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1.
- Across environmental gradients, some functional strategies are favoured over others resulting in differences in local species composition and distribution of any given functional trait. This generates among‐Species Trait Variability (STV) across the gradient (reflecting species turnover), as well as spatial Intraspecific Trait Variability (ITV), which together contribute to Community Trait Variability (CTV). Understanding functional trait responses of freshwater biota is critical for elucidating the mechanisms that operate during community assembly and addressing community level responses to climate warming.
- In freshwater insects, temperature and ecological conditions regulate growth rates. Here, we examined size‐related trait variability components of short‐dispersing stoneflies (Insecta: Plecoptera) within and among multispecies stonefly assemblages (henceforth referred to as communities), located along an elevational gradient in Sierra Nevada (Spain) to assess the components of trait‐elevation matching (STV, ITV, CTV).
- Relative to downstream reaches, headwaters hypothetically show greater internal physical habitat heterogeneity (large exposed rocks, tree roots, woody debris) and greater local species richness of cool‐water adapted stoneflies. As a result, we expected CTV to increase with elevation, with a higher contribution of STV than ITV in upper reaches due to higher species richness and trait divergence among them. In contrast, the pattern of ITV should vary depending on whether the main driver across elevation is species richness (decrease due to niche partitioning) or ecological conditions (increase associated to physical habitat heterogeneity).
- Eleven streams were sampled every 2 weeks over 1 year and five size‐related traits were measured on 6,893 individuals belonging to 16 species. Overall, STV made a much larger contribution to CTV than ITV, which only became an important contributor in species‐poor assemblages, especially in winter and autumn. Within each season, the trait‐elevation matching was weak. Functional species‐specific responses to the elevational gradient most often did not mirror the response of the entire communities, since highly variable (and even opposed or discontinuous) contributions to ITV were found across species.
- Overall, ITV contributed little to trait‐elevation matching, which suggests high vulnerability of short‐dispersing stoneflies to habitat shifting associated to future climate warming due to limited phenotypic plasticity. Moreover, varying functional trait patterns across species emphasise species‐specific responses to climate change as opposed to a unique whole community response. However, further trait‐based macroecological studies across freshwater macroinvertebrates lineages are needed to compare patterns and establish generalisations.
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Microbes are critical components of ecosystems and provide vital services (e.g., photosynthesis, decomposition, nutrient recycling). From the diverse roles microbes play in natural ecosystems, high levels of functional diversity result. Quantifying this diversity is challenging, because it is weakly associated with morphological differentiation. In addition, the small size of microbes hinders morphological and behavioral measurements at the individual level, as well as interactions between individuals. Advances in microbial community genetics and genomics, flow cytometry and digital analysis of still images are promising approaches. They miss out, however, on a very important aspect of populations and communities: the behavior of individuals. Video analysis complements these methods by providing in addition to abundance and trait measurements, detailed behavioral information, capturing dynamic processes such as movement, and hence has the potential to describe the interactions between individuals. We introduce BEMOVI, a package using the R and ImageJ software, to extract abundance, morphology, and movement data for tens to thousands of individuals in a video. Through a set of functions BEMOVI identifies individuals present in a video, reconstructs their movement trajectories through space and time, and merges this information into a single database. BEMOVI is a modular set of functions, which can be customized to allow for peculiarities of the videos to be analyzed, in terms of organisms features (e.g., morphology or movement) and how they can be distinguished from the background. We illustrate the validity and accuracy of the method with an example on experimental multispecies communities of aquatic protists. We show high correspondence between manual and automatic counts and illustrate how simultaneous time series of abundance, morphology, and behavior are obtained from BEMOVI. We further demonstrate how the trait data can be used with machine learning to automatically classify individuals into species and that information on movement behavior improves the predictive ability. 相似文献
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Arthur Escalas Lauren Hale James W. Voordeckers Yunfeng Yang Mary K. Firestone Lisa Alvarez‐Cohen Jizhong Zhou 《Ecology and evolution》2019,9(20):12000-12016
