1
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Matthews AE. Empirically tuned theory reveals why symbiont abundance 'mite' vary across hosts. J Anim Ecol 2024; 93:373-376. [PMID: 38351463 DOI: 10.1111/1365-2656.14057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 01/28/2024] [Indexed: 04/04/2024]
Abstract
Research Highlight: del Mar Labrador, M., Serrano, D., Doña, J., Aguilera, E., Arroyo, J. L., Atiénzar, F., Barba, E., Bermejo, A., Blanco, G., Borràs, A., Calleja, J. A., Cantó, J. L., Cortés, V., de la Puente, J., de Palacio, D., Fernández-González, S., Figuerola, J., Frías, Ó., Fuertes-Marcos, B. Garamszegi, L. Z., Gordo, Ó., Gurpegui, M., Kovács, I., Martínez, J. L., Meléndez, L., Mestre, A., Møller, A. P., Monrós, J. S., Moreno-Opo, R., Navarro, C., Pap, P. L., Pérez-Tris, J., Piculo, R., Ponce, C., Proctor, H., Rodríguez, R., Sallent, Á., Senar, J., Tella, J. L., Vágási, C. I., Vögeli, M., & Jovani, R. (2023). Host space, not energy or symbiont size, constrains feather mite abundance across passerine bird species. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.14032. Symbionts represent crucial links between species in ecosystems. Consequently, understanding their patterns of abundance is a major goal in the study of symbioses. However, multiple biotic and abiotic factors may regulate symbionts, and disentangling the mechanisms that drive variation in their abundance across host species is challenging. One promising strategy to approach this challenge is to incorporate biologically relevant data into theoretical models. In a recent study, Labrador et al. (2023) used this strategy to investigate the poorly understood symbiosis between feather mites and their avian hosts. They integrate a remarkable amount of empirical data with models based on the metabolic theory of ecology to determine what factors limit feather mite abundance across European passerines. Their quantitative analyses indicate that the number of feather barbs limits mite abundance across host species, suggesting that mite populations are spatially, but not energetically, constrained. These findings not only reveal mechanisms that may drive the variation in feather mite abundances across hosts, but also advance our understanding of the ecology of interspecific interactions more generally.
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Affiliation(s)
- Alix E Matthews
- College of Sciences and Mathematics and Molecular Biosciences Program, Arkansas State University, Jonesboro, Arkansas, USA
- Department of Biological Sciences, Arkansas State University, Jonesboro, Arkansas, USA
- Department of Biology, Rhodes College, Memphis, Tennessee, USA
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2
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Kindsvater HK, Juan‐Jordá M, Dulvy NK, Horswill C, Matthiopoulos J, Mangel M. Size-dependence of food intake and mortality interact with temperature and seasonality to drive diversity in fish life histories. Evol Appl 2024; 17:e13646. [PMID: 38333556 PMCID: PMC10848883 DOI: 10.1111/eva.13646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 12/06/2023] [Accepted: 01/05/2024] [Indexed: 02/10/2024] Open
Abstract
Understanding how growth and reproduction will adapt to changing environmental conditions is a fundamental question in evolutionary ecology, but predicting the responses of specific taxa is challenging. Analyses of the physiological effects of climate change upon life history evolution rarely consider alternative hypothesized mechanisms, such as size-dependent foraging and the risk of predation, simultaneously shaping optimal growth patterns. To test for interactions between these mechanisms, we embedded a state-dependent energetic model in an ecosystem size-spectrum to ask whether prey availability (foraging) and risk of predation experienced by individual fish can explain observed diversity in life histories of fishes. We found that asymptotic growth emerged from size-based foraging and reproductive and mortality patterns in the context of ecosystem food web interactions. While more productive ecosystems led to larger body sizes, the effects of temperature on metabolic costs had only small effects on size. To validate our model, we ran it for abiotic scenarios corresponding to the ecological lifestyles of three tuna species, considering environments that included seasonal variation in temperature. We successfully predicted realistic patterns of growth, reproduction, and mortality of all three tuna species. We found that individuals grew larger when environmental conditions varied seasonally, and spawning was restricted to part of the year (corresponding to their migration from temperate to tropical waters). Growing larger was advantageous because foraging and spawning opportunities were seasonally constrained. This mechanism could explain the evolution of gigantism in temperate tunas. Our approach addresses variation in food availability and individual risk as well as metabolic processes and offers a promising approach to understand fish life-history responses to changing ocean conditions.
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Affiliation(s)
- Holly K. Kindsvater
- Department of Fish and Wildlife ConservationVirginia Polytechnic Institute and State UniversityBlacksburgVirginiaUSA
| | - Maria‐José Juan‐Jordá
- Earth to Ocean Research Group, Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA)GipuzkoaSpain
- Instituto Español de Oceanografía (IEO‐CSIC), Centro Oceanográfico de MadridMadridSpain
| | - Nicholas K. Dulvy
- Earth to Ocean Research Group, Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
| | - Cat Horswill
- ZSL Institute of ZoologyLondonUK
- Centre for Biodiversity and Environmental Research, Department of Genetics, Evolution and EnvironmentUniversity College LondonLondonUK
| | - Jason Matthiopoulos
- Institute of Biodiversity, One Health and Veterinary MedicineUniversity of GlasgowGlasgowUK
| | - Marc Mangel
- Theoretical Ecology Group, Department of BiologyUniversity of BergenBergenNorway
- Institute of Marine Sciences and Department of Applied Mathematics and StatisticsUniversity of CaliforniaSanta CruzCaliforniaUSA
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3
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Abraham JO, Rowan J, O'Brien K, Sokolowski KG, Faith JT. Environmental context shapes the relationship between grass consumption and body size in African herbivore communities. Ecol Evol 2024; 14:e11050. [PMID: 38362169 PMCID: PMC10867881 DOI: 10.1002/ece3.11050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/24/2024] [Accepted: 02/05/2024] [Indexed: 02/17/2024] Open
Abstract
Though herbivore grass dependence has been shown to increase with body size across herbivore species, it is unclear whether this relationship holds at the community level. Here we evaluate whether grass consumption scales positively with body size within African large mammalian herbivore communities and how this relationship varies with environmental context. We used stable carbon isotope and community occurrence data to investigate how grass dependence scales with body size within 23 savanna herbivore communities throughout eastern and central Africa. We found that dietary grass fraction increased with body size for the majority of herbivore communities considered, especially when complete community data were available. However, the slope of this relationship varied, and rainfall seasonality and elephant presence were key drivers of the variation-grass dependence increased less strongly with body size where rainfall was more seasonal and where elephants were present. We found also that the dependence of the herbivore community as a whole on grass peaked at intermediate woody cover. Intraspecific diet variation contributed to these community-level patterns: common hippopotamus (Hippopotamus amphibius) and giraffe (Giraffa camelopardalis) ate less grass where rainfall was more seasonal, whereas Cape buffalo (Syncerus caffer) and savanna elephant (Loxodonta africana) grass consumption were parabolically related to woody cover. Our results indicate that general rules appear to govern herbivore community assembly, though some aspects of herbivore foraging behavior depend upon local environmental context.
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Affiliation(s)
- Joel O. Abraham
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNew JerseyUSA
| | - John Rowan
- Department of AnthropologyUniversity at AlbanyAlbanyNew YorkUSA
| | - Kaedan O'Brien
- Department of AnthropologyUniversity of UtahSalt Lake CityUtahUSA
- Natural History Museum of UtahUniversity of UtahSalt Lake CityUtahUSA
| | - Kathryn G. Sokolowski
- Department of AnthropologyUniversity of UtahSalt Lake CityUtahUSA
- Natural History Museum of UtahUniversity of UtahSalt Lake CityUtahUSA
| | - J. Tyler Faith
- Department of AnthropologyUniversity of UtahSalt Lake CityUtahUSA
- Natural History Museum of UtahUniversity of UtahSalt Lake CityUtahUSA
- Origins CentreUniversity of the WitwatersrandJohannesburgSouth Africa
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4
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Gusmão RAF, Tessarolo G, Dobrovolski R, Gonçalves‐Souza T. Body size and trophic structure explain global asymmetric response of tetrapod diversity to climate effects. Ecol Evol 2024; 14:e11047. [PMID: 38380066 PMCID: PMC10877556 DOI: 10.1002/ece3.11047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 02/22/2024] Open
Abstract
Although climate-based hypotheses are widely used to explain large-scale diversity patterns, they fall short of explaining the spatial variation among taxonomic groups. Integrating food web and metabolic theories into macroecology is a promising step forward, as they allow including explicit taxon-specific traits that can potentially mediate the relationship between climate and diversity. Our investigation focuses on the role of body size and trophic structure in mediating the influence of contemporary climate and historical climate change on global tetrapods species richness. We used piecewise structural equation modeling to assess the direct effects of contemporary climate and climate instability of species richness and the indirect effects of climate on tetrapod richness mediated by community-wide species traits. We found that birds and mammals are less sensitive to the direct effect of contemporary climate than amphibians and squamates. Contemporary climate and climate instability favored the species richness of mammals and amphibians. However, for birds and squamates, this link is only associated with contemporary climate. Moreover, we showed that community-wide traits are correlated with species richness gradients. However, we highlight that this relationship is dependent upon the specific traits and taxonomic groups. Specifically, bird communities with smaller bodies and bottom-heavy structures support higher species richness. Squamates also tend to be more diverse in communities with prevalence of smaller bodies, while mammals are correlated with top-heavy structures. Moreover, we showed that higher contemporary climate and climate instability reduce the species richness of birds and mammals through community-wide traits and indirectly increase squamate species richness. We also showed that body size and trophic structure are driving a global asymmetric response of tetrapod diversity to climate effects, which highlights the limitation to use the "typical" climate-based hypotheses. Furthermore, by combining multiple theories, our research contributes to a more realistic and mechanistic understanding of diversity patterns across taxonomic groups.
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Affiliation(s)
- Reginaldo A. F. Gusmão
- Graduate Program in Ethnobiology and Nature Conservation, Department of BiologyFederal Rural University of PernambucoRecifeBrazil
| | - Geiziane Tessarolo
- Laboratory of Biogeography and Aquatic EcologyState University of GoiásAnápolisBrazil
| | | | - Thiago Gonçalves‐Souza
- Graduate Program in Ethnobiology and Nature Conservation, Department of BiologyFederal Rural University of PernambucoRecifeBrazil
- Institute for Global Change Biology, School for Environment and SustainabilityUniversity of MichiganAnn ArborMichiganUSA
- Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborMichiganUSA
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5
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García-Gómez G, Hirst AG, Spencer M, Atkinson D. Responses of intraspecific metabolic scaling to temperature and activity differ between water- and air-breathing ectothermic vertebrates. Ecol Lett 2024; 27:e14389. [PMID: 38382913 DOI: 10.1111/ele.14389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 02/01/2024] [Accepted: 02/08/2024] [Indexed: 02/23/2024]
Abstract
Metabolism underpins all life-sustaining processes and varies profoundly with body size, temperature and locomotor activity. A current theory explains some of the size-dependence of metabolic rate (its mass exponent, b) through changes in metabolic level (L). We propose two predictive advances that: (a) combine the above theory with the evolved avoidance of oxygen limitation in water-breathers experiencing warming, and (b) quantify the overall magnitude of combined temperatures and degrees of locomotion on metabolic scaling across air- and water-breathers. We use intraspecific metabolic scaling responses to temperature (523 regressions) and activity (281 regressions) in diverse ectothermic vertebrates (fish, reptiles and amphibians) to show that b decreases with temperature-increased L in water-breathers, supporting surface area-related avoidance of oxygen limitation, whereas b increases with activity-increased L in air-breathers, following volume-related influences. This new theoretical integration quantitatively incorporates different influences (warming, locomotion) and respiration modes (aquatic, terrestrial) on animal energetics.
