1
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Szefer P, Molem K, Sau A, Novotny V. Weak effects of birds, bats, and ants on their arthropod prey on pioneering tropical forest gap vegetation. Ecology 2022; 103:e3690. [PMID: 35322403 DOI: 10.1002/ecy.3690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/18/2021] [Accepted: 01/18/2022] [Indexed: 11/11/2022]
Abstract
The relative roles of plants competing for resources versus top-down control of vegetation by herbivores, in turn impacted by predators, during early stages of tropical forest succession remain poorly understood. Here we examine the impact of insectivorous birds, bats and ants exclusion on arthropods communities on replicated 5x5 m of pioneering early successional vegetation plots in lowland tropical forest gaps in Papua New Guinea. In plots from which focal taxa of predators were excluded we observed increased biomass of herbivorous and predatory arthropods, and increased density, and decreased diversity of herbivorous insects. However, changes in the biomass of plants, herbivores and arthropod predators were positively correlated or uncorrelated between these three trophic levels and also between individual arthropod orders. Arthropod abundance and biomass correlated strongly with the plant biomass irrespective of the arthropods' trophic position - a signal of bottom-up control. Patterns in herbivore specialization confirm lack of a strong top-down control and were largely unaffected by the exclusion of insectivorous birds, bats and ants. No changes of plant-herbivore interaction networks were detected except for decrease in modularity of the exclosure plots. Our results suggest weak top-down control of herbivores, limited compensation between arthropod and vertebrate predators, and limited intra-guild predation by birds, bats and ants. Possible explanations are strong bottom-up control, a low activity of the higher order predators, especially birds, possibly also bats, in gaps, and continuous influx of herbivores from surrounding mature forest matrix.
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Affiliation(s)
- Piotr Szefer
- Faculty of Science, University of South Bohemia, Branišovská 1645/31a, České Budějovice, Czech Republic.,Biology Centre, Institute of Entomology, Czech Academy of Sciences, Branišovská 31, České Budějovice, Czech Republic
| | - Kenneth Molem
- New Guinea Binatang Research Centre, PO Box 604, Madang 511, Papua New Guinea
| | - Austin Sau
- New Guinea Binatang Research Centre, PO Box 604, Madang 511, Papua New Guinea
| | - Vojtech Novotny
- Faculty of Science, University of South Bohemia, Branišovská 1645/31a, České Budějovice, Czech Republic.,Biology Centre, Institute of Entomology, Czech Academy of Sciences, Branišovská 31, České Budějovice, Czech Republic
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2
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Abstract
Psychiatry has long debated whether the causes of mental illness can be better explained by reductionist or pluralistic accounts. Although the former relies on commonsense scientific bottom-up causal models, the latter (which typically include environmental, psychological, and/or socio-cultural risk factors) requires top-down causal processes often viewed with skepticism, especially by neuroscientists. We begin with four clinical vignettes which illustrate self-interventions wherein high-order psychological processes (e.g. religious beliefs or deep interpersonal commitments) appear to causally impact the risk for or the course of psychiatric/behavioral disorders. We then propose a model for how to understand this sort of top-down self-causation. Our model relies centrally on the concept of a control variable which, like a radio tuning dial, can implement a series of typically unknown physical processes to obtain the desired ends. We set this control variable in the context of an interventionist account of causation that assumes that a cause (C) produces an effect (E) when intervening on C (by manipulating it) is associated with a change in E. We extend this framework by arguing that certain psychological changes can result from individuals intervening on their own mental states and/or selection of environments. This in turn requires a conception of the self that contains mental capacities that are at least partially independent of one another. Although human beings cannot directly intervene on the neurobiological systems which instantiate risk for psychiatric illness, they can, via control variables at the psychological level, and/or by self-selection into protective environments, substantially alter their own risk.
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Affiliation(s)
- Kenneth S Kendler
- Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA, USA
- Department of Psychiatry, Virginia Commonwealth University, RichmondVA, USA
| | - James Woodward
- Department of History and Philosophy of Science, University of Pittsburgh, Pittsburgh, PA, USA
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3
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Zhong Z, Li X, Sanders D, Liu Y, Wang L, Ortega YK, Pearson DE, Wang D. Soil engineering by ants facilitates plant compensation for large herbivore removal of aboveground biomass. Ecology 2021; 102:e03312. [PMID: 33586130 DOI: 10.1002/ecy.3312] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 11/17/2020] [Accepted: 12/06/2020] [Indexed: 11/06/2022]
Abstract
The interplay between top-down and bottom-up processes determines ecosystem productivity. Yet, the factors that mediate the balance between these opposing forces remain poorly understood. Furthering this challenge, complex and often cryptic factors like ecosystem engineering and trait-mediated interactions may play major roles in mediating the outcomes of top-down and bottom-up interactions. In semiarid grasslands of northeastern China, we conducted a large-scale, three-year experiment to evaluate how soil engineering by ants and plasticity in plants independently and jointly influenced the top-down effects of grazing by a ubiquitous herbivore (cattle) on aboveground standing biomass of the dominant perennial grass, Leymus chinensis. Herbivory had strong top-down effects, reducing L. chinensis AB by 25% relative to baseline levels without cattle or ants. In contrast, soil engineering by ants facilitated weak bottom-up effects in the absence of herbivory. However, in the presence of herbivory, soil engineering effects were strong enough to fully offset herbivore removal of aboveground biomass. This outcome was mediated by L. chinensis's plasticity in reallocating growth from below- to aboveground biomass, a result linked to additive effects of engineers and herbivores increasing soil N availability and engineering effects improving soil structure. Soil engineering increased soil N by 12%, promoting aboveground biomass. Herbivores increased soil N by 13% via defecation, but this increase failed to offset their reductions in aboveground biomass in isolation. However, when combined, engineers and herbivores increased soil N by 26% and engineers improved soil bulk density, facilitating L. chinensis to shift resource allocations from below- to aboveground biomass sufficiently to fully offset herbivore suppression of aboveground biomass. Our results demonstrate that soil engineering and trait-mediated effects of plant plasticity can strongly mediate the outcome of top-down and bottom-up interactions. These cryptic but perhaps ubiquitous processes may help to explain the long-debated phenomenon of plant compensatory responses to large grazers.
