1
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Beer MA, Proft KM, Veillet A, Kozakiewicz CP, Hamilton DG, Hamede R, McCallum H, Hohenlohe PA, Burridge CP, Margres MJ, Jones ME, Storfer A. Disease-driven top predator decline affects mesopredator population genomic structure. Nat Ecol Evol 2024; 8:293-303. [PMID: 38191839 DOI: 10.1038/s41559-023-02265-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 11/02/2023] [Indexed: 01/10/2024]
Abstract
Top predator declines are pervasive and often have dramatic effects on ecological communities via changes in food web dynamics, but their evolutionary consequences are virtually unknown. Tasmania's top terrestrial predator, the Tasmanian devil, is declining due to a lethal transmissible cancer. Spotted-tailed quolls benefit via mesopredator release, and they alter their behaviour and resource use concomitant with devil declines and increased disease duration. Here, using a landscape community genomics framework to identify environmental drivers of population genomic structure and signatures of selection, we show that these biotic factors are consistently among the top variables explaining genomic structure of the quoll. Landscape resistance negatively correlates with devil density, suggesting that devil declines will increase quoll genetic subdivision over time, despite no change in quoll densities detected by camera trap studies. Devil density also contributes to signatures of selection in the quoll genome, including genes associated with muscle development and locomotion. Our results provide some of the first evidence of the evolutionary impacts of competition between a top predator and a mesopredator species in the context of a trophic cascade. As top predator declines are increasing globally, our framework can serve as a model for future studies of evolutionary impacts of altered ecological interactions.
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Affiliation(s)
- Marc A Beer
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Kirstin M Proft
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Anne Veillet
- Hilo Core Genomics Facility, University of Hawaii at Hilo, Hilo, HI, USA
| | - Christopher P Kozakiewicz
- Department of Integrative Biology, Michigan State University, W.K. Kellogg Biological Station, Hickory Corners, MI, USA
| | - David G Hamilton
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Rodrigo Hamede
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
- CANECEV, Centre de Recherches Ecologiques et Evolutives sur le Cancer, Montpellier, France
| | - Hamish McCallum
- Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
| | - Paul A Hohenlohe
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID, USA
| | | | - Mark J Margres
- Department of Integrative Biology, University of South Florida, Tampa, FL, USA
| | - Menna E Jones
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Andrew Storfer
- School of Biological Sciences, Washington State University, Pullman, WA, USA.
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2
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Ferreira CM, Dammhahn M, Eccard JA. Forager-mediated cascading effects on food resource species diversity. Ecol Evol 2022; 12:e9523. [PMID: 36415870 PMCID: PMC9674471 DOI: 10.1002/ece3.9523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/29/2022] [Indexed: 11/21/2022] Open
Abstract
Perceived predation risk varies in space and time. Foraging in this landscape of fear alters forager-resource interactions via cascading nonconsumptive effects. Estimating these indirect effects is difficult in natural systems. Here, we applied a novel measure to quantify the diversity at giving-up density that allows to test how spatial variation in perceived predation risk modifies the diversity of multispecies resources at local and regional spatial levels. Furthermore, we evaluated whether the nonconsumptive effects on resource species diversity can be explained by the preferences of foragers for specific functional traits and by the forager species richness. We exposed rodents of a natural community to artificial food patches, each containing an initial multispecies resource community of eight species (10 items each) mixed in sand. We sampled 35 landscapes, each containing seven patches in a spatial array, to disentangle effects at local (patch) and landscape levels. We used vegetation height as a proxy for perceived predation risk. After a period of three nights, we counted how many and which resource species were left in each patch to measure giving-up density and resource diversity at the local level (alpha diversity) and the regional level (gamma diversity and beta diversity). Furthermore, we used wildlife cameras to identify foragers and assess their species richness. With increasing vegetation height, i.e., decreasing perceived predation risk, giving-up density, and local alpha and regional gamma diversity decreased, and patches became less similar within a landscape (beta diversity increased). Foragers consumed more of the bigger and most caloric resources. The higher the forager species richness, the lower the giving-up density, and alpha and gamma diversity. Overall, spatial variation of perceived predation risk of foragers had measurable cascading effects on local and regional resource species biodiversity, independent of the forager species. Thus, nonconsumptive predation effects modify forager-resource interactions and might act as an equalizing mechanism for species coexistence.
