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Villamarín F, Jardine TD, Bunn SE, Malvasio A, Piña CI, Jacobi CM, Araújo DD, de Brito ES, de Moraes Carvalho F, da Costa ID, Verdade LM, Lara N, de Camargo PB, Miorando PS, Portelinha TCG, Marques TS, Magnusson WE. Body size predicts ontogenetic nitrogen stable-isotope (δ 15N) variation, but has little relationship with trophic level in ectotherm vertebrate predators. Sci Rep 2024; 14:14102. [PMID: 38890338 PMCID: PMC11189434 DOI: 10.1038/s41598-024-61969-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 05/13/2024] [Indexed: 06/20/2024] Open
Abstract
Large predators have disproportionate effects on their underlying food webs. Thus, appropriately assigning trophic positions has important conservation implications both for the predators themselves and for their prey. Large-bodied predators are often referred to as apex predators, implying that they are many trophic levels above primary producers. However, theoretical considerations predict both higher and lower trophic position with increasing body size. Nitrogen stable isotope values (δ15N) are increasingly replacing stomach contents or behavioral observations to assess trophic position and it is often assumed that ontogenetic dietary shifts result in higher trophic positions. Intraspecific studies based on δ15N values found a positive relationship between size and inferred trophic position. Here, we use datasets of predatory vertebrate ectotherms (crocodilians, turtles, lizards and fishes) to show that, although there are positive intraspecific relationships between size and δ15N values, relationships between stomach-content-based trophic level (TPdiet) and size are undetectable or negative. As there is usually no single value for 15N trophic discrimination factor (TDF) applicable to a predator species or its prey, estimates of trophic position based on δ15N in ectotherm vertebrates with large size ranges, may be inaccurate and biased. We urge a reconsideration of the sole use of δ15N values to assess trophic position and encourage the combined use of isotopes and stomach contents to assess diet and trophic level.
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Affiliation(s)
- Francisco Villamarín
- Grupo de Biogeografía y Ecología Espacial (BioGeoE2), Universidad Regional Amazónica Ikiam, Tena, Ecuador.
| | - Timothy D Jardine
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada
| | - Stuart E Bunn
- Australian Rivers Institute, Griffith University, Nathan, QLD, Australia
| | - Adriana Malvasio
- Laboratório de Ecologia e Zoologia (LABECZ), Curso de Engenharia Ambiental, Universidade Federal do Tocantins, Palmas, TO, Brazil
| | - Carlos Ignacio Piña
- Centro de Investigación Científica y de Transferencia Tecnológica a la Producción (Consejo Nacional de Investigaciones Científicas y Técnicas, Provincia de Entre Ríos, Universidad Autónoma de Entre Ríos), Diamante, Argentina
| | | | - Diogo Dutra Araújo
- Laboratório de Ecologia de Vertebrados Terrestres (LEVERT), Universidade do Vale do Rio dos Sinos, São Leopoldo, RS, Brazil
| | | | | | - Igor David da Costa
- Instituto do Noroeste Fluminense de Educação Superior, Universidade Federal Fluminense, Santo Antônio de Pádua, RJ, Brazil
| | | | - Neliton Lara
- Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Piracicaba, Brazil
| | | | | | - Thiago Costa Gonçalves Portelinha
- Laboratório de Caracterização de Impactos Ambientais (LCIA), Curso de Engenharia Ambiental, Universidade Federal do Tocantins, Palmas, TO, Brazil
| | - Thiago Simon Marques
- Laboratório de Ecologia Aplicada, Núcleo de Estudos Ambientais, Universidade de Sorocaba, Sorocaba, Brazil
| | - William E Magnusson
- Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
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2
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Sporta Caputi S, Kabala JP, Rossi L, Careddu G, Calizza E, Ventura M, Costantini ML. Individual diet variability shapes the architecture of Antarctic benthic food webs. Sci Rep 2024; 14:12333. [PMID: 38811641 PMCID: PMC11137039 DOI: 10.1038/s41598-024-62644-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 05/20/2024] [Indexed: 05/31/2024] Open
Abstract
Antarctic biodiversity is affected by seasonal sea-ice dynamics driving basal resource availability. To (1) determine the role of intraspecific dietary variability in structuring benthic food webs sustaining Antarctic biodiversity, and (2) understand how food webs and the position of topologically central species vary with sea-ice cover, single benthic individuals' diets were studied by isotopic analysis before sea-ice breakup and afterwards. Isotopic trophospecies (or Isotopic Trophic Units) were investigated and food webs reconstructed using Bayesian Mixing Models. As nodes, these webs used either ITUs regardless of their taxonomic membership (ITU-webs) or ITUs assigned to species (population-webs). Both were compared to taxonomic-webs based on taxa and their mean isotopic values. Higher resource availability after sea-ice breakup led to simpler community structure, with lower connectance and linkage density. Intra-population diet variability and compartmentalisation were crucial in determining community structure, showing population-webs to be more complex, stable and robust to biodiversity loss than taxonomic-webs. The core web, representing the minimal community 'skeleton' that expands opportunistically while maintaining web stability with changing resource availability, was also identified. Central nodes included the sea-urchin Sterechinus neumayeri and the bivalve Adamussium colbecki, whose diet is described in unprecedented detail. The core web, compartmentalisation and topologically central nodes represent crucial factors underlying Antarctica's rich benthic food web persistence.
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Affiliation(s)
- Simona Sporta Caputi
- Department of Environmental Biology, Sapienza University of Rome, Via Dei Sardi 70, 00185, Rome, Italy
- CoNISMa, National Inter-University Consortium for Marine Sciences, Piazzale Flaminio 9, 00196, Rome, Italy
| | - Jerzy Piotr Kabala
- Department of Environmental Biology, Sapienza University of Rome, Via Dei Sardi 70, 00185, Rome, Italy
| | - Loreto Rossi
- CoNISMa, National Inter-University Consortium for Marine Sciences, Piazzale Flaminio 9, 00196, Rome, Italy.
| | - Giulio Careddu
- Department of Environmental Biology, Sapienza University of Rome, Via Dei Sardi 70, 00185, Rome, Italy
- CoNISMa, National Inter-University Consortium for Marine Sciences, Piazzale Flaminio 9, 00196, Rome, Italy
| | - Edoardo Calizza
- Department of Environmental Biology, Sapienza University of Rome, Via Dei Sardi 70, 00185, Rome, Italy
- CoNISMa, National Inter-University Consortium for Marine Sciences, Piazzale Flaminio 9, 00196, Rome, Italy
| | - Matteo Ventura
- Department of Environmental Biology, Sapienza University of Rome, Via Dei Sardi 70, 00185, Rome, Italy
| | - Maria Letizia Costantini
- Department of Environmental Biology, Sapienza University of Rome, Via Dei Sardi 70, 00185, Rome, Italy
- CoNISMa, National Inter-University Consortium for Marine Sciences, Piazzale Flaminio 9, 00196, Rome, Italy
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3
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Anderson TM, Hepler SA, Holdo RM, Donaldson JE, Erhardt RJ, Hopcraft JGC, Hutchinson MC, Huebner SE, Morrison TA, Muday J, Munuo IN, Palmer MS, Pansu J, Pringle RM, Sketch R, Packer C. Interplay of competition and facilitation in grazing succession by migrant Serengeti herbivores. Science 2024; 383:782-788. [PMID: 38359113 DOI: 10.1126/science.adg0744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/10/2024] [Indexed: 02/17/2024]
Abstract
Competition, facilitation, and predation offer alternative explanations for successional patterns of migratory herbivores. However, these interactions are difficult to measure, leaving uncertainty about the mechanisms underlying body-size-dependent grazing-and even whether succession occurs at all. We used data from an 8-year camera-trap survey, GPS-collared herbivores, and fecal DNA metabarcoding to analyze the timing, arrival order, and interactions among migratory grazers in Serengeti National Park. Temporal grazing succession is characterized by a "push-pull" dynamic: Competitive grazing nudges zebra ahead of co-migrating wildebeest, whereas grass consumption by these large-bodied migrants attracts trailing, small-bodied gazelle that benefit from facilitation. "Natural experiments" involving intense wildfires and rainfall respectively disrupted and strengthened these effects. Our results highlight a balance between facilitative and competitive forces in co-regulating large-scale ungulate migrations.