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Affiliation(s)
- Zhiwei Zhong
- Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Ministry of Education/Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, 130024, China
| | - Xiaofei Li
- College of Resources and Environmental Sciences/Key Laboratory of Sustainable Utilization of Soil Resources in the Commodity Grain Bases in Jilin Province, Jilin Agricultural University, Changchun, 130118, China
| | - Dirk Sanders
- Environment and Sustainability Institute, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, TR10 9FE, United Kingdom
| | - Yiming Liu
- Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Ministry of Education/Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, 130024, China
| | - Ling Wang
- Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Ministry of Education/Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, 130024, China
| | - Yvette K Ortega
- Rocky Mountain Research Station, USDA Forest Service, 800 E. Beckwith Avenue, Missoula, Montana, 59801, USA
| | - Dean E Pearson
- Rocky Mountain Research Station, USDA Forest Service, 800 E. Beckwith Avenue, Missoula, Montana, 59801, USA.,Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, Montana, 59812, USA
| | - Deli Wang
- Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Ministry of Education/Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, 130024, China
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4
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Urban MC, Freidenfelds NA, Richardson JL. Microgeographic divergence of functional responses among salamanders under antagonistic selection from apex predators. Proc Biol Sci 2020; 287:20201665. [PMID: 33171095 DOI: 10.1098/rspb.2020.1665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A predator's functional response determines predator-prey interactions by describing the relationship between the number of prey available and the number eaten. Its shape and parameters fundamentally govern the dynamic equilibrium of predator-prey interactions and their joint abundances. Yet, estimates of these key parameters generally assume stasis in space and time and ignore the potential for local adaptation to alter feeding responses and the stability of trophic dynamics. Here, we evaluate if functional responses diverge among populations of spotted salamander (Ambystoma maculatum) larvae that face antagonistic selection on feeding strategies based on their own risk of predation. Common garden experiments revealed that spotted salamander from ponds with varying predation risks differed in their functional responses, suggesting an evolutionary response. Applying mechanistic equations, we discovered that the combined changes in attack rates, handling times and shape of the functional response enhanced feeding rate in environments with high densities of gape-limited predators. We suggest how these parameter changes could alter community equilibria and other emergent properties of food webs. Community ecologists might often need to consider how local evolution at fine scales alters key relationships in ways that alter local diversity patterns, food web dynamics, resource gradients and community responses to disturbance.
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Affiliation(s)
- Mark C Urban
- Department of Ecology and Evolutionary Biology, 75 North Eagleville Road, Unit 3043, Storrs, CT 06269, USA.,Center of Biological Risk, University of Connecticut, 75 North Eagleville Road, Unit 3043, Storrs, CT 06269, USA
| | - Nicole A Freidenfelds
- Department of Ecology and Evolutionary Biology, 75 North Eagleville Road, Unit 3043, Storrs, CT 06269, USA.,Department of Natural Resources and the Environment, University of Connecticut, 1376 Storrs Road, Unit 4087, Storrs, CT 06269, USA
| | - Jonathan L Richardson
- Department of Ecology and Evolutionary Biology, 75 North Eagleville Road, Unit 3043, Storrs, CT 06269, USA.,Department of Biology, University of Richmond, Gottwald Science Center, 138 UR Drive, Richmond, VA, USA
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5
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Lupyan G, Abdel Rahman R, Boroditsky L, Clark A. Effects of Language on Visual Perception. Trends Cogn Sci 2020; 24:930-944. [PMID: 33012687 DOI: 10.1016/j.tics.2020.08.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/22/2020] [Accepted: 08/25/2020] [Indexed: 11/24/2022]
Abstract
Does language change what we perceive? Does speaking different languages cause us to perceive things differently? We review the behavioral and electrophysiological evidence for the influence of language on perception, with an emphasis on the visual modality. Effects of language on perception can be observed both in higher-level processes such as recognition and in lower-level processes such as discrimination and detection. A consistent finding is that language causes us to perceive in a more categorical way. Rather than being fringe or exotic, as they are sometimes portrayed, we discuss how effects of language on perception naturally arise from the interactive and predictive nature of perception.
