本24061尾,隶属11科17属22种。群落优势种为鲫(Carassius auratus),占样本个体总数的76.38%;Shannon-Wiener多样性指数(H′)为1.0027,Simpson优势度指数(λ)为0.5959,Pielous均匀度指数(J′)为0.3244,Margalef种类丰富度指标(D)为2.0816,相对稀有种数(R)为90.91%;鱼类群落可分为3个生态类型:江海洄游性鱼类有3种、河湖洄游性鱼类1种和定居性鱼类18种。鱼类食性可分为5种类型:食鱼性鱼类9种、食无脊椎动物性鱼类2种、杂食性鱼类7种、食浮游生物性鱼类有3种和草食性鱼类1种。研究结果表明:大莲湖鱼类群落的多样性指标处于较低水平,稳定性较低;相对于黄埔江下游地区,大莲湖的食鱼性鱼类比例较高,说明位于黄浦江上游的大莲湖之水质好于下游流域。为保护和持续利用大莲湖鱼类资源,应加强监管和对生态环境的保护。     

景洪水库浮游植物群落结构变化及与水质的关系

景洪水库是澜沧江下游的重要梯级开发水库,具有重要的生态战略地位。为评估景洪水库水质和浮游植物群落结构现状,本研究根据库区水位和季节变化在2021年3月、6月、9月开展了库区水质和浮游植物监测。结果表明：景洪水库各监测点位水质较好,满足《地表水环境质量标准》Ⅱ类水质标准,富营养化评价结果为贫营养至中营养,但水质和营养状态从3月至9月呈现逐渐下降的趋势; 3月至9月浮游植物密度增加、多样性降低,随着季节变化浮游植物优势种发生明显改变,3月份优势种为隐藻门（Cryptophyta）和硅藻门（Bacillariophyta）,到9月份库区演变为蓝藻门（Cyanophyta）为主。RDA分析表明总有机碳和透明度与浮游植物群落结构变化显著相关。建议后期需加强景洪水库水生态环境监测与评估,预防水体富营养化和蓝藻水华的发生。     

澜沧江中下游鱼类现状及保护

据记载,分布于澜沧江中下游的鱼类达165种,而近几年的调查结果显示,能采集到的仅71种,鱼类资源呈下降趋势。目前,澜沧江中下游的鱼类种类和数量减少(尤以大、中型及珍稀特有鱼类为甚),而外来种种类和数量增加。据此,该文提出了严防外来种逃逸、限制捕捞强度及开展增殖放流等建议。     

汉江喜河库区形成对鱼类群落结构的影响

为了了解库区形成对鱼类群落结构组成的影响,于2011年秋季和2012年春季开展了汉江喜河库区鱼类资源调查.共捕获鱼类35种,隶属于4目6科,主要以鲤科(22种),鲿科(6种)为主.与该河段1980-1982年鱼类调查资料对比分析,喜河库区鱼类群落结构组成发生了较大程度改变,产漂流性卵及喜流水性鱼类种类下降,产粘性卵鱼类种类上升,其他生态类型的改变均受到产卵类型及喜流水性的关联影响,总体表现为喜河库区鱼类在繁殖、栖息习性及体型大小等方面呈现趋同化.推测大坝建设导致库区水文条件的改变是鱼类群落结构变化的主要原因,并提出相关保护措施.     