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Affiliation(s)
- T Michael Anderson
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Staci A Hepler
- Department of Statistical Sciences, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Ricardo M Holdo
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Jason E Donaldson
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Robert J Erhardt
- Department of Statistical Sciences, Wake Forest University, Winston-Salem, NC 27109, USA
| | - J Grant C Hopcraft
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow G61 1QH, UK
| | - Matthew C Hutchinson
- Department of Life & Environmental Sciences, University of California Merced, Merced, CA 95343, USA
| | - Sarah E Huebner
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, USA
| | - Thomas A Morrison
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow G61 1QH, UK
| | - Jeffry Muday
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Issack N Munuo
- Serengeti Wildlife Research Centre, 2113 Lemara, Arusha, TZ
| | - Meredith S Palmer
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Johan Pansu
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Robert M Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Robert Sketch
- Department of Statistical Sciences, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Craig Packer
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108, USA
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Wise DH, Mores RM, M. Pajda-De La O J, McCary MA. Pattern of seasonal variation in rates of predation between spider families is temporally stable in a food web with widespread intraguild predation. PLoS One 2023; 18:e0293176. [PMID: 37903108 PMCID: PMC10615273 DOI: 10.1371/journal.pone.0293176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 10/06/2023] [Indexed: 11/01/2023] Open
Abstract
Intraguild predation (IGP)-predation between generalist predators (IGPredator and IGPrey) that potentially compete for a shared prey resource-is a common interaction module in terrestrial food webs. Understanding temporal variation in webs with widespread IGP is relevant to testing food web theory. We investigated temporal constancy in the structure of such a system: the spider-focused food web of the forest floor. Multiplex PCR was used to detect prey DNA in 3,300 adult spiders collected from the floor of a deciduous forest during spring, summer, and fall over four years. Because only spiders were defined as consumers, the web was tripartite, with 11 consumer nodes (spider families) and 22 resource nodes: 11 non-spider arthropod taxa (order- or family-level) and the 11 spider families. Most (99%) spider-spider predation was on spider IGPrey, and ~90% of these interactions were restricted to spider families within the same broadly defined foraging mode (cursorial or web-spinning spiders). Bootstrapped-derived confidence intervals (BCI's) for two indices of web structure, restricted connectance and interaction evenness, overlapped broadly across years and seasons. A third index, % IGPrey (% IGPrey among all prey of spiders), was similar across years (~50%) but varied seasonally, with a summer rate (65%) ~1.8x higher than spring and fall. This seasonal pattern was consistent across years. Our results suggest that extensive spider predation on spider IGPrey that exhibits consistent seasonal variation in frequency, and that occurs primarily within two broadly defined spider-spider interaction pathways, must be incorporated into models of the dynamics of forest-floor food webs.
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Affiliation(s)
- David H. Wise
- Department of Biological Sciences, University of Illinois, Chicago, Illinois, United States of America
| | - Robin M. Mores
- Department of Biological Sciences, University of Illinois, Chicago, Illinois, United States of America
| | - Jennifer M. Pajda-De La O
- Department of Mathematics, Statistics, and Computer Science, University of Illinois, Chicago, Illinois, United States of America
| | - Matthew A. McCary
- Department of BioSciences, Rice University, Houston, Texas, United States of America
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5
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Parmentier T, Boeckx P, Bonte D, De Laender F. You are what your host eats: The trophic structure and food chain length of a symbiont community are coupled with the plastic diet of the host ant. J Anim Ecol 2023; 92:2028-2038. [PMID: 37602518 DOI: 10.1111/1365-2656.13994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/27/2023] [Indexed: 08/22/2023]
Abstract
Food chain length provides key information on the flow of nutrients and energy in ecosystems. Variation in food chain length has primarily been explained by environmental drivers such as ecosystem size and productivity. Most insights are obtained from theory or aquatic systems, but the importance of these drivers remains largely untested in terrestrial systems. We exploited red wood ant nests markedly differing in size as natural experiments to quantify the drivers of trophic structure and food chain length of their symbiont arthropod communities. Using stable isotopes, we explored the variation in the trophic positions of four symbiont species with the trophic position of the top predator as a proxy for food chain length of the symbiont community. Nest size did not affect food chain length, nor trophic distance between the symbionts. Instead, food chain length and the trophic positions of the symbionts were strongly affected by the host's foraging decisions. When the host diet shifted from predominantly herbivorous to more predacious, the trophic position of the symbionts and food chain length strongly increased. We show for the first time that a food web can be structured by biotic interactions with an engineering species rather than by abiotic environmental variables.
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Affiliation(s)
- T Parmentier
- Terrestrial Ecology Unit (TEREC), Department of Biology, Ghent University, Ghent, Belgium
- Research Unit of Environmental and Evolutionary Biology, Namur Institute of Complex Systems, and Institute of Life, Earth, and the Environment, University of Namur, Namur, Belgium
| | - P Boeckx
- Department of Green Chemistry and Technology, Ghent University, Ghent, Belgium
| | - D Bonte
- Terrestrial Ecology Unit (TEREC), Department of Biology, Ghent University, Ghent, Belgium
| | - F De Laender
- Research Unit of Environmental and Evolutionary Biology, Namur Institute of Complex Systems, and Institute of Life, Earth, and the Environment, University of Namur, Namur, Belgium
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6
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Schuman MJ, Snyder SL, Smoak CH, Schmid JR. Faunal Diet of Adult Cane Toads, Rhinella marina, in the Urban Landscape of Southwest Florida. Animals (Basel) 2023; 13:2898. [PMID: 37760298 PMCID: PMC10526063 DOI: 10.3390/ani13182898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
We investigated the diet of cane toads (Rhinella marina) inhabiting urbanized areas in southwest Florida to provide high taxonomic resolution of prey items, contrast toad diets between sampling seasons and sexes, and assess this invasive species' ecological role in the urban landscape. A pest control agency collected cane toads from two golf course communities in Naples, Florida, USA during November-December 2018 (early dry season) and June-July 2019 (early wet season), and faunal stomach contents were quantified from a random subsample of 240 adult toads (30 males and 30 females from each community and season). Yellow-banded millipedes (Anadenobolus monilicornis), big-headed ants (Pheidole spp.), and hunting billbugs (Sphenophorus venatus vestitus) were the most frequently consumed prey items and had the highest total numbers and/or volume with corresponding highest indices of relative importance. There was considerable overlap in the seasonal prey importance values for each golf course community and little if any difference in the importance values between toad sexes in each community. Nonetheless, big-headed ants were the most important prey in both communities during the wet season, while yellow-banded millipedes were the most important dry season prey in one community and hunting billbugs the most important in the other. Despite limited spatiotemporal sampling effort, our results indicated that cane toad was consuming arthropod taxa considered pests in the urban ecosystem. Further studies are needed to investigate the potential effects of human activities and environmental variability on the cane toad diet and to determine whether cane toads act as a biological control for pest populations.
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Affiliation(s)
| | | | | | - Jeffrey R. Schmid
- Conservancy of Southwest Florida, 1495 Smith Preserve Way, Naples, FL 34102, USA; (M.J.S.); (S.L.S.); (C.H.S.)