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Affiliation(s)
- Gary Lupyan
- University of Wisconsin-Madison, Madison, WI, USA.
| | | | | | - Andy Clark
- University of Sussex, Brighton, UK; Macquarie University, Sydney, Australia
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6
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Wirsing AJ, Heithaus MR, Brown JS, Kotler BP, Schmitz OJ. The context dependence of non-consumptive predator effects. Ecol Lett 2020; 24:113-129. [PMID: 32990363 DOI: 10.1111/ele.13614] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 01/10/2023]
Abstract
Non-consumptive predator effects (NCEs) are now widely recognised for their capacity to shape ecosystem structure and function. Yet, forecasting the propagation of these predator-induced trait changes through particular communities remains a challenge. Accordingly, focusing on plasticity in prey anti-predator behaviours, we conceptualise the multi-stage process by which predators trigger direct and indirect NCEs, review and distil potential drivers of contingencies into three key categories (properties of the prey, predator and setting), and then provide a general framework for predicting both the nature and strength of direct NCEs. Our review underscores the myriad factors that can generate NCE contingencies while guiding how research might better anticipate and account for them. Moreover, our synthesis highlights the value of mapping both habitat domains and prey-specific patterns of evasion success ('evasion landscapes') as the basis for predicting how direct NCEs are likely to manifest in any particular community. Looking ahead, we highlight two key knowledge gaps that continue to impede a comprehensive understanding of non-consumptive predator-prey interactions and their ecosystem consequences; namely, insufficient empirical exploration of (1) context-dependent indirect NCEs and (2) the ways in which direct and indirect NCEs are shaped interactively by multiple drivers of context dependence.
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Affiliation(s)
- Aaron J Wirsing
- School of Environmental and Forest Sciences, University of Washington, Box 352100, Seattle, WA, 98195, USA
| | - Michael R Heithaus
- Department of Biological Sciences, Marine Sciences Program, Florida International University, 3000 NE 151st St, North Miami, FL, 33181, USA
| | - Joel S Brown
- Department of Biological Sciences, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL, 60607, USA.,Department of Integrated Mathematical Oncology, Moffitt Cancer Center, 12902 Magnolia Dr, Tampa, FL, 33613, USA
| | - Burt P Kotler
- Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet, Ben-Gurion, 84990, Israel
| | - Oswald J Schmitz
- School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, 06511, USA
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7
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Getz LM, Toscano JC. The time-course of speech perception revealed by temporally-sensitive neural measures. Wiley Interdiscip Rev Cogn Sci 2020; 12:e1541. [PMID: 32767836 DOI: 10.1002/wcs.1541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 05/28/2020] [Accepted: 06/26/2020] [Indexed: 11/07/2022]
Abstract
Recent advances in cognitive neuroscience have provided a detailed picture of the early time-course of speech perception. In this review, we highlight this work, placing it within the broader context of research on the neurobiology of speech processing, and discuss how these data point us toward new models of speech perception and spoken language comprehension. We focus, in particular, on temporally-sensitive measures that allow us to directly measure early perceptual processes. Overall, the data provide support for two key principles: (a) speech perception is based on gradient representations of speech sounds and (b) speech perception is interactive and receives input from higher-level linguistic context at the earliest stages of cortical processing. Implications for models of speech processing and the neurobiology of language more broadly are discussed. This article is categorized under: Psychology > Language Psychology > Perception and Psychophysics Neuroscience > Cognition.
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Affiliation(s)
- Laura M Getz
- Department of Psychological Sciences, University of San Diego, San Diego, California, USA
| | - Joseph C Toscano
- Department of Psychological and Brain Sciences, Villanova University, Villanova, Pennsylvania, USA
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8
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Broderick MP, Anderson AJ, Lalor EC. Semantic Context Enhances the Early Auditory Encoding of Natural Speech. J Neurosci 2019; 39:7564-7575. [PMID: 31371424 PMCID: PMC6750931 DOI: 10.1523/jneurosci.0584-19.2019] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/20/2019] [Accepted: 07/29/2019] [Indexed: 01/22/2023] Open
Abstract
Speech perception involves the integration of sensory input with expectations based on the context of that speech. Much debate surrounds the issue of whether or not prior knowledge feeds back to affect early auditory encoding in the lower levels of the speech processing hierarchy, or whether perception can be best explained as a purely feedforward process. Although there has been compelling evidence on both sides of this debate, experiments involving naturalistic speech stimuli to address these questions have been lacking. Here, we use a recently introduced method for quantifying the semantic context of speech and relate it to a commonly used method for indexing low-level auditory encoding of speech. The relationship between these measures is taken to be an indication of how semantic context leading up to a word influences how its low-level acoustic and phonetic features are processed. We record EEG from human participants (both male and female) listening to continuous natural speech and find that the early cortical tracking of a word's speech envelope is enhanced by its semantic similarity to its sentential context. Using a forward modeling approach, we find that prediction accuracy of the EEG signal also shows the same effect. Furthermore, this effect shows distinct temporal patterns of correlation depending on the type of speech input representation (acoustic or phonological) used for the model, implicating a top-down propagation of information through the processing hierarchy. These results suggest a mechanism that links top-down prior information with the early cortical entrainment of words in natural, continuous speech.SIGNIFICANCE STATEMENT During natural speech comprehension, we use semantic context when processing information about new incoming words. However, precisely how the neural processing of bottom-up sensory information is affected by top-down context-based predictions remains controversial. We address this discussion using a novel approach that indexes a word's similarity to context and how well a word's acoustic and phonetic features are processed by the brain at the time of its utterance. We relate these two measures and show that lower-level auditory tracking of speech improves for words that are more related to their preceding context. These results suggest a mechanism that links top-down prior information with bottom-up sensory processing in the context of natural, narrative speech listening.
