黄河口水域主要鱼种的时空生态位宽度和重叠

生态位在研究群落结构、种间关系和生物多样性等方面具有重要作用。为深入了解黄河口水域鱼类群落结构和种间关系,本研究根据2013—2014年在黄河口水域进行的7个航次的渔业资源底拖网调查数据,应用平均拥挤度、生态位宽度和生态位重叠值等指数研究了该水域12种鱼类的时空生态位宽度和重叠特征。结果表明,黄河口水域主要鱼种时间生态位宽度变化范围为0～1.53,其中矛尾虾虎鱼(Chaemrichthys stigmatias)和方氏云鳚(Enedrias fangi)时间生态位宽度值较高,安氏新银鱼(Neosalanx anderssoni)和鮻(Liza haematocheila)较低。主要鱼种空间生态位宽度具有明显季节变化。所有鱼种间的平均空间生态位重叠值也有着明显的季节差异。生态位宽度和重叠值与各鱼种数量、分布、生态习性和生境状况密切相关,反映了该海域不同鱼种对生境资源的不同利用能力。     

东、黄海主要鱼类Q/B值与种群摄食量研究

利用东、黄海渔业资源调查所获得的数据,在测定年栖息平均水温、渐进体重、尾鳍外形比以及胃含物分析基础上,根据经验公式计算得出了东、黄海103种鱼类的Q/B值。Q/B值总体范围从3.09(黄鱼安鱼康)到19.13(七星底灯鱼),平均值为7.97。根据Q/B值和生物量评估了鱼类种群年摄食量。黄海的重要鱼类(鳀鱼、竹荚鱼、鲐鱼、细纹狮子鱼和小黄鱼),共消耗了449万t/年。东海的重要鱼类(竹荚鱼、带鱼、发光鲷、鳀鱼和蓝点马鲛),共消耗了175万t/年。97种鱼类在黄海共摄食约466万t/年,在东海共摄食278万t/年。同时对东、黄海主要饵料生物(磷虾类、鳀鱼、发光鲷、七星底灯鱼、细条天竺鲷、日本枪乌贼、桡足类、樱虾类、细螯虾和脊尾腹褐虾)被摄食量进行了估算。主要饵料生物在这两个海区共被消耗了555万t/年,占整个97种鱼类摄食消耗的74.6%。     

长江口盐沼湿地鱼类群落优势种的时空生态位特征

为了解长江口盐沼湿地优势鱼类群落结构及其种间关系,采用插网调查,利用2019年5—10月的调查数据,基于生态位宽度和生态位重叠度指数对长江口崇明东滩（31°27''N,121°56''E）和九段沙盐沼湿地（31°10''N,121°57''E）鱼类群落的优势种生态位进行研究。研究结果表明,春、夏、秋3个季节共采获10个优势种,其中鮻（Liza haematocheila）、花鲈（Lateolabrax maculatus）和拉氏狼牙虾虎鱼（Odontamblyopus rubicundus）在3个季节中均为优势种。在10个优势种中,时间生态位宽度值变化范围为0.11~1.70,其中拉氏狼牙虾虎鱼时间生态位宽度值最大,小黄鱼（Larimichthys polyactis）值最小;空间生态位宽度值变化范围为0.57~1.53,其中棱鮻（Liza carinatus）空间生态位宽度值最大,小黄鱼值最小。长江口盐沼湿地鱼类优势种生态位宽度呈现显著的季节性变化趋势。长江口盐沼湿地鱼类优势种的时空生态位重叠值较高,其中具重叠意义的鱼种对（species pairs）高达73.33%,具有显著重叠意义的鱼种对高达48.89%。结论认为,长江口盐沼湿地鱼类优势种的时空分布具有相似性,存在明显的竞争关系。     