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Brimacombe C, Bodner K, Michalska-Smith M, Poisot T, Fortin MJ. Shortcomings of reusing species interaction networks created by different sets of researchers. PLoS Biol 2023; 21:e3002068. [PMID: 37011096 PMCID: PMC10101633 DOI: 10.1371/journal.pbio.3002068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 04/13/2023] [Accepted: 03/07/2023] [Indexed: 04/05/2023] Open
Abstract
Given the requisite cost associated with observing species interactions, ecologists often reuse species interaction networks created by different sets of researchers to test their hypotheses regarding how ecological processes drive network topology. Yet, topological properties identified across these networks may not be sufficiently attributable to ecological processes alone as often assumed. Instead, much of the totality of topological differences between networks-topological heterogeneity-could be due to variations in research designs and approaches that different researchers use to create each species interaction network. To evaluate the degree to which this topological heterogeneity is present in available ecological networks, we first compared the amount of topological heterogeneity across 723 species interaction networks created by different sets of researchers with the amount quantified from non-ecological networks known to be constructed following more consistent approaches. Then, to further test whether the topological heterogeneity was due to differences in study designs, and not only to inherent variation within ecological networks, we compared the amount of topological heterogeneity between species interaction networks created by the same sets of researchers (i.e., networks from the same publication) with the amount quantified between networks that were each from a unique publication source. We found that species interaction networks are highly topologically heterogeneous: while species interaction networks from the same publication are much more topologically similar to each other than interaction networks that are from a unique publication, they still show at least twice as much heterogeneity as any category of non-ecological networks that we tested. Altogether, our findings suggest that extra care is necessary to effectively analyze species interaction networks created by different researchers, perhaps by controlling for the publication source of each network.
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Affiliation(s)
- Chris Brimacombe
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Korryn Bodner
- MAP Centre for Urban Health Solutions, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Matthew Michalska-Smith
- Department of Ecology, Evolution and Behavior, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Plant Pathology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Timothée Poisot
- Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
- Centre de la Science de la Biodiversité du Québec, Montréal, Québec, Canada
| | - Marie-Josée Fortin
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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Lozano-Bilbao E, Delgado-Suárez I, Paz-Montelongo S, Hardisson A, Pascual-Fernández JJ, Rubio C, Weller DG, Gutiérrez ÁJ. Risk Assessment and Characterization in Tuna Species of the Canary Islands According to Their Metal Content. Foods 2023; 12:foods12071438. [PMID: 37048259 PMCID: PMC10093732 DOI: 10.3390/foods12071438] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/22/2023] [Accepted: 03/26/2023] [Indexed: 03/31/2023] Open
Abstract
Bioaccumulation is the process by which living organisms accumulate substances, such as pesticides, heavy metals, and other pollutants, from their environment. These substances can accumulate in the organism’s tissues over time, leading to potential health risks. Bioaccumulation can occur in both aquatic and terrestrial ecosystems, and can have a significant impact on the health of both humans and wildlife. The objective of this study is to find out if the concentrations of metals in the tuna species of the Canary Islands are suitable for human consumption and if they pose a health risk. Fifteen samples of Acanthocybium solandri, Katsuwonus pelamis, Thunnus albacares, Thunnus obesus and Thunnus thynnus present in canaries were analyzed. Ten grams of muscle were taken from each specimen and the metals Al, Cd, Cr, Cu, Fe, Li, Ni, Pb and Zn were determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The tuna species that presented more metals with a higher concentration compared to the others was T. thynnus, reaching up to 100 times more than the other studied species in Fe content with 137.8 ± 100.9 mg/Kg, which may be due to the fact that it is the largest species that reaches ages of more than fifteen years. The species Thunnus thynnus should not be suitable for commercialization according to the current legislation on the concentrations of Cd in blue fish, since 75% of the specimens studied exceeded the concentration legislated for Cd. A total of 40% of the studied specimens of this this species exceeded the legislated values for the concentration of Pb in oily fish meat, so this species must be monitored to ensure that it does not pose a risk to human health.
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Affiliation(s)
- Enrique Lozano-Bilbao
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Facultad de Medicina, Universidad de La Laguna (ULL), Campus de Ofra, 38071 San Cristóbal de La Laguna, Spain
- Ecología Marina Aplicada y Pesquerías, i-UNAT, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017 Las Palmas de Gran Canaria, Spain
- Departamento de Biología Animal y Edafología y Geología, Unidad Departamental de Ciencias Marinas, Universidad de La Laguna, 38206 La Laguna, Santa Cruz de Tenerife, Spain
| | - Indira Delgado-Suárez
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Facultad de Medicina, Universidad de La Laguna (ULL), Campus de Ofra, 38071 San Cristóbal de La Laguna, Spain
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Área de Toxicología, Universidad de La Laguna, 38200 La Laguna, Santa Cruz de Tenerife, Spain
| | - Soraya Paz-Montelongo
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Facultad de Medicina, Universidad de La Laguna (ULL), Campus de Ofra, 38071 San Cristóbal de La Laguna, Spain
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Área de Toxicología, Universidad de La Laguna, 38200 La Laguna, Santa Cruz de Tenerife, Spain
- Correspondence:
| | - Arturo Hardisson
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Facultad de Medicina, Universidad de La Laguna (ULL), Campus de Ofra, 38071 San Cristóbal de La Laguna, Spain
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Área de Toxicología, Universidad de La Laguna, 38200 La Laguna, Santa Cruz de Tenerife, Spain
| | - José J. Pascual-Fernández
- Instituto Universitario de Investigación Social y Turismo (ISTUR), Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Carmen Rubio
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Facultad de Medicina, Universidad de La Laguna (ULL), Campus de Ofra, 38071 San Cristóbal de La Laguna, Spain
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Área de Toxicología, Universidad de La Laguna, 38200 La Laguna, Santa Cruz de Tenerife, Spain
| | - Dailos González Weller
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Facultad de Medicina, Universidad de La Laguna (ULL), Campus de Ofra, 38071 San Cristóbal de La Laguna, Spain
- Servicio Público Canario de Salud, Laboratorio Central, 38006 Santa Cruz de Tenerife, Spain
| | - Ángel J. Gutiérrez
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Facultad de Medicina, Universidad de La Laguna (ULL), Campus de Ofra, 38071 San Cristóbal de La Laguna, Spain
- Departamento de Obstetricia y Ginecología, Pediatría, Medicina Preventiva y Salud Pública, Toxicología, Medicina Legal y Forense y Parasitología, Área de Toxicología, Universidad de La Laguna, 38200 La Laguna, Santa Cruz de Tenerife, Spain
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Phillips EM, Pringle RM. Ecology: How mesopredators run with the big dogs. Curr Biol 2023; 33:R197-R199. [PMID: 36917945 DOI: 10.1016/j.cub.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Food webs are indispensable maps of community organization, but most are crudely drawn - an inconvenient truth that ecologists must confront. A new DNA metabarcoding study quantifies predator-prey interactions and ecological-network structure with long-overdue precision, supplying insight into how large and small carnivores coexist.
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Affiliation(s)
- Erin M Phillips
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Robert M Pringle
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
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10
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Lu Q, Cheng C, Xiao L, Li J, Li X, Zhao X, Lu Z, Zhao J, Yao M. Food webs reveal coexistence mechanisms and community organization in carnivores. Curr Biol 2023; 33:647-659.e5. [PMID: 36669497 DOI: 10.1016/j.cub.2022.12.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 11/11/2022] [Accepted: 12/20/2022] [Indexed: 01/20/2023]
Abstract
Globally, massive carnivore guild extirpations have led to trophic downgrading and compromised ecosystem services. However, the complexity of multi-carnivore food webs complicates accurate identification of species interactions and community organization. Here, we used fecal DNA metabarcoding to investigate three communities that together encompass eight large- and meso-carnivore species and their 44 prey taxa of the Qinghai-Tibet Plateau (QTP), one of the last places on Earth that still harbors intact carnivore assemblages. Quantitative food-web analyses revealed pronounced interspecific variations in the carnivores' prey compositions and dietary partitioning both between and within guilds. Additionally, body masses of the carnivores and their prey exhibited consistent hump-shaped correlations across communities. Overall, differences in prey diversity, size category, and proportional utilization among the carnivore species result in trophic niche segregation that likely promotes carnivore coexistence in the harsh QTP environment. Network structure analyses detected significant modularity in all food webs but nestedness in only one. Furthermore, network characterization identified pikas (Ochotona spp.), bharal (Pseudois nayaur), and domestic yak (Bos grunniens) as potential keystone prey across the areas. Our results paint a holistic and detailed picture of the QTP carnivore assemblages' trophic networks and demonstrate that the combined use of the molecular dietary approach and network analysis can generate structural insights into carnivore coexistence and can identify functionally important species in complex communities. Such knowledge can help safeguard carnivore guild integrity and enhance community resilience to environmental perturbations in the sensitive QTP ecosystems.