西藏拉鲁湿地和茶巴朗湿地外来鱼类群落结构及变动趋势

研究于2019—2021年在西藏拉鲁湿地和茶巴朗湿地使用刺网和地笼等组合渔具开展了鱼类实地调查, 分析了外来鱼类物种组成、优势种和群落功能多样性, 并结合已发表的文献资料, 探讨了西藏湿地外来鱼类群落结构的变动趋势及影响。结果表明, 共采集到外来鱼类10种, 隶属于4目5科, 包括鲫(Carassius auratus)、麦穗鱼(Pseudorasbora parva)、鲤(Cyprinus carpio)、丁鱥(Tinca tinca)、棒花鱼(Abbottina rivularis)、泥鳅(Misgurnus anguillicaudatus)、大鳞副泥鳅(Paramisgurnus dabryanus)、鲇(Silurus asotus)、小黄?(Micropercops swinhonis)和中华青鳉(Oryzias sinensis)。外来鱼类的个体数和重量分别占本地种和外来种总渔获物的94.86%和70.71%, 其中主要组成为鲫和麦穗鱼等小型鱼类。相对重要性指数(IRI)表明鲫、麦穗鱼、大鳞副泥鳅和鲤4种为拉鲁湿地外来鱼类优势物种, 鲫、麦穗鱼和小黄?3种为茶巴朗湿地的优势物种。在拉鲁湿地和茶巴朗湿地鱼类种类组成、个体数量和生物量中外来鱼类均已占据优势地位, 且外来鱼类的群落功能多样性(FD)亦高于土著鱼类。结合历史数据, 西藏拉鲁湿地和茶巴朗湿地已记录外来鱼类12种, 其中具高度入侵风险物种达6种, 外来鱼类物种数从2000年左右的2种增加到现在的10种, 且丁鱥和中华青鳉分别在西藏自然水体中和茶巴朗湿地中首次被发现。此外, 两个湿地12种外来鱼类均为拉萨市场中的常见经济鱼类及携带鱼类, 是由于放生而进入湿地自然水体中, 且鲫、大鳞副泥鳅和麦穗鱼等均已建立自然种群。因此, 加强对放生的科学管理及开展外来鱼类的长期监测, 是防范外来鱼类入侵及高原湿地生物多样性保护的迫切任务。     

Prediction of river ecological integrity after cascade hydropower dam construction on the mainstream of rivers in Longitudinal Range-Gorge Region (LRGR), China

Dam construction is considered the major factor contributing to significant modification of river ecosystems. The related ecological effects of these constructions on flow patterns, water quality, sediment etc. have led to increased concerns in recent years. Most of the works so far focus on the assessment of vulnerability, risk, and damages to single factors, such as soil conservation, fish reproduction or vegetation. Few works have been done on to analyzing and predicting the changes of the river ecosystem integrity (REI). Taking three important international rivers, Lancang River, Nu River and Yuan River in LRGR as a case study, the relationship between cascade dam construction and REI is analyzed. A model of the cascade dam construction and the REI is developed on Lancang River after cascade construction, and then it is applied on the Nu River and Yuan River to predict the changes of REI after the planned cascade construction. The results show that there are significant relationships between the cascade construction and the change of the REI. Before the cascade development, REI index of Nu River is the highest with a value of 0.844. Yuan River, the worst of the three before the cascade construction (0.719), is found to be the best one after the cascade construction (0.389). After the cascade construction, the REI index value of the Lancang River is likely to dramatically decrease from 0.825 to 0.274.     

CURRENT STATUS AND CONSERVATION PLANNING OF FISH BIODIVERSITY IN THE UPPER YANGTZE RIVER BASIN IN THE CONTEXT OF HYDROPOWER DEVELOPMENT北大核心CSCD

Nearly 90% of the hydropower resources in the Yangtze River basin are concentrated in the upper reaches of the Yangtze River. The cascaded hydropower dams and river channelization have caused habitat fragmentation and loss of fish diversity, which has aggravated the contradictions between hydropower development and environmental protection. This paper collected data on aquatic reserves (i.e. natural reserves and aquatic germplasm resources conservation zones) and cascade dams in the upper reaches of the Yangtze River, and vectorized the data in ArcGIS. Taking into account the diversity, richness and distribution of fish, we analyzed the changes in fish resources and the problems in the construction and management of the upper reaches of the Yangtze River. Therefore, several strategies have been proposed to reduce the conflicts between hydropower development and aquatic ecosystem protection, including conducting reserve census, evaluating management effectiveness of the protected areas for spatial optimization of the reserve networks, implementing the ecological restoration of essential fish habitats, implementing the rescue action plan for the upper Yangtze endangered endemic fish, establishing an efficient ecological compensation mechanism, and strengthening scientific monitoring and related research. These recommendations will provide a scientific basis for the coordinated development of hydropower exploitation and river ecological protection in the upper Yangtze River. © 2019, Institute of Hydrobiology, Chinese Academy of Sciences. All rights reserved.     