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Affiliation(s)
| | - Andrew G Hirst
- School of Environmental Sciences, University of Liverpool, Liverpool, UK
- School of Animal, Rural and Environmental Sciences, Nottingham Trent University, Nottingham, UK
- Centre for Ocean Life, National Institute for Aquatic Resources, Technical University of Denmark, Charlottenlund, Denmark
| | - Matthew Spencer
- School of Environmental Sciences, University of Liverpool, Liverpool, UK
| | - David Atkinson
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, UK
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6
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McGrath MJ, Schulte-Frohlinde A, Luyssaert S. New ways for (in)validating the forest carbon neutrality hypothesis. Glob Chang Biol 2024; 30:e16982. [PMID: 37902299 DOI: 10.1111/gcb.16982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 09/18/2023] [Accepted: 09/23/2023] [Indexed: 10/31/2023]
Abstract
Over 50 years ago, Eugene Odum postulated that mature or climax forests reside in carbon neutrality. As climate change rose to prominence in the international environmental agenda, the neutrality hypothesis transformed from an ecological principle to a justification for using forest management in combating climate change. Despite persistent efforts, Odum's neutrality hypothesis has resisted both confirmation and refutation. In this opinion we show the limitations of past efforts to (in)validate Odum's neutrality hypothesis and propose new research directions for the community to permit a more general confirmation or refutation with current and near-future observations. We then demonstrate such an approach by using metabolic theory to formulate testable predictions for the total sink strength considering soil, litter, and biomass of mature or climax forests based on observations of tree biomass and individual density. In doing so, we show that ecological theory can create additional relevant, testable hypotheses to provide timely support to decision-makers seeking to address one of the world's most pressing environmental challenges.
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Grants
- 101060309 Directorate-General XII, Science, Research, and Development
- 776810 Directorate-General XII, Science, Research, and Development
- 958927 Directorate-General XII, Science, Research, and Development
- SEP-210673589 Directorate-General XII, Science, Research, and Development
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Affiliation(s)
- Matthew Joseph McGrath
- Laboratoire des Sciences du Climat et de l'Environnement, UMR 8212 CEA-CNRS-UVSQ, Gif-sur-Yvette, France
| | - Augustine Schulte-Frohlinde
- Amsterdam Institute for Life and Environment, Department of Ecological Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Sebastiaan Luyssaert
- Amsterdam Institute for Life and Environment, Department of Ecological Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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7
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Taboada FG, Chust G, Santos Mocoroa M, Aldanondo N, Fontán A, Cotano U, Álvarez P, Erauskin-Extramiana M, Irigoien X, Fernandes-Salvador JA, Boyra G, Uriarte A, Ibaibarriaga L. Shrinking body size of European anchovy in the Bay of Biscay. Glob Chang Biol 2024; 30:e17047. [PMID: 38273534 DOI: 10.1111/gcb.17047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 10/21/2023] [Accepted: 10/31/2023] [Indexed: 01/27/2024]
Abstract
Decreased body size is often cited as a major response to ocean warming. Available evidence, however, questions the actual emergence of shrinking trends and the prevalence of temperature-driven changes in size over alternative drivers. In marine fish, changes in food availability or fluctuations in abundance, including those due to size-selective fishing, provide compelling mechanisms to explain changes in body size. Here, based on three decades of scientific survey data (1990-2021), we report a decline in the average body size-length and weight-of anchovy, Engraulis encrasicolus L., in the Bay of Biscay. Shrinking was evident in all age classes, from juveniles to adults. Allometric adjustment indicated slightly more pronounced declines in weight than in total length, which is consistent with a change toward a slender body shape. Trends in adult weight were nonlinear, with rates accelerating to an average decline of up to 25% decade-1 during the last two decades. We found a strong association between higher anchovy abundance and reduced juvenile size. The effect of density dependence was less clear later in life, and temperature became the best predictor of declines in adult size. Theoretical analyses based on a strategic model further suggested that observed patterns are consistent with a simultaneous, opposing effect of rising temperatures on accelerating early growth and decreasing adult size as predicted by the temperature-size rule. Macroecological assessment of ecogeographical-Bergmann's and James'-rules in anchovy size suggested that the observed decline largely exceeds intraspecific variation and might be the result of selection. Limitations inherent in the observational nature of the study recommend caution and a continued assessment and exploration of alternative drivers. Additional evidence of a climate-driven regime shift in the region suggests, however, that shrinking anchovy sizes may signal a long-lasting change in the structure and functioning of the Bay of Biscay ecosystem.
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Affiliation(s)
- Fernando G Taboada
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | - Guillem Chust
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | - María Santos Mocoroa
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | - Naroa Aldanondo
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | - Almudena Fontán
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | - Unai Cotano
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | - Paula Álvarez
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | | | - Xabier Irigoien
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | | | - Guillermo Boyra
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | - Andrés Uriarte
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | - Leire Ibaibarriaga
- AZTI Marine Research, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
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8
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Collyer G, Perkins DM, Petsch DK, Siqueira T, Saito V. Land-use intensification systematically alters the size structure of aquatic communities in the Neotropics. Glob Chang Biol 2023; 29:4094-4106. [PMID: 37059700 DOI: 10.1111/gcb.16720] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 03/16/2023] [Accepted: 03/24/2023] [Indexed: 05/03/2023]
Abstract
Land-use and land-cover transitions can affect biodiversity and ecosystem functioning in a myriad of ways, including how energy is transferred within food-webs. Size spectra (i.e. relationships between body size and biomass or abundance) provide a means to assess how food-webs respond to environmental stressors by depicting how energy is transferred from small to larger organisms. Here, we investigated changes in the size spectrum of aquatic macroinvertebrates along a broad land-use intensification gradient (from Atlantic Forest to mechanized agriculture) in 30 Brazilian streams. We expected to find a steeper size spectrum slope and lower total biomass in more disturbed streams due to higher energetic expenditure in physiologically stressful conditions, which has a disproportionate impact on large individuals. As expected, we found that more disturbed streams had fewer small organisms than pristine forest streams, but, surprisingly, they had shallower size spectrum slopes, which indicates that energy might be transferred more efficiently in disturbed streams. Disturbed streams were also less taxonomically diverse, suggesting that the potentially higher energy transfer in these webs might be channelled via a few efficient trophic links. However, because total biomass was higher in pristine streams, these sites still supported a greater number of larger organisms and longer food chains (i.e. larger size range). Our results indicate that land-use intensification decreases ecosystem stability and enhances vulnerability to population extinctions by reducing the possible energetic pathways while enhancing efficiency between the remaining food-web linkages. Our study represents a step forward in understanding how land-use intensification affects trophic interactions and ecosystem functioning in aquatic systems.
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Affiliation(s)
- Giovanna Collyer
- Graduate Program in Environmental Sciences, Federal University of São Carlos, São Carlos, Brazil
| | - Daniel M Perkins
- School of Life and Health Sciences, University of Roehampton, London, UK
| | - Danielle K Petsch
- Oceanography and Limnology Department, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Tadeu Siqueira
- Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Victor Saito
- Environmental Sciences Department, Federal University of São Carlos, São Carlos, Brazil
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9
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Udyawer V, Huveneers C, Jaine F, Babcock RC, Brodie S, Buscot MJ, Campbell HA, Harcourt RG, Hoenner X, Lédée EJI, Simpfendorfer CA, Taylor MD, Armstrong A, Barnett A, Brown C, Bruce B, Butcher PA, Cadiou G, Couturier LIE, Currey-Randall L, Drew M, Dudgeon CL, Dwyer RG, Espinoza M, Ferreira LC, Fowler A, Harasti D, Harborne AR, Knott NA, Lee K, Lloyd M, Lowry M, Marzullo T, Matley J, McAllister JD, McAuley R, McGregor F, Meekan M, Mills K, Norman BM, Oh B, Payne NL, Peddemors V, Piddocke T, Pillans RD, Reina RD, Rogers P, Semmens JM, Smoothey A, Speed CW, van der Meulen D, Heupel MR. Scaling of Activity Space in Marine Organisms across Latitudinal Gradients. Am Nat 2023; 201:586-602. [PMID: 36958006 DOI: 10.1086/723405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractUnifying models have shown that the amount of space used by animals (e.g., activity space, home range) scales allometrically with body mass for terrestrial taxa; however, such relationships are far less clear for marine species. We compiled movement data from 1,596 individuals across 79 taxa collected using a continental passive acoustic telemetry network of acoustic receivers to assess allometric scaling of activity space. We found that ectothermic marine taxa do exhibit allometric scaling for activity space, with an overall scaling exponent of 0.64. However, body mass alone explained only 35% of the variation, with the remaining variation best explained by trophic position for teleosts and latitude for sharks, rays, and marine reptiles. Taxon-specific allometric relationships highlighted weaker scaling exponents among teleost fish species (0.07) than sharks (0.96), rays (0.55), and marine reptiles (0.57). The allometric scaling relationship and scaling exponents for the marine taxonomic groups examined were lower than those reported from studies that had collated both marine and terrestrial species data derived using various tracking methods. We propose that these disparities arise because previous work integrated summarized data across many studies that used differing methods for collecting and quantifying activity space, introducing considerable uncertainty into slope estimates. Our findings highlight the benefit of using large-scale, coordinated animal biotelemetry networks to address cross-taxa evolutionary and ecological questions.
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10
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Lindmark M, Audzijonyte A, Blanchard JL, Gårdmark A. Temperature impacts on fish physiology and resource abundance lead to faster growth but smaller fish sizes and yields under warming. Glob Chang Biol 2022; 28:6239-6253. [PMID: 35822557 PMCID: PMC9804230 DOI: 10.1111/gcb.16341] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 05/28/2022] [Accepted: 06/27/2022] [Indexed: 05/29/2023]
Abstract
Resolving the combined effect of climate warming and exploitation in a food web context is key for predicting future biomass production, size-structure and potential yields of marine fishes. Previous studies based on mechanistic size-based food web models have found that bottom-up processes are important drivers of size-structure and fisheries yield in changing climates. However, we know less about the joint effects of 'bottom-up' and physiological effects of temperature; how do temperature effects propagate from individual-level physiology through food webs and alter the size-structure of exploited species in a community? Here, we assess how a species-resolved size-based food web is affected by warming through both these pathways and by exploitation. We parameterize a dynamic size spectrum food web model inspired by the offshore Baltic Sea food web, and investigate how individual growth rates, size-structure, and relative abundances of species and yields are affected by warming. The magnitude of warming is based on projections by the regional coupled model system RCA4-NEMO and the RCP 8.5 emission scenario, and we evaluate different scenarios of temperature dependence on fish physiology and resource productivity. When accounting for temperature-effects on physiology in addition to on basal productivity, projected size-at-age in 2050 increases on average for all fish species, mainly for young fish, compared to scenarios without warming. In contrast, size-at-age decreases when temperature affects resource dynamics only, and the decline is largest for young fish. Faster growth rates due to warming, however, do not always translate to larger yields, as lower resource carrying capacities with increasing temperature tend to result in decline in the abundance of larger fish and hence spawning stock biomass. These results suggest that to understand how global warming affects the size structure of fish communities, both direct metabolic effects and indirect effects of temperature via basal resources must be accounted for.
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Affiliation(s)
- Max Lindmark
- Department of Aquatic Resources, Institute of Coastal ResearchSwedish University of Agricultural SciencesÖregrundSweden
| | - Asta Audzijonyte
- Nature Research CentreVilniusLithuania
- Institute for Marine and Antarctic Studies and Centre for Marine SocioecologyUniversity of TasmaniaHobartTasmaniaAustralia
| | - Julia L. Blanchard
- Institute for Marine and Antarctic Studies and Centre for Marine SocioecologyUniversity of TasmaniaHobartTasmaniaAustralia
| | - Anna Gårdmark
- Department of Aquatic ResourcesSwedish University of Agricultural SciencesUppsalaSweden
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11
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Peacock SJ, Kutz SJ, Hoar BM, Molnár PK. Behaviour is more important than thermal performance for an Arctic host-parasite system under climate change. R Soc Open Sci 2022; 9:220060. [PMID: 36016913 PMCID: PMC9399711 DOI: 10.1098/rsos.220060] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 08/02/2022] [Indexed: 05/10/2023]
Abstract
Climate change is affecting Arctic ecosystems, including parasites. Predicting outcomes for host-parasite systems is challenging due to the complexity of multi-species interactions and the numerous, interacting pathways by which climate change can alter dynamics. Increasing temperatures may lead to faster development of free-living parasite stages but also higher mortality. Interactions between behavioural plasticity of hosts and parasites will also influence transmission processes. We combined laboratory experiments and population modelling to understand the impacts of changing temperatures on barren-ground caribou (Rangifer tarandus) and their common helminth (Ostertagia gruehneri). We experimentally determined the thermal performance curves for mortality and development of free-living parasite stages and applied them in a spatial host-parasite model that also included behaviour of the parasite (propensity for arrested development in the host) and host (long-distance migration). Sensitivity analyses showed that thermal responses had less of an impact on simulated parasite burdens than expected, and the effect differed depending on parasite behaviour. The propensity for arrested development and host migration led to distinct spatio-temporal patterns in infection. These results emphasize the importance of considering behaviour-and behavioural plasticity-when projecting climate-change impacts on host-parasite systems.