舟山群岛海域5种鳗的营养生态位及种间关系

海鳗等鳗鲡目鱼类是舟山群岛海域常见的近底层凶猛肉食性鱼类,研究鳗类的营养生态位可以了解其在舟山群岛海域生态系统中占据的营养层次。本研究以舟山群岛海域的海鳗（Muraenesox cinereus）、前肛鳗（Dysomma anguillare）、星康吉鳗（Conger myriaster）、食蟹豆齿鳗（Pisodonophis cancrivorus）和短尾吻鳗（Rhynchoconger ectenurus）为研究对象,利用碳氮稳定同位素技术分析这5种鳗的营养生态位及种间食物关系。结果显示：（1）舟山群岛海域5种鳗的δ13C范围是-21.91‰~-14.97‰（平均值-17.03±1.14‰）,δ15N范围为9.56‰~15.13‰（平均值11.50±1.36‰）;（2）非参数检验结果表明,不同物种间的碳氮稳定同位素比值之间均存在极显著差异;Pearson相关性分析表明,5种鳗总体的δ13C、δ15N值与肛长相关性均不显著,而除前肛鳗以外,其余4种鳗总体的δ13C值与肛长相关性不显著,δ15N值与肛长呈极显著正相关;（3）稳定同位素混合模型（SIAR）显示鱼类、虾类和口足类是鳗类的主要食物来源;（4）海鳗与其他4种鳗的营养生态位均有重叠,说明它们之间的食源有一定程度的同质化,存在食物竞争;食蟹豆齿鳗和短尾吻鳗的校正核心生态位面积（SEAc）最大,说明二者食性泛化,其摄食类群主要取决于饵料生物的易得性;前肛鳗、星康吉鳗和短尾吻鳗之间不存在生态位重叠,说明其摄食种类有所分化,体现了同域分布近缘种的食性差异。本研究阐述了舟山群岛海域5种鳗的种间食物关系和进化共存机制,可为研究舟山群岛海域高营养级类群的食物网结构特征提供参考。     

东、黄海黄鮟鱇的摄食习性及其随发育的变化

2008年5月～2009年2月,对东、黄海663尾黄鱼安鱼康的胃含物及其随发育的变化进行了研究。结果表明,黄鱼安鱼康摄取的食物有120余种,主要食物类群为硬骨鱼类和长尾类,主要食物种类有小黄鱼、短鳄齿鱼、细条天竺鱼、发光鲷和带鱼。在黄海南部、东海北部和东海南部3个区域,黄鱼安鱼康的摄食强度变化不显著,而食物组成具有显著差异;体长在45～650mm之间的6个体长组,黄鱼安鱼康的摄食强度变化也不显著,但食物组成差别较大,食物种类随黄鱼安鱼康体长的增加有显著的变化。食物多样性指数、食物种类和食物重量范围都随体长的增加而变化。其食物组成的聚类分析结果将黄鱼安鱼康的6个体长组分为两组,一组体长小于250mm,另一组体长大于250mm。     

北黄海细纹狮子鱼摄食生态的初步研究

根据2007年秋季在北黄海进行的定点底拖网调查,对细纹狮子鱼(Liparis tanakae)的摄食生态进行了初步研究。北黄海的细纹狮子鱼在秋季主要以虾类和底层鱼类为食,属于底栖动物食性鱼类,其优势饵料生物是脊腹褐虾(Crangon affinis)。在调查海域最北部的1号站位,细纹狮子鱼还摄食了较多的大泷六线鱼(Hexagrammos otakii)鱼卵。典范对应分析(CCA)表明,水深、经度、纬度和体长对细纹狮子鱼的食物组成有显著影响(P0.05),而性别和性腺成熟度则没有显著影响(P0.05)。脊腹褐虾体长与细纹狮子鱼体长之间呈显著的正相关(r=0.326,P0.05),而中华安乐虾(Eualus sinensis)体长与细纹狮子鱼体长之间没有显著的相关关系(r=0.219,P0.05);脊腹褐虾(r=-0.372,P0.01)和中华安乐虾(r=-0.799,P0.01)体长与细纹狮子鱼体长的比率与细纹狮子鱼体长之间均呈极显著的负相关关系。细纹狮子鱼的胃总质量和空胃质量均随着体长的增加呈指数增长。     

海州湾3种石首鱼的食物组成和生态位重叠

根据2011及2013年在海州湾及其邻近海域进行的渔业资源底拖网调查资料和胃含物分析数据,应用多元统计分析法和生态位重叠指数法等,研究了海州湾皮氏叫姑鱼、小黄鱼和棘头梅童鱼3种石首鱼的食物组成及其营养—空间二维生态位的重叠情况。结果显示,皮氏叫姑鱼属于底栖动物食性,主要摄食虾类、端足类和多毛类;小黄鱼属于底栖动物和游泳动物食性,主要摄食鱼类、虾类、头足类和磷虾;棘头梅童鱼属于底栖动物食性,主要摄食虾类、毛虾类、磷虾和糠虾。这3种石首鱼的营养生态位宽度较为接近,其中小黄鱼的营养生态位宽度(2.69)和空间生态位宽度(2.78)均最高,皮氏叫姑鱼的营养生态位宽度(2.59)最低,而棘头梅童鱼的空间生态位宽度(2.42)最低。3种石首鱼的营养生态位重叠指数为0.24～0.46,其中皮氏叫姑鱼与棘头梅童鱼的营养生态位重叠最高。它们的空间生态位重叠指数为0.19～0.30,表明这3种鱼在空间方面存在一定的分隔。它们的营养—空间二维生态位重叠指数为0.05～0.11,其中皮氏叫姑鱼与棘头梅童鱼的重叠指数最高,因此有可能发生激烈的食物竞争,而小黄鱼与皮氏叫姑鱼和棘头梅童鱼之间则可以通过营养和空间生态...     

