1
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Uricchio LH, Bruns EL, Hood M, Boots M, Antonovics J. Multimodal pathogen transmission as a limiting factor in host distribution. Ecology 2023; 104:e3956. [PMID: 36511901 PMCID: PMC9992245 DOI: 10.1002/ecy.3956] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 12/14/2022]
Abstract
Theoretical models suggest that infectious diseases could play a substantial role in determining the spatial extent of host species, but few studies have collected the empirical data required to test this hypothesis. Pathogens that sterilize their hosts or spread through frequency-dependent transmission could have especially strong effects on the limits of species' distributions because diseased hosts that are sterilized but not killed may continue to produce infectious stages and frequency-dependent transmission mechanisms are effective even at very low population densities. We collected spatial pathogen prevalence data and population abundance data for alpine carnations infected by the sterilizing pathogen Microbotryum dianthorum, a parasite that is spread through both frequency-dependent (vector-borne) and density-dependent (aerial spore transmission) mechanisms. Our 13-year study reveals rapid declines in population abundance without a compensatory decrease in pathogen prevalence. We apply a stochastic, spatial model of parasite spread that accommodates spatial habitat heterogeneity to investigate how the population dynamics depend on multimodal (frequency-dependent and density-dependent) transmission. We found that the observed rate of population decline could plausibly be explained by multimodal transmission, but is unlikely to be explained by either frequency-dependent or density-dependent mechanisms alone. Multimodal pathogen transmission rates high enough to explain the observed decline predicted that eventual local extinction of the host species is highly likely. Our results add to a growing body of literature showing how multimodal transmission can constrain species distributions in nature.
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Affiliation(s)
- Lawrence H. Uricchio
- Department of Biology, Tufts University, Medford, MA 02155
- Department of Integrative Biology, University of California, Berkeley, CA 94720
| | - Emily L. Bruns
- Department of Biology, University of Maryland, College Park, MD 20742
| | - Michael Hood
- Biology Department, Amherst College, Amherst, MA 01002
| | - Mike Boots
- Department of Integrative Biology, University of California, Berkeley, CA 94720
- Biosciences, University of Exeter, Penryn, UK, TR109FE
| | - Janis Antonovics
- Department of Biology, University of Virginia, Charlottesville, VA 22904
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2
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Shaw CL, Kennedy DA. Developing an empirical model for spillover and emergence: Orsay virus host range in Caenorhabditis. Proc Biol Sci 2022; 289:20221165. [PMID: 36126684 PMCID: PMC9489279 DOI: 10.1098/rspb.2022.1165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/24/2022] [Indexed: 11/20/2022] Open
Abstract
A lack of tractable experimental systems in which to test hypotheses about the ecological and evolutionary drivers of disease spillover and emergence has limited our understanding of these processes. Here we introduce a promising system: Caenorhabditis hosts and Orsay virus, a positive-sense single-stranded RNA virus that naturally infects C. elegans. We assayed species across the Caenorhabditis tree and found Orsay virus susceptibility in 21 of 84 wild strains belonging to 14 of 44 species. Confirming patterns documented in other systems, we detected effects of host phylogeny on susceptibility. We then tested whether susceptible strains were capable of transmitting Orsay virus by transplanting exposed hosts and determining whether they transmitted infection to conspecifics during serial passage. We found no evidence of transmission in 10 strains (virus undetectable after passaging in all replicates), evidence of low-level transmission in 5 strains (virus lost between passage 1 and 5 in at least one replicate) and evidence of sustained transmission in 6 strains (including all three experimental C. elegans strains) in at least one replicate. Transmission was strongly associated with viral amplification in exposed populations. Variation in Orsay virus susceptibility and transmission among Caenorhabditis strains suggests that the system could be powerful for studying spillover and emergence.
