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Pomeranz J, Junker JR, Gjoni V, Wesner JS. Maximum likelihood outperforms binning methods for detecting differences in abundance size spectra across environmental gradients. J Anim Ecol 2024; 93:267-280. [PMID: 38167802 DOI: 10.1111/1365-2656.14044] [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: 08/17/2023] [Accepted: 11/21/2023] [Indexed: 01/05/2024]
Abstract
Individual body size distributions (ISD) within communities are remarkably consistent across habitats and spatiotemporal scales and can be represented by size spectra, which are described by a power law. The focus of size spectra analysis is to estimate the exponent (λ ) of the power law. A common application of size spectra studies is to detect anthropogenic pressures. Many methods have been proposed for estimatingλ most of which involve binning the data, counting the abundance within bins, and then fitting an ordinary least squares regression in log-log space. However, recent work has shown that binning procedures return biased estimates ofλ compared to procedures that directly estimateλ using maximum likelihood estimation (MLE). While it is clear that MLE produces less biased estimates of site-specific λ's, it is less clear how this bias affects the ability to test for changes in λ across space and time, a common question in the ecological literature. Here, we used simulation to compare the ability of two normalised binning methods (equal logarithmic and log2 bins) and MLE to (1) recapture known values ofλ , and (2) recapture parameters in a linear regression measuring the change inλ across a hypothetical environmental gradient. We also compared the methods using two previously published body size datasets across a natural temperature gradient and an anthropogenic pollution gradient. Maximum likelihood methods always performed better than common binning methods, which demonstrated consistent bias depending on the simulated values ofλ . This bias carried over to the regressions, which were more accurate whenλ was estimated using MLE compared to the binning procedures. Additionally, the variance in estimates using MLE methods is markedly reduced when compared to binning methods. The error induced by binning methods can be of similar magnitudes as the variation previously published in experimental and observational studies, bringing into question the effect sizes of previously published results. However, while the methods produced different regression slope estimates, they were in qualitative agreement on the sign of those slopes (i.e. all negative or all positive). Our results provide further support for the direct estimation ofλ and its relative variation across environmental gradients using MLE over the more common methods of binning.
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Affiliation(s)
| | - James R Junker
- Great Lakes Research Center, Michigan Technological University, Houghton, Michigan, USA
- Louisiana Universities Marine Consortium, Chauvin, Louisiana, USA
| | - Vojsava Gjoni
- Department of Biology, University of South Dakota, Vermillion, South Dakota, USA
| | - Jeff S Wesner
- Department of Biology, University of South Dakota, Vermillion, South Dakota, USA
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Campillay-Llanos W, Córdova-Lepe FD, Moreno-Gómez FN. Coexistence, Energy, and Trophic Cascade in a Three-Level Food Chain Integrating Body Sizes. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.821176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Predation is a biological interaction that influences demographic patterns by modifying community structure. In the current ecological crisis, there is a need to better understand the conditions of coexistence between predators, prey and their resources. The body size is considered a key feature to explain community-scale phenomena, energetic, and evolutionary constraints. This raises the question of how species body size directly or indirectly affects the demographic patterns that enable coexistence. Considering the above, we conducted a theoretical study that implements a Rosenzweig-MacArthur type model, which represents a three-level chain that integrates body sizes and includes a Holling type I functional response. In this model, we characterize coexistence through body size-dependent net reproductive rates. Our results suggest that the body sizes of consumer species strongly affect the size-density relations and energy requirements. We obtain the negative relationship between body size and density of intermediate consumers and discuss the energy equivalence rule. Furthermore, larger predators have a more significant impact on the intensity of the trophic cascade than smaller predators. Finally, we discuss potential extensions and applications of our modeling approach.
