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1.
三峡水库与长寿湖水库鱼类碳、氮稳定同位素特征及营养级的比较 总被引：1，自引：0，他引：1
为探究人为活动对水库鱼类食物来源和营养级关系的影响，选择人为影响程度较低的三峡水库和影响程度较高的长寿湖水库为研究对象，应用碳、氮稳定同位素技术对两个水库鱼类δ13C值、δ15N值和营养级进行比较分析.结果显示：长寿湖水库鱼类δ13C平均值（-22.66‰±1.94‰）与三峡水库（-22.59‰±1.87‰）较为接近，但长寿湖鱼类的δ15N值（13.95‰ ±3.02‰）显著高于三峡水库鱼类的δ15N值（11.98‰ ±2.25‰）.根据δ15N值计算不同食性鱼类间的营养级，三峡水库营养级为肉食性鱼类 > 杂食性鱼类 > 浮游生物食性鱼类 > 草食性鱼类；而长寿湖中则表现为浮游生物食性鱼类 > 肉食性鱼类 > 杂食性鱼类 > 草食性鱼类，营养级出现了异常现象.这一结果表明，对于人为影响（如人工喂食鱼饲料等）较大的水体，采用δ15N值计算不同食性鱼类间的营养级存在不确定性. 相似文献
2.
淠河是安徽省内淮河右岸最大的支流,也是淮河中游重要的水源地.为了解淠河流域河源溪流鱼类的空间分布格局及其主要影响因素,本研究于2015年4—5月对6条河源溪流鱼类及其环境因子进行了调查.研究结果表明,6条溪流共采集鱼类19种,其中杂食性种类占57.9%,肉食性和植食性种类分别占26.3%和15.8%.所有种类中,宽鳍鱲(Zacco platypus)是主要优势种,绿太阳鱼(Lepomis cyanellus)为研究区域首次报道的外来入侵种.就6条溪流各样点的平均值而言,淠河西部3条溪流鱼类种类数及个体数均明显高于东部3条溪流,但重量却并没有类似趋势.Sorensen相似性分析表明,6条溪流鱼类组成具有较高相似性,且相对较小值主要位于高、低海拔溪流之间.除趋势对应分析二维空间排序与相似性分析结果一致.Pearson相关分析表明,影响鱼类种类数的主要是局域栖息地参数(包括海拔、流速、底质、水深、河宽和电导率)和溪流的空间位置参数(溪流级别、流量量级和下游量级);影响鱼类个体数和重量的均仅有局域栖息地参数中的底质因素.本研究结果可为淠河流域鱼类的保护和管理提供重要的基础资料. 相似文献
3.
为了加强长江中游地区大型无脊椎底栖动物的研究工作,2009年3月至2010年3月,对长江中游巴河支流的胜利河毛翅目优势种的生产力和营养基础进行了为期一年的调查研究.结果表明,胜利河中主要毛翅目优势种纹石蛾的生活史为一年3代.一至四级河流中,其生物量周年平均值分别为1.77、7.80、44.82、51.55 mg/m2.采用体长频率法测算的年均生产量为7.72 mg/m2,P/B系数为13.21.利用肠内含物分析法研究了胜利河中纹石蛾的营养结构.比较一至四级河流的营养基础发现,无形态碎屑为纹石蛾最常见的食物,占肠内含物的45.22%~62.92%;而对生产量贡献率最高的多是动物组织,达52.86%~68.58%.各季节的营养基础状况也有差异,春季无形态碎屑所占比例和对生产量的贡献率较高,而夏、秋和冬季动物组织则有更高的生产量贡献率.一至四级河流的年均物质通量分别为11.83、34.76、237.52和273.17g/(m2·a).由此可见,该优势种在河流生态系统中发挥着重要作用. 相似文献
4.
