稳定同位素技术在土壤跳虫研究上的应用

稳定同位素技术的发展和应用是20世纪90年代生态学研究方法最重要的进步之一.许多生态学过程都伴随着同位素比率的变化,根据这些变化可以追踪生态系统的物质循环和能量流动.近年来,许多学者把稳定同位素技术引入到土壤生态学,主要用于研究土壤碳循环和土壤生物之间的营养关系,在很大程度上提升了对地下生态系统的理解.跳虫作为土壤动物群落的重要组分,它的食性和营养位置一直存在着许多不确定性.稳定同位素技术的应用,为确定跳虫的食物来源、营养位置和营养关系提供了一个强大的工具.本文综述了稳定同位素技术在跳虫食性和营养级研究上的应用,并指出了不足之处以及今后的发展方向.     

稳定同位素分析在鸟类生态学中的应用

稳定同位素作为一种自然标记物是研究鸟类生态学的重要工具之一,与传统研究方法相比其呈现的信息更为真实全面,是一种日趋成熟的鸟类生态学研究方法。近几年该方法在鸟类迁徙生态学、取食生态学等方面取得较大成就,展现出传统研究方法无可比拟的优越性。但目前该方法在我国鸟类生态学上的应用较少,基于此,从迁徙、取食等方面分别阐述稳定同位素在鸟类生态学上的应用,以促进我国鸟类生态学的快速发展和推动稳定同位素生态学与其它学科的交叉融合。     

稳定性同位素技术在生态学上的应用

稳定性同位素技术早在20世纪70年代末期就被引入到生态学领域。最初是利用植物稳定性碳同位素的差异。开展了许多有关营养流动方面的研究;到90年代,稳定性碳和氮同位素被用来分析动物的食性、营养级位置关系以及食物链结构;本世纪初,由于技术的进步,稳定性同位素(特别是氢同位素)被用来开展动物迁徙习性方面的研究。到目前为止,国内有关这方面的研究还鲜有报道,而且对自然界存在的稳定性同位素的理解还存在一定偏差。本文主要介绍了稳定性同位素效应及其分馏原理、稳定性同位素在示踪动物食性信息、确定营养级位置关系、分析食物网结构以及研究动物迁徙生态学中的作用等方面的内容。     

基于稳定同位素的湿地食物源判定和食物网构建研究进展

湿地生物营养动力学是湿地生态系统结构和功能评价研究的基础.碳、氮稳定同位素作为识别营养关系的方法,已在湿地生态系统食物来源、组成和食物链传递研究中得到广泛运用.本文系统综述了稳定同位素食物贡献度计算模型和营养级确定的基本方法和理论;讨论了动物营养分馏值和基线的选择依据;概括了湿地生态系统典型食物源及其稳定同位素变化特征;总结了草食、杂食和肉食等不同营养级动物的食物来源.指出了稳定同位素在湿地食物源溯源和食物网研究中的不足;基于国内外研究现状和发展趋势及需求,展望了未来同位素技术在湿地食物网生态学研究中的运用前景和研究重点,提出需要加强稳定同位素营养分馏和基线的影响因素、样品处理和保存方式研究以及胃含物、分子标记物和多元素同位素结合分析.     

基于碳、氮稳定同位素技术的东太湖水生食物网结构

稳定同位素技术是研究生态系统食物网中物质循环与能量流动的有效技术之一。碳稳定同位素比值(δ13C)常用来分析消费者食物来源,而氮稳定同位素比值(δ15N)常用来确定生物在食物网中的营养位置。本研究应用碳、氮稳定同位素技术构建了东太湖食物网结构。结果表明:东太湖食物网主要由两条营养传递途径组成,即浮游植物为初级生产者的浮游营养传递途径和苦草等大型水生植物为初级生产者的近岸底层营养传递途径,湖中9种主要鱼虾类能量主要来自近岸底层传递;翘嘴鲌(Erythroculter ilishaeformis)、鳜(Siniperca chuatsi)和鲶(Silurus sp.)作为湖泊中的顶极捕食者,具有相对最高的营养级,并占据食物网的顶层。     