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Heather FJ, Blanchard JL, Edgar GJ, Trebilco R, Stuart‐Smith RD. Globally consistent reef size spectra integrating fishes and invertebrates. Ecol Lett 2020; 24:572-579. [DOI: 10.1111/ele.13661] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/19/2020] [Accepted: 11/21/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Freddie J. Heather
- Institute for Marine and Antarctic Studies University of Tasmania 20 Castray Esplanade, Battery Point Hobart TAS7004Australia
| | - Julia L. Blanchard
- Institute for Marine and Antarctic Studies University of Tasmania 20 Castray Esplanade, Battery Point Hobart TAS7004Australia
| | - Graham J. Edgar
- Institute for Marine and Antarctic Studies University of Tasmania 20 Castray Esplanade, Battery Point Hobart TAS7004Australia
| | - Rowan Trebilco
- Institute for Marine and Antarctic Studies University of Tasmania 20 Castray Esplanade, Battery Point Hobart TAS7004Australia
- CSIRO Oceans and Atmosphere Battery Point Hobart TAS7004Australia
| | - Rick D. Stuart‐Smith
- Institute for Marine and Antarctic Studies University of Tasmania 20 Castray Esplanade, Battery Point Hobart TAS7004Australia
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Seasonal and ontogenetic variation of whiting diet in the Eastern English Channel and the Southern North Sea. PLoS One 2020; 15:e0239436. [PMID: 32966332 PMCID: PMC7511009 DOI: 10.1371/journal.pone.0239436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 09/05/2020] [Indexed: 11/19/2022] Open
Abstract
An accurate description of trophic interactions is crucial to understand ecosystem functioning and sustainably manage marine ecosystems exploitation. Carbon and nitrogen stable isotopes were coupled with stomach content analyses to investigate whiting (Merlangius merlangus, Linnaeus, 1758) feeding behavior in the Eastern English Channel and Southern North Sea. Whiting juveniles and adults were sampled in autumn and winter to investigate both ontogenetic and seasonal changes. In addition, queen scallops (Aequipecten opercularis) samples were collected along with fish to be used as isotopic benthic baseline. Results indicated an ontogenetic diet change from crustaceans to fish and cephalopods. In autumn, δ15N values generally increased with fish size while in winter, a decrease of δ15N values with fish size was observed, as a potential result of spatial variation in baseline δ15N values. In winter, a nutrient-poor period, an increase in feeding intensity was observed, especially on the copepod Temora longicornis. This study provides further insights into whiting trophic ecology in relation to ontogenetic and seasonal variations, and it confirms the importance of combining several trophic analysis methods to understand ecosystem functioning.
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van Langevelde F, Comor V, de Bie S, Prins HHT, Thakur MP. Disturbance regulates the density-body-mass relationship of soil fauna. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02019. [PMID: 31600842 PMCID: PMC7003476 DOI: 10.1002/eap.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/03/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Theory on the density-body-mass (DBM) relationship predicts that the density of animal species decreases by the power of -0.75 per unit increase in their body mass, or by the power of -1 when taxa across trophic levels are studied. This relationship is, however, largely debated, as the slope often deviates from the theoretical predictions. Here, we tested the ability of the DBM relationship to reflect changes in the structure of communities subjected to an anthropogenic disturbance. The slope would become less steep if smaller animals were more impacted by the disturbance than the larger ones, whereas the slope would become steeper if larger animals were more affected than the smaller ones. We tested the changes in the DBM relationship by sampling soil fauna, i.e., nematodes, Collembola, and larger arthropods, from a semiarid grassland before and after spraying diesel fuel as disturbance. We applied three different treatments: a control, a light disturbance, and an intense disturbance. We found that the slopes of the DBM relationships before the disturbance were around -1 as predicted by theory. The slope became more positive (i.e., less steep) just after the disturbance, especially after the intense disturbance as smaller fauna suffered the most and early colonizers had larger body mass. Interestingly, we observed that the slopes converged back to -1 by 2 months post-disturbance. Our findings show that the response of soil fauna communities to anthropogenic disturbances could explain the large variation in observed slopes of the DBM relationships. We experimentally demonstrate that an animal community, when disturbed, shows a temporal pattern of DBM relationships ranging from deviations from the predicted slope to convergence to the predicted slope with time. We recommend that deviations in the DBM relationships after disturbances can provide insights in the trajectory of community recovery, and hence could be used for biomonitoring.