鄱阳湖流域饶河鱼类稳定同位素比值和营养级的空间变化 总被引：2，自引：2，他引：0
由于水文特征的变化和栖息生境的异质性,河流食物网结构存在着一定的空间变化.认识人类活动对河流食物网结构空间变化的影响能够为河流生态系统的科学管理提供有效指导.利用稳定同位素分析技术,测定枯水季节饶河不同地区初级生产者和鱼类的碳、氮稳定同位素比值(δ13C和δ15N),比较饶河下游鄱阳和中游海口河段4种常见鱼类的δ13C、δ15N值和营养级,并分析导致不同河段食物网结构差异的原因.结果表明,鄱阳与海口两个地区鱼类的δ13C值无显著差异,但δ15N值差异显著.鱼类的δ13C值变化范围在鄱阳河段大于海口河段,鳜(Siniperca chuatsi)和贝氏(Hemiculter bleekeri)在鄱阳河段的δ15N值要显著高于海口河段,而黄颡鱼(Pelteobagrus fulvidraco)和鲫(Carassius auratus)的δ15N值在鄱阳河段却表现更低.另一方面,除黄颡鱼外,鳜、贝氏和鲫在鄱阳河段的营养级均显著高于其在海口河段的营养级.研究认为,由于颗粒有机物和附着藻类的δ13C值在鄱阳与海口河段没有显著差异,因而导致鱼类的δ13C值也没有明显变化.不同生境下初级食物源δ15N值的差异及人为扰动的程度可能是影响饶河不同河段鱼类的δ15N值存在明显差异的主要原因. 相似文献
5.
运用稳定性同位素分析技术研究红鳍原鲌δ13C和δ15N值变化规律,进一步探讨贡湖湾、鲤山湾和东太湖3个典型水域的红鳍原鲌食性差异.结果显示,红鳍原鲌的δ13C值与体长、δ15N值与体长呈显著正相关关系,大个体的红鳍原鲌(体长138 mm)δ13C值和营养级显著高于小个体红鳍原鲌(体长138 mm),表明红鳍原鲌在生长过程中随着口裂的增大和捕食能力的加强发生了食性转变现象:食物来源由小型浮游动物向鱼类转变.红鳍原鲌的δ13C在3个水域中具有明显的空间异质性,东太湖(-25.17‰±2.56‰)作为养殖活动影响区均显著低于贡湖湾(-23.11‰±1.05‰)和鲤山湾(-22.73‰±1.31‰),而且个体普遍偏小,说明红鳍原鲌种群分布可能存在一定的区域性,会根据栖息环境选择食物来源.红鳍原鲌在高浓度蓝藻的环境下,偏向摄食较大个体的动物性饵料,减轻对浮游动物的摄食压力,间接控制水体富营养化的发展.另外,还讨论了红鳍原鲌对生态系统的影响,为其资源保护和合理配置利用提供理论依据. 相似文献
6.
基于ABAQUS显式有限元并行计算平台,采用大尺度二维精细化有限元非线性分析方法,研究泉州盆地地震效应特征.结果表明:(1)与基岩输入地震动相比,地表峰值加速度总体呈放大效应,且盆地不同位置的放大效应存在明显差异;(2)地表或基岩剧烈起伏及土层横向分布极不均匀处,地震动易产生局部聚集效应,相应地表地震动呈显著放大或缩小效应;地表加速度反应谱产生双峰甚至多峰现象.(3)在土层竖向、横向分布不均匀处,峰值加速度沿深度方向呈非单调递减,加速度反应谱沿深度存在较大差异.场地地震效应的二维非线性分析法能在一定程度上反映特殊场地条件对地震动效应的影响,该结果可为泉州盆地及类似盆地的场地设计地震动参数的确定提供参考依据. 相似文献
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黄浩 《中国科学:地球科学》2011,(10):1416-1423
为使[蜓]类形态种更接近客观真实的生物种,在[蜓]类化石鉴定中应从居群概念出发,利用居群的形态变异特征约束传统的形态鉴定.根据滇西小新寨剖面中二叠世沙子坡组单层采集的样品,笔者度量了其中Eopolydiexodina个体的特征形态参数（初房直径、内外圈尺寸与轴率）,并进一步结合形态统计学方法进行了化石居群层次的形态种鉴定.研究结果表明,该单层中Eopolydiexodina个体的特征形态参数虽表现出较大范围的变异,但形态变异基本连续且满足正态分布.因此,所研究个体的形态变异符合单个居群的形态变异特征,宜根据居群思想视作同一[蜓]种.本文的研究结果支持了同层产出的同属[蜓]类个体组成单个化石居群的假设. 相似文献
9.
将一种晚中新世小型猪科动物弓颌猪的头骨及下颌特征与现生猪科及西猯科材料进行对比,并对其进行形态功能分析.尽管相对窄的枕部以及相对短的头骨制约了头骨的摆动幅度,但发育吻骨和相对较强的吻部肌肉仍然使得弓颌猪具有很可观的拱掘能力.显著宽的前颧弓板以及强壮的犬齿弧形围龛在拱掘时对头骨及犬齿起保护作用.强烈会聚的顶嵴和强壮的面嵴表明弓颌猪发育强壮的咀嚼肌,这使得其可以迅速闭合口部,并使得下颌纵向及侧向的运动能力都很强.弓颌猪的头-颌关节形态及其相对较高的位置表明在咀嚼时既有压碎作用又有研磨作用.弓颌猪的颊齿冠面特征简单,表明其食物可能较现生猪科的食物柔软.推测弓颌猪的饮食结构可能介于森林型和开阔环境的现生猪科动物之间,生境可能为相对潮湿的森林边缘或靠近开阔的温带草原环境. 相似文献
10.