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Affiliation(s)
- Clara Mendes Ferreira
- Animal Ecology, Institute for Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
| | - Melanie Dammhahn
- Behavioural Biology, Institute for Neurobiology and Behavioural BiologyUniversity of MünsterMünsterGermany
| | - Jana A. Eccard
- Animal Ecology, Institute for Biochemistry and BiologyUniversity of PotsdamPotsdamGermany
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3
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Cogni R, Quental TB, Guimarães PR. Ehrlich and Raven escape and radiate coevolution hypothesis at different levels of organization: Past and future perspectives. Evolution 2022; 76:1108-1123. [PMID: 35262199 DOI: 10.1111/evo.14456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/02/2022] [Accepted: 02/22/2022] [Indexed: 01/21/2023]
Abstract
The classic paper by Ehrlich and Raven on coevolution will soon be 60 years old. Although they were not the first to develop the idea of coevolution, their thought-provoking paper certainly popularized this idea and inspired several generations of scientists interested in coevolution. Here, we describe some of their main contributions, quantitatively measure the impact of their seminal paper on different fields of research, and discuss how ideas related to their original paper might push the study of coevolution forward. To guide our discussion, we explore their original hypothesis into three research fields that are associated with distinct scales/levels of organization: (1) the genetic mechanisms underlying coevolutionary interactions; (2) the potential association between coevolutionary diversification and the organization of ecological networks; and (3) the micro- and macroevolutionary mechanisms and expected patterns under their hypothesis. By doing so, we discuss potentially overlooked aspects and future directions for the study of coevolutionary dynamics and diversification.
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Affiliation(s)
- Rodrigo Cogni
- Department of Ecology, University of São Paulo, São Paulo, SP, 05508-900, Brazil
| | - Tiago B Quental
- Department of Ecology, University of São Paulo, São Paulo, SP, 05508-900, Brazil
| | - Paulo R Guimarães
- Department of Ecology, University of São Paulo, São Paulo, SP, 05508-900, Brazil
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4
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Gorra TR, Garcia SCR, Langhans MR, Hoshijima U, Estes JA, Raimondi PT, Tinker MT, Kenner MC, Kroeker KJ. Southeast Alaskan kelp forests: inferences of process from large-scale patterns of variation in space and time. Proc Biol Sci 2022; 289:20211697. [PMID: 35042419 PMCID: PMC8767212 DOI: 10.1098/rspb.2021.1697] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/13/2021] [Indexed: 12/04/2022] Open
Abstract
Humans were considered external drivers in much foundational ecological research. A recognition that humans are embedded in the complex interaction networks we study can provide new insight into our ecological paradigms. Here, we use time-series data spanning three decades to explore the effects of human harvesting on otter-urchin-kelp trophic cascades in southeast Alaska. These effects were inferred from variation in sea urchin and kelp abundance following the post fur trade repatriation of otters and a subsequent localized reduction of otters by human harvest in one location. In an example of a classic trophic cascade, otter repatriation was followed by a 99% reduction in urchin biomass density and a greater than 99% increase in kelp density region wide. Recent spatially concentrated harvesting of otters was associated with a localized 70% decline in otter abundance in one location, with urchins increasing and kelps declining in accordance with the spatial pattern of otter occupancy within that region. While the otter-urchin-kelp trophic cascade has been associated with alternative community states at the regional scale, this research highlights how small-scale variability in otter occupancy, ostensibly due to spatial variability in harvesting or the risk landscape for otters, can result in within-region patchiness in these community states.