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Affiliation(s)
- Frank van Langevelde
- Resource Ecology GroupWageningen UniversityDroevendaalsesteeg 3aWageningen6708 PBThe Netherlands
- School of Life SciencesUniversity of KwaZulu‐NatalWestville CampusDurban4000South Africa
| | - Vincent Comor
- Resource Ecology GroupWageningen UniversityDroevendaalsesteeg 3aWageningen6708 PBThe Netherlands
| | - Steven de Bie
- Resource Ecology GroupWageningen UniversityDroevendaalsesteeg 3aWageningen6708 PBThe Netherlands
| | - Herbert H. T. Prins
- Resource Ecology GroupWageningen UniversityDroevendaalsesteeg 3aWageningen6708 PBThe Netherlands
| | - Madhav P. Thakur
- Department of Terrestrial EcologyNetherlands Institute of Ecology (NIOO‐KNAW)Droevendaalsesteeg 10Wageningen6708 PBThe Netherlands
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Arranz I, Hsieh CH, Mehner T, Brucet S. Systematic deviations from linear size spectra of lake fish communities are correlated with predator-prey interactions and lake-use intensity. OIKOS 2018. [DOI: 10.1111/oik.05355] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ignasi Arranz
- Univ. of Vic - Central Univ. of Catalonia, Vic; Catalonia Spain
- Dept of Biology, Concordia Univ; Montréal QC Canada
| | - Chih-hao Hsieh
- Inst. of Oceanography, Inst. of Ecology and Evolutionary Biology, Dept of Life Science, National Taiwan Univ; Taipei Taiwan
- Research Center for Environmental Changes, Academia Sinica; Taipei Taiwan
| | - Thomas Mehner
- Leibniz-Inst. of Freshwater Ecology and Inland Fisheries; Berlin Germany
| | - Sandra Brucet
- Univ. of Vic - Central Univ. of Catalonia, Vic; Catalonia Spain
- ICREA, Catalan Inst. for Research and Advanced Studies; Barcelona Catalonia Spain
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Mulder C, Mancinelli G. Contextualizing macroecological laws: A big data analysis on electrofishing and allometric scalings in Ohio, USA. ECOLOGICAL COMPLEXITY 2017. [DOI: 10.1016/j.ecocom.2017.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Edwards AM, Robinson JPW, Plank MJ, Baum JK, Blanchard JL. Testing and recommending methods for fitting size spectra to data. Methods Ecol Evol 2016. [DOI: 10.1111/2041-210x.12641] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew M. Edwards
- Pacific Biological Station, Fisheries and Oceans Canada 3190 Hammond Bay Road Nanaimo BC V9T 6N7 Canada
- Department of Biology University of Victoria PO Box 1700 STN CSC Victoria BC V8W 2Y2 Canada
| | - James P. W. Robinson
- Department of Biology University of Victoria PO Box 1700 STN CSC Victoria BC V8W 2Y2 Canada
| | - Michael J. Plank
- School of Mathematics and Statistics University of Canterbury Christchurch 8140 New Zealand
- Te Pūnaha Matatini, a New Zealand Centre of Research Excellence University of Auckland Auckland 1011 New Zealand
| | - Julia K. Baum
- Department of Biology University of Victoria PO Box 1700 STN CSC Victoria BC V8W 2Y2 Canada
| | - Julia L. Blanchard
- Institute for Marine and Antarctic Studies University of Tasmania Private Bag 129 Hobart TAS 7001 Australia
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Broadway KJ, Pyron M, Gammon JR, Murry BA. Shift in a large river fish assemblage: body-size and trophic structure dynamics. PLoS One 2015; 10:e0124954. [PMID: 25902144 PMCID: PMC4406865 DOI: 10.1371/journal.pone.0124954] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/20/2015] [Indexed: 11/23/2022] Open
Abstract
As the intensity and speed of environmental change increase at both local and global scales it is imperative that we gain a better understanding of the ecological implications of community shifts. While there has been substantial progress toward understanding the drivers and subsequent responses of community change (e.g. lake trophic state), the ecological impacts of food web changes are far less understood. We analyzed Wabash River fish assemblage data collected from 1974-2008, to evaluate temporal variation in body-size structure and functional group composition. Two parameters derived from annual community size-spectra were our major response variables: (1) the regression slope is an index of ecological efficiency and predator-prey biomass ratios, and (2) spectral elevation (regression midpoint height) is a proxy for food web capacity. We detected a large assemblage shift, over at least a seven year period, defined by dramatic changes in abundance (measured as catch-per-unit-effort) of the dominant functional feeding groups among two time periods; from an assemblage dominated by planktivore-omnivores to benthic invertivores. There was a concurrent increase in ecological efficiency (slopes increased over time) following the shift associated with an increase in large-bodied low trophic level fish. Food web capacity remained relatively stable with no clear temporal trends. Thus, increased ecological efficiency occurred simultaneous to a compensatory response that shifted biomass among functional feeding groups.