Functional diversity is increasingly recognized by microbial ecologists as the essential link between biodiversity patterns and ecosystem functioning, determining the trophic relationships and interactions between microorganisms, their participation in biogeochemical cycles, and their responses to environmental changes. Consequently, its definition and quantification have practical and theoretical implications. In this opinion paper, we present a synthesis on the concept of microbial functional diversity from its definition to its application. Initially, we revisit to the original definition of functional diversity, highlighting two fundamental aspects, the ecological unit under study and the functional traits used to characterize it. Then, we discuss how the particularities of the microbial world disallow the direct application of the concepts and tools developed for macroorganisms. Next, we provide a synthesis of the literature on the types of ecological units and functional traits available in microbial functional ecology. We also provide a list of more than 400 traits covering a wide array of environmentally relevant functions. Lastly, we provide examples of the use of functional diversity in microbial systems based on the different units and traits discussed herein. It is our hope that this paper will stimulate discussions and help the growing field of microbial functional ecology to realize a potential that thus far has only been attained in macrobial ecology. 相似文献
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Trait‐based approaches may improve understanding in ecology by linking environmental variation to fitness‐related characteristics of species. Most trait–environment studies focus on assemblage‐level relationships; yet intraspecific trait variation is important for community, ecosystem, and evolutionary processes, and has substantial implications for these approaches. Assessing population‐level trait–environment relationships could test the generality of trait models whilst assessing intraspecific variation. We evaluated the generality of the trilateral life history model (TLHM opportunistic, periodic, and equilibrium endpoints) for fishes – a well‐studied trait–environment model at the assemblage level – to populations of three stream fishes in the Midwestern United States in relation to flow regime. The TLHM adequately described major trade‐offs in traits amongst populations in all species. Some TLHM flow‐based predictions were confirmed, with periodic traits (high fecundity) favoured at sites with greater flow seasonality and lower flow variability in two species, and equilibrium traits (large eggs) in more stable flow conditions in two species. Size at maturity was also inversely related to variability in one species. However, relationships contradicting the TLHM were also found. Coupled with the explanatory power of the TLHM for populations, supporting relationships suggest that synthesizing habitat template models with demographic life history theory could be valuable. Trait–environment models that are well‐supported at multiple levels of biological organization could improve understanding of the impacts of environmental change on populations and communities and the valuable ecosystem services that they support. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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A global meta‐analysis of the relative extent of intraspecific trait variation in plant communities 
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下载免费PDF全文 Andrew Siefert Cyrille Violle Loïc Chalmandrier Cécile H. Albert Adrien Taudiere Alex Fajardo Lonnie W. Aarssen Christopher Baraloto Marcos B. Carlucci Marcus V. Cianciaruso Vinícius de L. Dantas Francesco de Bello Leandro D. S. Duarte Carlos R. Fonseca Grégoire T. Freschet Stéphanie Gaucherand Nicolas Gross Kouki Hikosaka Benjamin Jackson Vincent Jung Chiho Kamiyama Masatoshi Katabuchi Steven W. Kembel Emilie Kichenin Nathan J. B. Kraft Anna Lagerström Yoann Le Bagousse‐Pinguet Yuanzhi Li Norman Mason Julie Messier Tohru Nakashizuka Jacob McC. Overton Duane A. Peltzer I. M. Pérez‐Ramos Valério D. Pillar Honor C. Prentice Sarah Richardson Takehiro Sasaki Brandon S. Schamp Christian Schöb Bill Shipley Maja Sundqvist Martin T. Sykes Marie Vandewalle David A. Wardle 《Ecology letters》2015,18(12):1406-1419
Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, we conducted a meta‐analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the total trait variation among communities on average. The relative extent of ITV tended to be greater for whole‐plant (e.g. plant height) vs. organ‐level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait‐based community and ecosystem studies. 相似文献
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Xinghui Lu Runguo Zang Yi Ding Susan G. Letcher Wenxing Long Yunfeng Huang 《Biotropica》2014,46(4):404-414