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Affiliation(s)
- Torrey R. Gorra
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Sabrina C. R. Garcia
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Michael R. Langhans
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Umihiko Hoshijima
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - James A. Estes
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Pete T. Raimondi
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - M. Tim Tinker
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Michael C. Kenner
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Kristy J. Kroeker
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
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5
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Foster E, Watson J, Lemay MA, Tinker MT, Estes JA, Piercey R, Henson L, Ritland C, Miscampbell A, Nichol L, Hessing-Lewis M, Salomon AK, Darimont CT. Physical disturbance by recovering sea otter populations increases eelgrass genetic diversity. Science 2021; 374:333-336. [PMID: 34648338 DOI: 10.1126/science.abf2343] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Erin Foster
- Hakai Institute, Heriot Bay, BC V0P 1H0, Canada.,Department of Geography, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Jane Watson
- Department of Biology, Vancouver Island University, Nanaimo, BC V9R 5S5, Canada
| | | | - M Tim Tinker
- Nhydra Ecological Consulting, St. Margaret's Bay, NS B3Z 2G6, Canada.,Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95060, USA
| | - James A Estes
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95060, USA
| | | | - Lauren Henson
- Department of Geography, University of Victoria, Victoria, BC V8W 2Y2, Canada.,Raincoast Conservation Foundation, Bella Bella, BC V0T 1Z0, Canada
| | - Carol Ritland
- Genetic Data Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Allyson Miscampbell
- Genetic Data Centre, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Linda Nichol
- Cetacean Research Program, Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, BC V9T 6N7, Canada
| | | | - Anne K Salomon
- School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Chris T Darimont
- Hakai Institute, Heriot Bay, BC V0P 1H0, Canada.,Department of Geography, University of Victoria, Victoria, BC V8W 2Y2, Canada.,Raincoast Conservation Foundation, Bella Bella, BC V0T 1Z0, Canada
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6
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Benoit AD, Caruso CM. A sit-and-wait predator, but not an active-pursuit predator, alters pollinator-mediated selection on floral traits. Ecology 2021; 102:e03506. [PMID: 34319595 DOI: 10.1002/ecy.3506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 05/12/2021] [Accepted: 05/25/2021] [Indexed: 12/27/2022]
Abstract
Indirect species interactions are ubiquitous in nature, often outnumbering direct species interactions. Yet despite evidence that indirect interactions have strong ecological effects, relatively little is known about whether they can shape adaptive evolution by altering the strength and/or direction of natural selection. We tested whether indirect interactions affect the strength and direction of pollinator-mediated selection on floral traits of the bumble-bee pollinated wildflower Lobelia siphilitica. We estimated the indirect effects of two pollinator predators with contrasting hunting modes: dragonflies (Aeshnidae and Corduliidae) and ambush bugs (Phymata americana, Reduviidae). Because dragonflies are active pursuit predators, we hypothesized that they would strengthen pollinator-mediated selection by weakening plant-pollinator interactions (i.e., a density-mediated indirect effect). In contrast, because ambush bugs are sit-and-wait predators, we hypothesized that they would weaken or reverse the direction of pollinator-mediated selection by altering pollinator foraging behavior (i.e., a trait-mediated indirect effect). Specifically, if ambush bugs hunt from plants with traits that attract pollinators (i.e., prey), then pollinators will spend less time visiting those plants, weakening or reversing the direction of selection on attractive floral traits. We did not find evidence that high dragonfly abundance strengthened selection on floral traits via a density-mediated indirect effect: neither pollen limitation (a proxy for the strength of plant-pollinator interactions) nor directional selection on floral traits of L. siphilitica differed significantly between high- and low-dragonfly abundance treatments. In contrast, we did find evidence that ambush bug presence affected selection on floral traits via a trait-mediated indirect effect: ambush bugs hunted from L. siphilitica plants with larger daily floral displays, reversing the direction of pollinator-mediated selection on daily display size. These results suggest that indirect species interactions have the potential to shape adaptive evolution by altering natural selection.
