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Parravicini V, Bender MG, Villéger S, Leprieur F, Pellissier L, Donati FGA, Floeter SR, Rezende EL, Mouillot D, Kulbicki M. Coral reef fishes reveal strong divergence in the prevalence of traits along the global diversity gradient. Proc Biol Sci 2021; 288:20211712. [PMID: 34666520 PMCID: PMC8527194 DOI: 10.1098/rspb.2021.1712] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/22/2021] [Indexed: 11/12/2022] Open
Abstract
Coral reefs are experiencing declines due to climate change and local human impacts. While at a local scale these impacts induce biodiversity loss and shifts in community structure, previous biogeographical analyses recorded consistent taxonomic structure of fish communities across global coral reefs. This suggests that regional communities represent a random subset of the global species and traits pool, whatever their species richness. Using distributional data on 3586 fish species and latest advances in species distribution models, we show marked gradients in the prevalence of size classes and diet categories across the biodiversity gradient. This divergence in trait structure is best explained by reef isolation during past unfavourable climatic conditions, with large and piscivore fishes better represented in isolated areas. These results suggest the risk of a global community re-organization if the ongoing climate-induced reef fragmentation is not halted.
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Affiliation(s)
- V. Parravicini
- PSL Université Paris: EPHE-UPVD-CNRS, USR 3278 CRIOBE, University of Perpignan, 66860 Perpignan, France
- Institut Universitaire de France, Paris, France
| | - M. G. Bender
- Marine Macroecology and Conservation Lab, Departamento de Ecologia e Evolução, Universidade Federal de Santa Maria, RS 97105-900, Brazil
| | - S. Villéger
- MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Montpellier, France
| | - F. Leprieur
- Institut Universitaire de France, Paris, France
- MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Montpellier, France
| | - L. Pellissier
- Landscape Ecology, Institute of Terrestrial Ecosystems, ETH Zürich, 8044 Zürich, Switzerland
- Unit of Land Change Science, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - F. G. A. Donati
- Landscape Ecology, Institute of Terrestrial Ecosystems, ETH Zürich, 8044 Zürich, Switzerland
- Unit of Land Change Science, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - S. R. Floeter
- Marine Macroecology and Biogeography Lab, Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, SC 88010-970, Brazil
| | - E. L. Rezende
- Marine Macroecology and Biogeography Lab, Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, SC 88010-970, Brazil
- Departamento de Ecología, Center of Applied Ecology and Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - D. Mouillot
- Institut Universitaire de France, Paris, France
- MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Montpellier, France
| | - M. Kulbicki
- IRD, Institut de Recherche pour le Développement, UMR ‘Entropie’, LABEX Corail, University of Perpignan, 66860 Perpignan, France
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2
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Benestan L, Fietz K, Loiseau N, Guerin PE, Trofimenko E, Rühs S, Schmidt C, Rath W, Biastoch A, Pérez-Ruzafa A, Baixauli P, Forcada A, Arcas E, Lenfant P, Mallol S, Goñi R, Velez L, Höppner M, Kininmonth S, Mouillot D, Puebla O, Manel S. Restricted dispersal in a sea of gene flow. Proc Biol Sci 2021; 288:20210458. [PMID: 34004134 PMCID: PMC8131118 DOI: 10.1098/rspb.2021.0458] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/23/2021] [Indexed: 12/19/2022] Open
Abstract
How far do marine larvae disperse in the ocean? Decades of population genetic studies have revealed generally low levels of genetic structure at large spatial scales (hundreds of kilometres). Yet this result, typically based on discrete sampling designs, does not necessarily imply extensive dispersal. Here, we adopt a continuous sampling strategy along 950 km of coast in the northwestern Mediterranean Sea to address this question in four species. In line with expectations, we observe weak genetic structure at a large spatial scale. Nevertheless, our continuous sampling strategy uncovers a pattern of isolation by distance at small spatial scales (few tens of kilometres) in two species. Individual-based simulations indicate that this signal is an expected signature of restricted dispersal. At the other extreme of the connectivity spectrum, two pairs of individuals that are closely related genetically were found more than 290 km apart, indicating long-distance dispersal. Such a combination of restricted dispersal with rare long-distance dispersal events is supported by a high-resolution biophysical model of larval dispersal in the study area, and we posit that it may be common in marine species. Our results bridge population genetic studies with direct dispersal studies and have implications for the design of marine reserve networks.