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Affiliation(s)
- Stephanie J. Peacock
- Department of Ecosystem and Public Health, University of Calgary, 3280 Hospital Drive NW, Calgary, AB Canada, T2N 4Z6
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON Canada, M1C 1A4
| | - Susan J. Kutz
- Department of Ecosystem and Public Health, University of Calgary, 3280 Hospital Drive NW, Calgary, AB Canada, T2N 4Z6
| | - Bryanne M. Hoar
- Department of Ecosystem and Public Health, University of Calgary, 3280 Hospital Drive NW, Calgary, AB Canada, T2N 4Z6
| | - Péter K. Molnár
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON Canada, M1C 1A4
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON Canada, M5S 3B2
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12
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Abstract
At present, there is no simple, first principles-based, and general model for quantitatively describing the full range of observed biological temperature responses. Here we derive a general theory for temperature dependence in biology based on Eyring-Evans-Polanyi's theory for chemical reaction rates. Assuming only that the conformational entropy of molecules changes with temperature, we derive a theory for the temperature dependence of enzyme reaction rates which takes the form of an exponential function modified by a power law and that describes the characteristic asymmetric curved temperature response. Based on a few additional principles, our model can be used to predict the temperature response above the enzyme level, thus spanning quantum to classical scales. Our theory provides an analytical description for the shape of temperature response curves and demonstrates its generality by showing the convergence of all temperature dependence responses onto universal relationships-a universal data collapse-under appropriate normalization and by identifying a general optimal temperature, around 25 ∘C, characterizing all temperature response curves. The model provides a good fit to empirical data for a wide variety of biological rates, times, and steady-state quantities, from molecular to ecological scales and across multiple taxonomic groups (from viruses to mammals). This theory provides a simple framework to understand and predict the impact of temperature on biological quantities based on the first principles of thermodynamics, bridging quantum to classical scales.
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13
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Abstract
Species ranges are shifting in response to climate change, but most predictions disregard food-web interactions and, in particular, if and how such interactions change through time. Predator-prey interactions could speed up species range shifts through enemy release or create lags through biotic resistance. Here, we developed a spatially explicit model of interacting species, each with a thermal niche and embedded in a size-structured food-web across a temperature gradient that was then exposed to warming. We also created counterfactual single species models to contrast and highlight the effect of trophic interactions on range shifts. We found that dynamic trophic interactions hampered species range shifts across 450 simulated food-webs with up to 200 species each over 200 years of warming. All species experiencing dynamic trophic interactions shifted more slowly than single-species models would predict. In addition, the trailing edges of larger bodied species ranges shifted especially slowly because of ecological subsidies from small shifting prey. Trophic interactions also reduced the numbers of locally novel species, novel interactions and productive species, thus maintaining historical community compositions for longer. Current forecasts ignoring dynamic food-web interactions and allometry may overestimate species' tendency to track climate change.
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Affiliation(s)
- E W Tekwa
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA.,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - James R Watson
- College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Malin L Pinsky
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA
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14
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Phillips JA, Vargas Soto JS, Pawar S, Koprivnikar J, Benesh DP, Molnár PK. The effects of phylogeny, habitat and host characteristics on the thermal sensitivity of helminth development. Proc Biol Sci 2022; 289:20211878. [PMID: 35135354 PMCID: PMC8825990 DOI: 10.1098/rspb.2021.1878] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Helminth parasites are part of almost every ecosystem, with more than 300 000 species worldwide. Helminth infection dynamics are expected to be altered by climate change, but predicting future changes is difficult owing to lacking thermal sensitivity data for greater than 99.9% of helminth species. Here, we compiled the largest dataset to date on helminth temperature sensitivities and used the Metabolic Theory of Ecology to estimate activation energies (AEs) for parasite developmental rates. The median AE for 129 thermal performance curves was 0.67, similar to non-parasitic animals. Although exceptions existed, related species tended to have similar thermal sensitivities, suggesting some helminth taxa are inherently more affected by rising temperatures than others. Developmental rates were more temperature-sensitive for species from colder habitats than those from warmer habitats, and more temperature sensitive for species in terrestrial than aquatic habitats. AEs did not depend on whether helminth life stages were free-living or within hosts, whether the species infected plants or animals, or whether the species had an endotherm host in its life cycle. The phylogenetic conservatism of AE may facilitate predicting how temperature change affects the development of helminth species for which empirical data are lacking or difficult to obtain.
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Affiliation(s)
- Jessica Ann Phillips
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Department of Zoology, Oxford University, Oxford, UK
| | - Juan S Vargas Soto
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Laboratory of Quantitative Global Change Ecology, Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Samraat Pawar
- Department of Life Sciences, Imperial College London, Silwood Park, Ascot, UK
| | - Janet Koprivnikar
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Daniel P Benesh
- Molecular Parasitology, Humboldt University, Philippstr. 13, Haus 14, 10115 Berlin, Germany.,Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587 Berlin, Germany
| | - Péter K Molnár
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Laboratory of Quantitative Global Change Ecology, Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
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15
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Cerezer FO, Cáceres NC, Dambros CS. Effect of Productivity on Community Size Explains the Latitudinal Diversity Gradient of South American Small Mammals. Am Nat 2021; 198:E111-E121. [PMID: 34559610 DOI: 10.1086/716171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractAlthough many studies have shown that species richness increases from high to low latitudes (the latitudinal diversity gradient), the mechanisms responsible for generating and maintaining higher species richness in the tropics remain intensely debated. Here we investigate how the effects of temperature on speciation rates (kinetic effects) and the effects of productivity on community size (chemical effects) explain the latitudinal diversity gradient of South American small mammals. We implemented Bayesian models that integrate processes from the neutral and metabolic theories, comparing model predictions with empirical richness patterns. The neutral-metabolic model predicted the latitudinal richness gradient in South American small mammals. We found evidence that the effects of productivity on community size are more important for explaining differences in species richness than the effects of temperature on speciation rates. These results suggest that differences in species richness along latitudinal gradients are regulated primarily by the chemical effects of productivity on speciation-extinction dynamics.
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16
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Barreto E, Rangel TF, Coelho MTP, Cassemiro FAS, Zimmermann NE, Graham CH. Spatial variation in direct and indirect effects of climate and productivity on species richness of terrestrial tetrapods. Glob Ecol Biogeogr 2021; 30:1899-1908. [PMID: 34588924 PMCID: PMC8457120 DOI: 10.1111/geb.13357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 06/04/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
AIM We aimed to dissect the spatial variation of the direct and indirect effects of climate and productivity on global species richness of terrestrial tetrapods. LOCATION Global. TIME PERIOD Present. MAJOR TAXA STUDIED Terrestrial tetrapods. METHODS We used a geographically weighted path analysis to estimate and map the direct and indirect effects of temperature, precipitation and primary productivity on species richness of terrestrial tetrapods across the globe. RESULTS We found that all relationships shift in magnitude, and even in direction, among taxonomic groups, geographical regions and connecting paths. Direct effects of temperature and precipitation are generally stronger than both indirect effects mediated by productivity and direct effects of productivity. MAIN CONCLUSIONS Richness gradients seem to be driven primarily by effects of climate on organismal physiological limits and metabolic rates rather than by the amount of productive energy. Reptiles have the most distinct relationships across tetrapods, with a clear latitudinal pattern in the importance of temperature versus water.
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Affiliation(s)
- Elisa Barreto
- Programa de pós‐graduação em Ecologia e EvoluçãoUniversidade Federal de GoiásGoiâniaBrazil
- Swiss Federal Institute for Forest, Snow and LandscapeBirmensdorfSwitzerland
| | - Thiago F. Rangel
- Swiss Federal Institute for Forest, Snow and LandscapeBirmensdorfSwitzerland
- Departamento de EcologiaUniversidade Federal de GoiásGoiâniaBrazil
| | - Marco Túlio P. Coelho
- Programa de pós‐graduação em Ecologia e EvoluçãoUniversidade Federal de GoiásGoiâniaBrazil
| | - Fernanda A. S. Cassemiro
- Swiss Federal Institute for Forest, Snow and LandscapeBirmensdorfSwitzerland
- Departamento de EcologiaUniversidade Federal de GoiásGoiâniaBrazil
| | | | - Catherine H. Graham
- Swiss Federal Institute for Forest, Snow and LandscapeBirmensdorfSwitzerland
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17
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Schuster L, Cameron H, White CR, Marshall DJ. Metabolism drives demography in an experimental field test. Proc Natl Acad Sci U S A 2021; 118:e2104942118. [PMID: 34417293 PMCID: PMC8403948 DOI: 10.1073/pnas.2104942118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 07/19/2021] [Indexed: 12/21/2022] Open
Abstract
Metabolism should drive demography by determining the rates of both biological work and resource demand. Long-standing "rules" for how metabolism should covary with demography permeate biology, from predicting the impacts of climate change to managing fisheries. Evidence for these rules is almost exclusively indirect and in the form of among-species comparisons, while direct evidence is exceptionally rare. In a manipulative field experiment on a sessile marine invertebrate, we created experimental populations that varied in population size (density) and metabolic rate, but not body size. We then tested key theoretical predictions regarding relationships between metabolism and demography by parameterizing population models with lifetime performance data from our field experiment. We found that populations with higher metabolisms had greater intrinsic rates of increase and lower carrying capacities, in qualitative accordance with classic theory. We also found important departures from theory-in particular, carrying capacity declined less steeply than predicted, such that energy use at equilibrium increased with metabolic rate, violating the long-standing axiom of energy equivalence. Theory holds that energy equivalence emerges because resource supply is assumed to be independent of metabolic rate. We find this assumption to be violated under real-world conditions, with potentially far-reaching consequences for the management of biological systems.
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Affiliation(s)
- Lukas Schuster
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Hayley Cameron
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Craig R White
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Dustin J Marshall
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
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18
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Prinzing TS, Zhang Y, Wegner NC, Dulvy NK. Analytical methods matter too: Establishing a framework for estimating maximum metabolic rate for fishes. Ecol Evol 2021; 11:9987-10003. [PMID: 34367554 PMCID: PMC8328417 DOI: 10.1002/ece3.7732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 04/01/2021] [Accepted: 04/07/2021] [Indexed: 12/29/2022] Open
Abstract
Advances in experimental design and equipment have simplified the collection of maximum metabolic rate (MMR) data for a more diverse array of water-breathing animals. However, little attention has been given to the consequences of analytical choices in the estimation of MMR. Using different analytical methods can reduce the comparability of MMR estimates across species and studies and has consequences for the burgeoning number of macroecological meta-analyses using metabolic rate data. Two key analytical choices that require standardization are the time interval, or regression window width, over which MMR is estimated, and the method used to locate that regression window within the raw oxygen depletion trace. Here, we consider the effect of both choices by estimating MMR for two shark and two salmonid species of different activity levels using multiple regression window widths and three analytical methods: rolling regression, sequential regression, and segmented regression. Shorter regression windows yielded higher metabolic rate estimates, with a risk that the shortest windows (<1-min) reflect more system noise than MMR signal. Rolling regression was the best candidate model and produced the highest MMR estimates. Sequential regression models consistently produced lower relative estimates than rolling regression models, while the segmented regression model was unable to produce consistent MMR estimates across individuals. The time-point of the MMR regression window along the oxygen consumption trace varied considerably across individuals but not across models. We show that choice of analytical method, in addition to more widely understood experimental choices, profoundly affect the resultant estimates of MMR. We recommend that researchers (1) employ a rolling regression model with a reliable regression window tailored to their experimental system and (2) explicitly report their analytical methods, including publishing raw data and code.