鲚属两种群的形态变异及综合判别 总被引：10，自引：3，他引：10
测量了代表刀鲚种群和湖鲚种群形态特征的传统可量性状和框架参数,采用主成分分析法和逐步判别法,对它们进行形态综合分析.结果表明:两种群的形态差异主要是受额部有鳞部最前缘到背鳍起点的距离所影响的;所有25个形态参数数据判别分析,表明两种群形态差异极显著(P<0.01),判别准确率100％;利用挑选后的9项参数判别分析,表明两种群的形态差异极显著(P<0.01),判别准确率P1是95％-100%,P2是95.2％-100％,综合判别率为97.5％.对各形态参数进行单因子方差分析,计算各参数的差异系数,根据Mayr提出的75％规则,认为它们的形态差异仍然是种内不同地理种群的差异,还没有上升到亚种水平. 相似文献
11.
Persaud A. D. Dillon P. J. Molot L. A. Hargan K. E. 《Aquatic Sciences - Research Across Boundaries》2012,74(1):203-212
Animal body size is a driving force behind trophic interactions within biological communities, yet few studies have explored
relationships between body size and trophic position (based on δ15N) at a broad-scale in freshwater lakes. Therefore, our goals were to (1) determine whether body size is a good predictor
of trophic position for multiple pelagic zooplankton taxa and fish communities, and (2) examine how body size-trophic position
relationships at the community level compare to species level for fish. Zooplankton and fish were collected from 12 and 7
lakes, respectively, located in the Kawarthas, southern Ontario, Canada. The results indicated that for zooplankton, significant
positive but different relationships were found between body size and trophic position for cladocerans, in general, and Daphnia, but not Holopedium. For fish, at the lake community level six out of seven relationships were positive and significant, but again, different
among lakes. In contrast, at the species level only three of eight species-specific relationships were significant. Furthermore,
for two widespread species, Perca flavescens and Micropterus dolomieu, significant differences were found between community- and lake-specific species relationships. Our community-level models
and most species-level models provide evidence that trophic interactions in freshwater lakes are size-based. These results
demonstrate that general species models should be applied with caution when using body size to predict trophic position. Additionally,
the predictive power of some relationships found here is questionable since, albeit significant, their strengths are generally
low. Together, our results suggest that body size may have limited use in predicting trophic position of some biota in temperate
freshwater lakes. 相似文献
12.
《中国科学:地球科学(英文版)》2015,(7)
Fossil cyprinids from the upper part of the upper Eocene Youganwo Formation of Maoming, Guangdong, China were first studied in 1957 by Liu, who referred the only specimen to the genus Cyprinus as a new species, C. maomingensis. And this was suggested as one of the earliest records for fossil cyprinids. Unfortunately, this specimen is poorly preserved and reveals no more morphological information than its serrated last unbranched dorsal and anal fin rays. Recently, some new specimens were unearthed from the same locality, where C. maomingensis was discovered. In addition to the serrated dorsal and anal fin rays, these new materials also show that the pattern and shape of their pharyngeal teeth obviously differ from that of Cyprinus but resemble that of Procypris. However, its number of the branched dorsal fin rays and number of vertebrae are much less than that in Procypris. Morphologically, these specimens are closer to Procypris than to Cyprinus. This is the first report of fossil Procypris-like fish, and it implies that Procypris-like fish is an early member of the Tribe Cyprinini sensu stricto(sensu Yang et al., 2010) and the origin of this group can be traced back at least to the late Eocene. 相似文献
13.
Douglas H. Adams 《Marine pollution bulletin》2010,60(1):148-151
Wahoo, Acanthocybium solandri, are predatory oceanic fish that occur and are harvested in all tropical and subtropical oceans. Total mercury concentrations analyzed in dorsal muscle tissue of 208 wahoo from offshore waters of the southeastern United States and the Bahamas ranged from 0.021 to 3.4 mg/kg (wet weight), with a mean of 0.50 mg/kg (± 0.595 SD). Analyses indicated significant positive linear relationships between mercury and length, as well as, age of wahoo. The piscivorous nature, generally high trophic position, fast growth rate, and associated high metabolism of wahoo within tropical offshore pelagic environments may lead to comparatively higher concentrations of mercury over relatively short time periods. Mercury in wahoo, a highly mobile species consisting of one world-wide population, is regionally influenced by large-scale spatial differences in available mercury in selected prey fish species - many of which have been found to contain relatively high concentrations of mercury. 相似文献
14.