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Affiliation(s)
- Michael P Broderick
- School of Engineering, Trinity Centre for Bioengineering and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland,
| | - Andrew J Anderson
- Department of Biomedical Engineering, and
- Department of Neuroscience and Del Monte Institute for Neuroscience, University of Rochester, Rochester, New York 14627
| | - Edmund C Lalor
- School of Engineering, Trinity Centre for Bioengineering and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
- Department of Biomedical Engineering, and
- Department of Neuroscience and Del Monte Institute for Neuroscience, University of Rochester, Rochester, New York 14627
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9
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Bogdziewicz M, Marino S, Bonal R, Zwolak R, Steele MA. Rapid aggregative and reproductive responses of weevils to masting of North American oaks counteract predator satiation. Ecology 2018; 99:2575-2582. [PMID: 30182480 DOI: 10.1002/ecy.2510] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/07/2018] [Accepted: 08/20/2018] [Indexed: 11/09/2022]
Abstract
The predator satiation hypothesis posits that masting helps plants escape seed predation through starvation of predators in lean years, followed by satiation of predators in mast years. Importantly, successful satiation requires sufficiently delayed bottom-up effects of seed availability on seed consumers. However, some seed consumers may be capable of quick aggregative and reproductive responses to masting, which may jeopardize positive density dependence of seed survival. We used a 17-yr data set on seed production and insect (Curculio weevils) infestation of three North American oaks species (northern red Quercus rubra, white Q. alba, and chestnut oak Q. montana) to test predictions of the predation satiation hypothesis. Furthermore, we tested for the unlagged numerical response of Curculio to acorn production. We found that masting results in a bottom-up effect on the insect population; both through increased reproductive output and aggregation at seed-rich trees. Consequently, mast seeding in two out of three studied oaks (white and chestnut oak) did not help to escape insect seed predation, whereas, in the red oak, the escape depended on the synchronization of mast crops within the population. Bottom-up effects of masting on seed consumer populations are assumed to be delayed, and therefore to have negligible effects on seed survival in mast years. Our research suggests that insect populations may be able to mount rapid reproductive and aggregative responses when seed availability increases, possibly hindering satiation effects of masting. Many insect species are able to quickly benefit from pulsed resources, making mechanisms described here potentially relevant in many other systems.
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Affiliation(s)
- Michał Bogdziewicz
- Department of Systematic Zoology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614, Poznań, Poland
| | - Shealyn Marino
- Department of Biology, Wilkes University, Wilkes-Barre, Pennsylvania, 18766, USA
| | - Raul Bonal
- Forest Research Group, INDEHESA, University of Extremadura, Calle Virgen Puerto, 2, 10600, Plasencia, Spain.,DITEG Research Group, University of Castilla-La Mancha, Calle Altagracia, 50, 13003 Ciudad Real, Toledo, Spain
| | - Rafał Zwolak
- Department of Systematic Zoology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614, Poznań, Poland
| | - Michael A Steele
- Department of Biology, Wilkes University, Wilkes-Barre, Pennsylvania, 18766, USA
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10
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Zhong Z, Li X, Pearson D, Wang D, Sanders D, Zhu Y, Wang L. Ecosystem engineering strengthens bottom-up and weakens top-down effects via trait-mediated indirect interactions. Proc Biol Sci 2018; 284:rspb.2017.0894. [PMID: 28931733 PMCID: PMC5627195 DOI: 10.1098/rspb.2017.0894] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/09/2017] [Indexed: 11/15/2022] Open
Abstract
Trophic interactions and ecosystem engineering are ubiquitous and powerful forces structuring ecosystems, yet how these processes interact to shape natural systems is poorly understood. Moreover, trophic effects can be driven by both density- and trait-mediated interactions. Microcosm studies demonstrate that trait-mediated interactions may be as strong as density-mediated interactions, but the relative importance of these pathways at natural spatial and temporal scales is underexplored. Here, we integrate large-scale field experiments and microcosms to examine the effects of ecosystem engineering on trophic interactions while also exploring how ecological scale influences density- and trait-mediated interaction pathways. We demonstrate that (i) ecosystem engineering can shift the balance between top-down and bottom-up interactions, (ii) such effects can be driven by cryptic trait-mediated interactions, and (iii) the relative importance of density- versus trait-mediated interaction pathways can be scale dependent. Our findings reveal the complex interplay between ecosystem engineering, trophic interactions, and ecological scale in structuring natural systems.