The seedling stage is generally the most important bottleneck for the successful regeneration of trees in forests. The traits of seedlings, particularly biomass allocation and root traits, are more easily quantified than the traits of adults. In this study, we tested the hypothesis that seedling traits vary and trade‐off tracking the changing environment during secondary succession. We measured the major morphological traits of 27 dominant species and the major environmental factors in a chronosequence (30‐yr‐old fallow, 60‐yr‐old fallow, and old growth forest) after shifting cultivation in a tropical lowland rain forest on Hainan Island, China. The 30‐yr‐old fallow had higher light and nutrient availability, and the older forests had higher soil water content. Redundancy analysis based on species abundance and environmental factors revealed groups of seedlings that dominate in different stages of succession. Seedlings in different stages of succession had different strategies of biomass allocation for harvesting resources that varied in availability. Species characteristic of younger forest had higher allocation to roots and higher specific leaf area, while species characteristic of older forest had higher allocation to leaves. Our study suggests that the variations and trade‐offs in the major functional traits of tree seedlings among successional classes may reflect changes in environmental conditions during succession. 相似文献
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Meta‐analysis is an important tool for synthesizing research on a variety of topics in ecology and evolution, including molecular ecology, but can be susceptible to nonindependence. Nonindependence can affect two major interrelated components of a meta‐analysis: (i) the calculation of effect size statistics and (ii) the estimation of overall meta‐analytic estimates and their uncertainty. While some solutions to nonindependence exist at the statistical analysis stages, there is little advice on what to do when complex analyses are not possible, or when studies with nonindependent experimental designs exist in the data. Here we argue that exploring the effects of procedural decisions in a meta‐analysis (e.g. inclusion of different quality data, choice of effect size) and statistical assumptions (e.g. assuming no phylogenetic covariance) using sensitivity analyses are extremely important in assessing the impact of nonindependence. Sensitivity analyses can provide greater confidence in results and highlight important limitations of empirical work (e.g. impact of study design on overall effects). Despite their importance, sensitivity analyses are seldom applied to problems of nonindependence. To encourage better practice for dealing with nonindependence in meta‐analytic studies, we present accessible examples demonstrating the impact that ignoring nonindependence can have on meta‐analytic estimates. We also provide pragmatic solutions for dealing with nonindependent study designs, and for analysing dependent effect sizes. Additionally, we offer reporting guidelines that will facilitate disclosure of the sources of nonindependence in meta‐analyses, leading to greater transparency and more robust conclusions. 相似文献
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Jeroen Raes Ivica Letunic Takuji Yamada Lars Juhl Jensen Peer Bork 《Molecular systems biology》2011,7(1)
Using metagenomic ‘parts lists’ to infer global patterns on microbial ecology remains a significant challenge. To deduce important ecological indicators such as environmental adaptation, molecular trait dispersal, diversity variation and primary production from the gene pool of an ecosystem, we integrated 25 ocean metagenomes with geographical, meteorological and geophysicochemical data. We find that climatic factors (temperature, sunlight) are the major determinants of the biomolecular repertoire of each sample and the main limiting factor on functional trait dispersal (absence of biogeographic provincialism). Molecular functional richness and diversity show a distinct latitudinal gradient peaking at 20°N and correlate with primary production. The latter can also be predicted from the molecular functional composition of an environmental sample. Together, our results show that the functional community composition derived from metagenomes is an important quantitative readout for molecular trait‐based biogeography and ecology. 相似文献
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Species enter and persist in local communities because of their ecological fit to local conditions, and recently, ecologists have moved from measuring diversity as species richness and evenness, to using measures that reflect species ecological differences. There are two principal approaches for quantifying species ecological differences: functional (trait‐based) and phylogenetic pairwise distances between species. Both approaches have produced new ecological insights, yet at the same time methodological issues and assumptions limit them. Traits and phylogeny may provide different, and perhaps complementary, information about species' differences. To adequately test assembly hypotheses, a framework integrating the information provided by traits and phylogenies is required. We propose an intuitive measure for combining functional and phylogenetic pairwise distances, which provides a useful way to assess how functional and phylogenetic distances contribute to understanding patterns of community assembly. Here, we show that both traits and phylogeny inform community assembly patterns in alpine plant communities across an elevation gradient, because they represent complementary information. Differences in historical selection pressures have produced variation in the strength of the trait‐phylogeny correlation, and as such, integrating traits and phylogeny can enhance the ability to detect assembly patterns across habitats or environmental gradients. 相似文献