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Affiliation(s)
- Qi Lu
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Chen Cheng
- Center for Nature and Society, School of Life Sciences, Peking University, Beijing 100871, China; Shan Shui Conservation Center, Beijing 100871, China
| | - Lingyun Xiao
- School of Life Sciences, Peking University, Beijing 100871, China; Department of Health and Environmental Sciences, Xi'an Jiaotong Liverpool University, Suzhou, Jiangsu 215123, China
| | - Juan Li
- School of Life Sciences, Peking University, Beijing 100871, China; Department of Health and Environmental Sciences, Xi'an Jiaotong Liverpool University, Suzhou, Jiangsu 215123, China
| | - Xueyang Li
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Xiang Zhao
- Shan Shui Conservation Center, Beijing 100871, China
| | - Zhi Lu
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; Center for Nature and Society, School of Life Sciences, Peking University, Beijing 100871, China; Shan Shui Conservation Center, Beijing 100871, China
| | - Jindong Zhao
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Meng Yao
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
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11
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Walker RH, Hutchinson MC, Potter AB, Becker JA, Long RA, Pringle RM. Mechanisms of individual variation in large herbivore diets: Roles of spatial heterogeneity and state-dependent foraging. Ecology 2023; 104:e3921. [PMID: 36415899 PMCID: PMC10078531 DOI: 10.1002/ecy.3921] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/24/2022]
Abstract
Many populations of consumers consist of relatively specialized individuals that eat only a subset of the foods consumed by the population at large. Although the ecological significance of individual-level diet variation is recognized, such variation is difficult to document, and its underlying mechanisms are poorly understood. Optimal foraging theory provides a useful framework for predicting how individuals might select different diets, positing that animals balance the "opportunity cost" of stopping to eat an available food item against the cost of searching for something more nutritious; diet composition should be contingent on the distribution of food, and individual foragers should be more selective when they have greater energy reserves to invest in searching for high-quality foods. We tested these predicted mechanisms of individual niche differentiation by quantifying environmental (resource heterogeneity) and organismal (nutritional condition) determinants of diet in a widespread browsing antelope (bushbuck, Tragelaphus sylvaticus) in an African floodplain-savanna ecosystem. We quantified individuals' realized dietary niches (taxonomic richness and composition) using DNA metabarcoding of fecal samples collected repeatedly from 15 GPS-collared animals (range 6-14 samples per individual, median 12). Bushbuck diets were structured by spatial heterogeneity and constrained by individual condition. We observed significant individual-level partitioning of food plants by bushbuck both within and between two adjacent habitat types (floodplain and woodland). Individuals with home ranges that were closer together and/or had similar vegetation structure (measured using LiDAR) ate more similar diets, supporting the prediction that heterogeneous resource distribution promotes individual differentiation. Individuals in good nutritional condition had significantly narrower diets (fewer plant taxa), searched their home ranges more intensively (intensity-of-use index), and had higher-quality diets (percent digestible protein) than those in poor condition, supporting the prediction that animals with greater endogenous reserves have narrower realized niches because they can invest more time in searching for nutritious foods. Our results support predictions from optimal foraging theory about the energetic basis of individual-level dietary variation and provide a potentially generalizable framework for understanding how individuals' realized niche width is governed by animal behavior and physiology in heterogeneous landscapes.
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Affiliation(s)
- Reena H Walker
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
| | - Matthew C Hutchinson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Arjun B Potter
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Justine A Becker
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Ryan A Long
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
| | - Robert M Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
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12
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Manlick PJ, Cook JA, Newsome SD. The coupling of green and brown food webs regulates trophic position in a montane mammal guild. Ecology 2023; 104:e3949. [PMID: 36495220 DOI: 10.1002/ecy.3949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/26/2022] [Accepted: 11/11/2022] [Indexed: 12/14/2022]
Abstract
Food web ecology has revolutionized our understanding of ecological processes, but the drivers of food web properties like trophic position (TP) and food chain length are notoriously enigmatic. In terrestrial ecosystems, above- and belowground systems were historically compartmentalized into "green" and "brown" food webs, but the coupling of these systems by animal consumers is increasingly recognized, with potential consequences for trophic structure. We used stable isotope analysis (δ13 C, δ15 N) of individual amino acids to trace the flow of essential biomolecules and jointly measure multichannel feeding, food web coupling, and TP in a guild of small mammals. We then tested the hypothesis that brown energy fluxes to aboveground consumers increase terrestrial food chain length via cryptic trophic transfers during microbial decomposition. We found that the average small mammal consumer acquired nearly 70% of their essential amino acids (69.0% ± 7.6%) from brown food webs, leading to significant increases in TP across species and functional groups. Fungi were the primary conduit of brown energy to aboveground consumers, providing nearly half the amino acid budget for small mammals on average (44.3% ± 12.0%). These findings illustrate the tightly coupled nature of green and brown food webs and show that microbially mediated energy flow ultimately regulates food web structure in aboveground consumers. Consequently, we propose that the integration of green and brown energy channels is a cryptic driver of food chain length in terrestrial ecosystems.
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Affiliation(s)
- Philip J Manlick
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA.,Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico, USA.,Pacific Northwest Research Station, USDA Forest Service, Juneau, Alaska, USA
| | - Joseph A Cook
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA.,Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
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13
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Berman TS, Inbar M. Molecular identification of individual and seasonal variation in incidental ingestion of arthropods by free-ranging goats. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2022.1070088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The extent of direct interactions between large mammalian herbivores (LMH) and plant-dwelling arthropods (PDA), i.e., the ingestion of PDA by LMH, remains largely unexplored. Grazing LMH may ingest a variety of PDA, yet, it is unknown how different foraging strategies (i.e., browsing, grazing, etc.) influence the ingestion of PDA or whether individual variation within herds affects it. Here we examine how individual variation within a herd of browsing LMH impacts PDA ingestion. This was done using a DNA metabarcoding analysis on feces collected monthly from marked individuals within a herd of free-ranging goats. We found that goats frequently ingest PDA while feeding (all samples contains PDA), including a complex food-chain of herbivores, predators and parasites, which differed over the season and among individual goats. In total, 63 families of insects and 9 families of arachnids from 15 orders were ingested by the goats. Most ingested PDA were herbivores with reduced mobility, such as immature or sessile species. Highly mobile and noxious PDA were rarely detected. We show for the first time that ingestion of PDA by LMH is influenced by seasonal and individual variation within the herd and that it is common among LMH, regardless of feeding strategy or habitat.
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14
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Littleford-Colquhoun BL, Sackett VI, Tulloss CV, Kartzinel TR. Evidence-based strategies to navigate complexity in dietary DNA metabarcoding: A reply. Mol Ecol 2022; 31:5660-5665. [PMID: 36263899 DOI: 10.1111/mec.16712] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/06/2022] [Accepted: 09/23/2022] [Indexed: 01/13/2023]
Abstract
It is clearly beneficial to eliminate low-abundance sequences that arise in error during dietary DNA metabarcoding studies, but to purge all low-abundance sequences is to risk eliminating real sequences and complicating ecological analyses. Our prior literature review noted that DNA sequence relative read abundance (RRA) thresholds can help ameliorate false-positive taxon occurrences, but that historical emphasis on this utility has fostered uncertainty about the associated risk of inflating the false-negative rate (Littleford-Colquhoun et al., 2022). To address this, we combined a simulation study and an empirical data set to both illustrate the issue and provide blueprints for simulation studies and sensitivity analyses that can help investigators avoid overcorrecting and thereby bolster confidence in ecological inferences. Awareness of both the costs and the benefits of abundance-filtering is needed because accurately characterizing dietary distributions can be critically important for understanding animal diets, nutrition and trophic networks. Highlighting the need to raise awareness, a critique of our paper emphasized the misleading notion that "false positive interactions between species can present fundamentally incorrect network structures in network ecology, whereas false negatives will provide a correct but incomplete version of the network" (Tercel & Cuff, 2022). Asserting that the reliability of results will be eroded by false positives but resilient to the omission of true positives is risky and runs counter to evidence. Unfortunately, abundance-filtering methods can introduce false negatives at higher rates than they eliminate false positives and thereby undermine the analysis of otherwise reliable sequencing data. Overcorrecting can qualitatively alter and ultimately undermine ecological interpretations.