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Affiliation(s)
- Zhiwei Zhong
- Institute of Grassland Science/School of Environment, Northeast Normal University, and Key Laboratory of Vegetation Ecology/Key Laboratory for Wetland Ecology and Vegetation Restoration, Changchun, Jilin 130024, China
| | - Xiaofei Li
- Institute of Grassland Science/School of Environment, Northeast Normal University, and Key Laboratory of Vegetation Ecology/Key Laboratory for Wetland Ecology and Vegetation Restoration, Changchun, Jilin 130024, China
| | - Dean Pearson
- Rocky Mountain Research Station, USDA Forest Service, Missoula, MT 59801, USA.,Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Deli Wang
- Institute of Grassland Science/School of Environment, Northeast Normal University, and Key Laboratory of Vegetation Ecology/Key Laboratory for Wetland Ecology and Vegetation Restoration, Changchun, Jilin 130024, China
| | - Dirk Sanders
- Environment and Sustainability Institute, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, UK
| | - Yu Zhu
- Institute of Grassland Science/School of Environment, Northeast Normal University, and Key Laboratory of Vegetation Ecology/Key Laboratory for Wetland Ecology and Vegetation Restoration, Changchun, Jilin 130024, China
| | - Ling Wang
- Institute of Grassland Science/School of Environment, Northeast Normal University, and Key Laboratory of Vegetation Ecology/Key Laboratory for Wetland Ecology and Vegetation Restoration, Changchun, Jilin 130024, China
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11
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Kollars NM, Henry AK, Whalen MA, Boyer KE, Cusson M, Eklöf JS, Hereu CM, Jorgensen P, Kiriakopolos SL, Reynolds PL, Tomas F, Turner MS, Ruesink JL. Meta-Analysis of Reciprocal Linkages between Temperate Seagrasses and Waterfowl with Implications for Conservation. Front Plant Sci 2017; 8:2119. [PMID: 29312384 PMCID: PMC5744074 DOI: 10.3389/fpls.2017.02119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
Multi-trophic conservation and management strategies may be necessary if reciprocal linkages between primary producers and their consumers are strong. While herbivory on aquatic plants is well-studied, direct top-down control of seagrass populations has received comparatively little attention, particularly in temperate regions. Herein, we used qualitative and meta-analytic approaches to assess the scope and consequences of avian (primarily waterfowl) herbivory on temperate seagrasses of the genus Zostera. Meta-analyses revealed widespread evidence of spatio-temporal correlations between Zostera and waterfowl abundances as well as strong top-down effects of grazing on Zostera. We also documented the identity and diversity of avian species reported to consume Zostera and qualitatively assessed their potential to exert top-down control. Our results demonstrate that Zostera and their avian herbivores are ecologically linked and we suggest that bird herbivory may influence the spatial structure, composition, and functioning of the seagrass ecosystem. Therefore, the consequences of avian herbivory should be considered in the management of seagrass populations. Of particular concern are instances of seagrass overgrazing by waterfowl which result in long-term reductions in seagrass biomass or coverage, with subsequent impacts on local populations of waterfowl and other seagrass-affiliated species. While our results showed that bird density and type may affect the magnitude of the top-down effects of avian herbivory, empirical research on the strength, context-dependency, and indirect effects of waterfowl-Zostera interactions remains limited. For example, increased efforts that explicitly measure the effects of different functional groups of birds on seagrass abundance and/or document how climate change-driven shifts in waterfowl migratory patterns impact seagrass phenology and population structure will advance research programs for both ecologists and managers concerned with the joint conservation of both seagrasses and their avian herbivores.