小型水坝梯级开发对永宁河流域鱼类多样性的影响

永宁河是长江上游右岸的一级支流,其干、支流上共建有20余座小型水坝。为探究梯级水电站对鱼类多样性的影响,在永宁河流域设置共42个采样点,覆盖干支流及各个水坝,分别于2018年7月、10月和2019年1月、4月进行了四次鱼类资源调查。调查期间通过刺网、地笼、电捕等方法共采集到鱼类69种7332尾,隶属于4目13科54属,其中有长江上游特有鱼类13种,列入《中国脊椎动物红色名录》濒危和易危鱼类3种,国家二级重点保护鱼类岩原鲤(Procypris rabaudi)1种。Pinkas相对重要性指数(IRI)值较大主要为宽鳍鱲(Zacco platypus)、鲫(Carassius auratus)乐山小鳔鮈(Microphysogobio kiatingensis)等小型鱼类,29种鱼类的IRI值小于10;平均全长＜10cm的鱼类有24种3620尾,平均体重＜50g的鱼类有47种6493尾,鱼类规格较小,小型化严重。永宁河干流下游种类最多,多样性最高,干流中游鱼类数量最多。受自然环境以及水坝等的影响,永宁河的鱼类分布具有明显的空间差异。水坝类型对鱼类多样性有显著影响;而季节对鱼类多样性影响不显著。无水坝阻隔河段鱼类多样性著高于低头坝和高头坝阻隔河段;夏季的短距离洄游鱼类种数显著高于冬季和春季,但由于数量较少对鱼类多样性的季节性变化影响不明显。各种结果表明水坝阻隔对永宁河鱼类多样性和时空分布存在明显影响,为保护受小型水电站影响河流的鱼类多样性,有必要修复重要鱼类栖息地,适当拆除部分小型水坝,并科学开展增殖放流。     

基于环境DNA技术的赤水河秋季鱼类多样性分布特征

赤水河是长江上游少有的仍保持自然流态的大型一级支流,是长江鱼类重要的繁衍场和珍稀物种的保护地,摸清其鱼类多样性现状及鱼类群落结构特征对赤水河水生态恢复评估极为重要。于2021年9月对赤水河流域开展了鱼类多样性、分布及其特征调查,全流域共设置52个采样点,采用环境DNA技术采集并研究了赤水河鱼类的组成及其分布。结果显示通过环境DNA方法共调查到鱼类6目18科62属77种,包含16种长江特有鱼类。以鲤形目为主,占总数的87.87%。赤水河鱼类食性以杂食性和肉食性鱼类为主,群落结构上,处于下层水环境鱼类较多;赤水河鱼类优势种为宽鳍鱲(Y=0.205)、西昌华吸鳅(Y=0.085)、麦穗鱼(Y=0.068)、乌苏拟鲿(Y=0.033)、云南光唇鱼(Y=0.027);赤水河上游和下游鱼类群落(P<0.01)和Shannon-Wiener指数差异均显著(P<0.05)。海拔、流速、pH、电导率和温度是影响赤水河鱼类多样性的主要环境因素。为环境DNA技术在赤水河鱼类多样性调查中的应用提供了探索性研究,将有助于赤水河生物多样性的保护。     

基于Vortex模型分析金沙江水电开发对圆口铜鱼种群生存力的影响

圆口铜鱼(Coreius guichenoti)是长江上游特有鱼类,研究金沙江梯级水电开发背景下圆口铜鱼种群生存力变化对该物种的保护具有重要意义。Vortex模型在传统种群评估方法的基础上,引入种群年龄结构、繁殖体制、性比等因素,并考虑了环境、灾害、遗传等随机性对种群的影响,可模拟种群数量和生存力变化特征,是一种应用广泛的种群生存力分析模型。基于1981-2021年金沙江圆口铜鱼资源调查数据,采用Vortex模型构建了金沙江中下游干流大规模水电开发前、后两个时期圆口铜鱼种群生存力分析模型,考虑了水电开发下,水温、流速等环境变化对圆口铜鱼种群的影响,对比了两个时期圆口铜鱼种群数量、结构及生存力等。结果表明:水电开发前,严重过度捕捞对圆口铜鱼种群产生了显著威胁,10年内种群数量下降了12.5%,百年内种群内禀增长率为0.085,种群的生存和繁殖能力较稳定,灭绝概率为1%;水电开发后,10年内种群数量下降了42%,百年内种群内禀增长率降至-0.087,灭绝概率增大至36.1%,种群平均灭绝时间为83.7年,圆口铜鱼抵抗环境干扰的种群恢复能力降低,种群生存力受到影响。     

Mitochondrial DNA diversity of <Emphasis Type="Italic">Glyptothorax zanaensis</Emphasis> (Wu et al., 1981) populations in Nu River,China