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Affiliation(s)
- Kyle J. Broadway
- Institute for Great Lakes Research, Biology Dept., Central Michigan University, Mount Pleasant, MI 48858, United States of America
| | - Mark Pyron
- Department of Biology, Ball State University, Muncie, IN 47306, United States of America
| | - James R. Gammon
- Department of Biology, DePauw University, Greencastle, IN 46135, United States of America
| | - Brent A. Murry
- Institute for Great Lakes Research, Biology Dept., Central Michigan University, Mount Pleasant, MI 48858, United States of America
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Dossena M, Yvon-Durocher G, Grey J, Montoya JM, Perkins DM, Trimmer M, Woodward G. Warming alters community size structure and ecosystem functioning. Proc Biol Sci 2012; 279:3011-9. [PMID: 22496185 DOI: 10.1098/rspb.2012.0394] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Global warming can affect all levels of biological complexity, though we currently understand least about its potential impact on communities and ecosystems. At the ecosystem level, warming has the capacity to alter the structure of communities and the rates of key ecosystem processes they mediate. Here we assessed the effects of a 4°C rise in temperature on the size structure and taxonomic composition of benthic communities in aquatic mesocosms, and the rates of detrital decomposition they mediated. Warming had no effect on biodiversity, but altered community size structure in two ways. In spring, warmer systems exhibited steeper size spectra driven by declines in total community biomass and the proportion of large organisms. By contrast, in autumn, warmer systems had shallower size spectra driven by elevated total community biomass and a greater proportion of large organisms. Community-level shifts were mirrored by changes in decomposition rates. Temperature-corrected microbial and macrofaunal decomposition rates reflected the shifts in community structure and were strongly correlated with biomass across mesocosms. Our study demonstrates that the 4°C rise in temperature expected by the end of the century has the potential to alter the structure and functioning of aquatic ecosystems profoundly, as well as the intimate linkages between these levels of ecological organization.
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Affiliation(s)
- Matteo Dossena
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
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Arim M, Berazategui M, Barreneche JM, Ziegler L, Zarucki M, Abades SR. Determinants of Density–Body Size Scaling Within Food Webs and Tools for Their Detection. ADV ECOL RES 2011. [DOI: 10.1016/b978-0-12-386475-8.00001-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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Arim M, Abades SR, Laufer G, Loureiro M, Marquet PA. Food web structure and body size: trophic position and resource acquisition. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2009.17768.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Anderson C, Cabana G. Anthropogenic alterations of lotic food web structure: evidence from the use of nitrogen isotopes. OIKOS 2009. [DOI: 10.1111/j.1600-0706.2009.17368.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Blanchard JL, Jennings S, Law R, Castle MD, McCloghrie P, Rochet MJ, Benoît E. How does abundance scale with body size in coupled size-structured food webs? J Anim Ecol 2009; 78:270-80. [DOI: 10.1111/j.1365-2656.2008.01466.x] [Citation(s) in RCA: 173] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Jennings S, Barnes C, Sweeting CJ, Polunin NVC. Application of nitrogen stable isotope analysis in size-based marine food web and macroecological research. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:1673-1680. [PMID: 18438766 DOI: 10.1002/rcm.3497] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Interacting human and environmental pressures influence the structure and dynamics of marine food webs. To describe and predict the effects of these pressures, theoretical advances need to be supported by a capacity to validate the underlying models and assumptions. Here, we review recent applications of nitrogen stable isotope analysis in marine food web and macroecological research, with a focus on work that has paralleled a resurgence of interest in the development and application of size-based models. Nitrogen stable isotope data have been used to estimate intra- and inter-specific variation in trophic level, predator-prey size ratios, transfer efficiency, food chain length, relationships between predator and prey species diversity and the dynamics of energy use. Many of these estimates have contributed to the development, testing and parameterisation of food web and ecosystem models, some of which have been used to establish baselines for assessing the scale of human impacts. The interpretation of results depends on assumed fractionation but, when supported by sensitivity analyses and experimental validation, nitrogen stable isotope data provide valuable insights into the structuring of marine communities and ecosystems.