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Affiliation(s)
- Amanda D Benoit
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Christina M Caruso
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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7
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Benoit AD, Kalisz S. Predator Effects on Plant-Pollinator Interactions, Plant Reproduction, Mating Systems, and Evolution. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-012120-094926] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Plants are the foundation of the food web and therefore interact directly and indirectly with myriad organisms at higher trophic levels. They directly provide nourishment to mutualistic and antagonistic primary consumers (e.g., pollinators and herbivores), which in turn are consumed by predators. These interactions produce cascading indirect effects on plants (either trait-mediated or density-mediated). We review how predators affect plant-pollinator interactions and thus how predators indirectly affect plant reproduction, fitness, mating systems, and trait evolution. Predators can influence pollinator abundance and foraging behavior. In many cases, predators cause pollinators to visit plants less frequently and for shorter durations. This decline in visitation can lead to pollen limitation and decreased seed set. However, alternative outcomes can result due to differences in predator, pollinator, and plant functional traits as well as due to altered interaction networks with plant enemies. Furthermore, predators may indirectly affect the evolution of plant traits and mating systems.
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Affiliation(s)
- Amanda D. Benoit
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996, USA;,
| | - Susan Kalisz
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996, USA;,
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8
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Abdala‐Roberts L, Puentes A, Finke DL, Marquis RJ, Montserrat M, Poelman EH, Rasmann S, Sentis A, van Dam NM, Wimp G, Mooney K, Björkman C. Tri-trophic interactions: bridging species, communities and ecosystems. Ecol Lett 2019; 22:2151-2167. [PMID: 31631502 PMCID: PMC6899832 DOI: 10.1111/ele.13392] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/18/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023]
Abstract
A vast body of research demonstrates that many ecological and evolutionary processes can only be understood from a tri-trophic viewpoint, that is, one that moves beyond the pairwise interactions of neighbouring trophic levels to consider the emergent features of interactions among multiple trophic levels. Despite its unifying potential, tri-trophic research has been fragmented, following two distinct paths. One has focused on the population biology and evolutionary ecology of simple food chains of interacting species. The other has focused on bottom-up and top-down controls over the distribution of biomass across trophic levels and other ecosystem-level variables. Here, we propose pathways to bridge these two long-standing perspectives. We argue that an expanded theory of tri-trophic interactions (TTIs) can unify our understanding of biological processes across scales and levels of organisation, ranging from species evolution and pairwise interactions to community structure and ecosystem function. To do so requires addressing how community structure and ecosystem function arise as emergent properties of component TTIs, and, in turn, how species traits and TTIs are shaped by the ecosystem processes and the abiotic environment in which they are embedded. We conclude that novel insights will come from applying tri-trophic theory systematically across all levels of biological organisation.
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Affiliation(s)
- Luis Abdala‐Roberts
- Departamento de Ecología TropicalCampus de Ciencias Biológicas y AgropecuariasUniversidad Autónoma de YucatánKm. 15.5 Carretera Mérida‐XmatkuilMX‐97000MéridaYucatánMéxico
| | - Adriana Puentes
- Department of EcologySwedish University of Agricultural SciencesBox 7044SE‐750 07UppsalaSweden
| | - Deborah L. Finke
- Division of Plant SciencesUniversity of Missouri1‐33 Agriculture BuildingUS‐65211ColumbiaMOUSA
| | - Robert J. Marquis
- Department of Biology and the Whitney R. Harris World Ecology CenterUniversity of Missouri–St. Louis1 University BoulevardUS‐63121St. LouisMOUSA
| | - Marta Montserrat
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” (IHSM‐UMA‐CSIC)Consejo Superior de Investigaciones CientíficasE‐29750Algarrobo‐Costa (Málaga)Spain
| | - Erik H. Poelman
- Laboratory of EntomologyWageningen UniversityP.O. Box 166700 AAWageningenThe Netherlands
| | - Sergio Rasmann
- Institute of BiologyUniversity of NeuchâtelRue Emile‐Argand 11CH‐2000NeuchâtelSwitzerland
| | - Arnaud Sentis
- UMR RECOVERIRSTEAAix Marseille University3275 route Cézanne13182Aix‐en‐ProvenceFrance
| | - Nicole M. van Dam
- Molecular Interaction EcologyFriedrich‐Schiller‐University Jena & German Centre for Integrative Biodiversity Research (iDiv)Halle‐Jena‐LeipzigDeutscher Platz 5eDE‐04103LeipzigGermany
| | - Gina Wimp
- Department of BiologyGeorgetown University406 Reiss Science BuildingUS‐20057WashingtonDCUSA