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Affiliation(s)
- Nicole M. Kollars
- Center for Population Biology, University of California, Davis, Davis, CA, United States
| | - Amy K. Henry
- Committee on Evolutionary Biology, The University of Chicago, Chicago, IL, United States
| | - Matthew A. Whalen
- Department of Evolution and Ecology, University of California, Davis, Davis, CA, United States
- Hakai Institute, Vancouver, BC, Canada
| | - Katharyn E. Boyer
- Romberg Tiburon Center and Department of Biology, San Francisco State University, Tiburon, CA, United States
| | - Mathieu Cusson
- Département des Sciences Fondamentales & Québec-Océan, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada
| | - Johan S. Eklöf
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Clara M. Hereu
- Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, Mexico
| | | | - Stephanie L. Kiriakopolos
- Romberg Tiburon Center and Department of Biology, San Francisco State University, Tiburon, CA, United States
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States
| | - Pamela L. Reynolds
- Data Science Initiative, University of California, Davis, Davis, CA, United States
| | - Fiona Tomas
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States
- Instituto Mediterráneo de Estudios Avanzados, Universitat de les Illes Balears – Consejo Superior de Investigaciones Científicas, Esporles, Spain
| | - Mo S. Turner
- Department of Biology, University of Washington, Seattle, WA, United States
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12
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Abstract
Motion processing is thought of as a hierarchical system composed of higher and lower order components. Past research has shown that these components can be dissociated using motion priming paradigms in which the lower order system produces negative priming while the higher order system produces positive priming. By manipulating various stimulus parameters, researchers have probed these two systems using bistable test stimuli that permit only two motion interpretations. Here we employ maximally ambiguous test stimuli composed of randomly refreshing pixels in a task that allows observers to report more than just two types of motion percepts. We show that even with such stimuli, motion priming can constrain the unstructured random pixel patterns into coherent percepts of positive or negative apparent motion. Moreover, we find that the higher order system is uniquely susceptible to cognitive influences, as evidenced by a significant suppression of positive priming in the presence of alternative response options.
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13
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Lövei GL, Ferrante M. A review of the sentinel prey method as a way of quantifying invertebrate predation under field conditions. Insect Sci 2017; 24:528-542. [PMID: 27686246 DOI: 10.1111/1744-7917.12405] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 08/26/2016] [Accepted: 09/07/2016] [Indexed: 06/06/2023]
Abstract
Sentinel prey can provide a direct, quantitative measure of predation under field conditions. Live sentinel prey provides more realistic data but rarely allows the partitioning of the total predation pressure; artificial prey is less natural but traces left by different predators are identifiable, making it suitable for comparative studies. We reviewed the available evidence of the use of both types of invertebrate sentinel prey. Fifty-seven papers used real prey, usually measuring predation on a focal (often pest) species, with studies overwhelmingly from North America. The median predation was 25.8% d-1 . Artificial sentinel prey (45 papers) were used in both temperate and tropical areas, placed more above ground than at ground level. The most commonly used artificial prey imitated a caterpillar. Up to 14 predator groups were identified, registering a median of 8.8% d-1 predation; half the studies reported only bird predation. Predation on real prey was higher than on artificial ones, but invertebrate predation was not higher than vertebrate predation. Invertertebrate but not vertebrate predation was negatively related to prey size. Predation near the Equator was not higher than at higher latitudes, nor in cultivated than noncultivated habitats. The use of sentinel prey is not yet standardised in terms of prey size, arrangement, exposure period or data reporting. Due to the simplicity and ease of use of the method, such standardisation may increase the usefulness of comparative studies, contributing to the understanding of the importance and level of predation in various habitats worldwide.
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Affiliation(s)
- Gábor L Lövei
- Department of Agroecology, Flakkebjerg Research Centre, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Marco Ferrante
- Department of Agroecology, Flakkebjerg Research Centre, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
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14
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Breviglieri CPB, Romero GQ. Terrestrial vertebrate predators drive the structure and functioning of aquatic food webs. Ecology 2017; 98:2069-2080. [PMID: 28464251 DOI: 10.1002/ecy.1881] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 04/18/2017] [Accepted: 04/24/2017] [Indexed: 11/10/2022]
Abstract
Predators that forage at boundaries between ecosystems can affect prey from adjacent ecosystems, thereby triggering consumptive and non-consumptive cascading effects, which may affect diversity and food web structure across ecosystems. In the present study, we manipulated the access of insectivorous birds, lizards, and anurans to tank bromeliads in scrub vegetation in southern Brazil. We measured cascading effects on the community structure of aquatic invertebrates inhabiting bromeliad leaves and on the ecosystem processes of decomposition rate and bromeliad growth. The exclusion of terrestrial vertebrate predators increased the biomass of Odonate and Tabanid apex predators, which shifted the body size structure of the assemblage and generated inverted biomass pyramids that were top-heavy. Within bromeliads with larger aquatic predators, the species composition and abundance of other aquatic invertebrates also changed, resulting in higher abundance of mesopredators and scrapers, and lower abundance of shredders. Under those conditions, the detritus decomposition rate decreased, and bromeliads produced more leaves, perhaps because of the higher deposition of nitrogenous waste by mesopredators. Our results highlight that the effects of terrestrial vertebrate predators can propagate across aquatic ecosystems, altering species composition, body size structure, food web organization, and ecosystem function.