鸟类组织中稳定同位素周转率研究现状

稳定同位素分析技术被广泛应用于鸟类生态学多个方面的研究,如鸟类迁徙、营养级关系、生活史、食性等。根据不同的研究目的和要求,选择目标周期相对应的组织进行研究。在此前提下,掌握不同组织稳定同位素的周转率就显得尤为重要。目前国内有关鸟类组织稳定同位素周转率及其差异的研究较为有限,本文对国际上研究周转率的常见假说、方法和影响周转率的因素进行综述,旨在抛砖引玉,为利用稳定同位素技术开展鸟类学方面的研究提供依据。     

稳定同位素技术在水域生态系统研究中的应用

稳定同位素作为一种天然的示踪物,应用十分广泛,其在水域生态学中的应用也日益受到重视。生物同位素组成总是与其食物同位素组成相一致,能随食物的改变而相应地发生改变,是生物生存状况的理想指示物,为水域生态系统食物网结构与功能、物质流与能量流的研究提供了有力的技术支撑。在综评稳定同位素技术原理与方法的基础上,较为详细地对其应用于水域生态研究的理论基础与进展进行了总结。该方法的应用以水域中生产者同位素组成差异为前提,主要涉及确定食物来源、食物的贡献比例、营养级的确定、食物网结构的构建及鱼类等水生生物的洄游及迁移路线等方面,这些研究对了解生态系统的动态变化与外界环境对其影响具有重要意义。并对我国此类研究的前景和存在问题进行了探讨。     

应用稳定同位素技术构建胶州湾食物网的连续营养谱

根据2011年春季和秋季在胶州湾进行的渔业资源综合调查,应用稳定同位素示踪技术,分析了胶州湾主要渔业生物的碳、氮稳定同位素比值(δ13C,δ15N),并计算其营养级,进而构建胶州湾食物网的连续营养谱。分析的生物种类包括浮游植物、浮游动物、大型无脊椎动物和鱼类,其生物量之和占总渔获量的95%。结果表明,胶州湾食物网的δ13C值范围是-25.63‰—-17.16‰,跨度为8.47‰,平均值为(-19.42±1.80)‰;δ15N值范围是4.15‰—14.11‰,跨度为9.96‰,平均值为(11.98±1.77)‰。胶州湾食物网中的主要生物种类可以划分为4个营养组群,即初级生产者、初级消费者、次级消费者以及顶级捕食者。δ15N值分析显示,胶州湾主要生物种类的营养级范围是1.10—4.03。与文献中基于胃含物分析计算的营养级相比较,37个种类中有29种的营养级分析结果基本一致(在0.5个营养级的误差范围之内)。因此,氮稳定同位素法是一种研究水生生态系统食物网营养位置的有效方法。其中,有8种鱼类的营养级与历史文献相比有所下降,分析方法的不同可能是原因之一,此外,这些鱼种摄食饵料生物营养级的下降也是导致其营养级降低的另一个主要原因。根据营养级计算的结果,构建了胶州湾食物网的连续营养谱,胶州湾食物网中,绝大多数生物种类都属于初级和中级肉食性种类。     

饶河枯水期主要鱼类营养级位置及其影响因素

稳定同位素技术已经越来越多地被用来研究淡水生态系统的结构与功能。利用氮稳定同位素技术测定了枯水季节饶河鱼类等消费者的营养级位置,比较上、中、下游及入湖口鱼类营养级的空间差异,并分析了影响饶河鱼类营养级位置的主要因素。研究结果表明,饶河鱼类的δ15N值范围为4.7‰—15.6‰,大部分鱼类的δ15N值集中在10‰—14‰之间,其中鄱阳湖间下鱵的δ15N值最大,为(15.6±1.6)‰;乔木湾鲫的δ15N值最小值,为(4.7±0.9)‰。根据δ15N值计算可知,饶河鱼类占有3—4个营养等级。75%的鱼类种类所占的营养级大于3,而营养级小于2的鱼类种类不到10%,可能与枯水期鱼类活动范围受限,种间捕食作用增强,肉食性或饥饿现象增加有关。另外,饶河鱼类的营养级也存在着空间差异,表现为鄱阳湖湖区和入湖口处的鱼类营养级比上、中、下游的鱼类营养级要大。该结果与颗粒有机物POM的δ15N值呈现一致的变化,反映了饶河鱼类的营养级位置主要受到食物来源的影响,与鱼类的个体大小无明显相关。     