东、黄海六种鳗的食性

用饵料生物的生态类群的出现频率百分比组成来划分东、黄海6种鳗的生态属性和食性类型。通过对其食物组成的分析，发现这6种鳗的生态属性均为底层鱼类且分属3种食性类型：前肛鳗、黑尾吻鳗和银色突吻鳗属底栖生物食性；星康吉鳗和食蟹豆齿鳗属底栖生物和游泳动物食性；奇鳗属游泳动物食性。结果还表明：前肛鳗、星康吉鳗和黑尾吻鳗之间不存在食物竞争。同时建议在食性分析中使用食物的能量百分比这一指标，但需要进一步的收集基础数据。     

海州湾及其邻近海域鱼类群落结构冗余度

过度捕捞、环境污染等人类活动以及气候变化等影响着海洋鱼类群落动态及其稳定性。为深入研究海州湾海域鱼类群落结构及其变化,根据2011年、2013—2016年春、秋两季在该海域进行的渔业资源与环境调查数据,应用多元统计分析和结构冗余度分析方法,研究了海州湾海域春、秋季鱼类群落结构冗余度。结果显示,海州湾及邻近海域春、秋季鱼类均可划分为南北两个群落。春季北部群落的典型种包括方氏云鳚、细纹狮子鱼、黄鮟鱇和大泷六线鱼;南部群落的典型种为小黄鱼、短吻红舌鳎、方氏云鳚和星康吉鳗。秋季北部群落的典型种为棘绿鳍鱼、长蛇鲻和星康吉鳗;南部群落典型种包括短吻红舌鳎、棘头梅童鱼、鮸、矛尾虾虎鱼、小黄鱼和皮氏叫姑鱼。春、秋季鱼类群落响应单元数均为1,群落结构冗余度水平低;响应单元中种类与南、北鱼类群落典型种组成相似,表明海州湾春、秋季鱼类群落空间结构特征主要受方氏云鳚、细纹狮子鱼、小黄鱼、棘绿鳍鱼和长蛇鲻等少数种类决定。决定海州湾及邻近海域鱼类群落结构特征的可替代种类较少,当主要种类受损时,群落结构会发生较大变化,鱼类群落结构稳定性较低。     

基于碳氮稳定同位素的太湖鱼类营养生态位研究

为探究太湖鱼类的营养生态位特征，于2019~2020年开展了太湖鱼类的碳氮稳定同位素调查，分析了鱼类营养生态位大小、生态位重叠度及营养级。研究结果表明，鱼类δ13C值范围为-27.67‰~-17.92‰，δ15N值范围为6.02‰~20.31‰。营养生态位大小（SEAc值）范围为0.14‰2~20.43‰2，其中黄颡鱼的生态位最大，光泽黄颡鱼的生态位最小。短颌鲚、陈氏短吻银鱼和鲢的SEAc值均较小，表明他们利用的食物源和生境范围较窄，鳙的SEAc值较大，表明其利用的食物源和生境范围较广。鱼类的营养生态位重叠度为0~70.6%。大银鱼与翘嘴鲌的生态位重叠度最大（70.6%），其次为鲈与翘嘴鲌（39.9%），其余物种间的生态位重叠度范围为0~38.9%。短颌鲚与其他肉食性鱼类的生态位重叠度较小，表明他们之间的食物资源竞争较弱。陈氏短吻银鱼与鲢、鳙在生态位上存在明显的分离，这与陈氏短吻银鱼专食浮游动物有关。鱼类营养级范围为0.73~3.62，鮠一种的营养级最高，泥鳅的营养级最低。分析表明，鱼类营养生态位的大小与其摄食的食物种类以及对不同生境的利用程度有关；大部分鱼类间生态位重叠度较低，表明鱼类在资源利用上存在较大分离。本研究结果也为太湖鱼类食物网分析及渔业资源管理提供了基础数据。     