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Affiliation(s)
- Tanya S. Prinzing
- Earth to Ocean Research Group, Department of Biological SciencesSimon Fraser UniversityBurnabyBCCanada
| | - Yangfan Zhang
- Department of Zoology & Faculty of Land and Food SystemsUniversity of British ColumbiaVancouverBCCanada
| | - Nicholas C. Wegner
- Fisheries Resources DivisionSouthwest Fisheries Science CenterNational Marine Fisheries Service (NMFS)National Oceanic and Atmospheric Administration (NOAA)La JollaCalifornia
| | - Nicholas K. Dulvy
- Earth to Ocean Research Group, Department of Biological SciencesSimon Fraser UniversityBurnabyBCCanada
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19
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Burdon FJ. Understanding the connectivity of ecosystems in the Anthropocene. J Anim Ecol 2021; 90:1600-1604. [PMID: 34236087 DOI: 10.1111/1365-2656.13550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 05/30/2021] [Indexed: 11/26/2022]
Abstract
In focus: Nash, L. N., Antiqueira, P. A. P., Romero, G. Q., de Omena, P. M., and Kratina, P. (2021). Warming of aquatic ecosystems disrupts aquatic-terrestrial linkages in the tropics. Journal of Animal Ecology. Meta-ecosystem ecology offers a holistic framework linking populations, communities and ecosystems in heterogeneous landscapes. This perspective is particularly relevant as anthropogenic drivers of environmental change proliferate, with the potential for impacts to propagate to spatially connected habitats. In aquatic ecosystems, reciprocal exchanges of energy, materials and organisms that form strong connections with adjacent terrestrial habitats can be disrupted by human impacts. Nash et al. (2021) demonstrate how a warming environment alters aquatic-terrestrial linkages by measuring rates of aquatic insect emergence and decomposition in a tropical context. While decomposition predictably increased with warming, insect emergence was greatly reduced. Using metabolic theory, I highlight how these results deviate from previous studies and help underscore the need for comparative research in different biomes. I conclude by exploring where progress can be made in quantifying, predicting and utilising the connectivity of ecosystems to fully realise the potential of a meta-ecosystem perspective and help address the dual crises of biodiversity loss and climate change.
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Affiliation(s)
- Francis J Burdon
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
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20
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Wilmot OJ, Hood JM, Huryn AD, Benstead JP. Decomposing decomposition: isolating direct effects of temperature from other drivers of detrital processing. Ecology 2021; 102:e03467. [PMID: 34236706 DOI: 10.1002/ecy.3467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 11/16/2020] [Accepted: 03/15/2021] [Indexed: 11/09/2022]
Abstract
Understanding the observed temperature dependence of decomposition (i.e., its "apparent" activation energy) requires separation of direct effects of temperature on consumer metabolism (i.e., the "inherent" activation energy) from those driven by indirect seasonal patterns in phenology and biomass, and by longer-term, climate-driven shifts in acclimation, adaptation, and community assembly. Such parsing is important because studies that relate temperature to decomposition usually involve multi-season data and/or spatial proxies for long-term shifts, and so incorporate these indirect factors. The various effects of such factors can obscure the inherent temperature dependence of detrital processing. Separating the inherent temperature dependence of decomposition from other drivers is important for accurate prediction of the contribution of detritus-sourced greenhouse gases to climate warming and requires novel approaches to data collection and analysis. Here, we present breakdown rates of red maple litter incubated in coarse- and fine-mesh litterbags (the latter excluding macroinvertebrates) for serial approximately one-month increments over one year in nine streams along a natural temperature gradient (mean annual: 12.8°-16.4°C) from north Georgia to central Alabama, USA. We analyzed these data using distance-based redundancy analysis and generalized additive mixed models to parse the dependence of decomposition rates on temperature, seasonality, and shredding macroinvertebrate biomass. Microbial decomposition in fine-mesh bags was significantly influenced by both temperature and seasonality. Accounting for seasonality corrected the temperature dependence of decomposition rate from 0.25 to 0.08 eV. Shredder assemblage structure in coarse-mesh bags was related to temperature across both sites and seasons, shifting from "cold" stonefly-dominated communities to "warm" communities dominated by snails or crayfish. Shredder biomass was not a significant predictor of either coarse-mesh or macroinvertebrate-mediated (i.e., coarse- minus fine-mesh) breakdown rates, which were also jointly influenced by temperature and seasonality. Unlike fine-mesh bags, however, temperature dependence of litter breakdown did not differ between models with and without seasonality for either coarse-mesh (0.36 eV) or macroinvertebrate-mediated (0.13 eV) rates. We conclude that indirect (non-thermal) seasonal and site-level effects play a variable and potentially strong role in shaping the apparent temperature dependence of detrital breakdown. Such effects should be incorporated into studies designed to estimate inherent temperature dependence of slow ecological processes.
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Affiliation(s)
- Oliver J Wilmot
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, 35487, USA
| | - James M Hood
- Aquatic Ecology Laboratory, Department of Evolution, Ecology, and Organismal Biology, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio, 43212, USA
| | - Alexander D Huryn
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, 35487, USA
| | - Jonathan P Benstead
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, 35487, USA
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21
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Kearney MR. What is the status of metabolic theory one century after Pütter invented the von Bertalanffy growth curve? Biol Rev Camb Philos Soc 2020; 96:557-575. [PMID: 33205617 DOI: 10.1111/brv.12668] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/02/2020] [Accepted: 11/05/2020] [Indexed: 01/03/2023]
Abstract
Metabolic theory aims to tackle ecological and evolutionary problems by explicitly including physical principles of energy and mass exchange, thereby increasing generality and deductive power. Individual growth models (IGMs) are the fundamental basis of metabolic theory because they represent the organisational level at which energy and mass exchange processes are most tightly integrated and from which scaling patterns emerge. Unfortunately, IGMs remain a topic of great confusion and controversy about the origins of the ideas, their domain and breadth of application, their logical consistency and whether they can sufficiently capture reality. It is now 100 years since the first theoretical model of individual growth was put forward by Pütter. His insights were deep, but his model ended up being attributed to von Bertalanffy and his ideas largely forgotten. Here I review Pütter's ideas and trace their influence on existing theoretical models for growth and other aspects of metabolism, including those of von Bertalanffy, the Dynamic Energy Budget (DEB) theory, the Gill-Oxygen Limitation Theory (GOLT) and the Ontogenetic Growth Model (OGM). I show that the von Bertalanffy and GOLT models are minor modifications of Pütter's original model. I then synthesise, compare and critique the ideas of the two most-developed theories, DEB theory and the OGM, in relation to Pütter's original ideas. I formulate the Pütter, DEB and OGM models in the same structure and with the same notation to illustrate the major similarities and differences among them. I trace the confusion and controversy regarding these theories to the notions of anabolism, catabolism, assimilation and maintenance, the connections to respiration rate, and the number of parameters and state variables their models require. The OGM model has significant inconsistencies that stem from the interpretation of growth as the difference between anabolism and maintenance, and these issues seriously challenge its ability to incorporate development, reproduction and assimilation. The DEB theory is a direct extension of Pütter's ideas but with growth being the difference between assimilation and maintenance rather than anabolism and catabolism. The DEB theory makes the dynamics of Pütter's 'nutritive material' explicit as well as extending the scheme to include reproduction and development. I discuss how these three major theories for individual growth have been used to explain 'macrometabolic' patterns including the scaling of respiration, the temperature-size rule (first modelled by Pütter), and the connection to life history. Future research on the connections between theory and data in these macrometabolic topics have the greatest potential to advance the status of metabolic theory and its value for pure and applied problems in ecology and evolution.
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Affiliation(s)
- Michael R Kearney
- BioSciences4, School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
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22
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Junker JR, Cross WF, Benstead JP, Huryn AD, Hood JM, Nelson D, Gíslason GM, Ólafsson JS. Resource supply governs the apparent temperature dependence of animal production in stream ecosystems. Ecol Lett 2020; 23:1809-1819. [PMID: 33001542 PMCID: PMC7702057 DOI: 10.1111/ele.13608] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/06/2020] [Accepted: 08/17/2020] [Indexed: 11/27/2022]
Abstract
Rising global temperatures are changing how energy and materials move through ecosystems, with potential consequences for the role of animals in these processes. We tested a central prediction of the metabolic scaling framework-the temperature independence of animal community production-using a series of geothermally heated streams and a comprehensive empirical analysis. We show that the apparent temperature sensitivity of animal production was consistent with theory for individuals (Epind = 0.64 vs. 0.65 eV), but strongly amplified relative to theoretical expectations for communities, both among (Epamong = 0.67 vs. 0 eV) and within (Epwithin = 1.52 vs. 0 eV) streams. After accounting for spatial and temporal variation in resources, we show that the apparent positive effect of temperature was driven by resource supply, providing strong empirical support for the temperature independence of invertebrate production and the necessary inclusion of resources in metabolic scaling efforts.
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Affiliation(s)
- James R Junker
- Department of Ecology, Montana State University, Bozeman, MT, 59717, USA
| | - Wyatt F Cross
- Department of Ecology, Montana State University, Bozeman, MT, 59717, USA
| | - Jonathan P Benstead
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487, USA
| | - Alexander D Huryn
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487, USA
| | - James M Hood
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Translational Data Analytics Institute, The Aquatic Ecology Laboratory, Columbus, OH, 43212, USA
| | - Daniel Nelson
- Department of Biology, University of Oklahoma, Norman, OK, 73019, USA
| | - Gísli M Gíslason
- University of Iceland, Institute of Life and Environmental Sciences, Reykjavík, Iceland
| | - Jón S Ólafsson
- Institute of Marine and Freshwater Fisheries, Reykjavík, Iceland
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23
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Hu Z, Chen HYH, Yue C, Gong XY, Shao J, Zhou G, Wang J, Wang M, Xia J, Li Y, Zhou X, Michaletz ST. Traits mediate drought effects on wood carbon fluxes. Glob Chang Biol 2020; 26:3429-3442. [PMID: 32215999 DOI: 10.1111/gcb.15088] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 03/13/2020] [Accepted: 03/14/2020] [Indexed: 06/10/2023]
Abstract
CO2 fluxes from wood decomposition represent an important source of carbon from forest ecosystems to the atmosphere, which are determined by both wood traits and climate influencing the metabolic rates of decomposers. Previous studies have quantified the effects of moisture and temperature on wood decomposition, but these effects were not separated from the potential influence of wood traits. Indeed, it is not well understood how traits and climate interact to influence wood CO2 fluxes. Here, we examined the responses of CO2 fluxes from dead wood with different traits (angiosperm and gymnosperm) to 0%, 35%, and 70% rainfall reduction across seasonal temperature gradients. Our results showed that drought significantly decreased wood CO2 fluxes, but its effects varied with both taxonomical group and drought intensity. Drought-induced reduction in wood CO2 fluxes was larger in angiosperms than gymnosperms for the 35% rainfall reduction treatment, but there was no significant difference between these groups for the 70% reduction treatment. This is because wood nitrogen density and carbon quality were significantly higher in angiosperms than gymnosperms, yielding a higher moisture sensitivity of wood decomposition. These findings were demonstrated by a significant positive interaction effect between wood nitrogen and moisture on CO2 fluxes in a structural equation model. Additionally, we ascertained that a constant temperature sensitivity of CO2 fluxes was independent of wood traits and consistent with previous estimates for extracellular enzyme kinetics. Our results highlight the key role of wood traits in regulating drought responses of wood carbon fluxes. Given that both climate and forest management might extensively modify taxonomic compositions in the future, it is critical for carbon cycle models to account for such interactions between wood traits and climate in driving dynamics of wood decomposition.