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Affiliation(s)
- L. Benestan
- CEFE, PSL EPHE, Université Montpellier, CNRS, IRD, Université Paul-Valéry Montpellier 3, Montpellier, France
| | - K. Fietz
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - N. Loiseau
- MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Montpellier, France
| | - P. E. Guerin
- CEFE, PSL EPHE, Université Montpellier, CNRS, IRD, Université Paul-Valéry Montpellier 3, Montpellier, France
| | - E. Trofimenko
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - S. Rühs
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - C. Schmidt
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - W. Rath
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - A. Biastoch
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
- Kiel University, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - A. Pérez-Ruzafa
- Department of Ecology and Hydrology, Faculty of Biology, Espinardo, Regional Campus of International Excellence ‘Mare Nostrum’, University of Murcia, Murcia 30100, Spain
| | - P. Baixauli
- Department of Ecology and Hydrology, Faculty of Biology, Espinardo, Regional Campus of International Excellence ‘Mare Nostrum’, University of Murcia, Murcia 30100, Spain
| | - A. Forcada
- Department of Marine Sciences and Applied Biology, University of Alicante, P.O. Box 99, 03080 Alicante, Spain
| | - E. Arcas
- Department of Marine Sciences and Applied Biology, University of Alicante, P.O. Box 99, 03080 Alicante, Spain
| | - P. Lenfant
- Centre de Formation et de Recherche sur les Environnements Méditerranéens, Université Perpignan Via Domitia, CNRS, 66100 Perpignan, France
| | - S. Mallol
- Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Moll de Ponent s/n, 07015 Palma de Mallorca, Spain
| | - R. Goñi
- Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Moll de Ponent s/n, 07015 Palma de Mallorca, Spain
| | - L. Velez
- MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Montpellier, France
| | - M. Höppner
- Kiel University, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - S. Kininmonth
- School of Marine Studies, University of the South Pacific, Fiji
| | - D. Mouillot
- MARBEC, Univ Montpellier, CNRS, IFREMER, IRD, Montpellier, France
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - O. Puebla
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
- Ecology Department, Leibniz-Centre for Tropical Marine Research, Fahrenheitstraße 6, 28359 Bremen, Germany
| | - S. Manel
- CEFE, PSL EPHE, Université Montpellier, CNRS, IRD, Université Paul-Valéry Montpellier 3, Montpellier, France
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3
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Mouillot D, Parravicini V, Bellwood DR, Leprieur F, Huang D, Cowman PF, Albouy C, Hughes TP, Thuiller W, Guilhaumon F. Global marine protected areas do not secure the evolutionary history of tropical corals and fishes. Nat Commun 2016; 7:10359. [PMID: 26756609 PMCID: PMC4729959 DOI: 10.1038/ncomms10359] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 12/03/2015] [Indexed: 11/25/2022] Open
Abstract
Although coral reefs support the largest concentrations of marine biodiversity worldwide, the extent to which the global system of marine-protected areas (MPAs) represents individual species and the breadth of evolutionary history across the Tree of Life has never been quantified. Here we show that only 5.7% of scleractinian coral species and 21.7% of labrid fish species reach the minimum protection target of 10% of their geographic ranges within MPAs. We also estimate that the current global MPA system secures only 1.7% of the Tree of Life for corals, and 17.6% for fishes. Regionally, the Atlantic and Eastern Pacific show the greatest deficit of protection for corals while for fishes this deficit is located primarily in the Western Indian Ocean and in the Central Pacific. Our results call for a global coordinated expansion of current conservation efforts to fully secure the Tree of Life on coral reefs. Marine protected areas (MPAs) are established to conserve species, but the extent to which they also conserve evolutionary history is not clear. Here, Mouillot et al. show that for tropical corals and fish, the current global MPA network secures only 1.7 and 17.6% of phylogenetic diversity, respectively.