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Affiliation(s)
- Bethan L Littleford-Colquhoun
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, Rhode Island, USA.,Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA
| | - Violet I Sackett
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, Rhode Island, USA.,Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA
| | - Camille V Tulloss
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, Rhode Island, USA.,Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA
| | - Tyler R Kartzinel
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, Rhode Island, USA.,Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA
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15
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The generality of cryptic dietary niche differences in diverse large-herbivore assemblages. Proc Natl Acad Sci U S A 2022; 119:e2204400119. [PMID: 35994662 PMCID: PMC9436339 DOI: 10.1073/pnas.2204400119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Ecological niche differences are necessary for stable species coexistence but are often difficult to discern. Models of dietary niche differentiation in large mammalian herbivores invoke the quality, quantity, and spatiotemporal distribution of plant tissues and growth forms but are agnostic toward food plant species identity. Empirical support for these models is variable, suggesting that additional mechanisms of resource partitioning may be important in sustaining large-herbivore diversity in African savannas. We used DNA metabarcoding to conduct a taxonomically explicit analysis of large-herbivore diets across southeastern Africa, analyzing ∼4,000 fecal samples of 30 species from 10 sites in seven countries over 6 y. We detected 893 food plant taxa from 124 families, but just two families-grasses and legumes-accounted for the majority of herbivore diets. Nonetheless, herbivore species almost invariably partitioned food plant taxa; diet composition differed significantly in 97% of pairwise comparisons between sympatric species, and dissimilarity was pronounced even between the strictest grazers (grass eaters), strictest browsers (nongrass eaters), and closest relatives at each site. Niche differentiation was weakest in an ecosystem recovering from catastrophic defaunation, indicating that food plant partitioning is driven by species interactions, and was stronger at low rainfall, as expected if interspecific competition is a predominant driver. Diets differed more between browsers than grazers, which predictably shaped community organization: Grazer-dominated trophic networks had higher nestedness and lower modularity. That dietary differentiation is structured along taxonomic lines complements prior work on how herbivores partition plant parts and patches and suggests that common mechanisms govern herbivore coexistence and community assembly in savannas.
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16
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A network simplification approach to ease topological studies about the food-web architecture. Sci Rep 2022; 12:13948. [PMID: 35977970 PMCID: PMC9385703 DOI: 10.1038/s41598-022-17508-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 07/26/2022] [Indexed: 11/19/2022] Open
Abstract
Food webs studies are intrinsically complex and time-consuming. Network data about trophic interaction across different large locations and ecosystems are scarce in comparison with general ecological data, especially if we consider terrestrial habitats. Here we present a complex network strategy to ease the gathering of the information by simplifying the collection of data with a taxonomic key. We test how well the topology of three different food webs retain their structure at the resolution of the nodes across distinct levels of simplification, and we estimate how community detection could be impacted by this strategy. The first level of simplification retains most of the general topological indices; betweenness and trophic levels seem to be consistent and robust even at the higher levels of simplification. This result suggests that generalisation and standardisation, as a good practice in food webs science, could benefit the community, both increasing the amount of open data available and the comparison among them, thus providing support especially for scientists that are new in this field and for exploratory analysis.
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17
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Paula DP, Timbó RV, Togawa RC, Vogler AP, Andow DA. Quantitative prey species detection in predator guts across multiple trophic levels by mapping unassembled shotgun reads. Mol Ecol Resour 2022; 23:64-80. [DOI: 10.1111/1755-0998.13690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 06/11/2022] [Accepted: 07/05/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Débora P. Paula
- Embrapa Recursos Genéticos e Biotecnologia Brasília DF Brazil
| | - Renata V. Timbó
- Embrapa Recursos Genéticos e Biotecnologia Brasília DF Brazil
- Universidade de Brasília, Campus Universitário Darcy Ribeiro Brasília DF Brazil
| | | | - Alfried P. Vogler
- Imperial College London Ascot UK
- Department of Life Sciences Natural History Museum London UK
| | - David A. Andow
- Department of Entomology University of Minnesota St. Paul USA
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18
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Daskin JH, Becker JA, Kartzinel TR, Potter AB, Walker RH, Eriksson FAA, Buoncore C, Getraer A, Long RA, Pringle RM. Allometry of behavior and niche differentiation among congeneric African antelopes. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Joshua H. Daskin
- Department of Ecology & Evolutionary Biology Princeton University Princeton NJ USA
- Archbold Biological Station Venus FL USA
| | - Justine A. Becker
- Department of Ecology & Evolutionary Biology Princeton University Princeton NJ USA
- Department of Zoology & Physiology University of Wyoming Laramie WY USA
| | - Tyler R. Kartzinel
- Department of Ecology & Evolutionary Biology Brown University Providence RI USA
| | - Arjun B. Potter
- Department of Ecology & Evolutionary Biology Princeton University Princeton NJ USA
| | - Reena H. Walker
- Department of Fish and Wildlife Sciences University of Idaho Moscow ID USA
| | | | - Courtney Buoncore
- Department of Ecology & Evolutionary Biology Princeton University Princeton NJ USA
| | - Alexander Getraer
- Department of Ecology & Evolutionary Biology Princeton University Princeton NJ USA
| | - Ryan A. Long
- Department of Fish and Wildlife Sciences University of Idaho Moscow ID USA
| | - Robert M. Pringle
- Department of Ecology & Evolutionary Biology Princeton University Princeton NJ USA
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19
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Durso AM, Kieran TJ, Glenn TC, Mullin SJ. Comparison of Three Methods for Measuring Dietary Composition of Plains Hog-nosed Snakes. HERPETOLOGICA 2022. [DOI: 10.1655/herpetologica-d-21-00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Andrew M. Durso
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL 61920, USA
| | - Troy J. Kieran
- Department of Environmental Health Science, University of Georgia, Athens, GA 30602, USA
| | - Travis C. Glenn
- Department of Environmental Health Science, University of Georgia, Athens, GA 30602, USA
| | - Stephen J. Mullin
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL 61920, USA
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20
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Titcomb GC, Pansu J, Hutchinson MC, Tombak KJ, Hansen CB, Baker CCM, Kartzinel TR, Young HS, Pringle RM. Large-herbivore nemabiomes: patterns of parasite diversity and sharing. Proc Biol Sci 2022; 289:20212702. [PMID: 35538775 PMCID: PMC9091847 DOI: 10.1098/rspb.2021.2702] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Amidst global shifts in the distribution and abundance of wildlife and livestock, we have only a rudimentary understanding of ungulate parasite communities and parasite-sharing patterns. We used qPCR and DNA metabarcoding of fecal samples to characterize gastrointestinal nematode (Strongylida) community composition and sharing among 17 sympatric species of wild and domestic large mammalian herbivore in central Kenya. We tested a suite of hypothesis-driven predictions about the role of host traits and phylogenetic relatedness in describing parasite infections. Host species identity explained 27-53% of individual variation in parasite prevalence, richness, community composition and phylogenetic diversity. Host and parasite phylogenies were congruent, host gut morphology predicted parasite community composition and prevalence, and hosts with low evolutionary distinctiveness were centrally positioned in the parasite-sharing network. We found no evidence that host body size, social-group size or feeding height were correlated with parasite composition. Our results highlight the interwoven evolutionary and ecological histories of large herbivores and their gastrointestinal nematodes and suggest that host identity, phylogeny and gut architecture-a phylogenetically conserved trait related to parasite habitat-are the overriding influences on parasite communities. These findings have implications for wildlife management and conservation as wild herbivores are increasingly replaced by livestock.