冶金区节肢动物碳、氮稳定同位素组成及营养级关系

通过测定辽宁省葫芦岛锌厂不同生境植物和主要消费者的碳、氮稳定同位素比值,研究冶金区不同消费者碳、氮稳定同位素组成及不同消费者之间的关系.结果表明:节肢动物δ13C、δ15N值的变化范围分别为-12.61‰～-29.63‰、1.73‰～9.94‰,变化幅度较大.研究区植物以C3植物居多,导致不同群落生境动物δ13C值较低;螳螂、蜘蛛δ15N比值高于其他动物;通过营养级模型计算可知不同消费者之间的关系,蝗虫、蚱蜢等草食性动物形成第二营养级,即初级消费者;第三营养级包括蜘蛛、螳螂,为次级消费者.     

Stable isotope ecology in insects: a review

1. The use of stable isotope analysis (SIA) in ecological research has dramatically increased in recent years largely because it allows researchers to investigate ecological questions that have been previously difficult to address. 2. Ecological applications of SIA include estimating fundamental niche space and overlap, evaluating trophic or species level interactions, and investigating food web structure. Increasingly, researchers have been incorporating SIA in studies of animal migration, disease transmission, diet composition, nutrient assimilation, and body condition among others. 3. Studies using SIA to evaluate the ecology of terrestrial insects have lagged behind other taxonomic groups. This poor representation of stable isotope studies in publications likely stems from a lack of familiarity of entomologists with this technique. 4. An improved understanding of SIA, as well as the advantages and disadvantages specifically related to insect research, will benefit the field of entomology. In addition, insect-model systems provide unique opportunities for entomologists to incorporate SIA in their research to advance our knowledge of insect biology and the stable isotope ecology of insects. 5. We provide background information on stable isotopes, explain sources of isotopic variation, describe the processes of how isotopes are differentially routed and incorporated into an individual's tissues, explain the principles that influence isotopic fractionation and discrimination, highlight different methods and advancements in SIA, review innovative stable isotope studies, and provide an overview of common mistakes, considerations, and future directions entomologists can explore.     

Effects of food quality on tissue-specific isotope ratios in the mussel <Emphasis Type="Italic">Perna perna</Emphasis>

Investigations into trophic ecology and aquatic food web resolution are increasingly accomplished through stable isotope analysis. The incorporation of dietary and metabolic changes over time results in variations in isotope signatures and turnover rates of producers and consumers at tissue, individual, population and species levels. Consequently, the elucidation of trophic relationships in aquatic systems depends on establishing standard isotope values and tissue turnover rates for the level in question. This study investigated the effect of diet and food quality on isotopic signatures of four mussel tissues: adductor muscle, gonad, gill and mantle tissue from the brown mussel Perna perna. In the laboratory, mussels were fed one of the two isotopically distinct diets for 3 months. Although not all results were significant, overall δ¹³C ratios in adductor, mantle and gill tissues gradually approached food source signatures in both diets. PERMANOVA analyses revealed significant changes over time in tissue δ¹³C (mantle and gill) with both diets and in δ¹⁵N (all tissues) and C:N ratios (mantle and gill) for one diet only. The percentage of replaced carbon isotopes were calculated for the 3 month period and differed among tissues and between diets. The tissue with the highest and lowest amount of replaced isotopes over 81 days were mantle tissue on the kelp diet (33.89%) and adductor tissue on the fish food diet (4.14%), respectively. Percentages could not be calculated for any tissue in either diet for δ¹⁵N due to the lack of significant change in tissue nitrogen. Fractionation patterns in tissues for both diets can be linked to nutritional stress, suggesting that consumer isotopic signatures are strongly dependent on food quality, which can significantly affect the degree of isotopic enrichment within a trophic level.     