| | - Kailen Mooney
- Department of Ecology and Evolutionary BiologyUniversity of California Irvine321 Steinhaus HallUS‐92697IrvineCAUSA
| | - Christer Björkman
- Department of EcologySwedish University of Agricultural SciencesBox 7044SE‐750 07UppsalaSweden
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9
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Cerrano C, Bastari A, Calcinai B, Di Camillo C, Pica D, Puce S, Valisano L, Torsani F. Temperate mesophotic ecosystems: gaps and perspectives of an emerging conservation challenge for the Mediterranean Sea. EUROPEAN ZOOLOGICAL JOURNAL 2019. [DOI: 10.1080/24750263.2019.1677790] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- C. Cerrano
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - A. Bastari
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - B. Calcinai
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - C. Di Camillo
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - D. Pica
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - S. Puce
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - L. Valisano
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - F. Torsani
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
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10
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Huang F, Lankau R, Peng S. Coexistence via coevolution driven by reduced allelochemical effects and increased tolerance to competition between invasive and native plants. THE NEW PHYTOLOGIST 2018; 218:357-369. [PMID: 29205373 DOI: 10.1111/nph.14937] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 11/06/2017] [Indexed: 06/07/2023]
Abstract
Coevolution can promote long-term coexistence of two competing species if selection acts to reduce the fitness inequality between competitors and/or strengthen negative frequency dependence within each population. However, clear coevolution between plant competitors has been rarely documented. Plant invasions offer opportunities to capture the process of coevolution. Here we investigated how the developing relationship between an invasive forb, Alliaria petiolata, and a native competitor, Pilea pumila, may affect their long-term coexistence, by testing the competitive effects of populations of varying lengths of co-occurrence on each other across a chronosequence of invasion history. Alliaria petiolata and P. pumila tended to develop greater tolerance to competition over invasion history. Their coexistence was promoted more by increases in stabilizing relative to equalizing processes. These changes likely stem in part from reductions in allelopathic traits in the invader and evolution of tolerance in the native. These results suggested that some native species can evolve tolerance against the competitive effects of strong invaders, which likely promoted their persistence in invaded communities. However, the potential for coevolutionary rescue of competing populations is likely to vary across native species, and evolutionary processes should not be expected to compensate for the ecological consequences of exotic invasions.
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Affiliation(s)
- Fangfang Huang
- State Key Lab of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
- Guangdong Provincial Key Laboratory of Silviculture, Protection and Utilization, Guangdong Academy of Forestry, Guangzhou, 510520, China
| | - Richard Lankau
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Shaolin Peng
- State Key Lab of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
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11
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Abstract
Most species have one or more natural enemies, e.g., predators, parasites, pathogens, and herbivores, among others. These species in turn typically attack multiple victim species. This leads to the possibility of indirect interactions among those victims, both positive and negative. The term apparent competition commonly denotes negative indirect interactions between victim species that arise because they share a natural enemy. This indirect interaction, which in principle can be reflected in many facets of the distribution and abundance of individual species and more broadly govern the structure of ecological communities in time and space, pervades many natural ecosystems. It also is a central theme in many applied ecological problems, including the control of agricultural pests, harvesting, the conservation of endangered species, and the dynamics of emerging diseases. At one end of the scale of life, apparent competition characterizes intriguing aspects of dynamics within individual organisms—for example, the immune system is akin in many ways to a predator that can induce negative indirect interactions among different pathogens. At intermediate scales of biological organization, the existence and strength of apparent competition depend upon many contingent details of individual behavior and life history, as well as the community and spatial context within which indirect interactions play out. At the broadest scale of macroecology and macroevolution, apparent competition may play a major, if poorly understood, role in the evolution of species’ geographical ranges and adaptive radiations.
