1
|
Möller FM, Flöder S, Di Giuseppe G, Devi Moorthi S. Resource supply and intraspecific variation in inducible defense determine predator-prey interactions in an intraguild predation food web. Eur J Protistol 2024; 95:126114. [PMID: 39190947 DOI: 10.1016/j.ejop.2024.126114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 08/14/2024] [Accepted: 08/15/2024] [Indexed: 08/29/2024]
Abstract
This study investigated the dynamics of reciprocal phenotypic plasticity entailing inducible defense and offense in freshwater ciliate communities in response to altered resource supply and the extent of intraspecific trait variation. Communities consisted of Euplotes octocarinatus (intraguild prey) capable of inducible defense to escape predation, Stylonychia mytilus (intraguild predator) capable of inducible offense to expand its prey spectrum, and Cryptomonas sp. (algal resource). The extent of inducible defense was tested in ten different Euplotes strains in response to freeze-killed Stylonychia concentrate, revealing significant differences in their width and length development. In a subsequent 30-day experiment, four strains were incubated in monoculture and mixture with Stylonychia under continuous and pulsed microalgae supply. The polyclonal Euplotes population outperformed the monoclonal populations, except one, which developed the most pronounced inducible defense and retained the highest biovolume. Stylonychia fluctuated in size, but dominated all communities irrespective of clonal composition. Pulsed resource supply promoted biovolume production of both species. However, periods of resource depletion resulted in more Stylonychia resting cysts, allowing Euplotes to resume growth. Our study provides new insights into interactions of induced defense and intraguild predation under variable environmental conditions, emphasizing the relevance of intraspecific trait variation for predator-prey interactions and community dynamics.
Collapse
Affiliation(s)
- Fenja-Marie Möller
- Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, 26129 Oldenburg, Germany.
| | - Sabine Flöder
- Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, 26129 Oldenburg, Germany
| | | | - Stefanie Devi Moorthi
- Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstraße 114-118, 26129 Oldenburg, Germany
| |
Collapse
|
2
|
Hermann RJ, Pantel JH, Réveillon T, Becks L. Range of trait variation in prey determines evolutionary contributions to predator growth rates. J Evol Biol 2024; 37:693-703. [PMID: 38761100 DOI: 10.1093/jeb/voae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 04/12/2024] [Accepted: 05/15/2024] [Indexed: 05/20/2024]
Abstract
Evolutionary and ecological dynamics can occur on similar timescales and thus influence each other. While it has been shown that the relative contribution of ecological and evolutionary change to population dynamics can vary, it still remains unknown what influences these differences. Here, we test whether prey populations with increased variation in their defence and competitiveness traits will have a stronger impact on evolution for predator growth rates. We controlled trait variation by pairing distinct clonal lineages of the green alga Chlamydomonas reinhardtii with known traits as prey with the rotifer Brachionus calyciforus as predator and compared those results with a mechanistic model matching the empirical system. We measured the impact of evolution (shift in prey clonal frequency) and ecology (shift in prey population density) for predator growth rate and its dependency on trait variation using an approach based on a 2-way ANOVA. Our experimental results indicated that higher trait variation, i.e., a greater distance in trait space, increased the relative contribution of prey evolution to predator growth rate over 3-4 predator generations, which was also observed in model simulations spanning longer time periods. In our model, we also observed clone-specific results, where a more competitive undefended prey resulted in a higher evolutionary contribution, independent of the trait distance. Our results suggest that trait combinations and total prey trait variation combine to influence the contribution of evolution to predator population dynamics, and that trait variation can be used to identify and better predict the role of eco-evolutionary dynamics in predator-prey systems.