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Affiliation(s)
- Georgia C. Titcomb
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO, USA,Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA,Mpala Research Centre, Nanyuki, Kenya
| | - Johan Pansu
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA,ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Matthew C. Hutchinson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Kaia J. Tombak
- Mpala Research Centre, Nanyuki, Kenya,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA,Department of Anthropology, Hunter College of the City University of New York, New York, NY, USA
| | - Christina B. Hansen
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Christopher C. M. Baker
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA,US Army ERDC Cold Regions Research and Engineering Laboratory, Hanover, NH, USA
| | - Tyler R. Kartzinel
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA,Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI, USA,Institute at Brown for Environment and Society, Brown University, Providence, RI, USA
| | - Hillary S. Young
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA,Mpala Research Centre, Nanyuki, Kenya
| | - Robert M. Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
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21
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Grothjan JJ, Young EB. Bacterial Recruitment to Carnivorous Pitcher Plant Communities: Identifying Sources Influencing Plant Microbiome Composition and Function. Front Microbiol 2022; 13:791079. [PMID: 35359741 PMCID: PMC8964293 DOI: 10.3389/fmicb.2022.791079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Processes influencing recruitment of diverse bacteria to plant microbiomes remain poorly understood. In the carnivorous pitcher plant Sarracenia purpurea model system, individual pitchers open to collect rainwater, invertebrates and a diverse microbial community, and this detrital food web is sustained by captured insect prey. This study examined how potential sources of bacteria affect the development of the bacterial community within pitchers, how the host plant tissue affects community development and how established vs. assembling communities differ. In a controlled greenhouse experiment, seven replicate pitchers were allocated to five treatments to exclude specific bacterial sources or host tissue: milliQ water only, milliQ + insect prey, rainwater + prey, established communities + prey, artificial pitchers with milliQ + prey. Community composition and functions were examined over 8-40 weeks using bacterial gene sequencing and functional predictions, measurements of cell abundance, hydrolytic enzyme activity and nutrient transformations. Distinct community composition and functional differences between artificial and real pitchers confirm an important influence of host plant tissue on community development, but also suggest this could be partially related to host nutrient uptake. Significant recruitment of bacteria to pitchers from air was evident from many taxa common to all treatments, overlap in composition between milliQ, milliQ + prey, and rainwater + prey treatments, and few taxa unique to milliQ only pitchers. Community functions measured as hydrolytic enzyme (chitinase, protease) activity suggested a strong influence of insect prey additions and were linked to rapid transformation of insect nutrients into dissolved and inorganic sources. Bacterial taxa found in 6 of 7 replicate pitchers within treatments, the "core microbiome" showed tighter successional trajectories over 8 weeks than all taxa. Established pitcher community composition was more stable over 8 weeks, suggesting a diversity-stability relationship and effect of microinvertebrates on bacteria. This study broadly demonstrates that bacterial composition in host pitcher plants is related to both stochastic and specific bacterial recruitment and host plants influence microbial selection and support microbiomes through capture of insect prey.
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Affiliation(s)
- Jacob J. Grothjan
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Erica B. Young
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
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22
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Littleford‐Colquhoun BL, Freeman PT, Sackett VI, Tulloss CV, McGarvey LM, Geremia C, Kartzinel TR. The precautionary principle and dietary DNA metabarcoding: Commonly used abundance thresholds change ecological interpretation. Mol Ecol 2022; 31:1615-1626. [PMID: 35043486 PMCID: PMC9303378 DOI: 10.1111/mec.16352] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/06/2021] [Accepted: 01/07/2022] [Indexed: 01/13/2023]
Abstract
Dietary DNA metabarcoding enables researchers to identify and characterize trophic interactions with a high degree of taxonomic precision. It is also sensitive to sources of bias and contamination in the field and laboratory. One of the earliest and most common strategies for dealing with such sensitivities has been to remove all low-abundance sequences and conduct ecological analyses based on the presence or absence of food taxa. Although this step is now often perceived to be necessary, evidence of its sufficiency is lacking and more attention to the risk of introducing other errors is needed. Using computer simulations, we demonstrate that common strategies to remove low-abundance sequences can erroneously eliminate true dietary sequences in ways that impact downstream inferences. Using real data from well-studied wildlife populations in Yellowstone National Park, we further show how these strategies can markedly alter the composition of dietary profiles in ways that scale-up to obscure ecological interpretations about dietary generalism, specialism, and composition. Although the practice of removing low-abundance sequences may continue to be a useful strategy to address research questions that focus on a subset of relatively abundant foods, its continued widespread use risks generating misleading perceptions about the structure of trophic networks. Researchers working with dietary DNA metabarcoding data-or similar data such as environmental DNA, microbiomes, or pathobiomes-should be aware of drawbacks and consider alternative bioinformatic, experimental, and statistical solutions.
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Affiliation(s)
- Bethan L. Littleford‐Colquhoun
- Department of Ecology, Evolution, and Organismal BiologyBrown UniversityProvidenceRhode IslandUSA,Institute at Brown for Environment and SocietyBrown UniversityProvidenceRhode IslandUSA
| | - Patrick T. Freeman
- Department of Ecology, Evolution, and Organismal BiologyBrown UniversityProvidenceRhode IslandUSA,Institute at Brown for Environment and SocietyBrown UniversityProvidenceRhode IslandUSA
| | - Violet I. Sackett
- Department of Ecology, Evolution, and Organismal BiologyBrown UniversityProvidenceRhode IslandUSA,Institute at Brown for Environment and SocietyBrown UniversityProvidenceRhode IslandUSA
| | - Camille V. Tulloss
- Department of Ecology, Evolution, and Organismal BiologyBrown UniversityProvidenceRhode IslandUSA,Institute at Brown for Environment and SocietyBrown UniversityProvidenceRhode IslandUSA
| | - Lauren M. McGarvey
- Yellowstone Center for Resources, Yellowstone National ParkMammoth Hot SpringsWyomingUSA
| | - Chris Geremia
- Yellowstone Center for Resources, Yellowstone National ParkMammoth Hot SpringsWyomingUSA
| | - Tyler R. Kartzinel
- Department of Ecology, Evolution, and Organismal BiologyBrown UniversityProvidenceRhode IslandUSA,Institute at Brown for Environment and SocietyBrown UniversityProvidenceRhode IslandUSA
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23
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Hutchinson MC, Dobson AP, Pringle RM. Dietary abundance distributions: Dominance and diversity in vertebrate diets. Ecol Lett 2021; 25:992-1008. [PMID: 34967090 DOI: 10.1111/ele.13948] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/08/2021] [Accepted: 11/23/2021] [Indexed: 01/31/2023]
Abstract
Diet composition is among the most important yet least understood dimensions of animal ecology. Inspired by the study of species abundance distributions (SADs), we tested for generalities in the structure of vertebrate diets by characterising them as dietary abundance distributions (DADs). We compiled data on 1167 population-level diets, representing >500 species from six vertebrate classes, spanning all continents and oceans. DADs near-universally (92.5%) followed a hollow-curve shape, with scant support for other plausible rank-abundance-distribution shapes. This strong generality is inherently related to, yet incompletely explained by, the SADs of available food taxa. By quantifying dietary generalisation as the half-saturation point of the cumulative distribution of dietary abundance (sp50, minimum number of foods required to account for 50% of diet), we found that vertebrate populations are surprisingly specialised: in most populations, fewer than three foods accounted for at least half the diet. Variation in sp50 was strongly associated with consumer type, with carnivores being more specialised than herbivores or omnivores. Other methodological (sampling method and effort, taxonomic resolution), biological (body mass, frugivory) and biogeographic (latitude) factors influenced sp50 to varying degrees. Future challenges include identifying the mechanisms underpinning the hollow-curve DAD, its generality beyond vertebrates, and the biological determinants of dietary generalisation.