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Affiliation(s)
- Clara L. Shaw
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - David A. Kennedy
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
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3
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Abbott KC, Eppinga MB, Umbanhowar J, Baudena M, Bever JD. Microbiome influence on host community dynamics: Conceptual integration of microbiome feedback with classical host-microbe theory. Ecol Lett 2021; 24:2796-2811. [PMID: 34608730 PMCID: PMC9292004 DOI: 10.1111/ele.13891] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/28/2021] [Accepted: 08/31/2021] [Indexed: 01/11/2023]
Abstract
Microbiomes have profound effects on host fitness, yet we struggle to understand the implications for host ecology. Microbiome influence on host ecology has been investigated using two independent frameworks. Classical ecological theory powerfully represents mechanistic interactions predicting environmental dependence of microbiome effects on host ecology, but these models are notoriously difficult to evaluate empirically. Alternatively, host-microbiome feedback theory represents impacts of microbiome dynamics on host fitness as simple net effects that are easily amenable to experimental evaluation. The feedback framework enabled rapid progress in understanding microbiomes' impacts on plant ecology, and can also be applied to animal hosts. We conceptually integrate these two frameworks by deriving expressions for net feedback in terms of mechanistic model parameters. This generates a precise mapping between net feedback theory and classic population modelling, thereby merging mechanistic understanding with experimental tractability, a necessary step for building a predictive understanding of microbiome influence on host ecology.
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Affiliation(s)
| | - Maarten B Eppinga
- University of Zurich, Zurich, Switzerland.,Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, The Netherlands
| | | | - Mara Baudena
- Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, The Netherlands.,National Research Council of Italy, Institute of Atmospheric Sciences, and Climate (CNR-ISAC), Torino, Italy
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4
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Terry JCD, Chen J, Lewis OT. Natural enemies have inconsistent impacts on the coexistence of competing species. J Anim Ecol 2021; 90:2277-2288. [PMID: 34013519 DOI: 10.1111/1365-2656.13534] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/30/2021] [Indexed: 11/27/2022]
Abstract
The role of natural enemies in promoting coexistence of competing species has generated substantial debate. Modern coexistence theory provides a detailed framework to investigate this topic, but there have been remarkably few empirical applications to the impact of natural enemies. We tested experimentally the capacity for a generalist enemy to promote coexistence of competing insect species, and the extent to which any impact can be predicted by trade-offs between reproductive rate and susceptibility to natural enemies. We used experimental mesocosms to conduct a fully factorial pairwise competition experiment for six rainforest Drosophila species, with and without a generalist pupal parasitoid. We then parameterised models of competition and examined the coexistence of each pair of Drosophila species within the framework of modern coexistence theory. We found idiosyncratic impacts of parasitism on pairwise coexistence, mediated through changes in fitness differences, not niche differences. There was no evidence of an overall reproductive rate-susceptibility trade-off. Pairwise reproductive rate-susceptibility relationships were not useful shortcuts for predicting the impact of parasitism on coexistence. Our results exemplify the value of modern coexistence theory in multi-trophic contexts and the importance of contextualising the impact of generalist natural enemies to determine their impact. In the set of species investigated, competition was affected by the higher trophic level, but the overall impact on coexistence cannot be easily predicted just from knowledge of relative susceptibility. Methodologically, our Bayesian approach highlights issues with the separability of model parameters within modern coexistence theory and shows how using the full posterior parameter distribution improves inferences. This method should be widely applicable for understanding species coexistence in a range of systems.
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Affiliation(s)
- J Christopher D Terry
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Jinlin Chen
- Department of Zoology, University of Oxford, Oxford, UK
| | - Owen T Lewis
- Department of Zoology, University of Oxford, Oxford, UK
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5
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Experimental evidence of the importance of multitrophic structure for species persistence. Proc Natl Acad Sci U S A 2021; 118:2023872118. [PMID: 33727421 DOI: 10.1073/pnas.2023872118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ecological theory predicts that species interactions embedded in multitrophic networks shape the opportunities for species to persist. However, the lack of experimental support of this prediction has limited our understanding of how species interactions occurring within and across trophic levels simultaneously regulate the maintenance of biodiversity. Here, we integrate a mathematical approach and detailed experiments in plant-pollinator communities to demonstrate the need to jointly account for species interactions within and across trophic levels when estimating the ability of species to persist. Within the plant trophic level, we show that the persistence probability of plant species increases when introducing the effects of plant-pollinator interactions. Across trophic levels, we show that the persistence probabilities of both plants and pollinators exhibit idiosyncratic changes when experimentally manipulating the multitrophic structure. Importantly, these idiosyncratic effects are not recovered by traditional simulations. Our work provides tractable experimental and theoretical platforms upon which it is possible to investigate the multitrophic factors affecting species persistence in ecological communities.