Collapse
Affiliation(s)
- Ruben J Hermann
- Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Jelena H Pantel
- Ecological Modelling, Faculty of Biology, University Duisburg Essen, Essen, Germany
- Laboratoire Chrono-environnement, UMR 6249 CNRS-UFC, 16 Route de Gray, 25030 Besanc, France
| | - Tom Réveillon
- Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Lutz Becks
- Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| |
Collapse
|
3
|
Ronk A, Boldgiv B, Casper BB, Liancourt P. Leaf trait plasticity reveals interactive effects of temporally disjunct grazing and warming on plant communities. Oecologia 2024; 204:833-843. [PMID: 38573499 PMCID: PMC11062997 DOI: 10.1007/s00442-024-05540-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 03/03/2024] [Indexed: 04/05/2024]
Abstract
Changes in climate and grazing intensity influence plant-community compositions and their functional structure. Yet, little is known about their possible interactive effects when climate change mainly has consequences during the growing season and grazing occurs off growing season (dormant season grazing). We examined the contribution of trait plasticity to the immediate responses in the functional structure of plant community due to the interplay between these two temporally disjunct drivers. We conducted a field experiment in the northern Mongolian steppe, where climate was manipulated by open-top chambers (OTCs) for two growing seasons, increasing temperature and decreasing soil moisture (i.e., increased aridity), and grazing was excluded for one dormant season between these two growing seasons. We calculated the community-weighted mean (CWM) and the functional diversity (FD) of six leaf traits. Based on a variance partitioning approach, we evaluated how much of the responses in CWM and FD to OTCs and dormant season grazing occur through plasticity. The interactive effect of OTCs and the dormant season grazing were detected only after considering the role of trait plasticity. Overall, OTCs influenced the responses in CWM more than in FD, but the effects of OTCs were much less pronounced where dormant season grazing occurred. Thus, warming (together with decreased soil moisture) and the elimination of dormant season grazing could interact to impact the functional trait structure of plant communities through trait plasticity. Climate change effects should be considered in the context of altered land use, even if temporally disjunct.
Collapse
Affiliation(s)
- Argo Ronk
- Department of Biology, University of Pennsylvania, Philadelphia, USA
| | - Bazartseren Boldgiv
- Department of Biology, National University of Mongolia, Ulaanbaatar, 14201, Mongolia
| | - Brenda B Casper
- Department of Biology, University of Pennsylvania, Philadelphia, USA
| | - Pierre Liancourt
- Department of Botany, State Museum of Natural History Stuttgart, Stuttgart, Germany.
- Department of Evolution and Ecology, University of Tübingen, Tübingen, Germany.
| |
Collapse
|
4
|
Chen X, Guo X, Xiong W, Zhan A. Pollution-driven morphological plasticity in a running water ecosystem. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:2783-2791. [PMID: 34378129 DOI: 10.1007/s11356-021-15802-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Various types of pollutants derived from rapid industrialization and urbanization have largely threaten biodiversity and functioning of freshwater ecosystems globally. Morphological plasticity, especially body size-associated traits, is considered a functional response to water pollution in species, as such changes are often directly related to functioning of freshwater ecosystems through dynamics of food webs. However, detailed dynamics of pollution impacts on morphological plasticity remain largely unknown, particularly in the wild. Here, we used the model planktonic rotifer Brachionus calyciflorus to assess morphological response to chemical pollution in a river reach disturbed by sewage discharges. Multiple analyses showed dynamic morphological response to water pollution in wild B. calyciflorus populations. The distance between anterior lateral spines, lorica length, and egg short diameter were the most sensitive morphological indicators to water pollution, while spine length was stable in varied pollution conditions. Interestingly, body size and egg size were increased with accentuated water pollution, suggesting that wild populations maintain fitness by increasing feeding efficiency and reducing vulnerability to predation and ensure survival by producing large newborns in polluted environments. Total ammonia nitrogen was the leading nitrogen pollutant affecting body size, while total phosphorus and elements of Mn and As were the key factors relating to egg size. The results obtained here provide new sights into biological consequences of environmental pollution in the wild, thus advancing our understanding of pollution impacts on structure and functioning of freshwater ecosystems.
Collapse
Affiliation(s)
- Xingyu Chen
- College of Resources Environment and Tourism, Capital Normal University, 105 West Third Ring Road, Haidian District, Beijing, 100048, China
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, China
| | - Xiaoyu Guo
- College of Resources Environment and Tourism, Capital Normal University, 105 West Third Ring Road, Haidian District, Beijing, 100048, China
| | - Wei Xiong
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, China
| | - Aibin Zhan
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, China.