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Affiliation(s)
- D Mouillot
- UMR 9190 MARBEC, IRD-CNRS-IFREMER-UM, Université de Montpellier, Montpellier 34095, France.,Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - V Parravicini
- CRIOBE, USR 3278 CNRS-EPHE-UPVD, Labex 'Corail', University of Perpignan, Perpignan 66860, France
| | - D R Bellwood
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - F Leprieur
- UMR 9190 MARBEC, IRD-CNRS-IFREMER-UM, Université de Montpellier, Montpellier 34095, France
| | - D Huang
- Department of Biological Sciences and Tropical Marine Science Institute, National University of Singapore, Singapore 117543, Singapore
| | - P F Cowman
- Department of Ecology &Evolutionary Biology, Yale University, 21 Sachem St, New Haven, Connecticut 06511 USA
| | - C Albouy
- Département de biologie, chimie et géographie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Canada G5L 3A1
| | - T P Hughes
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - W Thuiller
- Laboratoire d'Écologie Alpine (LECA), Univ. Grenoble Alpes, Grenoble F-38000, France.,Laboratoire d'Écologie Alpine (LECA), CNRS, Grenoble F-38000, France
| | - F Guilhaumon
- UMR 9190 MARBEC, IRD-CNRS-IFREMER-UM, Université de Montpellier, Montpellier 34095, France
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Elleouet J, Albouy C, Ben Rais Lasram F, Mouillot D, Leprieur F. A trait-based approach for assessing and mapping niche overlap between native and exotic species: the Mediterranean coastal fish fauna as a case study. DIVERS DISTRIB 2014. [DOI: 10.1111/ddi.12235] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- J. Elleouet
- UMR 5119 ECOSYM “Ecologie des Systèmes Marins Côtiers” (CNRS, IRD, IFREMER, UM1, UM2); place Eugène Bataillon 34095 Montpellier Cedex 5 France
- Centre for Forest Conservation Genetics; University of British Columbia; 2424 Main Mall Vancouver BC V6T 1Z4 Canada
| | - C. Albouy
- UMR 5119 ECOSYM “Ecologie des Systèmes Marins Côtiers” (CNRS, IRD, IFREMER, UM1, UM2); place Eugène Bataillon 34095 Montpellier Cedex 5 France
- Département de biologie, chimie et géographie; Université du Québec à Rimouski; 300 Allée des Ursulines G5L 3A1 Québec Canada
| | - F. Ben Rais Lasram
- Laboratoire Écosystèmes et Ressources Aquatiques UR03AGRO1; Institut National Agronomique de Tunisie; 43 avenue Charles Nicolle 1082 Tunis Tunisia
| | - D. Mouillot
- UMR 5119 ECOSYM “Ecologie des Systèmes Marins Côtiers” (CNRS, IRD, IFREMER, UM1, UM2); place Eugène Bataillon 34095 Montpellier Cedex 5 France
| | - F. Leprieur
- UMR 5119 ECOSYM “Ecologie des Systèmes Marins Côtiers” (CNRS, IRD, IFREMER, UM1, UM2); place Eugène Bataillon 34095 Montpellier Cedex 5 France
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Pellissier L, Leprieur F, Parravicini V, Cowman PF, Kulbicki M, Litsios G, Olsen SM, Wisz MS, Bellwood DR, Mouillot D. Quaternary coral reef refugia preserved fish diversity. Science 2014; 344:1016-9. [DOI: 10.1126/science.1249853] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Canard EF, Mouquet N, Mouillot D, Stanko M, Miklisova D, Gravel D. Empirical evaluation of neutral interactions in host-parasite networks. Am Nat 2014; 183:468-79. [PMID: 24642492 DOI: 10.1086/675363] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
While niche-based processes have been invoked extensively to explain the structure of interaction networks, recent studies propose that neutrality could also be of great importance. Under the neutral hypothesis, network structure would simply emerge from random encounters between individuals and thus would be directly linked to species abundance. We investigated the impact of species abundance distributions on qualitative and quantitative metrics of 113 host-parasite networks. We analyzed the concordance between neutral expectations and empirical observations at interaction, species, and network levels. We found that species abundance accurately predicts network metrics at all levels. Despite host-parasite systems being constrained by physiology and immunology, our results suggest that neutrality could also explain, at least partially, their structure. We hypothesize that trait matching would determine potential interactions between species, while abundance would determine their realization.