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Affiliation(s)
- Simon Jennings
- Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft NR33 0HT, UK.
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Predicting the abundance of European stream macroinvertebrates using biological attributes. Oecologia 2008; 156:65-73. [PMID: 18270744 DOI: 10.1007/s00442-008-0972-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 01/10/2008] [Indexed: 10/22/2022]
Abstract
Is there a relationship between the abundance of organisms and particular biological attributes? To assess this old, yet still acutely debated key question of ecology, we have used large databases on 312 stream macroinvertebrate genera (from 27 orders) that describe (1) invertebrate abundance at 527 least human-impacted European stream sites, (2) 11 biological traits (size, life-history, food, among others) described in 61 biological trait categories (BTCs; e.g. small, intermediate or large size) and (3) 14 attributes indicating specialization (AISs; e.g. species richness, size and food diversity). We applied interactive procedures to obtain models (for BTCs, AISs and a mixture of both descriptions) explaining as much as possible of the abundance variability of the genera with the lowest number of significant and ecologically meaningful attributes and assessed the predictive power of these models (in crosswise validations) by comparing predicted and observed abundances. Mean European invertebrate abundance increased with BTC affinities favouring viability in stream systems (e.g. attachment to the stream bottom to resist the flow, aquatic passive dispersal with the flow, exploitation of abundant food sources) and decreased with BTC affinities disfavouring this viability (e.g. drag force increase associated with larger body size, flow exposure associated with aerial respiration). Abundance consistently decreased with specialization of the genera (e.g. low species richness, oddity of their overall BTC profile from an "average" European genus). The model including a mixture of a few BTCs and AISs had the greatest predictive power: it predicted 35% of the observed abundance (ln-transformed) variability of the genera; these predictions were marginally affected by taxonomy (using orders as categorical variables). We conclude that a better appreciation of the influence of the examined taxonomic diversity, number and type of biological attributes, environmental system and spatial scale could enable abundance predictions using different sets of biological attributes for different taxonomic groups and systems.
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Jennings S, De Oliveira JAA, Warr KJ. Measurement of body size and abundance in tests of macroecological and food web theory. J Anim Ecol 2007; 76:72-82. [PMID: 17184355 DOI: 10.1111/j.1365-2656.2006.01180.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Mean body mass (W) and mean numerical (N) or biomass (B) abundance are frequently used as variables to describe populations and species in macroecological and food web studies. 2. We investigate how the use of mean W and mean N or B, rather than other measures of W and/or accounting for the properties of all individuals, can affect the outcome of tests of macroecological and food web theory. 3. Theoretical and empirical analyses demonstrate that mean W, W at maximum biomass (W(mb)), W when energy requirements are greatest (W(me)) and the W when a species uses the greatest proportion of the energy available to all species in a W class (W(mpe)) are not consistently related. 4. For a population at equilibrium, relationships between mean W and W(me) depend on the slope b of the relationship between trophic level and W. For marine fishes, data show that b varies widely among species and thus mean W is an unreliable indicator of the role of a species in the food web. 5. Two different approaches, 'cross-species' and 'all individuals' have been used to estimate slopes of abundance-body mass relationships and to test the energetic equivalence hypothesis and related theory. The approaches, based on relationships between (1) log(10) mean W and log(10) mean N or B, and (2) log(10) W and log(10) N or B of all individuals binned into log(10) W classes (size spectra), give different slopes and confidence intervals with the same data. 6. Our results show that the 'all individuals' approach has the potential to provide more powerful tests of the energetic equivalence hypothesis and role of energy availability in determining slopes, but new theory and empirical analysis are needed to explain distributions of species relative abundance at W. 7. Biases introduced when working with mean W in macroecological and food web studies are greatest when species have indeterminate growth, when relationships between W and trophic level are strong and when the range of species'W is narrow.
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Affiliation(s)
- Simon Jennings
- Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, Lowestoft, NR33 0HT, UK.
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