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Affiliation(s)
- Zhenhong Hu
- Tiantong National Field Observation Station for Forest Ecosystem, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, China
- College of Natural Resources and Environment, Joint Institute for Environmental Research & Education, South China Agricultural University, Guangzhou, China
| | - Han Y H Chen
- Faculty of Natural Resources Management, Lakehead University, Thunder Bay, ON, Canada
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Chao Yue
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, China
| | - Xiao Ying Gong
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, China
| | - Junjiong Shao
- Tiantong National Field Observation Station for Forest Ecosystem, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Guiyao Zhou
- Tiantong National Field Observation Station for Forest Ecosystem, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Jiawei Wang
- Tiantong National Field Observation Station for Forest Ecosystem, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Minhuang Wang
- Department of Ecology, School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, China
| | - Jianyang Xia
- Tiantong National Field Observation Station for Forest Ecosystem, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
- Institute of Eco-Chongming (IEC), Shanghai, China
| | - Yongtao Li
- College of Natural Resources and Environment, Joint Institute for Environmental Research & Education, South China Agricultural University, Guangzhou, China
| | - Xuhui Zhou
- Tiantong National Field Observation Station for Forest Ecosystem, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
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24
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Jacquet C, Gounand I, Altermatt F. How pulse disturbances shape size-abundance pyramids. Ecol Lett 2020; 23:1014-1023. [PMID: 32282125 DOI: 10.1111/ele.13508] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/27/2019] [Accepted: 03/02/2020] [Indexed: 01/04/2023]
Abstract
Ecological pyramids represent the distribution of abundance and biomass of living organisms across body-sizes. Our understanding of their expected shape relies on the assumption of invariant steady-state conditions. However, most of the world's ecosystems experience disturbances that keep them far from such a steady state. Here, using the allometric scaling between population growth rate and body-size, we predict the response of size-abundance pyramids within a trophic guild to any combination of disturbance frequency and intensity affecting all species in a similar way. We show that disturbances narrow the base of size-abundance pyramids, lower their height and decrease total community biomass in a nonlinear way. An experimental test using microbial communities demonstrates that the model captures well the effect of disturbances on empirical pyramids. Overall, we demonstrate both theoretically and experimentally how disturbances that are not size-selective can nonetheless have disproportionate impacts on large species.
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Affiliation(s)
- Claire Jacquet
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zürich, Switzerland.,Department of Aquatic Ecology, Swiss Federal Institute of Aquatic Science and Technology, Eawag, Dübendorf, Switzerland
| | - Isabelle Gounand
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zürich, Switzerland.,Department of Aquatic Ecology, Swiss Federal Institute of Aquatic Science and Technology, Eawag, Dübendorf, Switzerland.,Sorbonne Université, CNRS, UPEC, CNRS, IRD, INRA, Institut d'écologie et des sciences de l'environnement, IEES,, Paris, France
| | - Florian Altermatt
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zürich, Switzerland.,Department of Aquatic Ecology, Swiss Federal Institute of Aquatic Science and Technology, Eawag, Dübendorf, Switzerland
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25
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Abstract
Scaling laws relating body mass to species characteristics are among the most universal quantitative patterns in biology. Within major taxonomic groups, the 4 key ecological variables of metabolism, abundance, growth, and mortality are often well described by power laws with exponents near 3/4 or related to that value, a commonality often attributed to biophysical constraints on metabolism. However, metabolic scaling theories remain widely debated, and the links among the 4 variables have never been formally tested across the full domain of eukaryote life, to which prevailing theory applies. Here we present datasets of unprecedented scope to examine these 4 scaling laws across all eukaryotes and link them to test whether their combinations support theoretical expectations. We find that metabolism and abundance scale with body size in a remarkably reciprocal fashion, with exponents near ±3/4 within groups, as expected from metabolic theory, but with exponents near ±1 across all groups. This reciprocal scaling supports "energetic equivalence" across eukaryotes, which hypothesizes that the partitioning of energy in space across species does not vary significantly with body size. In contrast, growth and mortality rates scale similarly both within and across groups, with exponents of ±1/4. These findings are inconsistent with a metabolic basis for growth and mortality scaling across eukaryotes. We propose that rather than limiting growth, metabolism adjusts to the needs of growth within major groups, and that growth dynamics may offer a viable theoretical basis to biological scaling.
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26
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Ho HC, Tylianakis JM, Zheng JX, Pawar S. Predation risk influences food-web structure by constraining species diet choice. Ecol Lett 2019; 22:1734-1745. [PMID: 31389145 DOI: 10.1111/ele.13334] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/23/2019] [Accepted: 06/09/2019] [Indexed: 01/24/2023]
Abstract
The foraging behaviour of species determines their diet and, therefore, also emergent food-web structure. Optimal foraging theory (OFT) has previously been applied to understand the emergence of food-web structure through a consumer-centric consideration of diet choice. However, the resource-centric viewpoint, where species adjust their behaviour to reduce the risk of predation, has not been considered. We develop a mechanistic model that merges metabolic theory with OFT to incorporate the effect of predation risk on diet choice to assemble food webs. This 'predation-risk-compromise' (PR) model better captures the nestedness and modularity of empirical food webs relative to the classical optimal foraging model. Specifically, compared with optimal foraging alone, risk-mitigated foraging leads to more-nested but less-modular webs by broadening the diet of consumers at intermediate trophic levels. Thus, predation risk significantly affects food-web structure by constraining species' ability to forage optimally, and needs to be considered in future work.
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Affiliation(s)
- Hsi-Cheng Ho
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY, UK
| | - Jason M Tylianakis
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY, UK.,School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, NZ
| | - Jonathan X Zheng
- Department of Electrical and Electronic Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Samraat Pawar
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, SL5 7PY, UK
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27
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Abstract
Population growth metrics such as R0 are usually asymmetric functions of temperature, with cold-skewed curves arising when the positive effects of a temperature increase outweigh the negative effects, and warm-skewed curves arising in the opposite case. Classically, cold-skewed curves are interpreted as more beneficial to a species under climate warming, because cold-skewness implies increased population growth over a larger proportion of the species's fundamental thermal niche than warm-skewness. However, inference based on the shape of the fitness curve alone, and without considering the synergistic effects of net reproduction, density and dispersal, may yield an incomplete understanding of climate change impacts. We formulate a moving-habitat integrodifference equation model to evaluate how fitness curve skewness affects species' range size and abundance during climate warming. In contrast to classic interpretations, we find that climate warming adversely affects populations with cold-skewed fitness curves, positively affects populations with warm-skewed curves and has relatively little or mixed effects on populations with symmetric curves. Our results highlight the synergistic effects of fitness curve skewness, spatially heterogeneous densities and dispersal in climate change impact analyses, and that the common approach of mapping changes only in R0 may be misleading.
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Affiliation(s)
- Amy Hurford
- Department of Biology, Memorial University, St John's, Newfoundland and Labrador, Canada A1B 3X9.,Department of Mathematics and Statistics, Memorial University, St John's, Newfoundland and Labrador, Canada A1B 3X9
| | - Christina A Cobbold
- School of Mathematics and Statistics, University of Glasgow, University Place, Glasgow G12 8QS, UK
| | - Péter K Molnár
- Department of Biological Sciences, University of Toronto at Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4.,Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
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28
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Brummer AB, Newman EA. Derivations of the Core Functions of the Maximum Entropy Theory of Ecology. Entropy (Basel) 2019; 21:E712. [PMID: 33267426 DOI: 10.3390/e21070712] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/15/2019] [Accepted: 07/15/2019] [Indexed: 11/17/2022]
Abstract
The Maximum Entropy Theory of Ecology (METE), is a theoretical framework of macroecology that makes a variety of realistic ecological predictions about how species richness, abundance of species, metabolic rate distributions, and spatial aggregation of species interrelate in a given region. In the METE framework, "ecological state variables" (representing total area, total species richness, total abundance, and total metabolic energy) describe macroecological properties of an ecosystem. METE incorporates these state variables into constraints on underlying probability distributions. The method of Lagrange multipliers and maximization of information entropy (MaxEnt) lead to predicted functional forms of distributions of interest. We demonstrate how information entropy is maximized for the general case of a distribution, which has empirical information that provides constraints on the overall predictions. We then show how METE's two core functions are derived. These functions, called the "Spatial Structure Function" and the "Ecosystem Structure Function" are the core pieces of the theory, from which all the predictions of METE follow (including the Species Area Relationship, the Species Abundance Distribution, and various metabolic distributions). Primarily, we consider the discrete distributions predicted by METE. We also explore the parameter space defined by the METE's state variables and Lagrange multipliers. We aim to provide a comprehensive resource for ecologists who want to understand the derivations and assumptions of the basic mathematical structure of METE.
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29
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Griffin JN, Silliman BR. Predator size-structure and species identity determine cascading effects in a coastal ecosystem. Ecol Evol 2018; 8:12435-12442. [PMID: 30619556 PMCID: PMC6308854 DOI: 10.1002/ece3.4571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/22/2018] [Accepted: 08/30/2018] [Indexed: 11/24/2022] Open
Abstract
Cascading consequences of predator extinctions are well documented, but impacts of perturbations to predator size-structure and how these vary across species remain unclear. Body size is hypothesized to be a key trait governing individual predators' impact on ecosystems. Therefore, shifts in predator size-structure should trigger ecosystem ramifications which are consistent across functionally similar species. Using a US salt marsh as a model system, we tested this hypothesis by manipulating size class (small, medium, and large) and size diversity (combination of all three size classes) within two closely related and functionally similar predatory crab species over 4 months. Across treatments, predators suppressed densities of a dominant grazer and an ecosystem engineer, enhanced plant biomass, and altered sediment properties (redox potential and saturation). Over the metabolically equivalent experimental predator treatments, small size class predators had stronger average impacts on response variables, and size class interacted with predator species identity to drive engineer suppression. Within both predator species, size diversity increased cannibalism and slightly weakened the average impact. These results show that predator impacts in a salt marsh ecosystem are determined by both size class and size diversity; they also highlight that size class can have species-dependent and response-dependent effects, underlining the challenge of generalizing trait effects.
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Affiliation(s)
| | - Brian R. Silliman
- Division of Marine Science and Conservation, Nicholas School of the EnvironmentDuke UniversityBeaufortNorth Carolina
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30
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Hillaert J, Hovestadt T, Vandegehuchte ML, Bonte D. Size-dependent movement explains why bigger is better in fragmented landscapes. Ecol Evol 2018; 8:10754-10767. [PMID: 30519404 PMCID: PMC6262741 DOI: 10.1002/ece3.4524] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/05/2018] [Accepted: 08/18/2018] [Indexed: 12/04/2022] Open
Abstract
Body size is a fundamental trait known to allometrically scale with metabolic rate and therefore a key determinant of individual development, life history, and consequently fitness. In spatially structured environments, movement is an equally important driver of fitness. Because movement is tightly coupled with body size, we expect habitat fragmentation to induce a strong selection pressure on size variation across and within species. Changes in body size distributions are then, in turn, expected to alter food web dynamics. However, no consensus has been reached on how spatial isolation and resource growth affect consumer body size distributions. Our aim was to investigate how these two factors shape the body size distribution of consumers under scenarios of size-dependent and size-independent consumer movement by applying a mechanistic, individual-based resource-consumer model. We also assessed the consequences of altered body size distributions for important ecosystem traits such as resource abundance and consumer stability. Finally, we determined those factors that explain most variation in size distributions. We demonstrate that decreasing connectivity and resource growth select for communities (or populations) consisting of larger species (or individuals) due to strong selection for the ability to move over longer distances if the movement is size-dependent. When including size-dependent movement, intermediate levels of connectivity result in increases in local size diversity. Due to this elevated functional diversity, resource uptake is maximized at the metapopulation or metacommunity level. At these intermediate levels of connectivity, size-dependent movement explains most of the observed variation in size distributions. Interestingly, local and spatial stability of consumer biomass is lowest when isolation and resource growth are high. Finally, we highlight that size-dependent movement is of vital importance for the survival of populations or communities within highly fragmented landscapes. Our results demonstrate that considering size-dependent movement is essential to understand how habitat fragmentation and resource growth shape body size distributions-and the resulting metapopulation or metacommunity dynamics-of consumers.
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Affiliation(s)
- Jasmijn Hillaert
- Department of BiologyTerrestrial Ecology UnitGhent UniversityGhentBelgium
| | - Thomas Hovestadt
- Department of Animal Ecology and Tropical BiologyBiocenterUniversity of WuerzburgWuerzburgGermany
| | | | - Dries Bonte
- Department of BiologyTerrestrial Ecology UnitGhent UniversityGhentBelgium
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31
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Perkins DM, Durance I, Edwards FK, Grey J, Hildrew AG, Jackson M, Jones JI, Lauridsen RB, Layer-Dobra K, Thompson MSA, Woodward G. Bending the rules: exploitation of allochthonous resources by a top-predator modifies size-abundance scaling in stream food webs. Ecol Lett 2018; 21:1771-1780. [PMID: 30257275 DOI: 10.1111/ele.13147] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/04/2018] [Accepted: 07/29/2018] [Indexed: 11/29/2022]
Abstract
Body mass-abundance (M-N) allometries provide a key measure of community structure, and deviations from scaling predictions could reveal how cross-ecosystem subsidies alter food webs. For 31 streams across the UK, we tested the hypothesis that linear log-log M-N scaling is shallower than that predicted by allometric scaling theory when top predators have access to allochthonous prey. These streams all contained a common and widespread top predator (brown trout) that regularly feeds on terrestrial prey and, as hypothesised, deviations from predicted scaling increased with its dominance of the fish assemblage. Our study identifies a key beneficiary of cross-ecosystem subsidies at the top of stream food webs and elucidates how these inputs can reshape the size-structure of these 'open' systems.