台州南部近岸海域春秋季主要鱼类生态位及其种间联结性

根据2016年秋季(10月)和2017年春季(4月)台州南部近岸海域的渔业资源调查资料,将2次调查中分别出现的优势种及重要种定义为主要鱼类,并采用相对重要性指数、生态位测定、方差比率、卡方检验、Pearson相关检验和Spearman秩相关检验等方法分析主要鱼类间的生态位和种间关系。结果显示,秋季主要鱼类8种,春季11种,2季共有主要鱼类5种。秋季主要鱼类的生态位宽度值与生态位重叠值总体上略高于春季,秋季广生态位种(Bi≥2.40)、中生态位种(1.60≤Bi<2.40)和窄生态位种(Bi<1.60)依次有4种、3种和1种,春季则依次有4种、5种和2种;秋季生态位重叠显著(Oik≥0.6)的种对数占总种对数的32.14%,春季则仅占12.73%。秋季,总体联结性分析结果显示主要鱼类间总体上呈显著负关联,卡方检验、Pearson相关检验和Spearman秩相关检验显示群落中正负关联比依次为1.50、1.33和2.11,其检验显著率依次约为0%、17.86%和10.71%。春季,总体联结性分析结果结果显示主要鱼类间总体上呈不显著负关联,卡方检验、Pearson相关检验和Spea...     

Freshwater ecosystem vulnerability: Is native climatic niche good enough to predict invasion events?

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Modelling the potential distribution of two tropical freshwater fish species under climate change scenarios

1. Climate change is causing shifts in the distribution patterns of freshwater fish at various spatio-temporal scales. Tropical freshwater fish are vulnerable, especially in areas where a high impact of climate change is predicted; thus, there is an increasing need to predict these shifts to determine conservation and adaptation strategies.
2. Ecological niche models offer a reliable way to predict the effects of climate change on species distribution. Potential shifts in the distribution of tropical fish were tested under two scenarios (4.5 – moderate and 8.5 – extreme) with three general circulation models for years 2050 and 2070 using maximum entropy software using as models two predatory species – the tropical gar Atractosteus tropicus and the giant cichlid Petenia splendida.
3. The potential distribution of both species was associated with warm and humid–sub-humid conditions. Future projections showed a higher availability of suitable areas for both species resulting from the expansion of warmer conditions in the middle and upper basins of the Central American mountain range and centre of the Yucatan Peninsula.
4. Ecological niche models of keystone or umbrella species such as A. tropicus and P. splendida could be useful to support conservation plans of protected areas. The potential distribution of both species covers areas of high suitability including six important biosphere reserves in Mexico, three protected areas in Guatemala and part of the Mesoamerican biological corridor.
5. Despite the potential expansion of the present distribution range suggested by the models, it is important to consider the biological and ecological requirements of the species and the ecological implications of these potential shifts in distribution. Both scenarios could have several implications at genetic, population, and ecosystem levels.

     

Use of ecological niche modelling to predict distributions of freshwater fish species in Kansas

Abstract – An essential innovation in aquatic biodiversity research would be a robust approach to accurately predict species’ potential distributions. In this paper, I conduct an analysis to test the efficacy of ecological niche modelling for predicting fish species’ potential distributions using an artificial‐intelligence algorithm, the Genetic Algorithm for Rule‐Set Prediction (GARP). Models of species’ ecological niches are developed using GARP, and projected onto geography to predict species distributions. To test the validity of this approach, I used freshwater fish distribution data for twelve fish species occurring in Kansas. These taxa were chosen to represent phylogenetic, distribution, and habit diversity. I subset these data by omitting half of the counties from model building, and test models using the omitted counties. Models were tested using Receiver Operating Characteristic (ROC) analyses. Of the species tested, all were statistically significant with the models showing excellent predictive ability. Omission errors across taxa ranged from 0 to 17%. This inferential capacity opens doors to many synthetic analyses based on primary point‐occurrence data.     

Microdistribution and fluctuations in niche overlap in a rocky shore cichlid community in Lake Victoria

Abstract— The microdistribution of ten numerically dominant species in a fish community at a rocky island in Lake Victoria was studied using invasive sampling. All were haplochromine cichlids. The community was characterized by high fish densities and by a dominance of Aufwuchs feeders . Species were non-randomly distributed, showing significant associations with water depth and other topographic parameters. Species occupied unique positions in a network of recurrent species groups. Niche partitioning through differential microdistribution was even more subtle than that reported for Lake Malawi's rock-dwelling cichlids. Species-specific microdistribution fitted qualitative predictions from ideal free distribution models with asymmetrical interference competition for food. No evidence was found for interspecific contest competition for space. Temporal niche shifts have been observed between periods of high and low water levels. Owing to a combination of reduced habitat availability with niche expansion in most species, niche overlap was larger during the lowwater period.     