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing, 100049, China.
| |
Collapse
|
5
|
Wood ZT, Lopez LK, Symons CC, Robinson RR, Palkovacs EP, Kinnison MT. Drivers and cascading ecological consequences of Gambusia affinis trait variation. Am Nat 2021; 199:E91-E110. [DOI: 10.1086/717866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
6
|
Fontana S, Rasmann S, de Bello F, Pomati F, Moretti M. Reconciling trait based perspectives along a trait-integration continuum. Ecology 2021; 102:e03472. [PMID: 34260747 DOI: 10.1002/ecy.3472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 04/09/2021] [Accepted: 05/18/2021] [Indexed: 11/08/2022]
Abstract
Trait based ecology has developed fast in the last decades, aiming to both explain mechanisms of community assembly, and predict patterns in nature, such as the effects of biodiversity shifts on key ecosystem processes. This body of work has stimulated the development of several conceptual frameworks and analytical methods, as well as the production of trait databases covering a growing number of taxa and organizational levels (from individuals to guilds). However, this breeding ground of novel concepts and tools currently lacks a general and coherent framework, under which functional traits can help ecologists organize their research aims, and serve as the common currency to unify several scientific disciplines. Specifically, we see a need to bridge the gaps between community ecology, ecosystem ecology, and evolutionary biology, in order to address the most pressing environmental issues of our time. To achieve this integration goal, we define a trait-integration continuum, which reconciles alternative trait definitions and approaches in ecology. This continuum outlines a coherent progression of biological scales, along which traits interact and hierarchically integrate from genetic information, to whole organism fitness-related traits, to trait syndromes and functional groups. Our conceptual scheme proposes that lower-level trait integration is closer to the inference of ecoevolutionary mechanisms determining population and community properties, whereas higher-level trait integration is most suited to the prediction of ecosystem processes. Within these two extremes, trait integration varies on a continuous scale, which relates directly to the inductive-deductive loop that should characterize the scientific method. With our proposed framework, we aim to facilitate scientists in contextualising their research based on the trait-integration levels that matter most to their specific goals. Explicitly acknowledging the existence of a trait-integration continuum is a promising way for framing the appropriate questions, thus obtaining reliable answers and results that are comparable across studies and disciplines.
Collapse
Affiliation(s)
- Simone Fontana
- Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland.,Nature Conservation and Landscape Ecology, University of Freiburg, Tennenbacher Straße 4, Freiburg, 79106, Germany
| | - Sergio Rasmann
- Laboratory of Functional Ecology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel, 2000, Switzerland
| | - Francesco de Bello
- Department of Botany, Faculty of Sciences, University of South Bohemia, Na Zlate Stoce 1, České Budějovice, 370 05, Czech Republic.,Desertification Research Centre (CIDE-CSIC), Carretera Moncada-Náquera, Km 4,5, Moncada (Valencia), 46113, Spain
| | - Francesco Pomati
- Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, Dübendorf, 8600, Switzerland
| | - Marco Moretti
- Biodiversity and Conservation Biology, Swiss Federal Research Institute WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| |
Collapse
|
7
|
Perälä T, Kuparinen A. Eco-evolutionary dynamics driven by fishing: From single species models to dynamic evolution within complex food webs. Evol Appl 2020; 13:2507-2520. [PMID: 33294005 PMCID: PMC7691468 DOI: 10.1111/eva.13058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 06/16/2020] [Accepted: 06/23/2020] [Indexed: 01/04/2023] Open
Abstract
Evidence of contemporary evolution across ecological time scales stimulated research on the eco-evolutionary dynamics of natural populations. Aquatic systems provide a good setting to study eco-evolutionary dynamics owing to a wealth of long-term monitoring data and the detected trends in fish life-history traits across intensively harvested marine and freshwater systems. In the present study, we focus on modelling approaches to simulate eco-evolutionary dynamics of fishes and their ecosystems. Firstly, we review the development of modelling from single species to multispecies approaches. Secondly, we advance the current state-of-the-art methodology by implementing evolution of life-history traits of a top predator into the context of complex food web dynamics as described by the allometric trophic network (ATN) framework. The functioning of our newly developed eco-evolutionary ATNE framework is illustrated using a well-studied lake food web. Our simulations show how both natural selection arising from feeding interactions and size-selective fishing cause evolutionary changes in the top predator and how those feed back to its prey species and further cascade down to lower trophic levels. Finally, we discuss future directions, particularly the need to integrate genomic discoveries into eco-evolutionary projections.