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Affiliation(s)
- Robert D. Holt
- Department of Biology, University of Florida, Gainesville, Florida 32611 USA
| | - Michael B. Bonsall
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
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12
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Lee DE, Kissui BM, Kiwango YA, Bond ML. Migratory herds of wildebeests and zebras indirectly affect calf survival of giraffes. Ecol Evol 2016; 6:8402-8411. [PMID: 28031792 PMCID: PMC5167056 DOI: 10.1002/ece3.2561] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 09/14/2016] [Accepted: 09/22/2016] [Indexed: 11/24/2022] Open
Abstract
In long‐distance migratory systems, local fluctuations in the predator–prey ratio can exhibit extreme variability within a single year depending upon the seasonal location of migratory species. Such systems offer an opportunity to empirically investigate cyclic population density effects on short‐term food web interactions by taking advantage of the large seasonal shifts in migratory prey biomass. We utilized a large‐mammal predator–prey savanna food web to evaluate support for hypotheses relating to the indirect effects of “apparent competition” and “apparent mutualism” from migratory ungulate herds on survival of resident megaherbivore calves, mediated by their shared predator. African lions (Panthera leo) are generalist predators whose primary, preferred prey are wildebeests (Connochaetes taurinus) and zebras (Equus quagga), while lion predation on secondary prey such as giraffes (Giraffa camelopardalis) may change according to the relative abundance of the primary prey species. We used demographic data from five subpopulations of giraffes in the Tarangire Ecosystem of Tanzania, East Africa, to test hypotheses relating to direct predation and indirect effects of large migratory herds on calf survival of a resident megaherbivore. We examined neonatal survival via apparent reproduction of 860 adult females, and calf survival of 449 giraffe calves, during three precipitation seasons over 3 years, seeking evidence of some effect on neonate and calf survival as a consequence of the movements of large herds of migratory ungulates. We found that local lion predation pressure (lion density divided by primary prey density) was significantly negatively correlated with giraffe neonatal and calf survival probabilities. This supports the apparent mutualism hypothesis that the presence of migratory ungulates reduces lion predation on giraffe calves. Natural predation had a significant effect on giraffe calf and neonate survival, and could significantly affect giraffe population dynamics. If wildebeest and zebra populations in this ecosystem continue to decline as a result of increasingly disrupted migrations and poaching, then giraffe calves will face increased predation pressure as the predator–prey ratio increases. Our results suggest that the widespread population declines observed in many migratory systems are likely to trigger demographic impacts in other species due to indirect effects like those shown here.
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13
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Daskin JH, Pringle RM. Does primary productivity modulate the indirect effects of large herbivores? A global meta-analysis. J Anim Ecol 2016; 85:857-68. [PMID: 27007672 DOI: 10.1111/1365-2656.12522] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 03/11/2016] [Indexed: 12/13/2022]
Abstract
Indirect effects of large mammalian herbivores (LMH), while much less studied than those of apex predators, are increasingly recognized to exert powerful influences on communities and ecosystems. The strength of these effects is spatiotemporally variable, and several sets of authors have suggested that they are governed in part by primary productivity. However, prior theoretical and field studies have generated conflicting results and predictions, underscoring the need for a synthetic global analysis. We conducted a meta-analysis of the direction and magnitude of large mammalian herbivore-initiated indirect interactions using 67 published studies comprising 456 individual responses. We georeferenced 41 of these studies (comprising 253 responses from 33 locations on five continents) to a satellite-derived map of primary productivity. Because predator assemblages might also influence the impact of large herbivores, we conducted a similar analysis using a global map of large carnivore species richness. In general, LMH reduced the abundance of other consumer species and also tended to reduce consumer richness, although the latter effect was only marginally significant. There was a pronounced reduction in the strength of negative (i.e. suppressive, due e.g., to competition) indirect effects of LMH on consumer abundance in more productive ecosystems. In contrast, positive (facilitative) indirect effects were not significantly correlated with productivity, likely because these comprised a more heterogeneous array of mechanisms. We found no effect of carnivore species richness on herbivore-initiated indirect effect strength. Our findings help to resolve the fundamental problem of ecological contingency as it pertains to the strength of an understudied class of multitrophic interactions. Moreover, these results will aid in predicting the indirect effects of anthropogenic wildlife declines and irruptions, and how these effects might be mediated by climatically driven shifts in resource availability. To the extent that intact ungulate guilds help to suppress populations of small animals that act as agricultural pests and disease reservoirs, the negative impacts of large mammal declines on human well-being may be relatively stronger in low-productivity areas.