稳定同位素技术在鲨鱼摄食和洄游行为研究中的应用

随着稳定同位素分析技术的不断成熟,其在生态学领域中的应用也增长迅速,并成为动物摄食生态学的重要研究工具.鲨鱼因其在生物系统进化过程中的独特地位和海洋生态系统中的重要作用已成为海洋食物网研究的重点,然而国内针对鲨鱼摄食习性和洄游行为等方面的研究仍处于起步阶段.本文在总结了国内外鲨鱼稳定同位素分析组织样品选取和样品预处理方法的基础上,系统归纳了稳定同位素技术在鲨鱼摄食生态学,尤其在其摄食和洄游行为研究领域中的应用,着重分析稳定同位素技术在鲨鱼稳定同位素判别值和更新速率、食性分析、营养级评估、洄游路径分析和生态位分布等核心问题上的应用现状和发展前景,以期为国内学者开展鲨鱼类基础生物、生态学研究提供有益参考.     

Determining trophic niche width: an experimental test of the stable isotope approach

Determining the trophic niche width of an animal population and the relative degree to which a generalist population consists of dietary specialists are long‐standing problems of ecology. It has been proposed that the variance of stable isotope values in consumer tissues could be used to quantify trophic niche width of consumer populations. However, this promising idea has not yet been rigorously tested. By conducting controlled laboratory experiments using model consumer populations (Daphnia sp., Crustacea) with controlled diets, we investigated the effect of individual‐ and population‐level specialisation and generalism on consumer δ¹³C mean and variance values. While our experimental data follow general expectations, we extend current qualitative models to quantitative predictions of the dependence of isotopic variance on dietary correlation time, a measure for the typical time over which a consumer changes its diet. This quantitative approach allows us to pinpoint possible procedural pitfalls and critical sources of measurement uncertainty. Our results show that the stable isotope approach represents a powerful method for estimating trophic niche widths, especially when taking the quantitative concept of dietary correlation time into account.     

Use of compound-specific nitrogen isotope analysis of amino acids in trophic ecology: assumptions,applications, and implications

Knowledge of the diet source and trophic position of organisms is fundamental in food web science. Since the 1980s, stable isotopes of light elements such as ¹³C and ¹⁵N have provided unique information on the food web structure in a variety of ecosystems. More recently, novel isotope tools such as stable isotopes of heavy elements, radioisotopes, and compound-specific isotope analysis, have been examined by researchers. Here I reviewed the use of compound-specific nitrogen isotope analysis of amino acids (CSIA-AA) as a useful dietary tracer in food web ecology. Its three key features—(1) offsetting against isotopic variation; (2) universality of the trophic discrimination factor; and (3) sensitivity to source mixing—were compared with conventional isotope analysis for the bulk tissue of organisms. These three advantages of CSIA-AA will allow future researchers to (1) estimate the integrated trophic position (iTP) of animal communities; (2) infer trophic transfer efficiency (TTE) in food webs; and (3) quantify contributions from different resources to animals, all of which are crucial for understanding the relationship between biodiversity and multi-trophic ecosystem functioning. Further development of trophic ecology will be facilitated by both methodological refinement of CSIA-AA and its application to a wider range of organisms, food webs, and ecosystems.     

Multi-Scale Effects of Nestling Diet on Breeding Performance in a Terrestrial Top Predator Inferred from Stable Isotope Analysis

Inter-individual diet variation within populations is likely to have important ecological and evolutionary implications. The diet-fitness relationships at the individual level and the emerging population processes are, however, poorly understood for most avian predators inhabiting complex terrestrial ecosystems. In this study, we use an isotopic approach to assess the trophic ecology of nestlings in a long-lived raptor, the Bonelli’s eagle Aquila fasciata, and investigate whether nestling dietary breath and main prey consumption can affect the species’ reproductive performance at two spatial scales: territories within populations and populations over a large geographic area. At the territory level, those breeding pairs whose nestlings consumed similar diets to the overall population (i.e. moderate consumption of preferred prey, but complemented by alternative prey categories) or those disproportionally consuming preferred prey were more likely to fledge two chicks. An increase in the diet diversity, however, related negatively with productivity. The age and replacements of breeding pair members had also an influence on productivity, with more fledglings associated to adult pairs with few replacements, as expected in long-lived species. At the population level, mean productivity was higher in those population-years with lower dietary breadth and higher diet similarity among territories, which was related to an overall higher consumption of preferred prey. Thus, we revealed a correspondence in diet-fitness relationships at two spatial scales: territories and populations. We suggest that stable isotope analyses may be a powerful tool to monitor the diet of terrestrial avian predators on large spatio-temporal scales, which could serve to detect potential changes in the availability of those prey on which predators depend for breeding. We encourage ecologists and evolutionary and conservation biologists concerned with the multi-scale fitness consequences of inter-individual variation in resource use to employ similar stable isotope-based approaches, which can be successfully applied to complex ecosystems such as the Mediterranean.     