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6
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Kendig AE, Svahnström VJ, Adhikari A, Harmon PF, Flory SL. Emerging fungal pathogen of an invasive grass: Implications for competition with native plant species. PLoS One 2021; 16:e0237894. [PMID: 33647021 PMCID: PMC7920361 DOI: 10.1371/journal.pone.0237894] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 02/08/2021] [Indexed: 11/18/2022] Open
Abstract
Infectious diseases and invasive species can be strong drivers of biological systems that may interact to shift plant community composition. For example, disease can modify resource competition between invasive and native species. Invasive species tend to interact with a diversity of native species, and it is unclear how native species differ in response to disease-mediated competition with invasive species. Here, we quantified the biomass responses of three native North American grass species (Dichanthelium clandestinum, Elymus virginicus, and Eragrostis spectabilis) to disease-mediated competition with the non-native invasive grass Microstegium vimineum. The foliar fungal pathogen Bipolaris gigantea has recently emerged in Microstegium populations, causing a leaf spot disease that reduces Microstegium biomass and seed production. In a greenhouse experiment, we examined the effects of B. gigantea inoculation on two components of competitive ability for each native species: growth in the absence of competition and biomass responses to increasing densities of Microstegium. Bipolaris gigantea inoculation affected each of the three native species in unique ways, by increasing (Dichanthelium), decreasing (Elymus), or not changing (Eragrostis) their growth in the absence of competition relative to mock inoculation. Bipolaris gigantea inoculation did not, however, affect Microstegium biomass or mediate the effect of Microstegium density on native plant biomass. Thus, B. gigantea had species-specific effects on native plant competition with Microstegium through species-specific biomass responses to B. gigantea inoculation, but not through modified responses to Microstegium density. Our results suggest that disease may uniquely modify competitive interactions between invasive and native plants for different native plant species.
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Affiliation(s)
- Amy E. Kendig
- Agronomy Department, University of Florida, Gainesville, Florida, United States of America
| | | | - Ashish Adhikari
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
| | - Philip F. Harmon
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
| | - S. Luke Flory
- Agronomy Department, University of Florida, Gainesville, Florida, United States of America
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7
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Porath‐Krause A, Campbell R, Shoemaker L, Sieben A, Strauss AT, Shaw AK, Seabloom EW, Borer ET. Pliant pathogens: Estimating viral spread when confronted with new vector, host, and environmental conditions. Ecol Evol 2021; 11:1877-1887. [PMID: 33614010 PMCID: PMC7882977 DOI: 10.1002/ece3.7178] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 11/19/2020] [Accepted: 12/21/2020] [Indexed: 11/20/2022] Open
Abstract
Pathogen spread rates are determined, in part, by the performance of pathogens under altered environmental conditions and their ability to persist while switching among hosts and vectors.To determine the effects of new conditions (host, vector, and nutrient) on pathogen spread rate, we introduced a vector-borne viral plant pathogen, Barley Yellow Dwarf Virus PAV (BYDV-PAV) into hosts, vectors, and host nutrient supplies that it had not encountered for thousands of viral generations. We quantified pathogen prevalence over the course of two serial inoculations under the new conditions. Using individual-level transmission rates from this experiment, we parameterized a dynamical model of disease spread and projected spread across host populations through a growing season.A change in nutrient conditions (increased supply of phosphorus) reduced viral transmission whereas shifting to a new vector or host species had no effect on infection prevalence. However, the reduction in the new nutrient environment was only temporary; infection prevalence recovered after the second inoculation. Synthesis. These results highlight how robust the pathogen, BYDV-PAV, is to changes in its biotic and abiotic environment. Our study also highlights the need to quantify longitudinal infection information beyond snapshot assessments to project disease risk for pathogens in new environments.