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Affiliation(s)
- Crasso Paulo Bosco Breviglieri
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, Campinas, Sao Paulo, CEP 13083-970, Brazil
| | - Gustavo Quevedo Romero
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, Campinas, Sao Paulo, CEP 13083-970, Brazil
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15
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Heckman RW, Halliday FW, Wilfahrt PA, Mitchell CE. Effects of native diversity, soil nutrients, and natural enemies on exotic invasion in experimental plant communities. Ecology 2017; 98:1409-1418. [PMID: 28273331 DOI: 10.1002/ecy.1796] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 02/08/2017] [Accepted: 02/16/2017] [Indexed: 11/05/2022]
Abstract
Many factors can promote exotic plant success. Three of these factors-greater pressure from natural enemies on natives, increased soil nutrient supply, and low native species richness-may interact during invasions. To test for independent and interactive effects of these drivers, we planted herbaceous perennial communities at two levels of native richness (monocultures and five-species polycultures). We then factorially manipulated soil nutrient supply and access to these communities by aboveground foliar enemies (fungal pathogens and insect herbivores), and allowed natural colonization to proceed for four years. We predicted that nutrient addition would increase exotic success, while enemy exclusion and increasing native richness would reduce exotic success. Additionally, we expected that enemy exclusion would reduce the benefits of nutrient addition to exotic species most in species-poor communities, and that this effect would be weaker in species-rich communities. In total, we found no evidence that nutrient supply, enemy access, and native richness interacted to influence exotic success. Furthermore, native richness had no effect on exotic success. Instead, nutrient addition increased, and enemy exclusion decreased, exotic success independently. As predicted, enemy exclusion reduced exotic success, primarily by slowing the decline in abundance of planted native species. Together, these results demonstrate that multiple drivers of exotic success can act independently within a single system.
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Affiliation(s)
- Robert W Heckman
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Fletcher W Halliday
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Peter A Wilfahrt
- Curriculum for the Environment and Ecology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
| | - Charles E Mitchell
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA.,Curriculum for the Environment and Ecology, University of North Carolina, Chapel Hill, North Carolina, 27599, USA
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16
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Breviglieri CPB, Oliveira PS, Romero GQ. Fear Mediates Trophic Cascades: Nonconsumptive Effects of Predators Drive Aquatic Ecosystem Function. Am Nat 2017; 189:490-500. [PMID: 28410025 DOI: 10.1086/691262] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Predators control prey populations and influence communities and the functioning of ecosystems through a combination of consumptive and nonconsumptive effects. These effects can be locally confined to one ecosystem but can also be extended to neighboring ecosystems. In this study, we investigated the nonconsumptive effects of terrestrial avian predators on the communities of aquatic invertebrates inhabiting bromeliads and on the functioning of these natural ecosystems. Bromeliads with stuffed birds placed nearby showed a decrease in aquatic damselfly larvae abundance and biomass, and we can infer that these changes were caused by antipredator responses. These larvae, which are top predators in bromeliad ecosystems, changed the composition of the entire aquatic invertebrate community. While total species richness, mesopredator richness, and shredder abundance increased in the presence of birds, scraper biomass decreased, possibly as a consequence of the increase in mesopredator richness. High scraper biomass in the absence of birds may have accelerated detrital decomposition, making more nutrients available for bromeliads, which grew more. These results show that nonconsumptive effects triggered by terrestrial predators can cascade down to lower trophic levels and dramatically affect the functioning of aquatic ecosystems, which can in turn alter nutrient provision to terrestrial ecosystems.
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17
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Abstract
Recent research suggests that visual perception of social categories is shaped not only by facial features but also by higher-order social cognitive processes (e.g., stereotypes, attitudes, goals). Building on neural computational models of social perception, we outline a perspective of how multiple bottom-up visual cues are flexibly integrated with a range of top-down processes to form perceptions, and we identify a set of key brain regions involved. During this integration, 'hidden' social category activations are often triggered which temporarily impact perception without manifesting in explicit perceptual judgments. Importantly, these hidden impacts and other aspects of the perceptual process predict downstream social consequences - from politicians' electoral success to several evaluative biases - independently of the outcomes of that process.
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Affiliation(s)
| | - Kerri L Johnson
- Department of Communication Studies and Psychology, University of California Los Angeles (UCLA), Los Angeles, CA 90095, USA
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18
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Avital-Cohen R, Tsal Y. Top-Down Processes Override Bottom-Up Interference in the Flanker Task. Psychol Sci 2016; 27:651-8. [PMID: 26993739 DOI: 10.1177/0956797616631737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 01/19/2016] [Indexed: 11/16/2022] Open
Abstract
Distractor interference in the flanker task is commonly viewed as an outcome of unintentional, involuntary processing, a by-product of attention-controlled processing of the target. An important implication of this notion is that the distractors are not subjected to top-down processing of their own. We tested this idea in a modified version of the flanker task, in which letter targets (S or O) were sometimes flanked by ambiguous distractors (a character that could be S or 5 or one that could be O or 0). Distractor interference was dependent on participants' expectations regarding the category of the distractors (i.e., letters or digits). For example, the O-0 distractor interfered with responding to S when it was perceived as a letter, but not when it was perceived as a digit. Hence, participants applied top-down processing to the peripheral distractors independently of the top-down processing applied to the targets. The fact that to-be-ignored peripheral distractors were processed to such a high level raises questions regarding the fundamental differences between target and distractor processing, and the quality of attentional filtering.