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Affiliation(s)
- Joshua H Daskin
- Department of Ecology and Evolutionary Biology, 106A Guyot Hall, Princeton University, Princeton, NJ, 08540, USA
| | - Robert M Pringle
- Department of Ecology and Evolutionary Biology, 106A Guyot Hall, Princeton University, Princeton, NJ, 08540, USA
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Taylor RA, Ryan SJ, Brashares JS, Johnson LR. Hunting, food subsidies, and mesopredator release: the dynamics of crop‐raiding baboons in a managed landscape. Ecology 2016; 97:951-60. [DOI: 10.1890/15-0885.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Rachel A. Taylor
- Integrative Biology University of South Florida Tampa Florida 33620 USA
| | - Sadie J. Ryan
- Geography and Emerging Pathogens Institute University of Florida Gainesville Florida 32611 USA
| | - Justin S. Brashares
- Environmental Science, Policy and Management UC Berkeley Berkeley California 94720 USA
| | - Leah R. Johnson
- Integrative Biology University of South Florida Tampa Florida 33620 USA
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15
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Beyond the Black Queen Hypothesis. ISME JOURNAL 2016; 10:2085-91. [PMID: 26953598 DOI: 10.1038/ismej.2016.22] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 01/06/2016] [Accepted: 01/08/2016] [Indexed: 11/08/2022]
Abstract
The Black Queen Hypothesis, recently proposed to explain an evolution of dependency based on gene loss, is gaining ground. This paper focuses on how the evolution of dependency transforms interactions and the community. Using agent-based modeling we suggest that species specializing in the consumption of a common good escape competition and therefore favor coexistence. This evolutionary trajectory could open the way for novel long-lasting interactions and a need to revisit the classically accepted assembly rules. Such evolutionary events also reshape the structure and dynamics of communities, depending on the spatial heterogeneity of the common good production. Let Black be the new black!
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Jones AW, Post DM. Does intraspecific competition promote variation? A test via synthesis. Ecol Evol 2016; 6:1646-55. [PMID: 27087931 PMCID: PMC4801976 DOI: 10.1002/ece3.1991] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 12/21/2015] [Accepted: 01/05/2016] [Indexed: 11/11/2022] Open
Abstract
Competitive diversification, that is, when increasing intraspecific competition promotes population niche expansion, is commonly invoked in evolutionary studies and currently plays a central role in how we conceptualize the process of adaptive diversification. Despite the frequency with which this idea is cited, the empirical evidence for the process is somewhat limited, and the findings of these studies have yet to be weighed objectively through synthesis. Here, we sought to fill this gap by reviewing the existing literature and collecting the data necessary to assess the evidence for competition as a diversifying force. Additionally, we sought to test a more recent hypothesis, which suggests that competition can act to both promote and inhibit dietary diversification depending on the degree to which a consumer depletes its resources. The surprising result of this synthesis was that increasing competition did not have a mean positive effect on population‐level diet breadth or the degree of individual specialization. Instead, we found that increasing intraspecific competition had a restricting effect on population‐level diet breadth in as many cases as it had a diversifying effect. This wide disparity in the effect of competition on consumer diet variation was negatively related to a metric for consumer resource depletion. Altogether, these findings call into question a long‐standing assumption of basic evolutionary models and lend some support to recent theoretical predictions. Specifically, these findings support the idea that competition is primarily diversifying for species with a small effect (per unit biomass) on their resources and that resource depletion limits the diversifying effect of competition for consumers with larger ecological effects.