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Affiliation(s)
- Anita Porath‐Krause
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
| | - Ryan Campbell
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
| | - Lauren Shoemaker
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
- Present address:
Department of BotanyUniversity of WyomingLaramieWYUSA
| | - Andrew Sieben
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
- Present address:
Department of BotanyUniversity of WyomingLaramieWYUSA
| | - Alexander T. Strauss
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
- Present address:
Odum School of EcologyUniversity of GeorgiaAthensGAUSA
| | - Allison K. Shaw
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
| | - Eric W. Seabloom
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
| | - Elizabeth T. Borer
- Department of Ecology, Evolution, and BehaviorUniversity of MinnesotaSt. PaulMNUSA
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8
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Jiang J, Abbott KC, Baudena M, Eppinga MB, Umbanhowar JA, Bever JD. Pathogens and Mutualists as Joint Drivers of Host Species Coexistence and Turnover: Implications for Plant Competition and Succession. Am Nat 2020; 195:591-602. [PMID: 32216667 DOI: 10.1086/707355] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The potential for either pathogens or mutualists to alter the outcome of interactions between host species has been clearly demonstrated experimentally, but our understanding of their joint influence remains limited. Individually, pathogens and mutualists can each stabilize (via negative feedback) or destabilize (via positive feedback) host-host interactions. When pathogens and mutualists are both present, the potential for simultaneous positive and negative feedbacks can generate a wide range of possible effects on host species coexistence and turnover. Extending existing theoretical frameworks, we explore the range of dynamics generated by simultaneous interactions with pathogens and mutualists and identify the conditions for pathogen or mutualist mediation of host coexistence. We then explore the potential role of microbial mutualists and pathogens in plant species turnover during succession. We show how a combination of positive and negative plant-microbe feedbacks can generate a coexistence state that is part of a set of alternative stable states. This result implies that the outcomes of coexistence from classical plant-soil feedback experiments may be susceptible to disturbances and that empirical investigations of microbially mediated coexistence would benefit from consideration of interactive effects of feedbacks generated from different distinct components of the plant microbiome.
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9
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Smull DM, Pendleton N, Kleinhesselink AR, Adler PB. Climate change, snow mold and the Bromus tectorum invasion: mixed evidence for release from cold weather pathogens. AOB PLANTS 2019; 11:plz043. [PMID: 31559006 PMCID: PMC6756605 DOI: 10.1093/aobpla/plz043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Climate change is reducing the depth and duration of winter snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced snowpack might promote B. tectorum population growth by decreasing damage from snow molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early snowmelt and either fungicide addition or snow mold infection of B. tectorum. The greenhouse experiment confirmed that the snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and snow mold inoculation had no effect on survival. We did find interactive effects of snowmelt and fungal treatments on B. tectorum seed production: with ambient snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation.
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Affiliation(s)
- Danielle M Smull
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, UT, USA
| | - Nicole Pendleton
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, UT, USA
| | - Andrew R Kleinhesselink
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, UT, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Peter B Adler
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, UT, USA
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10
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Rapti Z, Stewart Merrill TE, Mueller-Brennan B, Kavouras JH, Cáceres CE. Indirect effects in a planktonic disease system. Theor Popul Biol 2019; 130:132-142. [PMID: 31319041 DOI: 10.1016/j.tpb.2019.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 07/09/2019] [Accepted: 07/10/2019] [Indexed: 11/16/2022]
Abstract
Indirect effects, both density- and trait-mediated, have been known to act in tandem with direct effects in the interactions of numerous species. They have been shown to affect populations embedded in competitive and mutualistic networks alike. In this work, we introduce a four-dimensional system of ordinary differential equations and investigate the interplay between direct density-effects and density- and trait-mediated indirect effects that take place in a yeast parasite-zooplankton host-incompetent competitor system embedded in a food web which also includes resources and predators. Among our main findings is the demonstration that indirect effects cause qualitative and quantitative changes almost indistinguishable from direct effects and the corroboration through our analysis of the fact that the effects of direct and indirect mechanisms cannot be disentangled. Our results underpin the conclusions of past studies calling for comprehensive models that incorporate both direct and indirect effects to better describe field data.
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Affiliation(s)
- Zoi Rapti
- Department of Mathematics, University of Illinois at Urbana-Champaign, 1409 W. Green St., Urbana, IL 61801, USA.