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Affiliation(s)
- E F Canard
- Institut des Sciences de l'Evolution, Unité Mixte de Recherche (UMR) CNRS 5554, Université Montpellier 2 (UM2), 34095 Montpellier Cedex 5, France
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7
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Ternengo S, Levron C, Mouillot D, Marchand B. Site influence in parasite distribution from fishes of the Bonifacio Strait Marine Reserve (Corsica Island, Mediterranean Sea). Parasitol Res 2009; 104:1279-87. [DOI: 10.1007/s00436-008-1323-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 12/16/2008] [Indexed: 10/21/2022]
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8
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Krasnov BR, Korallo-Vinarskaya NP, Vinarski MV, Shenbrot GI, Mouillot D, Poulin R. Searching for general patterns in parasite ecology: host identity versus environmental influence on gamasid mite assemblages in small mammals. Parasitology 2007; 135:229-42. [PMID: 17908362 DOI: 10.1017/s003118200700368x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
SUMMARYThe abundance and diversity of parasites vary among different populations of host species. In some host-parasite associations, much of the variation seems to depend on the identity of the host species, whereas in other cases it is better explained by local environmental conditions. The few parasite taxa investigated to date make it difficult to discern any general pattern governing large-scale variation in abundance or diversity. Here, we test whether the abundance and diversity of gamasid mites parasitic on small mammals across different regions of the Palaearctic are determined mainly by host identity or by parameters of the abiotic environment. Using data from 42 host species from 26 distinct regions, we found that mite abundances on different populations of the same host species were more similar to each other than expected by chance, and varied significantly among host species, with half of the variance among samples explained by differences between host species. A similar but less pronounced pattern was observed for mite diversity, measured both as species richness and as the taxonomic distinctness of mite species within an assemblage. Strong environmental effects were also observed, with local temperature and precipitation correlating with mite abundance and species richness, respectively, across populations of the same host species, for many of the host species examined. These results are compared to those obtained for other groups of parasites, notably fleas, and discussed in light of attempts to find general rules governing the geographical variation in the abundance and diversity of parasite assemblages.
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Affiliation(s)
- B R Krasnov
- Mitrani Department of Desert Ecology, Ben-Gurion University of Negev, Israel.
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9
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Foata J, Mouillot D, Culioli JL, Marchand B. Influence of season and host age on wild boar parasites in Corsica using indicator species analysis. J Helminthol 2007; 80:41-5. [PMID: 16469171 DOI: 10.1079/joh2005329] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractThe indicator value (Ind Val) method which combines measures of fidelity and specificity has been used in a study on wild boar parasites in Corsica during 2001–2003. Because of its resilience to changes in abundance,IndValis a particularly effective tool for ecological bioindication. TheInd Valmethod showed how season can influence the occurrence of parasite species in the wild boar, and also identified parasites as bioindicators relative to host age. The randomization test identified five parasite species having a significant indicator value for the season (the ticks,Hyalomma aegyptiumandRhipicephalus sanguineus, the louse,Haematopinus suisand the nematodesGlobocephalus urosubulatusandAscaris suumand two indicator species of an age class (the nematodesG. urosubulatusandMetastrongylussp.). Data on species composition and infection levels would help improve the monitoring and management of parasitism in Suidae populations.
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Affiliation(s)
- J Foata
- Laboratory Parasites and Mediterranean Ecosystems, Faculty of Sciences and Techniques, University of Corsica, 20250 Corte, France.
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Krasnov BR, Morand S, Mouillot D, Shenbrot GI, Khokhlova IS, Poulin R. Resource predictability and host specificity in fleas: the effect of host body mass. Parasitology 2006; 133:81-8. [PMID: 16566852 DOI: 10.1017/s0031182006000059] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Revised: 12/28/2005] [Accepted: 01/24/2006] [Indexed: 11/07/2022]
Abstract
Ecological specialization is hypothesized to result from the exploitation of predictable resource bases. For parasitic organisms, one prediction is that parasites of large-bodied host species, which tend to be long-lived, should specialize on these hosts, whereas parasites of small host species, which represent more ephemeral and less predictable resources, should become generalists. We tested this prediction by quantifying the association between the level of host specificity of fleas and the mean body mass of their mammalian hosts, using published data from 2 large, distinct geographical regions (South Africa and northern North America). In general, we found supporting evidence that flea host specificity, measured either as the number of host species exploited or their taxonomic distinctness, became more pronounced with increasing host body mass. There were, however, some discrepancies among the results depending on the different measures of host specificity, the geographical region studied, or whether we used the raw values or phylogenetically independent contrasts. These are discussed with respect to other forces acting on the evolution of host specificity in parasites, as well as in the context of the regions' contrasting evolutionary histories. Overall, though, our findings indicate that the exploitation of large-bodied, and therefore long-lived, host species has promoted specialization in fleas, most likely because these hosts represent predictable resources.
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Affiliation(s)
- B R Krasnov
- Ramon Science Center and Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, P.O. Box 194, Mizpe Ramon 80600, Israel.