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Affiliation(s)
- Matthew C Hutchinson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA.,Institute of Evolutionary Biology and Environmental Studies, Universität Zürich, Zürich, Switzerland
| | - Andrew P Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Robert M Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
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24
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Tombak KJ, Hansen CB, Kinsella JM, Pansu J, Pringle RM, Rubenstein DI. The gastrointestinal nematodes of plains and Grevy's zebras: Phylogenetic relationships and host specificity. Int J Parasitol Parasites Wildl 2021; 16:228-235. [PMID: 34712556 PMCID: PMC8529100 DOI: 10.1016/j.ijppaw.2021.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/11/2021] [Accepted: 10/11/2021] [Indexed: 01/08/2023]
Abstract
Equids are chronically infected with parasitic strongyle nematodes. There is a rich literature on horse strongyles, but they are difficult to identify morphologically and genetic studies on strongyles infecting other equid species are few, hampering studies of host specificity. We sequenced expelled worms from two sympatric zebra species in central Kenya to expand the strongyle phylogeny and used DNA metabarcoding on faecal samples to genetically characterize zebra nemabiomes for the first time. We generated sequences for several species new to public genetic reference databases, all of which are typical strongyles in wild zebras (i.e., the three species of Cylindropharynx and Cyathostomum montgomeryi), and identified their closest relatives. We also discovered an apparent fungus infecting a quarter of the expelled Crossocephalus viviparus worms, a hyperabundant nematode species in the family Atractidae, hinting at the possibility that zebra host-parasite dynamics may involve a zebra-fungus mutualism. The two zebra species had similar nemabiomes; we found a complete overlap in the list of nematode species they carry and very similar prevalence (i.e., proportion of hosts infected) for the different nematode species. Our study suggests limited host-specificity in zebra strongyles and high potential for transmission between the plains zebra and the endangered Grevy's zebra.
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Affiliation(s)
- Kaia J. Tombak
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
- Department of Anthropology, Hunter College of the City University of New York, 695 Park Ave, New York, NY, USA, 10065
- Corresponding author. Department of Anthropology, Hunter College of the City University of New York, 695 Park Ave, New York, NY, 10065, USA.
| | - Christina B. Hansen
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
| | | | - Johan Pansu
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Robert M. Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
| | - Daniel I. Rubenstein
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
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25
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Lu Q, Xiao L, Cheng C, Lu Z, Zhao J, Yao M. Snow Leopard Dietary Preferences and Livestock Predation Revealed by Fecal DNA Metabarcoding: No Evidence for Apparent Competition Between Wild and Domestic Prey. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.783546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Accurate assessments of the patterns and drivers of livestock depredation by wild carnivores are vital for designing effective mitigation strategies to reduce human-wildlife conflict. Snow leopard’s (Panthera uncia) range extensively overlaps pastoralist land-use and livestock predation there is widely reported, but the ecological determinants of livestock consumption by snow leopards remain obscure. We investigated snow leopard dietary habits at seven sites across the Sanjiangyuan region of the Qinghai–Tibetan Plateau (QTP), an area central to the species’ global range. Snow leopard abundance, wild prey composition, and livestock density varied among those sites, thus allowing us to test the effects of various factors on snow leopard diet and livestock predation. Using DNA metabarcoding, we obtained highly resolved dietary data from 351 genetically verified snow leopard fecal samples. We then analyzed the prey preferences of snow leopards and examined ecological factors related to their livestock consumption. Across the sites, snow leopard prey was composed mainly of wild ungulates (mean = 81.5% of dietary sequences), particularly bharal (Pseudois nayaur), and supplemented with livestock (7.62%) and smaller mammals (marmots, pikas, mice; 10.7%). Snow leopards showed a strong preference for bharal, relative to livestock, based on their densities. Interestingly, both proportional and total livestock consumption by snow leopards increased linearly with local livestock biomass, but not with livestock density. That, together with a slight negative relationship with bharal density, supports apparent facilitation between wild and domestic prey. We also found a significant positive correlation between population densities of snow leopard and bharal, yet those densities showed slight negative relationships with livestock density. Our results highlight the importance of sufficient wild ungulate abundance to the conservation of viable snow leopard populations. Additionally, livestock protection is critically needed to reduce losses to snow leopard depredation, especially where local livestock abundances are high.
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26
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Shao X, Lu Q, Xiong M, Bu H, Shi X, Wang D, Zhao J, Li S, Yao M. Prey partitioning and livestock consumption in the world's richest large carnivore assemblage. Curr Biol 2021; 31:4887-4897.e5. [PMID: 34551283 DOI: 10.1016/j.cub.2021.08.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/13/2021] [Accepted: 08/30/2021] [Indexed: 12/26/2022]
Abstract
Large mammalian carnivores have undergone catastrophic declines during the Anthropocene across the world. Despite their pivotal roles as apex predators in food webs and ecosystem dynamics, few detailed dietary datasets of large carnivores exist, prohibiting deep understanding of their coexistence and persistence in human-dominated landscapes. Here, we present fine-scaled, quantitative trophic interactions among sympatric carnivores from three assemblages in the Mountains of Southwest China, a global biodiversity hotspot harboring the world's richest large-carnivore diversity, derived from DNA metabarcoding of 1,097 fecal samples. These assemblages comprise a large-carnivore guild ranging from zero to five species along with two mesocarnivore species. We constructed predator-prey food webs for each assemblage and identified 95 vertebrate prey taxa and 260 feeding interactions in sum. Each carnivore species consumed 6-39 prey taxa, and dietary diversity decreased with increased carnivore body mass across guilds. Dietary partitioning was more evident between large-carnivore and mesocarnivore guilds, yet different large carnivores showed divergent proportional utilization of different-sized prey correlating with their own body masses. Large carnivores particularly selected livestock in Tibetan-dominated regions, where the indigenous people show high tolerance toward wild predators. Our results suggest that dietary niche partitioning and livestock subsidies facilitate large-carnivore sympatry and persistence and have key implications for sustainable conservation promoting human-carnivore coexistence.
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Affiliation(s)
- Xinning Shao
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Qi Lu
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Mengyin Xiong
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Hongliang Bu
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Xiaoyun Shi
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Dajun Wang
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Jindong Zhao
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Sheng Li
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
| | - Meng Yao
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
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27
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Abstract
Resource partitioning stabilizes species coexistence but has long been difficult to measure. DNA metabarcoding reveals previously hidden dimensions of this problem and insights relevant for understanding and fostering coexistence - not just among wild carnivores, but also between carnivores and people.
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Affiliation(s)
- Robert M Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
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Berman TS, Inbar M. Revealing cryptic interactions between large mammalian herbivores and plant-dwelling arthropods via DNA metabarcoding. Ecology 2021; 103:e03548. [PMID: 34618914 PMCID: PMC9286824 DOI: 10.1002/ecy.3548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/24/2021] [Accepted: 07/16/2021] [Indexed: 11/08/2022]
Abstract
In the past decade, it has become clear that omnivory, feeding on more than one trophic level, is important in natural and agricultural systems. Large mammalian herbivores (LMH) frequently encounter plant‐dwelling arthropods (PDA) on their food plants. Yet, ingestion of PDA by LMH is only rarely addressed and the extent of this direct trophic interaction, especially at the PDA community level, remains unknown. Using a DNA‐metabarcoding analysis on feces of free‐ranging cattle from a replicated field experiment of heavily and moderately grazed paddocks, we reveal that feeding cattle (incidentally) ingest an entire food chain of PDA including herbivores, predators and parasites. Overall, 25 families of insects and four families of arachnids were ingested, a pattern that varied over the season, but not with grazing intensity. We identified the functional groups of PDA vulnerable to ingestion, such as sessile species and immature life stages. Most of the fecal samples (76%) contained sequences belonging to PDA, indicating that direct interactions are frequent. This study highlights the complex trophic connections between LMH and PDA. It may even be appropriate to consider LMH as omnivorous enemies of PDA.
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Affiliation(s)
- Tali S Berman
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, 3498838, Israel
| | - Moshe Inbar
- Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, 3498838, Israel
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29
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Pozas-Schacre C, Casey JM, Brandl SJ, Kulbicki M, Harmelin-Vivien M, Strona G, Parravicini V. Congruent trophic pathways underpin global coral reef food webs. Proc Natl Acad Sci U S A 2021; 118:e2100966118. [PMID: 34544855 PMCID: PMC8488628 DOI: 10.1073/pnas.2100966118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2021] [Indexed: 11/18/2022] Open
Abstract
Ecological interactions uphold ecosystem structure and functioning. However, as species richness increases, the number of possible interactions rises exponentially. More than 6,000 species of coral reef fishes exist across the world's tropical oceans, resulting in an almost innumerable array of possible trophic interactions. Distilling general patterns in these interactions across different bioregions stands to improve our understanding of the processes that govern coral reef functioning. Here, we show that across bioregions, tropical coral reef food webs exhibit a remarkable congruence in their trophic interactions. Specifically, by compiling and investigating the structure of six coral reef food webs across distinct bioregions, we show that when accounting for consumer size and resource availability, these food webs share more trophic interactions than expected by chance. In addition, coral reef food webs are dominated by dietary specialists, which makes trophic pathways vulnerable to biodiversity loss. Prey partitioning among these specialists is geographically consistent, and this pattern intensifies when weak interactions are disregarded. Our results suggest that energy flows through coral reef communities along broadly comparable trophic pathways. Yet, these critical pathways are maintained by species with narrow, specialized diets, which threatens the existence of coral reef functioning in the face of biodiversity loss.