The hillstream fish, Glyptothorax zanaensis (Wu et al., Oceanol Limnol Sin 12:74–79, 1981) is a freshwater teleost species belonging to the order Siluriformes, endemic to Nu River and Lancang River basin. Because wild stocks of G. zanaensis have declined substantially in recent years, owing to overexploitation, pollution, illegal fishing practices and the development of hydroelectricity in the Nu River, the populations of G. zanaensis have markedly declined in recent years. We studied the mitochondrial DNA cyt b gene to assess the genetic diversity of G. zanaensis in seven tributaries of the Nu River. Seventy variable sites defined 15 haplotypes in 153 individuals. Haplotype diversity and nucleotide diversity were 0.542 ± 0.014 and 0.011 ± 0.007, respectively. The Sunzu River site had the highest haplotype diversity (Hd, 0.893 ± 0.014) and nucleotide diversity ( Pi, 0.010 ± 0.012). Genetic diversity was low in the Dong River, Fengwei River and Mengtong River. Pairwise F _ST values ranged from 0.00 to 1.00. Significant F _ST values were found for Sunzu River sampled sites paired with all other populations and Mengtong river sampled site paired with the others. Furthermore, the Nanpeng River sampled site was significantly differentiated from the Luoming River, Dong River and Fengwei River sampled sites. Such knowledge is essential for developing appropriate policies for the rational management of G. zanaensis.     

Fish and fisheries in the Upper Mekong: current assessment of the fish community, threats and conservation

The Mekong flows north to south, through six countries in south–east Asia. Many studies have concentrated on fish and fisheries in the Lower Mekong, which has been identified as one of the largest inland fisheries in the world with an incredibly rich diversity of species. In contrast, fish and fisheries in the Upper Mekong (Lancang River) have remained relatively undocumented. In this paper, we synthesized information on freshwater fish biodiversity and fisheries in the Upper Mekong and documented 173 species and subspecies (including 87 endemic species) among 7 orders, 23 families and 100 genera. We divided the Upper Mekong into 17 sub-basins based on Digital Elevation Model (DEM) and then used fish species data to cluster the sub-basins. Four parts (the headwater, the upper reach, the middle reach and the lower reach) and one lake have distinct fish species communities associated with them. There was a linear relationship between fish species (x) and endemic species (y) as y = 0.5464x − 3.2926. Relationship between species number or endemic species number (y) and mean altitude (x) can be described as y = −54.352 ln(x) + 460.79 or y = −30.381 ln(x) + 253.85, respectively. Fisheries kept as about 6,000 t from 1989 to 1998, and then steadily increased to 10,000 t in 2004. We reviewed the overall threats to the Upper Mekong fish and fisheries, and found that hydrological alteration is the largest threat in the basin, followed by over fishing and the introduction of exotic species. In terms of specific river sections, water pollution was the most serious threat to fishes in the upper reach of the Upper Mekong, whilst migratory fishes in the lower reach of the Upper Mekong are seriously threatened by the construction of cascade dams. The Buyuan River and the Nanla River were identified as important feeding and spawning habitats for upstream migrant species and should be considered as a priority for conservation.     

DNA barcoding reveals the temporal community composition of drifting fish eggs in the lower Hongshui River,China

Determining the temporal community composition of fish eggs in particular regions and understanding the reproductive times of regional fish taxa are key aspects of the management and regulation of regional fish stocks. However, it is extremely difficult to accurately identify fish eggs due to the absence of diagnostic morphological characters. We sampled fish eggs in the lower Hongshuihe River (an upper mainstem of the Pearl River) between May and September 2020. We then used DNA barcoding to determine the species composition of the egg pool and to predict the spawning periods of the identified species. A total of 641 eggs and 17 larvae were chosen for molecular identification; 397 eggs and 17 larvae yielded high‐quality barcoding sequences. The high failure rate (~38%) was most likely due to long‐term storage in low concentrations of ethanol prior to molecular analysis. We successfully classified 392 eggs into 10 species and 13 larvae into four species using public databases. Most of the species identified in the egg pool were small and/or benthic, and migratory species were rare. This may partially reflect the adverse effects of hydropower cascade development in this river section. We also found that spawning periods tended to be species‐specific. Our study provides a reference for the conservation and management of regional fishery stocks.     

Temporal changes in fish diversity in lotic and lentic environments along a reservoir cascade

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