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11
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12
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Krasnov BR, Mouillot D, Khokhlova IS, Shenbrot GI, Poulin R. Covariance in species diversity and facilitation among non-interactive parasite taxa: all against the host. Parasitology 2006; 131:557-68. [PMID: 16174421 DOI: 10.1017/s0031182005007912] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2005] [Revised: 03/16/2005] [Accepted: 03/16/2005] [Indexed: 11/05/2022]
Abstract
Different parasite taxa exploit different host resources and are often unlikely to interact directly. It is unclear, however, whether the diversity of any given parasite taxon is indirectly influenced by that of other parasite taxa on the same host. Some components of host immune defences may operate simultaneously against all kinds of parasites, whereas investment by the host in specific defences against one type of parasite may come at the expense of defence against other parasites. We investigated the relationships between the species diversity of 4 higher taxa of ectoparasites (fleas, sucking lice, mesostigmatid mites, and ixodid ticks), and between the species richness of ectoparasites and endoparasitic helminths, across different species of rodent hosts. Our analyses used 2 measures of species diversity, species richness and taxonomic distinctness, and controlled for the potentially confounding effects of sampling effort and phylogenetic relationships among host species. We found positive pairwise correlations between the species richness of fleas, mites and ticks; however, there was no association between species richness of any of these 3 groups and that of lice. We also found a strong positive relationship between the taxonomic distinctness of ecto- and endoparasite assemblages across host species. These results suggest the existence of a process of apparent facilitation among unrelated taxa in the organization of parasite communities. We propose explanations based on host immune responses, involving acquired cross-resistance to infection and interspecific variation in immunocompetence among hosts, to account for these patterns.
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Affiliation(s)
- B R Krasnov
- Ramon Science Center and Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, P.O. Box 194, Mizpe Ramon 80600, Israel.
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13
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Muñoz G, Mouillot D, Poulin R. Testing the niche apportionment hypothesis with parasite communities: is random assortment always the rule? Parasitology 2006; 132:717-24. [PMID: 16412258 DOI: 10.1017/s0031182005009613] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 11/07/2005] [Accepted: 11/08/2005] [Indexed: 11/05/2022]
Abstract
Niche apportionment models have only been applied once to parasite communities. Only the random assortment model (RA), which indicates that species abundances are independent from each other and that interspecific competition is unimportant, provided a good fit to 3 out of 6 parasite communities investigated. The generality of this result needs to be validated, however. In this study we apply 5 niche apportionment models to the parasite communities of 14 fish species from the Great Barrier Reef. We determined which model fitted the data when using either numerical abundance or biomass as an estimate of parasite abundance, and whether the fit of niche apportionment models depends on how the parasite community is defined (e.g. ecto, endoparasites or all parasites considered together). The RA model provided a good fit for the whole community of parasites in 7 fish species when using biovolume (as a surrogate of biomass) as a measure of species abundance. The RA model also fitted observed data when ecto- and endoparasites were considered separately, using abundance or biovolume, but less frequently. Variation in fish sizes among species was not associated with the probability of a model fitting the data. Total numerical abundance and biovolume of parasites were not related across host species, suggesting that they capture different aspects of abundance. Biovolume is not only a better measurement to use with niche-orientated models, it should also be the preferred descriptor to analyse parasite community structure in other contexts. Most of the biological assumptions behind the RA model, i.e. randomness in apportioning niche space, lack of interspecific competition, independence of abundance among different species, and species with variable niches in changeable environments, are in accordance with some previous findings on parasite communities. Thus, parasite communities may generally be unsaturated with species, with empty niches, and interspecific interactions may generally be unimportant in determining parasite community structure.
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Affiliation(s)
- G Muñoz
- School of Molecular and Microbial Sciences, Department of Microbiology and Parasitology; University of Queensland, Brisbane 4072, Qld, Australia
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14
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Abstract
Host specificity has 2 independent facets: the extent to which different host species are used by a parasite, and the phylogenetic distances among these hosts. Although the number of host species exploited by a parasite commonly is used as a measure of host specificity, it fails to capture ecological and phylogenetic differences among hosts. Here, a new index of host specificity, S(TD)*, is developed and illustrated. This index measures the average taxonomic distinctness among the host species used by a parasite, weighted for the parasite's prevalence in the different hosts. For a given number of host species, the index approaches its minimum value when a parasite achieves high prevalence in a few closely related host species, and the index approaches its highest value when a parasite reaches its highest prevalence values in distantly related host species. Simple hypothetical examples are used to demonstrate the index's computation and some of its properties. The new index is influenced independently both by the taxonomic (or phylogenetic) affinities of a set of host species and by the distribution of prevalence values among these hosts. A single value cannot truly capture all the nuances of a phenomenon as complex as host specificity; nevertheless, the proposed index incorporates the features of specificity that are most relevant to parasitologists and will be a useful tool for comparative studies.