Collapse
Affiliation(s)
- Tommi Perälä
- Department of Biological and Environmental SciencesUniversity of JyväskyläJyväskyläFinland
| | - Anna Kuparinen
- Department of Biological and Environmental SciencesUniversity of JyväskyläJyväskyläFinland
| |
Collapse
|
8
|
Medvedev SG, Sedikhin NV, Krasnov BR. Intraspecific variation of body size in fleas: effects of host sex and flea phenology. Parasitol Res 2020; 119:3211-3220. [PMID: 32888066 DOI: 10.1007/s00436-020-06867-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 08/26/2020] [Indexed: 11/28/2022]
Abstract
We investigated the effects of host sex and flea phenology (estimated as periods of high versus low abundance) on individual body size in four fleas of small mammals. Amalaraeus penicilliger and Ctenophthalmus uncinatus are ectoparasites of the bank vole Myodes glareolus, whereas Doratopsylla dasycnema and Palaeopsylla soricis are ectoparasites of the common shrew Sorex araneus. We found significant effects of host sex and phenology on the body size of all flea species, although there was no general trend in the directions of these effects. Larger A. penicilliger were found on female hosts, whereas larger P. soricis were found on male hosts. In the remaining species, larger fleas were collected from male hosts during periods of high abundance (male C. uncinatus and female D. dasycnema) and from female hosts during periods of low abundance (male C. uncinatus). Regarding phenology, larger fleas were recorded during periods of either high (A. penicilliger, C. uncinatus, D. dasycnema) or low (C. uncinatus, P. soricis) abundance, but this depended on flea and/or host sex. We conclude that the directions of the host sex and phenology effects varied between flea species. Furthermore, the direction of the host sex effect was mediated by the effect of phenology and vice versa.
Collapse
Affiliation(s)
- Sergei G Medvedev
- Zoological Institute, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Nikolai V Sedikhin
- Zoological Institute, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Boris R Krasnov
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Sede Boqer Campus, Ben-Gurion University of the Negev, 8499000, Midreshet Ben-Gurion, Israel.
| |
Collapse
|
9
|
Lachish S, Brandell EE, Craft ME, Dobson AP, Hudson PJ, MacNulty DR, Coulson T. Investigating the Dynamics of Elk Population Size and Body Mass in a Seasonal Environment Using a Mechanistic Integral Projection Model. Am Nat 2020; 196:E23-E45. [PMID: 32673097 DOI: 10.1086/708723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Environmentally mediated changes in body size often underlie population responses to environmental change, yet this is not a universal phenomenon. Understanding when phenotypic change underlies population responses to environmental change is important for obtaining insights and robust predictions of population dynamics in a changing world. We develop a dynamic integral projection model that mechanistically links environmental conditions to demographic rates and phenotypic traits (body size) via changes in resource availability and individual energetics. We apply the model to the northern Yellowstone elk population and explore population responses to changing patterns of seasonality, incorporating the interdependence of growth, demography, and density-dependent processes operating through population feedback on available resources. We found that small changes in body size distributions can have large impacts on population dynamics but need not cause population responses to environmental change. Environmental changes that altered demographic rates directly, via increasing or decreasing resource availability, led to large population impacts in the absence of substantial changes to body size distributions. In contrast, environmentally driven shifts in body size distributions could occur with little consequence for population dynamics when the effect of environmental change on resource availability was small and seasonally restricted and when strong density-dependent processes counteracted expected population responses. These findings highlight that a robust understanding of how associations between body size and demography influence population responses to environmental change will require knowledge of the shape of the relationship between phenotypic distributions and vital rates, the population status with regard to its carrying capacity, and importantly the nature of the environmentally driven change in body size and carrying capacity.