| | - Tara E Stewart Merrill
- Program in Ecology, Evolution and Conservation Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL 61801, USA
| | - Bridget Mueller-Brennan
- Department of Mathematics, University of Illinois at Urbana-Champaign, 1409 W. Green St., Urbana, IL 61801, USA
| | - Jerry H Kavouras
- Department of Biology, Lewis University, Romeoville, IL 60446, USA
| | - Carla E Cáceres
- Department of Evolution, Ecology and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL 61801, USA
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11
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Goedknegt MA, Nauta R, Markovic M, Buschbaum C, Folmer EO, Luttikhuizen PC, van der Meer J, Waser AM, Wegner KM, Thieltges DW. How invasive oysters can affect parasite infection patterns in native mussels on a large spatial scale. Oecologia 2019; 190:99-113. [DOI: 10.1007/s00442-019-04408-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 04/29/2019] [Indexed: 10/26/2022]
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12
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Uricchio LH, Daws SC, Spear ER, Mordecai EA. Priority Effects and Nonhierarchical Competition Shape Species Composition in a Complex Grassland Community. Am Nat 2019; 193:213-226. [PMID: 30720356 PMCID: PMC8518031 DOI: 10.1086/701434] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Niche and fitness differences control the outcome of competition, but determining their relative importance in invaded communities—which may be far from equilibrium—remains a pressing concern. Moreover, it is unclear whether classic approaches for studying competition, which were developed predominantly for pairs of interacting species, will fully capture dynamics in complex species assemblages. We parameterized a population-dynamic model using competition experiments of two native and three exotic species from a grassland community. We found evidence for minimal fitness differences or niche differences between the native species, leading to slow replacement dynamics and priority effects, but large fitness advantages allowed exotics to unconditionally invade natives. Priority effects driven by strong interspecific competition between exotic species drove single-species dominance by one of two exotic species in 80% of model outcomes, while a complex mixture of nonhierarchical competition and coexistence between native and exotic species occurred in the remaining 20%. Fungal infection, a commonly hypothesized coexistence mechanism, had weak fitness effects and is unlikely to substantially affect coexistence. In contrast to previous work on pairwise outcomes in largely native-dominated communities, our work supports a role for nearly neutral dynamics and priority effects as drivers of species composition in invaded communities.
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13
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Spear ER, Mordecai EA. Foliar pathogens are unlikely to stabilize coexistence of competing species in a California grassland. Ecology 2018; 99:2250-2259. [DOI: 10.1002/ecy.2427] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 04/18/2018] [Accepted: 05/24/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Erin R. Spear
- Biology Department Stanford University Stanford California 94305USA
| | - Erin A. Mordecai
- Biology Department Stanford University Stanford California 94305USA
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14
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McLeish M, Sacristán S, Fraile A, García-Arenal F. Scale dependencies and generalism in host use shape virus prevalence. Proc Biol Sci 2018; 284:rspb.2017.2066. [PMID: 29263286 DOI: 10.1098/rspb.2017.2066] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/20/2017] [Indexed: 01/01/2023] Open
Abstract
Processes that generate the distribution of pathogens and their interactions with hosts are not insensitive to changes in spatial scale. Spatial scales and species traits are often selected intentionally, based on practical considerations, ignoring biases that the scale and type of observation may introduce. Specifically, these biases might change the interpretation of disease-diversity relationships that are reported as either 'dilution' or 'amplification' effects. Here, we combine field data of a host-pathogen community with empirical models to test the effects that (i) spatial scale and (ii) host range have on the relationship between plant-virus infection prevalence and diversity. We show that prevalence-diversity relationships are scale-dependent and can produce opposite effects associated with different habitats at sub-ecosystem scales. The total number of host species of each virus reflected generalism at the ecosystem scale. However, plasticity in host range resembled habitat-specific specialization and also changed model predictions. We show that habitat heterogeneity, ignored at larger (ecosystem) spatial scales, influences pathogen distributions. Hence, understanding disease distributions and the evolution of pathogens requires reconciling specific hypotheses of the study with an appropriate spatial scale, or scales, and consideration of traits, such as host range, that might strongly contribute to biotic interactions.