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Federico Morelli Yanina Benedetti Anders Pape Mller Richard A. Fuller 《Ecology and evolution》2019,9(14):8378-8386
Measuring the extent to which a species is specialized is a major challenge in ecology, with important repercussions for fundamental research as well as for applied ecology and conservation. Here, we develop a multidimensional index of specialization based on five sets of ecological characteristics of breeding bird species. We used two recent databases of species traits of European birds based on foraging ecology, habitat, and breeding characteristics. The indices of specialization were calculated by applying the Gini coefficient, an index of inequality. The Gini coefficient is a measure of statistical dispersion on a scale between 0 and 1, reflecting a gradient from low to high specialization, respectively. Finally, we tested the strength of the phylogenetic signal of each specialization index to understand how the variance of such indices is shared throughout the phylogeny. The methods for constructing and evaluating a multidimensional index of bird specialization could also be applied to other taxa and regions, offering a simple but useful tool, particularly suited for global or biogeographic studies, as a contribution to comparative estimates of the degree of specialization of species. 相似文献
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- Monaghan and Soares (2014) suggested that combining traits with log‐transformed abundance of taxa may cause anomalies in analyses of stream macroinvertebrate communities. While they addressed an important issue in stream ecology, here we present an opposite view. To identify the causes of these contrasting opinions, we carefully examined the examples provided by Monaghan and Soares (2014) and demonstrated how traits can be weighted by the presence, abundance and log‐transformed abundance of the taxa in a meaningful way.
- We found that Monaghan and Soares (2014), following other authors, use the term ‘weighting’ differently from classical papers of stream ecology. The general practice is to calculate the sum of trait values multiplied by the abundance of each taxon and divide it by the total invertebrate abundance to get a community‐level trait value. In contrast, Monaghan and Soares (2014) did not perform the final division and consequently did not get a standardised community‐level trait value. It follows that the term ‘weighting’ is used with different meanings in stream ecology, and ecologists should keep these differences in mind.
- We agree with Monaghan and Soares (2014) that the addition of log‐transformed data is equivalent to multiplication on an arithmetic scale. However, we disagree that this provides an inconsistent scaling that confounds quantitative analyses. Using example data sets, we illustrate how trait‐based data analysis can be performed in community ecology in a meaningful way.
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Gianluigi Ottaviani James L. Tsakalos Gunnar Keppel Ladislav Mucina 《Ecology and evolution》2018,8(1):435-440
Complex processes related to biotic and abiotic forces can impose limitations to assembly and composition of plant communities. Quantifying the effects of these constraints on plant functional traits across environmental gradients, and among communities, remains challenging. We define ecological constraint (Ci) as the combined, limiting effect of biotic interactions and environmental filtering on trait expression (i.e., the mean value and range of functional traits). Here, we propose a set of novel parameters to quantify this constraint by extending the trait‐gradient analysis (TGA) methodology. The key parameter is ecological constraint, which is dimensionless and can be measured at various scales, for example, on population and community levels. It facilitates comparing the effects of ecological constraints on trait expressions across environmental gradients, as well as within and among communities. We illustrate the implementation of the proposed parameters using the bark thickness of 14 woody species along an aridity gradient on granite outcrops in southwestern Australia. We found a positive correlation between increasing environmental stress and strength of ecological constraint on bark thickness expression. Also, plants from more stressful habitats (shrublands on shallow soils and in sun‐exposed locations) displayed higher ecological constraint for bark thickness than plants in more benign habitats (woodlands on deep soils and in sheltered locations). The relative ease of calculation and dimensionless nature of Ci allow it to be readily implemented at various scales and make it widely applicable. It therefore has the potential to advance the mechanistic understanding of the ecological processes shaping trait expression. Some future applications of the new parameters could be investigating the patterns of ecological constraints (1) among communities from different regions, (2) on different traits across similar environmental gradients, and (3) for the same trait across different gradient types. 相似文献