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Affiliation(s)
- Daniel M Perkins
- Department of Life Sciences, Whitelands College, University of Roehampton, London, SW15 4JD, UK
| | - Isabelle Durance
- Cardiff Water Research Institute, Cardiff School of Biosciences, Cardiff University, PO Box 915, Cardiff, CF10 3TL, UK
| | - Francois K Edwards
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.,Centre for Ecology and Hydrology, Wallingford, OX10 8BB, UK
| | - Jonathan Grey
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.,Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Alan G Hildrew
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.,Freshwater Biological Association, The Ferry Landing, Far Sawrey, Ambleside, Cumbria, LA22 OLP, UK
| | - Michelle Jackson
- Grand Challenges in Ecosystems and the Environment, Department of Life Sciences, Imperial College London, Silwood Park Campus, Berkshire, SL5 7PY, UK
| | - J Iwan Jones
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.,Centre for Ecology and Hydrology, Wallingford, OX10 8BB, UK
| | - Rasmus B Lauridsen
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.,Game & Wildlife Conservation Trust, Burgate Manor, Fordingbridge, Hampshire, SP6 1EF, UK
| | - Katrin Layer-Dobra
- Grand Challenges in Ecosystems and the Environment, Department of Life Sciences, Imperial College London, Silwood Park Campus, Berkshire, SL5 7PY, UK
| | - Murray S A Thompson
- Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk, NR33 0HT, UK
| | - Guy Woodward
- Grand Challenges in Ecosystems and the Environment, Department of Life Sciences, Imperial College London, Silwood Park Campus, Berkshire, SL5 7PY, UK
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32
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Hillaert J, Vandegehuchte ML, Hovestadt T, Bonte D. Information use during movement regulates how fragmentation and loss of habitat affect body size. Proc Biol Sci 2018; 285:20180953. [PMID: 30111596 PMCID: PMC6111160 DOI: 10.1098/rspb.2018.0953] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/16/2018] [Indexed: 12/30/2022] Open
Abstract
An individual's body size is central to its behaviour and physiology, and tightly linked to its movement ability. The spatial arrangement of resources and a consumer's capacity to locate them are therefore expected to exert strong selection on consumer body size. We investigated the evolutionary impact of both the fragmentation and loss of habitat on consumer body size and its feedback effects on resource distribution, under varying levels of information used during habitat choice. We developed a mechanistic, individual-based, spatially explicit model, including several allometric rules for key consumer traits. Our model reveals that as resources become more fragmented and scarce, informed habitat choice selects for larger body sizes while random habitat choice promotes small sizes. Information use may thus be an overlooked explanation for the observed variation in body size responses to habitat fragmentation. Moreover, we find that resources can accumulate and aggregate if information about resource abundance is incomplete. Informed movement results in stable resource-consumer dynamics and controlled resources across space. However, habitat loss and fragmentation destabilize local dynamics and disturb resource suppression by the consumer. Considering information use during movement is thus critical to understand the eco-evolutionary dynamics underlying the functioning and structuring of consumer communities.
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Affiliation(s)
- Jasmijn Hillaert
- Department of Biology, Terrestrial Ecology Unit, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Martijn L Vandegehuchte
- Department of Biology, Terrestrial Ecology Unit, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Thomas Hovestadt
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Wuerzburg, Emil-Fischer-Strasse 32, 97074 Wuerzburg, Germany
| | - Dries Bonte
- Department of Biology, Terrestrial Ecology Unit, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
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33
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Abstract
There are still significant uncertainties in the magnitude and direction of carbon fluxes through coastal ecosystems. An important component of these biogeochemical budgets is ecosystem metabolism, the net result of organismal metabolic processes within an ecosystem. In this paper, I present a synthesis of published ecosystem metabolism studies from coastal ecosystems and describe an empirical observation that size-dependent patterns in aquatic gross primary production and community respiration exist across a wide range of coastal geomorphologies. Ecosystem metabolism scales to the 3/4 power with volume in deeper estuaries dominated by pelagic primary production and nearly linearly with area in shallow estuaries dominated by benthic primary production. These results can be explained by applying scaling arguments for efficient, directed transport networks developed to explain similar size-dependent patterns in organismal metabolism. The main conclusion from this synthesis is that the residence time of new, nutrient-rich water is a fundamental organizing principle for the observed patterns. Residence time changes allometrically with size in pelagic ecosystems because velocities change by only an order of magnitude across systems that span more than ten orders of magnitude in size. This nonisometric change in velocity with size requires lower specific metabolic rates at larger ecosystem sizes. This change in transport may also explain a shift from predominantly net heterotrophy to net autotrophy with increasing size. The scaling results are applied to the total estuarine area in the continental United States to estimate the contribution of estuarine systems to the overall coastal budget of organic carbon.
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34
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Gillooly JF, Gomez JP, Mavrodiev EV. A broad-scale comparison of aerobic activity levels in vertebrates: endotherms versus ectotherms. Proc Biol Sci 2018; 284:rspb.2016.2328. [PMID: 28202808 DOI: 10.1098/rspb.2016.2328] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/23/2017] [Indexed: 01/16/2023] Open
Abstract
Differences in the limits and range of aerobic activity levels between endotherms and ectotherms remain poorly understood, though such differences help explain basic differences in species' lifestyles (e.g. movement patterns, feeding modes, and interaction rates). We compare the limits and range of aerobic activity in endotherms (birds and mammals) and ectotherms (fishes, reptiles, and amphibians) by evaluating the body mass-dependence of VO2 max, aerobic scope, and heart mass in a phylogenetic context based on a newly constructed vertebrate supertree. Contrary to previous work, results show no significant differences in the body mass scaling of minimum and maximum oxygen consumption rates with body mass within endotherms or ectotherms. For a given body mass, resting rates and maximum rates were 24-fold and 30-fold lower, respectively, in ectotherms than endotherms. Factorial aerobic scope ranged from five to eight in both groups, with scope in endotherms showing a modest body mass-dependence. Finally, maximum consumption rates and aerobic scope were positively correlated with residual heart mass. Together, these results quantify similarities and differences in the potential for aerobic activity among ectotherms and endotherms from diverse environments. They provide insights into the models and mechanisms that may underlie the body mass-dependence of oxygen consumption.
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Affiliation(s)
- James F Gillooly
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Juan Pablo Gomez
- Department of Biology, University of Florida, Gainesville, FL 32611, USA.,Spatial Epidemiology and Ecology Research Laboratory, University of Florida, Gainesville, FL 32610, USA
| | - Evgeny V Mavrodiev
- Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA
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35
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Abstract
Under the leadership of Drs. Vincent P. Dole, Marie Nyswander, and Mary Jeanne Kreek, in collaboration with the psychologist, Norman Gordon and sociologist, Herman Joseph at The Rockefeller University beginning in the 1960s, the first medical treatment for heroin addiction was developed. Drs. Dole, Nyswander and Kreek also developed the first hypothesis of opiate addiction as a metabolic disease. This biological revolution challenged beliefs about addiction, spurred further research and challenged legal positions of the judiciary and the broader criminal justice system (Dole & Nyswander, 1967 ).
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Affiliation(s)
- Herman Joseph
- a National Research and Development (Emeritus) , New York , New York , USA.,b Stop Stigma Now , Larchmont , New York , USA
| | - Joycelyn Sue Woods
- b Stop Stigma Now , Larchmont , New York , USA.,c National Alliance for Medication Assisted Recovery , New York , New York , USA.,d The MARS Project , Bronx , New York , USA
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36
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Barnes AD, Jochum M, Lefcheck JS, Eisenhauer N, Scherber C, O'Connor MI, de Ruiter P, Brose U. Energy Flux: The Link between Multitrophic Biodiversity and Ecosystem Functioning. Trends Ecol Evol 2018; 33:186-197. [PMID: 29325921 DOI: 10.1016/j.tree.2017.12.007] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 12/06/2017] [Accepted: 12/13/2017] [Indexed: 01/02/2023]
Abstract
Relating biodiversity to ecosystem functioning in natural communities has become a paramount challenge as links between trophic complexity and multiple ecosystem functions become increasingly apparent. Yet, there is still no generalised approach to address such complexity in biodiversity-ecosystem functioning (BEF) studies. Energy flux dynamics in ecological networks provide the theoretical underpinning of multitrophic BEF relationships. Accordingly, we propose the quantification of energy fluxes in food webs as a powerful, universal tool for understanding ecosystem functioning in multitrophic systems spanning different ecological scales. Although the concept of energy flux in food webs is not novel, its application to BEF research remains virtually untapped, providing a framework to foster new discoveries into the determinants of ecosystem functioning in complex systems.
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Affiliation(s)
- Andrew D Barnes
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany; Institute of Biology, Leipzig University, Deutscher Platz 5e, 04103 Leipzig, Germany; Institute of Landscape Ecology, University of Münster, Heisenbergstrasse 2, 48149 Münster, Germany.
| | - Malte Jochum
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland
| | | | - Nico Eisenhauer
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany; Institute of Biology, Leipzig University, Deutscher Platz 5e, 04103 Leipzig, Germany
| | - Christoph Scherber
- Institute of Landscape Ecology, University of Münster, Heisenbergstrasse 2, 48149 Münster, Germany
| | - Mary I O'Connor
- Department of Zoology and Biodiversity Research Centre, Univ. of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Peter de Ruiter
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098XH Amsterdam, The Netherlands; Biometris, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Ulrich Brose
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany; Institute of Ecology, Friedrich Schiller University Jena, Dornburger-Str. 159, 07743 Jena, Germany
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37
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Padfield D, Lowe C, Buckling A, Ffrench-Constant R, Jennings S, Shelley F, Ólafsson JS, Yvon-Durocher G. Metabolic compensation constrains the temperature dependence of gross primary production. Ecol Lett 2017; 20:1250-1260. [PMID: 28853241 PMCID: PMC6849571 DOI: 10.1111/ele.12820] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/10/2017] [Accepted: 06/21/2017] [Indexed: 11/29/2022]
Abstract
Gross primary production (GPP) is the largest flux in the carbon cycle, yet its response to global warming is highly uncertain. The temperature dependence of GPP is directly linked to photosynthetic physiology, but the response of GPP to warming over longer timescales could also be shaped by ecological and evolutionary processes that drive variation in community structure and functional trait distributions. Here, we show that selection on photosynthetic traits within and across taxa dampens the effects of temperature on GPP across a catchment of geothermally heated streams. Autotrophs from cold streams had higher photosynthetic rates and after accounting for differences in biomass among sites, biomass-specific GPP was independent of temperature in spite of a 20 °C thermal gradient. Our results suggest that temperature compensation of photosynthetic rates constrains the long-term temperature dependence of GPP, and highlights the importance of considering physiological, ecological and evolutionary mechanisms when predicting how ecosystem-level processes respond to warming.