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Affiliation(s)
- Michael McLeish
- Centro de Biotecnología y Genómica de Plantas UPM-INIA and Escuela Técnica Superior de Ingeniería Agronómica, Agroambiental y de Biosistemas (ETSIAAB), Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, Madrid 28223, Spain
| | - Soledad Sacristán
- Centro de Biotecnología y Genómica de Plantas UPM-INIA and Escuela Técnica Superior de Ingeniería Agronómica, Agroambiental y de Biosistemas (ETSIAAB), Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, Madrid 28223, Spain
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas UPM-INIA and Escuela Técnica Superior de Ingeniería Agronómica, Agroambiental y de Biosistemas (ETSIAAB), Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, Madrid 28223, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas UPM-INIA and Escuela Técnica Superior de Ingeniería Agronómica, Agroambiental y de Biosistemas (ETSIAAB), Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, Madrid 28223, Spain
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15
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McLeish MJ, Fraile A, García-Arenal F. Ecological Complexity in Plant Virus Host Range Evolution. Adv Virus Res 2018; 101:293-339. [PMID: 29908592 DOI: 10.1016/bs.aivir.2018.02.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The host range of a plant virus is the number of species in which it can reproduce. Most studies of plant virus host range evolution have focused on the genetics of host-pathogen interactions. However, the distribution and abundance of plant viruses and their hosts do not always overlap, and these spatial and temporal discontinuities in plant virus-host interactions can result in various ecological processes that shape host range evolution. Recent work shows that the distributions of pathogenic and resistant genotypes, vectors, and other resources supporting transmission vary widely in the environment, producing both expected and unanticipated patterns. The distributions of all of these factors are influenced further by competitive effects, natural enemies, anthropogenic disturbance, the abiotic environment, and herbivory to mention some. We suggest the need for further development of approaches that (i) explicitly consider resource use and the abiotic and biotic factors that affect the strategies by which viruses exploit resources; and (ii) are sensitive across scales. Host range and habitat specificity will largely determine which phyla are most likely to be new hosts, but predicting which host and when it is likely to be infected is enormously challenging because it is unclear how environmental heterogeneity affects the interactions of viruses and hosts.
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Affiliation(s)
- Michael J McLeish
- Centro de Biotecnología y Genómica de Plantas UPM-INIA, and E.T.S.I. Agrícola, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas UPM-INIA, and E.T.S.I. Agrícola, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas UPM-INIA, and E.T.S.I. Agrícola, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain.
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16
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Long-term studies are needed to reveal the effects of pathogen accumulation on invaded plant communities. Biol Invasions 2018. [DOI: 10.1007/s10530-017-1520-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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17
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Chiuffo MC, Policelli N, Moyano J, Torres A, Rodriguez-Cabal MA, Nuñez MA. Still no evidence that pathogen accumulation can revert the impact of invasive plant species. Biol Invasions 2018. [DOI: 10.1007/s10530-017-1519-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Flory SL, Alba C, Clay K, Holt RD, Goss EM. Emerging pathogens can suppress invaders and promote native species recovery. Biol Invasions 2017. [DOI: 10.1007/s10530-017-1438-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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19
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Larios L, Hallett LM, Suding KN. Where and how to restore in a changing world: a demographic‐based assessment of resilience. J Appl Ecol 2017. [DOI: 10.1111/1365-2664.12946] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Loralee Larios
- Division of Biological Sciences University of Montana Missoula MT USA
- Department of Botany and Plant Sciences University of California Riverside CA USA
| | - Lauren M. Hallett
- Department of Ecology and Evolutionary Biology Institute of Arctic and Alpine Research University of Colorado Boulder CO USA
- Environmental Studies Program Department of Biology University of Oregon Eugene OR USA
| | - Katharine N. Suding
- Department of Ecology and Evolutionary Biology Institute of Arctic and Alpine Research University of Colorado Boulder CO USA
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20
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Young HS, Parker IM, Gilbert GS, Sofia Guerra A, Nunn CL. Introduced Species, Disease Ecology, and Biodiversity-Disease Relationships. Trends Ecol Evol 2016; 32:41-54. [PMID: 28029377 DOI: 10.1016/j.tree.2016.09.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/25/2016] [Accepted: 09/26/2016] [Indexed: 11/29/2022]
Abstract
Species introductions are a dominant component of biodiversity change but are not explicitly included in most discussions of biodiversity-disease relationships. This is a major oversight given the multitude of effects that introduced species have on both parasitism and native hosts. Drawing on both animal and plant systems, we review the competing mechanistic pathways by which biological introductions influence parasite diversity and prevalence. While some mechanisms - such as local changes in phylogenetic composition and global homogenization - have strong explanatory potential, the net effects of introduced species, especially at local scales, remain poorly understood. Integrative, community-scale studies that explicitly incorporate introduced species are needed to make effective predictions about the effects of realistic biodiversity change and conservation action on disease.