Collapse
|
10
|
Garnier A, Hulot FD, Petchey OL. Manipulating the strength of organism-environment feedback increases nonlinearity and apparent hysteresis of ecosystem response to environmental change. Ecol Evol 2020; 10:5527-5543. [PMID: 32607172 PMCID: PMC7319241 DOI: 10.1002/ece3.6294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 11/08/2022] Open
Abstract
Theory predicts that organism-environment feedbacks play a central role in how ecological communities respond to environmental change. Strong feedback causes greater nonlinearity between environmental change and ecosystem state, increases the likelihood of hysteresis in response to environmental change, and augments the possibility of alternative stable regimes. To illustrate these predictions and their dependence on a temporal scale, we simulated a minimal ecosystem model. To test the predictions, we manipulated the feedback strength between the metabolism and the dissolved oxygen concentration in an aquatic heterotrophic tri-trophic community in microecosystems. The manipulation consisted of five levels, ranging from low to high feedback strength by altering the oxygen diffusivity: free gas exchange between the microcosm atmosphere and the external air (metabolism not strongly affecting environmental oxygen), with the regular addition of 200, 100, or 50 ml of air and no gas exchange. To test for nonlinearity and hysteresis in response to environmental change, all microecosystems experienced a gradual temperature increase from 15 to 25°C and then back to 15°C. We regularly measured the dissolved oxygen concentration, total biomass, and species abundance. Nonlinearity and hysteresis were higher in treatments with stronger organism-environment feedbacks. There was no evidence that stronger feedback increased the number of observed ecosystem states. These empirical results are in broad agreement with the theory that stronger feedback increases nonlinearity and hysteresis. They therefore represent one of the first direct empirical tests of the importance of feedback strength. However, we discuss several limitations of the study, which weaken confidence in this interpretation. Research demonstrating the causal effects of feedback strength on ecosystem responses to environmental change should be placed at the core of efforts to plan for sustainable ecosystems.
Collapse
Affiliation(s)
- Aurélie Garnier
- URPP Global Change and BiodiversityUniversity of ZurichZürichSwitzerland
- Institute for Marine Ecosystem and Fisheries ScienceUniversity of HamburgHamburgGermany
| | - Florence D. Hulot
- Université Paris‐SaclayCNRS, AgroParisTechEcologie Systématique et EvolutionOrsayFrance
| | - Owen L. Petchey
- URPP Global Change and BiodiversityUniversity of ZurichZürichSwitzerland
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZürichSwitzerland
| |
Collapse
|
11
|
Wood ZT, Fryxell DC, Moffett ER, Kinnison MT, Simon KS, Palkovacs EP. Prey adaptation along a competition-defense tradeoff cryptically shifts trophic cascades from density- to trait-mediated. Oecologia 2020; 192:767-778. [PMID: 31989320 DOI: 10.1007/s00442-020-04610-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/16/2020] [Indexed: 11/25/2022]
Abstract
Trophic cascades have become a dominant paradigm in ecology, yet considerable debate remains about the relative strength of density- (consumptive) and trait-mediated (non-consumptive) effects in trophic cascades. This debate may, in part, be resolved by considering prey experience, which shapes prey traits (through genetic and plastic change) and influences prey survival (and therefore density). Here, we investigate the cascading role of prey experience through the addition of mosquitofish (Gambusia affinis) from predator-experienced or predator-naïve sources to mesocosms containing piscivorous largemouth bass (Micropterus salmoides), zooplankton, and phytoplankton. These two sources were positioned along a competition-defense tradeoff. Results show that predator-naïve mosquitofish suffered higher depredation rates, which drove a density-mediated cascade, whereas predator-experienced mosquitofish exhibited higher survival but fed less, which drove a trait-mediated cascade. Both cascades were similar in strength, leading to indistinguishable top-down effects on lower trophic levels. Therefore, the accumulation of prey experience with predators can cryptically shift cascade mechanisms from density- to trait-mediated.