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Affiliation(s)
- Daniel Padfield
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK
| | - Chris Lowe
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK.,Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Angus Buckling
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK.,Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Richard Ffrench-Constant
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | -
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Simon Jennings
- Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, NR33 0HT, UK.,School of Environmental Sciences, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.,International Council for the Exploration of the Sea, H. C. Andersens Boulevard 44-46, 1553, Copenhagen V, Denmark
| | - Felicity Shelley
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Jón S Ólafsson
- Marine and Freshwater Research Institute, Árleyni 22, 112, Reykjavik, Iceland
| | - Gabriel Yvon-Durocher
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK
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Follstad Shah JJ, Kominoski JS, Ardón M, Dodds WK, Gessner MO, Griffiths NA, Hawkins CP, Johnson SL, Lecerf A, LeRoy CJ, Manning DWP, Rosemond AD, Sinsabaugh RL, Swan CM, Webster JR, Zeglin LH. Global synthesis of the temperature sensitivity of leaf litter breakdown in streams and rivers. Glob Chang Biol 2017; 23:3064-3075. [PMID: 28039909 DOI: 10.1111/gcb.13609] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 11/26/2016] [Indexed: 05/06/2023]
Abstract
Streams and rivers are important conduits of terrestrially derived carbon (C) to atmospheric and marine reservoirs. Leaf litter breakdown rates are expected to increase as water temperatures rise in response to climate change. The magnitude of increase in breakdown rates is uncertain, given differences in litter quality and microbial and detritivore community responses to temperature, factors that can influence the apparent temperature sensitivity of breakdown and the relative proportion of C lost to the atmosphere vs. stored or transported downstream. Here, we synthesized 1025 records of litter breakdown in streams and rivers to quantify its temperature sensitivity, as measured by the activation energy (Ea , in eV). Temperature sensitivity of litter breakdown varied among twelve plant genera for which Ea could be calculated. Higher values of Ea were correlated with lower-quality litter, but these correlations were influenced by a single, N-fixing genus (Alnus). Ea values converged when genera were classified into three breakdown rate categories, potentially due to continual water availability in streams and rivers modulating the influence of leaf chemistry on breakdown. Across all data representing 85 plant genera, the Ea was 0.34 ± 0.04 eV, or approximately half the value (0.65 eV) predicted by metabolic theory. Our results indicate that average breakdown rates may increase by 5-21% with a 1-4 °C rise in water temperature, rather than a 10-45% increase expected, according to metabolic theory. Differential warming of tropical and temperate biomes could result in a similar proportional increase in breakdown rates, despite variation in Ea values for these regions (0.75 ± 0.13 eV and 0.27 ± 0.05 eV, respectively). The relative proportions of gaseous C loss and organic matter transport downstream should not change with rising temperature given that Ea values for breakdown mediated by microbes alone and microbes plus detritivores were similar at the global scale.
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Affiliation(s)
- Jennifer J Follstad Shah
- Environmental and Sustainability Studies/Department of Geography, University of Utah, Salt Lake City, UT, 84112, USA
- Department of Watershed Sciences, Utah State University, Logan, UT, 84322, USA
| | - John S Kominoski
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Marcelo Ardón
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, USA
| | - Walter K Dodds
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Mark O Gessner
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 16775, Stechlin, Germany
- Department of Ecology, Berlin Institute of Technology (TU Berlin), Ernst-Reuter-Platz 1, 10587, Berlin, Germany
| | - Natalie A Griffiths
- Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Charles P Hawkins
- Department of Watershed Sciences, Utah State University, Logan, UT, 84322, USA
| | - Sherri L Johnson
- Pacific Northwest Research Station, US Forest Service, Corvallis, OR, 97331, USA
| | - Antoine Lecerf
- Université de Toulouse, UPS, INP, CNRS, EcoLab (Laboratoire d'Écologie Fonctionnelle et Environnement), 31062, Toulouse, France
| | - Carri J LeRoy
- Environmental Studies Program, The Evergreen State College, Olympia, WA, 98505, USA
| | - David W P Manning
- School of Environment and Natural Resources, Ohio State University, Columbus, OH, 43210, USA
| | - Amy D Rosemond
- Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA
| | - Robert L Sinsabaugh
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Christopher M Swan
- Department of Geography and Environmental Systems, University of Maryland-Baltimore County, Baltimore, MD, 21250, USA
| | - Jackson R Webster
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Lydia H Zeglin
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
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Nelson D, Benstead JP, Huryn AD, Cross WF, Hood JM, Johnson PW, Junker JR, Gíslason GM, Ólafsson JS. Experimental whole-stream warming alters community size structure. Glob Chang Biol 2017; 23:2618-2628. [PMID: 27868314 DOI: 10.1111/gcb.13574] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/03/2016] [Accepted: 11/07/2016] [Indexed: 06/06/2023]
Abstract
How ecological communities respond to predicted increases in temperature will determine the extent to which Earth's biodiversity and ecosystem functioning can be maintained into a warmer future. Warming is predicted to alter the structure of natural communities, but robust tests of such predictions require appropriate large-scale manipulations of intact, natural habitat that is open to dispersal processes via exchange with regional species pools. Here, we report results of a two-year whole-stream warming experiment that shifted invertebrate assemblage structure via unanticipated mechanisms, while still conforming to community-level metabolic theory. While warming by 3.8 °C decreased invertebrate abundance in the experimental stream by 60% relative to a reference stream, total invertebrate biomass was unchanged. Associated shifts in invertebrate assemblage structure were driven by the arrival of new taxa and a higher proportion of large, warm-adapted species (i.e., snails and predatory dipterans) relative to small-bodied, cold-adapted taxa (e.g., chironomids and oligochaetes). Experimental warming consequently shifted assemblage size spectra in ways that were unexpected, but consistent with thermal optima of taxa in the regional species pool. Higher temperatures increased community-level energy demand, which was presumably satisfied by higher primary production after warming. Our experiment demonstrates how warming reassembles communities within the constraints of energy supply via regional exchange of species that differ in thermal physiological traits. Similar responses will likely mediate impacts of anthropogenic warming on biodiversity and ecosystem function across all ecological communities.
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Affiliation(s)
- Daniel Nelson
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487 USA
| | - Jonathan P Benstead
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487 USA
| | - Alexander D Huryn
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487 USA
| | - Wyatt F Cross
- Department of Ecology, Montana State University, Bozeman, MT, 59717, USA
| | - James M Hood
- Department of Evolution, Ecology and Organismal Biology, The Aquatic Ecology Laboratory, The Ohio State University, Columbus, OH, 43212, USA
| | - Philip W Johnson
- Department of Civil, Construction and Environmental Engineering, University of Alabama, Tuscaloosa, AL, 35487, USA
| | - James R Junker
- Department of Ecology, Montana State University, Bozeman, MT, 59717, USA
| | - Gísli M Gíslason
- Institute of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland
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40
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Sinsabaugh RL, Moorhead DL, Xu X, Litvak ME. Plant, microbial and ecosystem carbon use efficiencies interact to stabilize microbial growth as a fraction of gross primary production. New Phytol 2017; 214:1518-1526. [PMID: 28233327 DOI: 10.1111/nph.14485] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/19/2017] [Indexed: 06/06/2023]
Abstract
The carbon use efficiency of plants (CUEa ) and microorganisms (CUEh ) determines rates of biomass turnover and soil carbon sequestration. We evaluated the hypothesis that CUEa and CUEh counterbalance at a large scale, stabilizing microbial growth (μ) as a fraction of gross primary production (GPP). Collating data from published studies, we correlated annual CUEa , estimated from satellite imagery, with locally determined soil CUEh for 100 globally distributed sites. Ecosystem CUEe , the ratio of net ecosystem production (NEP) to GPP, was estimated for each site using published models. At the ecosystem scale, CUEa and CUEh were inversely related. At the global scale, the apparent temperature sensitivity of CUEh with respect to mean annual temperature (MAT) was similar for organic and mineral soils (0.029°C-1 ). CUEa and CUEe were inversely related to MAT, with apparent sensitivities of -0.009 and -0.032°C-1 , respectively. These trends constrain the ratio μ : GPP (= (CUEa × CUEh )/(1 - CUEe )) with respect to MAT by counterbalancing the apparent temperature sensitivities of the component processes. At the ecosystem scale, the counterbalance is effected by modulating soil organic matter stocks. The results suggest that a μ : GPP value of c. 0.13 is a homeostatic steady state for ecosystem carbon fluxes at a large scale.
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Affiliation(s)
| | - Daryl L Moorhead
- Department of Environmental Sciences, University of Toledo, Toledo, OH, 43606, USA
| | - Xiaofeng Xu
- Biology Department, San Diego State University, San Diego, CA, 92182, USA
| | - Marcy E Litvak
- Biology Department, University of New Mexico, Albuquerque, NM, 87131, USA
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41
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Ward BA, Marañón E, Sauterey B, Rault J, Claessen D. The Size Dependence of Phytoplankton Growth Rates: A Trade-Off between Nutrient Uptake and Metabolism. Am Nat 2016; 189:170-177. [PMID: 28107051 DOI: 10.1086/689992] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Rates of metabolism and population growth are often assumed to decrease universally with increasing organism size. Recent observations have shown, however, that maximum population growth rates among phytoplankton smaller than ∼6 μm in diameter tend to increase with organism size. Here we bring together observations and theory to demonstrate that the observed change in slope is attributable to a trade-off between nutrient uptake and the potential rate of internal metabolism. Specifically, we apply an established model of phytoplankton growth to explore a trade-off between the ability of cells to replenish their internal quota (which increases with size) and their ability to synthesize new biomass (which decreases with size). Contrary to the metabolic theory of ecology, these results demonstrate that rates of resource acquisition (rather than metabolism) provide the primary physiological constraint on the growth rates of some of the smallest and most numerically abundant photosynthetic organisms on Earth.
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Abstract
Insects are typified by their small size, large numbers, impressive reproductive output and rapid growth. However, insect growth is not simply rapid; rather, insects follow a qualitatively distinct trajectory to many other animals. Here we present a mechanistic growth model for insects and show that increasing specific assimilation during the growth phase can explain the near-exponential growth trajectory of insects. The presented model is tested against growth data on 50 insects, and compared against other mechanistic growth models. Unlike the other mechanistic models, our growth model predicts energy reserves per biomass to increase with age, which implies a higher production efficiency and energy density of biomass in later instars. These predictions are tested against data compiled from the literature whereby it is confirmed that insects increase their production efficiency (by 24 percentage points) and energy density (by 4 J mg(-1)) between hatching and the attainment of full size. The model suggests that insects achieve greater production efficiencies and enhanced growth rates by increasing specific assimilation and increasing energy reserves per biomass, which are less costly to maintain than structural biomass. Our findings illustrate how the explanatory and predictive power of mechanistic growth models comes from their grounding in underlying biological processes.
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Affiliation(s)
- James L Maino
- School of BioSciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Michael R Kearney
- School of BioSciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
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43
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Abstract
The area and thickness of respiratory surfaces, and the constraints they impose on passive oxygen diffusion, have been linked to differences in oxygen consumption rates and/or aerobic activity levels in vertebrates. However, it remains unclear how respiratory surfaces and associated diffusion rates vary with body mass across vertebrates, particularly in relation to the body mass scaling of oxygen consumption rates. Here we address these issues by first quantifying the body mass dependence of respiratory surface area and respiratory barrier thickness for a diversity of endotherms (birds and mammals) and ectotherms (fishes, amphibians, and reptiles). Based on these findings, we then use Fick's law to predict the body mass scaling of oxygen diffusion for each group. Finally, we compare the predicted body mass dependence of oxygen diffusion to that of oxygen consumption in endotherms and ectotherms. We find that the slopes and intercepts of the relationships describing the body mass dependence of passive oxygen diffusion in these two groups are statistically indistinguishable from those describing the body mass dependence of oxygen consumption. Thus, the area and thickness of respiratory surfaces combine to match oxygen diffusion capacity to oxygen consumption rates in both air- and water-breathing vertebrates. In particular, the substantially lower oxygen consumption rates of ectotherms of a given body mass relative to those of endotherms correspond to differences in oxygen diffusion capacity. These results provide insights into the long-standing effort to understand the structural attributes of organisms that underlie the body mass scaling of oxygen consumption.