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Affiliation(s)
- R Poulin
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
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Abstract
Different animal species have different probabilities of being discovered and described by scientists, and these probabilities are determined to a large extent by the biological characteristics of these species. For instance, species with broader geographical ranges are more likely to be encountered by collectors than species with restricted distributions; indeed, the size of the geographical range is often the best predictor of a species' date of description. For parasitic organisms, host specificity may be similarly linked to the probability of a species being found. Here, using data on 170 helminth species parasitic in freshwater fishes, we show that host specificity is associated with the year in which the helminths were described. Helminths that exploit more host species, and to a lesser degree those that exploit a broader taxonomic range of host species, tend to be discovered earlier than the more host-specific helminths. This pattern was observed across all helminth species, as well as within the different helminth taxa (trematodes, cestodes, nematodes and acanthocephalans). Our results demonstrate that the parasite species known at any given point in time are not a random subset of existing species, but rather a biased subset with respect to the parasites' biological properties.
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Affiliation(s)
- R Poulin
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
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16
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Abstract
Recent studies of the forces behind the diversification of parasite assemblages have shed light on many aspects of parasite biodiversity. By using only parasite species richness as their measure of diversity, however, previous investigations have ignored the relatedness among parasite species and the taxonomic structure of the assemblages, which contain much information about their evolutionary origins. Here, we performed a comparative analysis across 50 species of fish from the coast of Brazil; we evaluated the effects of several host traits (body size, social behaviour, feeding habits, preference for benthicvs. pelagic habitats, depth range, and ability to enter brackish waters) on the diversity of their assemblages of metazoan parasites. As measures of diversity, we used parasite species richness, as well as the average taxonomic distinctness of the assemblage and its variance; the latter measures are based on the average taxonomic distance between any two parasite species in an assemblage. Unlike parasite species richness, taxonomic distinctness was unaffected by the number of host individuals examined per species. Fish body length proved to be the main predictor of parasite species richness, even when controlling for the confounding influences of host phylogeny and sampling effort, although it did not correlate with measures of parasite taxonomic distinctness. Predatory fish also had higher parasite species richness than planktivores, but this trend could not be confirmed using phylogenetically independent contrasts between host taxa. The main host feature associated with the taxonomic diversity of parasites was schooling behaviour, with schooling fish having more taxonomically diverse parasite assemblages than those of their non-schooling relatives. When focusing on endoparasite species only, both predatory feeding habits and a broad depth range were associated with the taxonomic distinctness of parasites. Our results suggest that certain host traits (i.e. body size) determine how many parasite species a host can accumulate over evolutionary time, whereas different host features influence the processes causing the taxonomic diversification of parasite assemblages.
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Affiliation(s)
- J L Luque
- Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, Caixa Postal 74.508, CEP 23851-970, Seropédica, RJ, Brazil
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17
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Abstract
The host specificity of a parasite is not merely a function of how many host species it can exploit, but also of how closely related these host species are to each other. Here, a new index of host specificity is proposed, one that takes into account the average taxonomic or phylogenetic distance between pairs of host species used by a parasite. The index is derived from measures of taxonomic distinctness used in biodiversity studies. It is easy to compute and interpret, ranging from a minimum value of 1 when all host species are members of the same genus, to a maximum of 5, when all host species belong to different classes. The variance of this measure can also be computed, and provides additional information on the taxonomic or phylogenetic structure of the host assemblage. Using data on helminth parasites of Canadian freshwater fishes, we show that the new index, unlike the mere number of known host species, is independent of study effort i.e. the number of published records of a parasite. Although the index and the number of known hosts are not entirely independent statistically, each captures a different aspect of host specificity. For instance, although acanthocephalans infect significantly more host species than trematodes, cestodes or nematodes, there is no difference in the average index value among these 4 helminth taxa, suggesting that the average taxonomic distances between the host species of a parasite do not vary among these higher taxa. We recommend the use of our new index in future comparative studies of host specificity, in particular when the focus is on the evolutionary history of parasites and of their past colonizations of host lineages.
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Affiliation(s)
- R Poulin
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.
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18
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Mouillot D, Lepretre A, Andrei-Ruiz MC, Mouillot F, Viale D. A stochastic model for the spatial distribution of species based on an aggregation–repulsion rule. POPUL ECOL 2000. [DOI: 10.1007/pl00012007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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