Collapse
Affiliation(s)
- Zachary T Wood
- School of Biology and Ecology, Ecology and Environmental Sciences Program, University of Maine, Orono, ME, 04469, USA.
| | - David C Fryxell
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
- School of Environment, University of Auckland, Auckland, 1142, New Zealand
| | - Emma R Moffett
- School of Environment, University of Auckland, Auckland, 1142, New Zealand
| | - Michael T Kinnison
- School of Biology and Ecology, Ecology and Environmental Sciences Program, University of Maine, Orono, ME, 04469, USA
| | - Kevin S Simon
- School of Environment, University of Auckland, Auckland, 1142, New Zealand
| | - Eric P Palkovacs
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| |
Collapse
|
12
|
Yang J, Lu J, Chen Y, Yan E, Hu J, Wang X, Shen G. Large Underestimation of Intraspecific Trait Variation and Its Improvements. FRONTIERS IN PLANT SCIENCE 2020; 11:53. [PMID: 32117390 PMCID: PMC7031497 DOI: 10.3389/fpls.2020.00053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 01/15/2020] [Indexed: 05/22/2023]
Abstract
Intraspecific trait variation (ITV) is common feature of natural communities and has gained increasing attention due to its significant ecological effects on community dynamics and ecosystem functioning. However, the estimation of ITV per se has yet to receive much attention, despite the need for accurate ITV estimation for trait-based ecological inferences. It remains unclear if, and to what extent, current estimations of ITV are biased. The most common method used to quantify ITV is the coefficient of variation (CV), which is dimensionless and can therefore be compared across traits, species, and studies. Here, we asked which CV estimator and data normalization method are optimal for quantifying ITV, and further identified the minimum sample size required for ±5% accuracy assuming a completely random sample scheme. To these ends, we compared the performance of four existing CV estimators, together with new simple composite estimators, across different data normalizations, and sample sizes using both a simulated and empirical trait datasets from local to regional scales. Our results consistently showed that the most commonly used ITV estimator (CV 1= σsample /μsample ), often underestimated ITV-in some cases by nearly 50%-and that underestimation varies largely among traits and species. The extent of this bias depends on the sample size, skewness and kurtosis of the trait value distribution. The bias in ITV can be substantially reduced by using log-transforming trait data and alternative CV estimators that take into consideration the above dependencies. We find that the CV4 estimator, also known as Bao's CV estimator, combined with log data normalization, exhibits the lowest bias and can reach ±5% accuracy with sample sizes greater than 20 for almost all examined traits and species. These results demonstrated that many previous ITV measurements may be substantially underestimated and, further, that these underestimations are not equal among species and traits even using the same sample size. These problems can be largely solved by log-transforming trait data first and then using the Bao's CV to quantify ITV. Together, our findings facilitate a more accurate understanding of ITV in community structures and dynamics, and may also benefit studies in other research areas that depend on accurate estimation of CV.
Collapse
Affiliation(s)
- Jing Yang
- Tiantong National Station for Forest Ecosystem Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Jiahui Lu
- Tiantong National Station for Forest Ecosystem Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yue Chen
- Tiantong National Station for Forest Ecosystem Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Enrong Yan
- Tiantong National Station for Forest Ecosystem Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China
| | - Junhua Hu
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Xihua Wang
- Tiantong National Station for Forest Ecosystem Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China
| | - Guochun Shen
- Tiantong National Station for Forest Ecosystem Research, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China
- *Correspondence: Guochun Shen,
| |
Collapse
|
13
|
Pennekamp F, Clobert J, Schtickzelle N. The interplay between movement, morphology and dispersal in Tetrahymena ciliates. PeerJ 2019; 7:e8197. [PMID: 31871838 PMCID: PMC6924321 DOI: 10.7717/peerj.8197] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 11/12/2019] [Indexed: 11/29/2022] Open
Abstract
Understanding how and why individual movement translates into dispersal between populations is a long-term goal in ecology. Movement is broadly defined as ‘any change in the spatial location of an individual’, whereas dispersal is more narrowly defined as a movement that may lead to gene flow. Because the former may create the condition for the latter, behavioural decisions that lead to dispersal may be detectable in underlying movement behaviour. In addition, dispersing individuals also have specific sets of morphological and behavioural traits that help them coping with the costs of movement and dispersal, and traits that mitigate costs should be under selection and evolve if they have a genetic basis. Here, we experimentally study the relationships between movement behaviour, morphology and dispersal across 44 genotypes of the actively dispersing unicellular, aquatic model organism Tetrahymena thermophila. We used two-patch populations to quantify individual movement trajectories, as well as activity, morphology and dispersal rate. First, we studied variation in movement behaviour among and within genotypes (i.e. between dispersers and residents) and tested whether this variation can be explained by morphology. Then, we addressed how much the dispersal rate is driven by differences in the underlying movement behaviour. Genotypes revealed clear differences in terms of movement speed and linearity. We also detected marked movement differences between resident and dispersing individuals, mediated by the genotype. Movement variation was partly explained by morphological properties such as cell size and shape, with larger cells consistently showing higher movement speed and higher linearity. Genetic differences in activity and movement were positively related to the observed dispersal and jointly explained 47% of the variation in dispersal rate. Our study shows that a detailed understanding of the interplay between morphology, movement and dispersal may have potential to improve dispersal predictions over broader spatio-temporal scales.