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Affiliation(s)
- Andrew W Jones
- Department of Ecology and Evolutionary Biology Yale University 165 Prospect Street New Haven Connecticut 06511 USA
| | - David M Post
- Department of Ecology and Evolutionary Biology Yale University 165 Prospect Street New Haven Connecticut 06511 USA
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Reznick D. Hard and Soft Selection Revisited: How Evolution by Natural Selection Works in the Real World. J Hered 2015; 107:3-14. [PMID: 26424874 DOI: 10.1093/jhered/esv076] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 08/25/2015] [Indexed: 11/13/2022] Open
Abstract
The modern synthesis of evolutionary biology unified Darwin's natural selection with Mendelian genetics, but at the same time it created the dilemma of genetic load. Lewontin and Hubby's (1966) and Harris's (1966) characterization of genetic variation in natural populations increased the apparent burden of this load. Neutrality or near neutrality of genetic variation was one mechanism proposed for the revealed excessive genetic variation. Bruce Wallace coined the term "soft selection" to describe an alternative way for natural selection to operate that was consistent with observed variation. He envisioned nature as presenting ecological vacancies that could be filled by diverse genotypes. Survival and successful reproduction was a combined function of population density, genotype, and genotype frequencies, rather than a fixed value of the relative fitness of each genotype. My goal in this review is to explore the importance of soft selection in the real world. My motive and that of my colleagues as described here is not to explain what maintains genetic variation in natural populations, but rather to understand the factors that shape how organisms adapt to natural environments. We characterize how feedbacks between ecology and evolution shape both evolution and ecology. These feedbacks are mediated by density- and frequency-dependent selection, the mechanisms that underlie soft selection. Here, I report on our progress in characterizing these types of selection with a combination of a consideration of the published literature and the results from my collaborators' and my research on natural populations of guppies.
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Affiliation(s)
- David Reznick
- From the Department of Biology, University of California, Riverside, CA 92521, USA
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Affiliation(s)
- Rodolfo Dirzo
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
| | - Hillary S Young
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Mauro Galetti
- Departamento de Ecologia, Universidade Estadual Paulista, Rio Claro, SP, 13506-900, Brazil
| | - Gerardo Ceballos
- Instituto de Ecología, Universidad Nacional Autónoma de México, AP 70-275, México D.F. 04510, Mexico
| | - Nick J B Isaac
- Natural Environment Research Council (NERC) Centre for Ecology and Hydrology, Benson Lane, Crowmarsh Gifford, Oxfordshire, OX10 8BB, UK
| | - Ben Collen
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
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Ripple WJ, Estes JA, Beschta RL, Wilmers CC, Ritchie EG, Hebblewhite M, Berger J, Elmhagen B, Letnic M, Nelson MP, Schmitz OJ, Smith DW, Wallach AD, Wirsing AJ. Status and ecological effects of the world's largest carnivores. Science 2014; 343:1241484. [PMID: 24408439 DOI: 10.1126/science.1241484] [Citation(s) in RCA: 1592] [Impact Index Per Article: 159.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Large carnivores face serious threats and are experiencing massive declines in their populations and geographic ranges around the world. We highlight how these threats have affected the conservation status and ecological functioning of the 31 largest mammalian carnivores on Earth. Consistent with theory, empirical studies increasingly show that large carnivores have substantial effects on the structure and function of diverse ecosystems. Significant cascading trophic interactions, mediated by their prey or sympatric mesopredators, arise when some of these carnivores are extirpated from or repatriated to ecosystems. Unexpected effects of trophic cascades on various taxa and processes include changes to bird, mammal, invertebrate, and herpetofauna abundance or richness; subsidies to scavengers; altered disease dynamics; carbon sequestration; modified stream morphology; and crop damage. Promoting tolerance and coexistence with large carnivores is a crucial societal challenge that will ultimately determine the fate of Earth's largest carnivores and all that depends upon them, including humans.
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Affiliation(s)
- William J Ripple
- Trophic Cascades Program, Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
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Strauss SY. Ecological and evolutionary responses in complex communities: implications for invasions and eco-evolutionary feedbacks. OIKOS 2013. [DOI: 10.1111/j.1600-0706.2013.01093.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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