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Biological data are often intrinsically hierarchical (e.g., species from different genera, plants within different mountain regions), which made mixed‐effects models a common analysis tool in ecology and evolution because they can account for the non‐independence. Many questions around their practical applications are solved but one is still debated: Should we treat a grouping variable with a low number of levels as a random or fixed effect? In such situations, the variance estimate of the random effect can be imprecise, but it is unknown if this affects statistical power and type I error rates of the fixed effects of interest. Here, we analyzed the consequences of treating a grouping variable with 2–8 levels as fixed or random effect in correctly specified and alternative models (under‐ or overparametrized models). We calculated type I error rates and statistical power for all‐model specifications and quantified the influences of study design on these quantities. We found no influence of model choice on type I error rate and power on the population‐level effect (slope) for random intercept‐only models. However, with varying intercepts and slopes in the data‐generating process, using a random slope and intercept model, and switching to a fixed‐effects model, in case of a singular fit, avoids overconfidence in the results. Additionally, the number and difference between levels strongly influences power and type I error. We conclude that inferring the correct random‐effect structure is of great importance to obtain correct type I error rates. We encourage to start with a mixed‐effects model independent of the number of levels in the grouping variable and switch to a fixed‐effects model only in case of a singular fit. With these recommendations, we allow for more informative choices about study design and data analysis and make ecological inference with mixed‐effects models more robust for small number of levels. 相似文献
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海洋微生物的化学生态学研究进展 总被引：1，自引：0，他引：1
近年来,海洋生物的化学生态学研究已成为国际化学生态学研究的亮点之一.该领域的研究不仅为生物进化研究提供了理论依据,也对海洋生态养殖、海洋生态环境保护以及海洋资源的可持续发展具有重要意义.本文从海洋动物、植物、微生物三方面综述了它们与海洋微生物之间的化学生态学关系.海洋动物与微生物的化学生态学作用主要包括抗菌、抗附着、共生3种关系.以发现具有生态学效应的化学信号物质的分子结构为主线,介绍了海洋植物和微生物方面的研究进展,并对该领域的关键性问题和发展方向进行了展望. 相似文献
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Samantha K. Dawson Carlos Prez Carmona Manuela Gonzlez&#x;Surez Mari Jnsson Filipe Chichorro Max Mallen&#x;Cooper Yolanda Melero Helen Moor John P. Simaika Alexander Bradley Duthie 《Ecology and evolution》2021,11(23):16434
Trait and functional trait approaches have revolutionized ecology improving our understanding of community assembly, species coexistence, and biodiversity loss. Focusing on traits promotes comparability across spatial and organizational scales, but terms must be used consistently. While several papers have offered definitions, it remains unclear how ecologists operationalize “trait” and “functional trait” terms. Here, we evaluate how researchers and the published literatures use these terms and explore differences among subdisciplines and study systems (taxa and biome). By conducting both a survey and a literature review, we test the hypothesis that ecologists’ working definition of “trait” is adapted or altered when confronting the realities of collecting, analyzing and presenting data. From 486 survey responses and 712 reviewed papers, we identified inconsistencies in the understanding and use of terminology among researchers, but also limited inclusion of definitions within the published literature. Discrepancies were not explained by subdiscipline, system of study, or respondent characteristics, suggesting there could be an inconsistent understanding even among those working in related topics. Consistencies among survey responses included the use of morphological, phonological, and physiological traits. Previous studies have called for unification of terminology; yet, our study shows that proposed definitions are not consistently used or accepted. Sources of disagreement include trait heritability, defining and interpreting function, and dealing with organisms in which individuals are not clearly recognizable. We discuss and offer guidelines for overcoming these disagreements. The diversity of life on Earth means traits can represent different features that can be measured and reported in different ways, and thus, narrow definitions that work for one system will fail in others. We recommend ecologists embrace the breadth of biodiversity using a simplified definition of “trait” more consistent with its common use. Trait‐based approaches will be most powerful if we accept that traits are at least as diverse as trait ecologists. 相似文献
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Dominique Gravel 《Ecology and evolution》2013,3(4):1125-1139
High‐throughput sequencing is becoming increasingly important in microbial ecology, yet it is surprisingly under‐used to generate or test biogeographic hypotheses. In this contribution, we highlight how adding these methods to the ecologist toolbox will allow the detection of new patterns, and will help our understanding of the structure and dynamics of diversity. Starting with a review of ecological questions that can be addressed, we move on to the technical and analytical issues that will benefit from an increased collaboration between different disciplines. 相似文献