Collapse
Affiliation(s)
- Frank Pennekamp
- Earth and Life Institute & Biodiversity Research Centre, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Jean Clobert
- Station d'Ecologie Théorique et Expérimentale, CNRS, Moulis, France
| | - Nicolas Schtickzelle
- Earth and Life Institute & Biodiversity Research Centre, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| |
Collapse
|
14
|
Gao X, Chen H, Govaert L, Wang W, Yang J. Responses of zooplankton body size and community trophic structure to temperature change in a subtropical reservoir. Ecol Evol 2019; 9:12544-12555. [PMID: 31788196 PMCID: PMC6875572 DOI: 10.1002/ece3.5718] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/18/2019] [Accepted: 09/15/2019] [Indexed: 01/07/2023] Open
Abstract
Understanding the effects of global warming on trait variation and trophic structure is a crucial challenge in the 21st century. However, there is a lack of general patterns that can be used to predict trait variation and community trophic structure under the ongoing environmental change. We investigated the responses of body size and community trophic structure of zooplankton to climate related factors (e.g., temperature). Isotopic niche breadth was applied to investigate the community trophic structure across a 1-year study from a subtropical reservoir (Tingxi Reservoir) in southeastern China. Body size and community isotopic niche breadth of zooplankton were larger during water mixing than stratification periods and correlated significantly with water temperature change along the time series. The contributions of intra- and intertaxonomic components to body size and community trophic structure variation showed significant relationships with the temperature change going from the mixing to stratification periods. Water temperature imposed direct effect on body size, while direct and indirect effect on the community trophic structure of zooplankton occurred through trophic redundancy along time series. Water temperature and community properties (e.g., body size, trophic redundancy, or trophic interaction) showed complex interactions and integrated to influence community trophic structure of zooplankton. Our results can expand the knowledge of how elevated temperature will alter individual trait and community trophic structure under future climate change.
Collapse
Affiliation(s)
- Xiaofei Gao
- Aquatic EcoHealth GroupKey Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentChinese Academy of SciencesXiamenChina
- Fujian Key Laboratory of Watershed EcologyInstitute of Urban EnvironmentChinese Academy of SciencesXiamenChina
- University of Chinese Academy of SciencesBeijingChina
| | - Huihuang Chen
- Aquatic EcoHealth GroupKey Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentChinese Academy of SciencesXiamenChina
- Fujian Key Laboratory of Watershed EcologyInstitute of Urban EnvironmentChinese Academy of SciencesXiamenChina
| | - Lynn Govaert
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZürichSwitzerland
- Department of Aquatic EcologyEawag: Swiss Federal Institute of Aquatic Science and TechnologyDübendorfSwitzerland
- Laboratory of Aquatic Ecology, Evolution and ConservationKU LeuvenLeuvenBelgium
| | - Wenping Wang
- Aquatic EcoHealth GroupKey Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentChinese Academy of SciencesXiamenChina
- Fujian Key Laboratory of Watershed EcologyInstitute of Urban EnvironmentChinese Academy of SciencesXiamenChina
- University of Chinese Academy of SciencesBeijingChina
| | - Jun Yang
- Aquatic EcoHealth GroupKey Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentChinese Academy of SciencesXiamenChina
- Fujian Key Laboratory of Watershed EcologyInstitute of Urban EnvironmentChinese Academy of SciencesXiamenChina
| |
Collapse
|