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Affiliation(s)
- James F Gillooly
- Department of Biology, University of Florida, Gainesville, FL 32611;
| | - Juan Pablo Gomez
- Department of Biology, University of Florida, Gainesville, FL 32611; Florida Museum of Natural History, University of Florida, Gainesville, FL 32611
| | - Evgeny V Mavrodiev
- Florida Museum of Natural History, University of Florida, Gainesville, FL 32611
| | - Yue Rong
- Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611
| | - Eric S McLamore
- Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611
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44
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Gibert JP, Chelini MC, Rosenthal MF, DeLong JP. Crossing regimes of temperature dependence in animal movement. Glob Chang Biol 2016; 22:1722-36. [PMID: 26854767 DOI: 10.1111/gcb.13245] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 01/21/2016] [Accepted: 01/29/2016] [Indexed: 05/16/2023]
Abstract
A pressing challenge in ecology is to understand the effects of changing global temperatures on food web structure and dynamics. The stability of these complex ecological networks largely depends on how predator-prey interactions may respond to temperature changes. Because predators and prey rely on their velocities to catch food or avoid being eaten, understanding how temperatures may affect animal movement is central to this quest. Despite our efforts, we still lack a mechanistic understanding of how the effect of temperature on metabolic processes scales up to animal movement and beyond. Here, we merge a biomechanical approach, the Metabolic Theory of Ecology and empirical data to show that animal movement displays multiple regimes of temperature dependence. We also show that crossing these regimes has important consequences for population dynamics and stability, which depend on the parameters controlling predator-prey interactions. We argue that this dependence upon interaction parameters may help explain why experimental work on the temperature dependence of interaction strengths has so far yielded conflicting results. More importantly, these changes in the temperature dependence of animal movement can have consequences that go well beyond ecological interactions and affect, for example, animal communication, mating, sensory detection, and any behavioral modality dependent on the movement of limbs. Finally, by not taking into account the changes in temperature dependence reported here we might not be able to properly forecast the impact of global warming on ecological processes and propose appropriate mitigation action when needed.
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Affiliation(s)
- Jean P Gibert
- School of Biological Sciences, University of Nebraska - Lincoln, Lincoln, NE, 68588, USA
| | - Marie-Claire Chelini
- School of Biological Sciences, University of Nebraska - Lincoln, Lincoln, NE, 68588, USA
| | - Malcolm F Rosenthal
- School of Biological Sciences, University of Nebraska - Lincoln, Lincoln, NE, 68588, USA
| | - John P DeLong
- School of Biological Sciences, University of Nebraska - Lincoln, Lincoln, NE, 68588, USA
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45
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McDole Somera T, Bailey B, Barott K, Grasis J, Hatay M, Hilton BJ, Hisakawa N, Nosrat B, Nulton J, Silveira CB, Sullivan C, Brainard RE, Rohwer F. Energetic differences between bacterioplankton trophic groups and coral reef resistance. Proc Biol Sci 2016; 283:20160467. [PMID: 27097927 PMCID: PMC4855391 DOI: 10.1098/rspb.2016.0467] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 03/31/2016] [Indexed: 01/03/2023] Open
Abstract
Coral reefs are among the most productive and diverse marine ecosystems on the Earth. They are also particularly sensitive to changing energetic requirements by different trophic levels. Microbialization specifically refers to the increase in the energetic metabolic demands of microbes relative to macrobes and is significantly correlated with increasing human influence on coral reefs. In this study, metabolic theory of ecology is used to quantify the relative contributions of two broad bacterioplankton groups, autotrophs and heterotrophs, to energy flux on 27 Pacific coral reef ecosystems experiencing human impact to varying degrees. The effective activation energy required for photosynthesis is lower than the average energy of activation for the biochemical reactions of the Krebs cycle, and changes in the proportional abundance of these two groups can greatly affect rates of energy and materials cycling. We show that reef-water communities with a higher proportional abundance of microbial autotrophs expend more metabolic energy per gram of microbial biomass. Increased energy and materials flux through fast energy channels (i.e. water-column associated microbial autotrophs) may dampen the detrimental effects of increased heterotrophic loads (e.g. coral disease) on coral reef systems experiencing anthropogenic disturbance.
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Affiliation(s)
- Tracey McDole Somera
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Barbara Bailey
- Department of Mathematics and Statistics, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Katie Barott
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Juris Grasis
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Mark Hatay
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Brett J Hilton
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Nao Hisakawa
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Bahador Nosrat
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - James Nulton
- Department of Mathematics and Statistics, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Cynthia B Silveira
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Chris Sullivan
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gillman Drive, La Jolla, CA 92093, USA
| | - Russell E Brainard
- NOAA Fisheries, Pacific Islands Fisheries Science Center, 1125 B Ala Moana Boulevard, Honolulu, HI 96814, USA
| | - Forest Rohwer
- Biology Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
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46
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Okie JG, Van Horn DJ, Storch D, Barrett JE, Gooseff MN, Kopsova L, Takacs-Vesbach CD. Niche and metabolic principles explain patterns of diversity and distribution: theory and a case study with soil bacterial communities. Proc Biol Sci 2016; 282:20142630. [PMID: 26019154 DOI: 10.1098/rspb.2014.2630] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The causes of biodiversity patterns are controversial and elusive due to complex environmental variation, covarying changes in communities, and lack of baseline and null theories to differentiate straightforward causes from more complex mechanisms. To address these limitations, we developed general diversity theory integrating metabolic principles with niche-based community assembly. We evaluated this theory by investigating patterns in the diversity and distribution of soil bacteria taxa across four orders of magnitude variation in spatial scale on an Antarctic mountainside in low complexity, highly oligotrophic soils. Our theory predicts that lower temperatures should reduce taxon niche widths along environmental gradients due to decreasing growth rates, and the changing niche widths should lead to contrasting α- and β-diversity patterns. In accord with the predictions, α-diversity, niche widths and occupancies decreased while β-diversity increased with increasing elevation and decreasing temperature. The theory also successfully predicts a hump-shaped relationship between α-diversity and pH and a negative relationship between α-diversity and salinity. Thus, a few simple principles explained systematic microbial diversity variation along multiple gradients. Such general theory can be used to disentangle baseline effects from more complex effects of temperature and other variables on biodiversity patterns in a variety of ecosystems and organisms.
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Affiliation(s)
- Jordan G Okie
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - David J Van Horn
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - David Storch
- Center for Theoretical Study, Charles University, Prague, Czech Republic Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic Department of Biological Sciences, Virginia Technological Institute, Blacksburg, VA, USA
| | - John E Barrett
- Department of Biological Sciences, Virginia Technological Institute, Blacksburg, VA, USA
| | - Michael N Gooseff
- Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA
| | - Lenka Kopsova
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
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47
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Padfield D, Yvon-Durocher G, Buckling A, Jennings S, Yvon-Durocher G. Rapid evolution of metabolic traits explains thermal adaptation in phytoplankton. Ecol Lett 2016; 19:133-142. [PMID: 26610058 PMCID: PMC4991271 DOI: 10.1111/ele.12545] [Citation(s) in RCA: 153] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/06/2015] [Accepted: 10/19/2015] [Indexed: 11/28/2022]
Abstract
Understanding the mechanisms that determine how phytoplankton adapt to warming will substantially improve the realism of models describing ecological and biogeochemical effects of climate change. Here, we quantify the evolution of elevated thermal tolerance in the phytoplankton, Chlorella vulgaris. Initially, population growth was limited at higher temperatures because respiration was more sensitive to temperature than photosynthesis meaning less carbon was available for growth. Tolerance to high temperature evolved after ≈ 100 generations via greater down-regulation of respiration relative to photosynthesis. By down-regulating respiration, phytoplankton overcame the metabolic constraint imposed by the greater temperature sensitivity of respiration and more efficiently allocated fixed carbon to growth. Rapid evolution of carbon-use efficiency provides a potentially general mechanism for thermal adaptation in phytoplankton and implies that evolutionary responses in phytoplankton will modify biogeochemical cycles and hence food web structure and function under warming. Models of climate futures that ignore adaptation would usefully be revisited.
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Affiliation(s)
- Daniel Padfield
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Genevieve Yvon-Durocher
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Angus Buckling
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Simon Jennings
- Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, NR33 0HT, UK
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Gabriel Yvon-Durocher
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
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48
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Abstract
Climate is changing rapidly in the Arctic. This has important implications for parasites of Arctic ungulates, and hence for the welfare of Arctic peoples who depend on caribou, reindeer, and muskoxen for food, income, and a focus for cultural activities. In this Opinion article we briefly review recent work on the development of predictive models for the impacts of climate change on helminth parasites and other pathogens of Arctic wildlife, in the hope that such models may eventually allow proactive mitigation and conservation strategies. We describe models that have been developed using the metabolic theory of ecology. The main strength of these models is that they can be easily parameterized using basic information about the physical size of the parasite. Initial results suggest they provide important new insights that are likely to generalize to a range of host-parasite systems.
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Affiliation(s)
- Andy Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Eno Hall, Princeton, NJ 08544, USA.
| | - Péter K Molnár
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada
| | - Susan Kutz
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada
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49
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Abstract
Understanding the effects of individual organisms on material cycles and energy fluxes within ecosystems is central to predicting the impacts of human-caused changes on climate, land use, and biodiversity. Here we present a theory that integrates metabolic (organism-based bottom-up) and systems (ecosystem-based top-down) approaches to characterize how the metabolism of individuals affects the flows and stores of materials and energy in ecosystems. The theory predicts how the average residence time of carbon molecules, total system throughflow (TST), and amount of recycling vary with the body size and temperature of the organisms and with trophic organization. We evaluate the theory by comparing theoretical predictions with outputs of numerical models designed to simulate diverse ecosystem types and with empirical data for real ecosystems. Although residence times within different ecosystems vary by orders of magnitude-from weeks in warm pelagic oceans with minute phytoplankton producers to centuries in cold forests with large tree producers-as predicted, all ecosystems fall along a single line: residence time increases linearly with slope = 1.0 with the ratio of whole-ecosystem biomass to primary productivity (B/P). TST was affected predominantly by primary productivity and recycling by the transfer of energy from microbial decomposers to animal consumers. The theory provides a robust basis for estimating the flux and storage of energy, carbon, and other materials in terrestrial, marine, and freshwater ecosystems and for quantifying the roles of different kinds of organisms and environments at scales from local ecosystems to the biosphere.
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50
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Palamara GM, Childs DZ, Clements CF, Petchey OL, Plebani M, Smith MJ. Inferring the temperature dependence of population parameters: the effects of experimental design and inference algorithm. Ecol Evol 2014; 4:4736-50. [PMID: 25558365 PMCID: PMC4278823 DOI: 10.1002/ece3.1309] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 09/25/2014] [Accepted: 10/01/2014] [Indexed: 11/22/2022] Open
Abstract
Understanding and quantifying the temperature dependence of population parameters, such as intrinsic growth rate and carrying capacity, is critical for predicting the ecological responses to environmental change. Many studies provide empirical estimates of such temperature dependencies, but a thorough investigation of the methods used to infer them has not been performed yet. We created artificial population time series using a stochastic logistic model parameterized with the Arrhenius equation, so that activation energy drives the temperature dependence of population parameters. We simulated different experimental designs and used different inference methods, varying the likelihood functions and other aspects of the parameter estimation methods. Finally, we applied the best performing inference methods to real data for the species Paramecium caudatum. The relative error of the estimates of activation energy varied between 5% and 30%. The fraction of habitat sampled played the most important role in determining the relative error; sampling at least 1% of the habitat kept it below 50%. We found that methods that simultaneously use all time series data (direct methods) and methods that estimate population parameters separately for each temperature (indirect methods) are complementary. Indirect methods provide a clearer insight into the shape of the functional form describing the temperature dependence of population parameters; direct methods enable a more accurate estimation of the parameters of such functional forms. Using both methods, we found that growth rate and carrying capacity of Paramecium caudatum scale with temperature according to different activation energies. Our study shows how careful choice of experimental design and inference methods can increase the accuracy of the inferred relationships between temperature and population parameters. The comparison of estimation methods provided here can increase the accuracy of model predictions, with important implications in understanding and predicting the effects of temperature on the dynamics of populations.
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Affiliation(s)
- Gian Marco Palamara
- Department of Evolutionary Biology and Environmental Studies, University of Zurich Wintherthurerstrase 190, CH-8057, Zurich, Switzerland ; Computational Science Laboratory, Microsoft Research Cambridge, CB1 2FB, UK
| | - Dylan Z Childs
- Department of Animal and Plant Sciences, University of Sheffield Sheffield, S10 2TN, UK
| | - Christopher F Clements
- Department of Evolutionary Biology and Environmental Studies, University of Zurich Wintherthurerstrase 190, CH-8057, Zurich, Switzerland
| | - Owen L Petchey
- Department of Evolutionary Biology and Environmental Studies, University of Zurich Wintherthurerstrase 190, CH-8057, Zurich, Switzerland
| | - Marco Plebani
- Department of Evolutionary Biology and Environmental Studies, University of Zurich Wintherthurerstrase 190, CH-8057, Zurich, Switzerland
| | - Matthew J Smith
- Computational Science Laboratory, Microsoft Research Cambridge, CB1 2FB, UK
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