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Affiliation(s)
- Chloé Pozas-Schacre
- Paris Sciences et Lettres Université Paris: Ecole Pratique des Hautes Etudes-Université de Perpignan Via Domitia-Centre National de la Recherche Scientifique, Unité de Service et de Recherche 3278 Centre de Recherches Insulaires et Observatoire de l'Environnement, Université de Perpignan, 66860 Perpignan, France;
- Laboratoire d'Excellence "CORAIL," 66860 Perpignan, France
| | - Jordan M Casey
- Paris Sciences et Lettres Université Paris: Ecole Pratique des Hautes Etudes-Université de Perpignan Via Domitia-Centre National de la Recherche Scientifique, Unité de Service et de Recherche 3278 Centre de Recherches Insulaires et Observatoire de l'Environnement, Université de Perpignan, 66860 Perpignan, France
- Laboratoire d'Excellence "CORAIL," 66860 Perpignan, France
- Department of Marine Science, Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373
| | - Simon J Brandl
- Paris Sciences et Lettres Université Paris: Ecole Pratique des Hautes Etudes-Université de Perpignan Via Domitia-Centre National de la Recherche Scientifique, Unité de Service et de Recherche 3278 Centre de Recherches Insulaires et Observatoire de l'Environnement, Université de Perpignan, 66860 Perpignan, France
- Laboratoire d'Excellence "CORAIL," 66860 Perpignan, France
- Department of Marine Science, Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373
- Fondation pour la Recherche sur la Biodiversité, Centre for the Synthesis and Analysis of Biodiversity, 34000 Montpellier, France
| | - Michel Kulbicki
- Unité Mixte de Recherche Entropie, Labex Corail, Institut de Recherche pour le Développement, Université de Perpignan, 66860 Perpignan, France
| | - Mireille Harmelin-Vivien
- Instititut Méditerranéen d'Océanologie, Unité Mixte 110 Aix-Marseille Université, Centre National de la Recherche Scientifique/Institut National des Sciences de l'Univers, Institut pour la Recherche et le Développement, 13288 Marseille, France
| | - Giovanni Strona
- Department of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Valeriano Parravicini
- Paris Sciences et Lettres Université Paris: Ecole Pratique des Hautes Etudes-Université de Perpignan Via Domitia-Centre National de la Recherche Scientifique, Unité de Service et de Recherche 3278 Centre de Recherches Insulaires et Observatoire de l'Environnement, Université de Perpignan, 66860 Perpignan, France;
- Laboratoire d'Excellence "CORAIL," 66860 Perpignan, France
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30
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Regulation by the Pitcher Plant Sarracenia purpurea of the Structure of its Inquiline Food Web. AMERICAN MIDLAND NATURALIST 2021. [DOI: 10.1674/0003-0031-186.1.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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31
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Fortin MJ, Dale MRT, Brimacombe C. Network ecology in dynamic landscapes. Proc Biol Sci 2021; 288:20201889. [PMID: 33906397 PMCID: PMC8080002 DOI: 10.1098/rspb.2020.1889] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 04/01/2021] [Indexed: 12/25/2022] Open
Abstract
Network ecology is an emerging field that allows researchers to conceptualize and analyse ecological networks and their dynamics. Here, we focus on the dynamics of ecological networks in response to environmental changes. Specifically, we formalize how network topologies constrain the dynamics of ecological systems into a unifying framework in network ecology that we refer to as the 'ecological network dynamics framework'. This framework stresses that the interplay between species interaction networks and the spatial layout of habitat patches is key to identifying which network properties (number and weights of nodes and links) and trade-offs among them are needed to maintain species interactions in dynamic landscapes. We conclude that to be functional, ecological networks should be scaled according to species dispersal abilities in response to landscape heterogeneity. Determining how such effective ecological networks change through space and time can help reveal their complex dynamics in a changing world.
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Affiliation(s)
- Marie-Josée Fortin
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Mark R. T. Dale
- Ecosystem Science and Management, University of Northern British Columbia, Prince George, British Columbia, Canada
| | - Chris Brimacombe
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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32
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McCary MA, Schmitz OJ. Invertebrate functional traits and terrestrial nutrient cycling: Insights from a global meta-analysis. J Anim Ecol 2021; 90:1714-1726. [PMID: 33782983 DOI: 10.1111/1365-2656.13489] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/12/2021] [Indexed: 11/30/2022]
Abstract
Functional traits are useful for characterizing variation in community and ecosystem dynamics. Most advances in trait-based ecology to date centre on plant functional traits, although there is an increasing recognition that animal traits are also key contributors to processes operating at the community or ecosystem scale. Terrestrial invertebrates are incredibly diverse and ubiquitous animals with important roles in nutrient cycling. Despite their widespread influence on ecosystem processes, we currently lack a synthetic understanding of how invertebrate functional traits affect terrestrial nutrient cycling. We present a meta-analysis of 511 paired observations from 122 papers that examined how invertebrate functional traits affected litter decomposition rates, nitrogen pools and litter C:N ratios. Based on the available data, we specifically assessed the effects of feeding mode (bioturbation, detritus shredding, detritus grazing, leaf chewing, leaf piercing, ambush predators, active hunting predators) and body size (macro- and micro-invertebrates) on nutrient cycling. The effects of invertebrates on terrestrial nutrient cycling varied according to functional trait. The inclusion of both macro- (≥2 mm) and micro-invertebrates (<2 mm) increased litter decomposition by 20% and 19%, respectively. All detritivorous feeding modes enhanced litter decomposition rates, with bioturbators, detritus shredders and detritus grazers increasing decomposition by 28%, 22% and 15%, respectively. Neither herbivore feeding mode (e.g. leaf chewers and leaf piercers) nor predator hunting mode (ambush and active hunting) affected decomposition. We also revealed that bioturbators and detritus grazers increased soil nitrogen availability by 99% and 70%, respectively, and that leaf-chewing herbivores had a weak effect on litterfall stoichiometry via reducing C:N ratios by 11%. Although functional traits might be useful predictors of ecosystem processes, our findings suggest context-dependent effects of invertebrate traits on terrestrial nutrient cycling. Detritivore functional traits (i.e. bioturbators, detritus shredders and detritus grazers) are more consistent with increased rates of nutrient cycling, whereas our currently characterized predator and herbivore traits are less predictive. Future research is needed to identify, standardize and deliberately study the impacts of invertebrate functional traits on nutrient cycling in hopes of revealing the key functional traits governing ecosystem functioning worldwide.
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Ross SRP, Suzuki Y, Kondoh M, Suzuki K, Villa Martín P, Dornelas M. Illuminating the intrinsic and extrinsic drivers of ecological stability across scales. Ecol Res 2021. [DOI: 10.1111/1440-1703.12214] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Samuel R. P.‐J. Ross
- Department of Zoology, School of Natural Sciences Trinity College Dublin Dublin Ireland
| | - Yuka Suzuki
- Biodiversity and Biocomplexity Unit Okinawa Institute of Science and Technology Graduate University Okinawa Japan
| | - Michio Kondoh
- Graduate School of Life Sciences Tohoku University Sendai Japan
| | - Kenta Suzuki
- Integrated Bioresource Information Division RIKEN BioResource Research Center Ibaraki Japan
| | - Paula Villa Martín
- Biological Complexity Unit Okinawa Institute of Science and Technology Graduate University Okinawa Japan
| | - Maria Dornelas
- Centre for Biological Diversity University of St Andrews St Andrews UK
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