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Affiliation(s)
- Hillary S Young
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, USA.
| | - Ingrid M Parker
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Gregory S Gilbert
- Department of Environmental Studies, University of California, Santa Cruz, CA, USA
| | - Ana Sofia Guerra
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Charles L Nunn
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA; Duke Global Health Institute, Duke University, Durham, NC, USA
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21
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Searle CL, Cortez MH, Hunsberger KK, Grippi DC, Oleksy IA, Shaw CL, de la Serna SB, Lash CL, Dhir KL, Duffy MA. Population Density, Not Host Competence, Drives Patterns of Disease in an Invaded Community. Am Nat 2016; 188:554-566. [PMID: 27788345 DOI: 10.1086/688402] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Generalist parasites can strongly influence interactions between native and invasive species. Host competence can be used to predict how an invasive species will affect community disease dynamics; the addition of a highly competent, invasive host is predicted to increase disease. However, densities of invasive and native species can also influence the impacts of invasive species on community disease dynamics. We examined whether information on host competence alone could be used to accurately predict the effects of an invasive host on disease in native hosts. We first characterized the relative competence of an invasive species and a native host species to a native parasite. Next, we manipulated species composition in mesocosms and found that host competence results did not accurately predict community dynamics. While the invasive host was more competent than the native, the presence of the native (lower competence) host increased disease in the invasive (higher competence) host. To identify potential mechanisms driving these patterns, we analyzed a two-host, one-parasite model parameterized for our system. Our results demonstrate that patterns of disease were primarily driven by relative population densities, mediated by asymmetry in intra- and interspecific competition. Thus, information on host competence alone may not accurately predict how an invasive species will influence disease in native species.
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22
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Community Ecology of Fungal Pathogens on Bromus tectorum. SPRINGER SERIES ON ENVIRONMENTAL MANAGEMENT 2016. [DOI: 10.1007/978-3-319-24930-8_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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23
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Bever JD, Mangan SA, Alexander HM. Maintenance of Plant Species Diversity by Pathogens. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2015. [DOI: 10.1146/annurev-ecolsys-112414-054306] [Citation(s) in RCA: 245] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- James D. Bever
- Department of Biology, Indiana University, Bloomington, Indiana 47405;
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045
| | - Scott A. Mangan
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Helen M. Alexander
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas 66045
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24
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Ke PJ, Miki T. Incorporating the soil environment and microbial community into plant competition theory. Front Microbiol 2015; 6:1066. [PMID: 26500621 PMCID: PMC4597134 DOI: 10.3389/fmicb.2015.01066] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 09/17/2015] [Indexed: 11/25/2022] Open
Abstract
Plants affect microbial communities and abiotic properties of nearby soils, which in turn influence plant growth and interspecific interaction, forming a plant-soil feedback (PSF). PSF is a key determinant influencing plant population dynamics, community structure, and ecosystem functions. Despite accumulating evidence for the importance of PSF and development of specific PSF models, different models are not yet fully integrated. Here, we review the theoretical progress in understanding PSF. When first proposed, PSF was integrated with various mathematical frameworks to discuss its influence on plant competition. Recent theoretical models have advanced PSF research at different levels of ecological organizations by considering multiple species, applying spatially explicit simulations to examine how local-scale predictions apply to larger scales, and assessing the effect of PSF on plant temporal dynamics over the course of succession. We then review two foundational models for microbial- and litter-mediated PSF. We present a theoretical framework to illustrate that although the two models are typically presented separately, their behavior can be understood together by invasibility analysis. We conclude with suggestions for future directions in PSF theoretical studies, which include specifically addressing microbial diversity to integrate litter- and microbial-mediated PSF, and apply PSF to general coexistence theory through a trait-based approach.
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Affiliation(s)
- Po-Ju Ke
- Department of Biology, Stanford UniversityStanford, CA, USA
- Institute of Oceanography, National Taiwan UniversityTaipei, Taiwan
| | - Takeshi Miki
- Institute of Oceanography, National Taiwan UniversityTaipei, Taiwan
- Research Center for Environmental Changes, Academia SinicaTaipei, Taiwan
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25
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Mordecai EA, Molinari NA, Stahlheber KA, Gross K, D'Antonio C. Controls over native perennial grass exclusion and persistence in California grasslands invaded by annuals. Ecology 2015; 96:2643-52. [DOI: 10.1890/14-2023.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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26
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Climatic variation and seed persistence: freeze–thaw cycles lower survival via the joint action of abiotic stress and fungal pathogens. Oecologia 2015; 179:609-16. [DOI: 10.1007/s00442-015-3369-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 06/03/2015] [Indexed: 10/23/2022]
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