为了解向家坝水电工程对金沙江下游鱼类多样性的影响,基于2016—2018年邵女坪(库首)、绥江(库中)和桧溪(库尾)3个江段的鱼类群落调查数据,分析了向家坝库区鱼类物种、分类和功能多样性空间格局,结合蓄水前(2011年)和蓄水初期(2015年)的资料,探讨了蓄水后向家坝库区不同维度鱼类多样性的变化趋势。向家坝库区各江段以广适性的瓦氏黄颡鱼(Pelteobagrus vachelli)和静水性的(Hemiculter leucisculus)占优势,两者的数量百分比分别为30.15%±14.82%和13.91%±11.16%。非度量多维尺度分析显示,蓄水后向家坝库区库首邵女坪和库中绥江鱼类群落差异最小,库首邵女坪和库尾桧溪鱼类群落差异最大;库中绥江在蓄水前、蓄水初期和2016—2018年3个时期的鱼类群落差异均较大,表明蓄水后绥江江段鱼类群落经历了剧烈变化。库区不同江段鱼类Margalef丰富度指数、Shannon-Wiener多样性指数和Pielou均匀度指数均表现为:桧溪>邵女坪>绥江,鱼类分类多样性指数和分类差异指数均表现为:桧溪>绥江>邵女坪。库区鱼类摄食、运动和繁殖等不同维度的功能多样性(功能丰富度、功能均匀度、功能离散度)空间格局不同,但总体上库中绥江鱼类功能丰富度最高,功能均匀度最低。与蓄水前相比,绥江江段鱼类物种、分类多样性呈下降趋势,鱼类功能丰富度和均匀度也有下降趋势。蓄水后绥江江段鱼类群落主要功能性状发生了明显变化,如蓄水前以下位口、纺锤形体型鱼类占优势,蓄水后以端位口、侧扁形体型鱼类占优势。不同维度多样性指数侧重于鱼类多样性的不同方面,结合多种指数分析有利于更全面地了解鱼类群落对环境变化和外界干扰的响应。研究结果有助于深入了解水电工程建设对金沙江下游鱼类多样性的影响,为鱼类多样性保护提供依据,也可为长江“十年禁渔”效果评估提供本底资料。 相似文献
15.
《Limnologica》2021
Studies on the anatomy of sulcus and outline morphometrics of the three population groups of Trichogaster lalia were carried out to examine the effects of anthropogenic stressors (dams and barrages) on the function-related morphological variability of the fish. Altogether 150 samples of the fish were procured from three geographically isolated rivers namely Ganga, Gomti and Yamuna. The features based on images and morphological indices of sulcus, otolith and body shape of the fish were analysed and compared using uni and multivariate statistical procedures. Rostrum, anti-rostrum and margins of sagittal otolith and cauda of sulcus predominantly varied among three population groups of the fish. Variations in geometric morphometrics of sulcus, otolith-outline, combination of both and body shape indicated the existence of three distinct groups of the fish where individuals of river Gomti and Ganga were found to be closer to each other compared to that of river Yamuna. Mantel test showed an overall good correlation between the morphometric data-sets based on otolith and body shape in delineating three groups of the fish. Understanding of the environmental factors influencing the variations in function-related morphology of the different groups of T. lalia is essential to identify the boundaries of the different groups of the fish and to implement the appropriate strategies for their conservation. 相似文献
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Glyphosate is globally a widely used herbicide, yet there is little information on their toxicity to marine fishes. Java medaka, a small tropical fish native to coastal areas in several Southeast Asian countries, is viewed as a suitable candidate for toxicity test and thus was used for this study. Java medaka adults were cultured in the laboratory and the fertilized eggs of the F2 generation were exposed to different concentrations of glyphosate-based herbicide (100, 200, 300, 400 and 500 ppm) until they hatched. The survival and hatching rates of the embryos, changes in the heart rate and morphological impairments were recorded. Generally, survival and hatching percentage decreased as glyphosate concentration increased. Absence of pectoral fin(s) and cornea, permanently bent tail, irregular shaped abdomen, and cell disruption in the fin, head and abdomen are among the common teratogenic effects observed. Furthermore, risk factor also increased with the increased in glyphosate concentrations. 相似文献
18.