Quantifying Inter- and Intra-Population Niche Variability Using Hierarchical Bayesian Stable Isotope Mixing Models

Variability in resource use defines the width of a trophic niche occupied by a population. Intra-population variability in resource use may occur across hierarchical levels of population structure from individuals to subpopulations. Understanding how levels of population organization contribute to population niche width is critical to ecology and evolution. Here we describe a hierarchical stable isotope mixing model that can simultaneously estimate both the prey composition of a consumer diet and the diet variability among individuals and across levels of population organization. By explicitly estimating variance components for multiple scales, the model can deconstruct the niche width of a consumer population into relevant levels of population structure. We apply this new approach to stable isotope data from a population of gray wolves from coastal British Columbia, and show support for extensive intra-population niche variability among individuals, social groups, and geographically isolated subpopulations. The analytic method we describe improves mixing models by accounting for diet variability, and improves isotope niche width analysis by quantitatively assessing the contribution of levels of organization to the niche width of a population.     

Combining stable isotope analysis and conventional techniques to improve knowledge of the diet of the European Roller Coracias garrulus

Diet studies are crucial for understanding the ecology and evolution of species, as well as for establishing appropriate conservation and management strategies. However, they remain methodologically challenging due to variation between seasons, sites, sexes or age groups and even variation between individuals. Due to method‐specific characteristics and biases, a combination of existing techniques can overcome the inherent limitations of each technique and provide a more accurate and broad picture of species’ food preferences. Here, we examine diet information obtained using three different assessment methods to better understand the trophic ecology of the European Roller Coracias garrulus, a species targeted by conservation measures in Europe. First, we analysed regurgitated pellets and video‐recordings to report the diet composition of adult and nestling Rollers, respectively. Secondly, we used stable isotope analysis (SIA) to investigate adult sexual diet segregation as well as to confirm the main findings regarding adult and nestling diets obtained through conventional methods. Based on the analysis of pellets, the diet of adult Rollers was dominated by Coleoptera, whereas camera images revealed that the diet of nestlings was dominated by Orthoptera, mainly grasshoppers and bush crickets. Blood isotopic signatures of adult and nestling Rollers confirmed the results obtained through pellet and video‐recording techniques. Of the three methods, pellet analysis provided the most comprehensive trophic information regarding the detectable prey spectrum and prey species contribution, as well as basic diet information for the SIA. Our results also highlight the potential of SIA for assessing intraspecific variation in diet by sampling individuals of known age and sex, which is often unfeasible through conventional approaches. SIA analysis showed no differences in δ¹³C and δ¹⁵N ratios of blood between males and females and a high degree of overlap amongst isotopic niches, suggesting no sex‐specific partitioning in resource use. Overall, we showed that the combination of different methods could be used to gain new and clearer insights into avian trophic ecology that are essential for informing habitat management aiming to improve availability of foraging resources.     

鸟类组织稳定同位素分析样品的预处理方法

稳定同位素分析样品在进行同位素质谱分析之前需要适当的处理,然而如何处理尚未形成统一的标准。本文结合鸟类组织稳定同位素分析样品的测试流程,介绍了鸟类学研究领域稳定同位素技术应用中涉及的分析样品解冻清洗、干燥、分离纯化、研磨和储存等前处理方法,并对不同组织常用的处理方法及分析样品测定中有待解决的问题展开了讨论。旨在抛砖引玉,为利用稳定同位素技术开展鸟类学方面的研究提供科学参考和技术支持。