胶州湾5种虾虎鱼类的营养和空间生态位

应用Shannon-Wiener指数和Pianka重叠指数分析了胶州湾5种虾虎鱼类的食物组成、营养生态位宽度、空间生态位宽度及其重叠,通过计算营养空间二维生态位重叠指数探讨了5种虾虎鱼类种间食物竞争与空间分布的关系。结果表明,胶州湾的5种虾虎鱼均属底栖动物食性,其中斑尾刺虾虎鱼(Synechogobius ommaturus)主要以虾类、多毛类和鱼类为食,而六丝钝尾虾虎鱼(Amblychaeturichthys hexanema)、红狼牙虾虎鱼(Odontamblyopus lace-pedii)、纹缟虾虎鱼(Tridentiger trigonocephalus)和钟馗虾虎鱼(Tridentiger barbatus)则主要摄食桡足类、钩虾、涟虫等小型底栖甲壳动物。在5种虾虎鱼中,六丝钝尾虾虎鱼的营养生态位宽度最高(2.65),纹缟虾虎鱼的空间生态位宽度最高(2.01),而红狼牙虾虎鱼的营养生态位宽度和空间生态位宽度均最低(分别为1.26和0.97)。5种虾虎鱼之间的营养生态位重叠指数在0.03~0.64之间,其中六丝钝尾虾虎鱼与钟馗虾虎鱼的营养生态位重叠指数最高(0.64);空间生态位重叠指数在0.08~0.91之间,最高值出现在红狼牙虾虎鱼与钟馗虾虎鱼之间(0.91);营养空间二维生态位重叠指数在0.0032~0.3648之间,其中钟馗虾虎鱼与六丝钝尾虾虎鱼的营养空间二维生态位重叠指数最高(0.3648),因此最有可能出现激烈的食物竞争,其他鱼种之间则通过营养或空间生态位的分化而降低了种间竞争的程度。     

Dietary plasticity of Arctic charr (Salvelinus alpinus) facilitates coexistence with competitively superior European whitefish (Coregonus lavaretus)

Abstract – Habitat use and diet of Arctic charr (Salvelinus alpinus) coexisting with European whitefish (Coregonus lavaretus) and grayling (Thymallus thymallus) were studied in one deep and two relatively shallow subarctic lakes in northern Norway. Stomach content and stable isotope analyses revealed clear and temporally stable resource partitioning between the species in all three lakes. Arctic charr had a wide and flexible trophic niche and was the only piscivorous species. In contrast, whitefish and grayling had remarkably stable planktivorous and benthivorous niches, respectively. In the deepest lake, Arctic charr together with grayling mainly utilised littoral benthos, while piscivory was more prevalent in Arctic charr in the two shallower lakes. In one of the shallow lakes, whitefish was apparently relegated to the inferior profundal niche because of dominance of the littoral by grayling. Our results suggest that Arctic charr may not necessarily need an extensive profundal zone as a refuge, but can coexist with whitefish if a third competing fish species like grayling occurs in the littoral habitat or if profitable small prey fish are available. The study demonstrates that strong dietary plasticity of Arctic charr is instrumental in the observed coexistence with the commonly competitively superior whitefish.     

Degree of feeding niche overlap uniformises the distribution of interspecific territories in a Malawian cichlid community

Cichlid fishes in the rocky littoral zones of Lake Malawi are among the most diverse endemic fish communities of the world. They segregate food resources, but considerable niche overlaps have been reported by numerous studies in this field. If their niches largely overlap, the heterospecific individuals are expected to behave like conspecific individuals. Instead of studying their niche segregation, we investigated the spatial distribution patterns of adult males of nine abundant cichlid species by point process analysis, with due attention to niche partitioning, as measured by stable isotope analysis. Because their feeding habitats are restricted by intra‐ and interspecific interferences over the mating and feeding territories respectively, we hypothesised that the interspecific feeding territories of species with nearly similar niche tended to be distributed uniformly. Although the typical territorial animals are expected to be distributed uniformly, the distribution pattern of intraspecific mating territory was judged to be uniform only for two out of nine species. This result suggests that each species has its specific preference for territorial locations or their locations are restricted by interspecific interactions. The latter explanation was partially supported by the agreed locations of gravity centres between intraspecific mating and interspecific feeding territories. Species pairs with similar isotope ratios tended to show a uniform distribution of interspecific feeding territories. Thus, individual species pairs keep a certain distance from each other by using nearly similar food resources. This result suggests that some cichlid species coexist not only through niche segregation but also through territorial interactions, like conspecific individuals.