CHANG Mee-mann 《中国科学D辑(英文版)》2009,52(2):189-202
A new Eocene catostomid genus and species, Plesiomyxocyprinus arratiae, is described from Huadian, Jilin Province, northeastern China. The materials include a nearly complete skeleton, dozens
of pharyngeal bones with teeth, and a number of disarticulated bones. The new articulated specimen is large-sized and deep-bodied,
with an estimated standard length of ca. 300 mm and body depth of 156 mm or about half of its standard length. The assignment
of the fish to the Catostomidae is based on its falciform pharyngeal bone with one row of numerous (more than 50) compressed
teeth, and the bone is much smaller than in cyprinids, especially given the size of the fish. The new fish distinguishes itself
from all known catostomids (both extinct and extant) in its long anal fin with four unbranched and 17–18 branched rays, and
its extremely short caudal peduncle that is only about one fourth of its depth. Plesiomyxocyprinus arratiae resembles the Eocene-Oligocene transpacific-distributed Amyzon in many general skeletal characters. However, it shows a few characters uniquely shared with the Recent catostomid Myxocyprinus asiaticus. Those include a very long dorsal fin with about 50 branched fin rays, the end of dorsal fin rays being close to the caudal
fin base, and anal rays stretching posteriorly beyond the base of caudal fin. It is the first fossil catostomid that shows
a close relationship to the endemic Myxocyprinus now living in the Yangtze River and Minjiang River, China. The discovery of Plesiomyxocyprinus arratiae, along with two previously described possible catostomid genera Jianghanichthys and Vasnetzovia, may indicate that the divergence of the Catostomidae started much earlier, in the middle Eocene or earlier, on the western
side of the Pacific than on its eastern side.
Supported by National Natural Science Foundation of China (Grant No. 40432003, J0630965), Cypriniformes Tree of Life under
the U.S. National Science Foundation to R. Mayden (Grant No. EF0431326), and Ecocarp Project (European Commission, INCO-DEV
Programme) (Grant No. ICA4-CT-2001- 10024) 相似文献
19.
《Limnologica》2020
The removal of native forest affects stream characteristics, processes, and organisms at the local scale. We compared the structure of fish assemblages between microbasins impacted by deforestation and those in pristine condition in the Amazonian Machado River basin, Brazil. Fish were collected with seine and dip nets along an 80-m stretch of 28 streams. At each site, we recorded physical, chemical, and land-water ecotone variables. We collected 6,586 specimens of 109 species, being 39 and 18 of them exclusively of forested and deforested streams, respectively. Non-significant differences were found for abundance and species richness between forested and deforested streams. A total of four main trophic groups were identified. Carnivores were more abundant in forested streams, whereas herbivores, omnivores and detritivores species were the most abundant in deforested streams. The deforested streams showed higher abundance and richness of algae and periphyton consumers, while forested streams presented higher abundance and richness of invertebrate consumers. Forested streams presented longer foodchains, higher occurrence and abundance of species that have more specialized habits and are intolerant to degraded environments, whereas generalist and tolerant species predominated in deforested streams. We conclude that species composition in Amazonian streams predictably responds to the degree of forest cover. 相似文献
20.
Jari Syväranta Pia Högmander Tapio Keskinen Juha Karjalainen Roger I. Jones 《Aquatic Sciences - Research Across Boundaries》2011,73(1):79-89
We used carbon and nitrogen stable isotope analyses to assess the relative contributions from pelagic and littoral energy sources to higher trophic levels in a lake ecosystem before and after a major food web perturbation. The food web structure of the lake was altered when the population sizes of the most abundant fish species (small perch, roach and bream) were reduced during an attempt to improve water quality by biomanipulation. Fish removal was followed by dense year classes of young fish, which subsequently increased the utilisation of pelagic resources. This was reflected as a decrease in relative energy contribution from littoral sources and also led to more distinct pelagic and littoral food chains after fish removal. Community metrics calculated from stable isotope data indicated increased trophic diversity and occupied niche area, and reduced trophic redundancy in the food web. However, only minor changes were observed in fish trophic positions, although roach and pike occupied slightly lower trophic positions after fish removal. Despite the Jyväsjärvi ecosystem becoming more dependent on pelagic energy after fish removals, the littoral energy contribution was still substantial, particularly to certain fish species. Hence, our results support recent arguments for the importance of benthic production in lake ecosystems. More generally, our results illustrate how large-scale perturbations of food web structure can alter energy flow patterns through an entire ecosystem. 相似文献