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Affiliation(s)
| | - Yehoshua Tsal
- School of Psychological Sciences, Tel Aviv University
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Elliott KH, Betini GS, Dworkin I, Norris DR. Experimental evidence for within- and cross-seasonal effects of fear on survival and reproduction. J Anim Ecol 2016; 85:507-15. [PMID: 26713420 DOI: 10.1111/1365-2656.12487] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022]
Abstract
Fear of predation can have non-lethal effects on individuals within a season but whether, and to what extent, these effects carry over into subsequent seasons is not known. Using a replicated seasonal population of the common fruit fly, Drosophila melanogaster, we examined both within- and cross-seasonal effects of fear on survival and reproductive output. Compared to controls, flies exposed to the scent of mantid (Tenodera sinensis) predators in the non-breeding season had 64% higher mortality, and lost 60% more mass by the end of the non-breeding season and, in the subsequent breeding season, produced 20% fewer offspring that weighed 9% less at maturity. Flies exposed to the scent of mantids in the breeding season did not produce fewer offspring, but their offspring developed faster and weighed less as adults compared to the controls. Our results demonstrate how effects of fear can be manifested both within and across seasons and emphasize the importance of understanding how events throughout the annual cycle influence individual success of animals living in seasonal environments.
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Affiliation(s)
- Kyle H Elliott
- Department of Integrative Biology, University of Guelph, Guelph, Canada, N1G 2W1.,Department of Natural Resource Sciences, McGill University, Ste Anne-de-Bellevue, Canada, H9X 3V9
| | - Gustavo S Betini
- Department of Integrative Biology, University of Guelph, Guelph, Canada, N1G 2W1
| | - Ian Dworkin
- Department of Biology, McMaster University, Hamilton, Canada, L8S 4K1
| | - D Ryan Norris
- Department of Integrative Biology, University of Guelph, Guelph, Canada, N1G 2W1
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20
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Abstract
The introduction of invasive species, which often differ functionally from the components of the recipient community, generates ecological impacts that propagate along the food web. This review aims to determine how consistent the impacts of aquatic invasions are across taxa and habitats. To that end, we present a global meta-analysis from 151 publications (733 cases), covering a wide range of invaders (primary producers, filter collectors, omnivores and predators), resident aquatic community components (macrophytes, phytoplankton, zooplankton, benthic invertebrates and fish) and habitats (rivers, lakes and estuaries). Our synthesis suggests a strong negative influence of invasive species on the abundance of aquatic communities, particularly macrophytes, zooplankton and fish. In contrast, there was no general evidence for a decrease in species diversity in invaded habitats, suggesting a time lag between rapid abundance changes and local extinctions. Invaded habitats showed increased water turbidity, nitrogen and organic matter concentration, which are related to the capacity of invaders to transform habitats and increase eutrophication. The expansion of invasive macrophytes caused the largest decrease in fish abundance, the filtering activity of filter collectors depleted planktonic communities, omnivores (including both facultative and obligate herbivores) were responsible for the greatest decline in macrophyte abundance, and benthic invertebrates were most negatively affected by the introduction of new predators. These impacts were relatively consistent across habitats and experimental approaches. Based on our results, we propose a framework of positive and negative links between invasive species at four trophic positions and the five different components of recipient communities. This framework incorporates both direct biotic interactions (predation, competition, grazing) and indirect changes to the water physicochemical conditions mediated by invaders (habitat alteration). Considering the strong trophic links that characterize aquatic ecosystems, this framework is relevant to anticipate the far-reaching consequences of biological invasions on the structure and functionality of aquatic ecosystems.
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Affiliation(s)
- Belinda Gallardo
- Doñana Biological Station (EBD-CSIC), Américo Vespucio s/n, Isla de la Cartuja, Sevilla, 41092, Spain
| | - Miguel Clavero
- Doñana Biological Station (EBD-CSIC), Américo Vespucio s/n, Isla de la Cartuja, Sevilla, 41092, Spain
| | - Marta I Sánchez
- Doñana Biological Station (EBD-CSIC), Américo Vespucio s/n, Isla de la Cartuja, Sevilla, 41092, Spain
| | - Montserrat Vilà
- Doñana Biological Station (EBD-CSIC), Américo Vespucio s/n, Isla de la Cartuja, Sevilla, 41092, Spain
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Abstract
A tidal wave of recent research purports to have discovered that higher-level states such as moods, action capabilities, and categorical knowledge can literally and directly affect how things look. Are these truly effects on perception, or might some instead reflect influences on judgment, memory, or response bias? Here, we exploited an infamous art-historical reasoning error (the so-called "El Greco fallacy") to demonstrate that multiple alleged top-down effects (including effects of morality on lightness perception and effects of action capabilities on spatial perception) cannot truly be effects on perception. We suggest that this error may also contaminate several other varieties of top-down effects and that this discovery has implications for debates over the continuity (or lack thereof) of perception and cognition.
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22
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Popko DA, Walton WE. Small-stature emergent macrophytes and crepuscular sprinkler disturbance reduce mosquito abundance in wetland mesocosms. J Vector Ecol 2013; 38:379-389. [PMID: 24581369 DOI: 10.1111/j.1948-7134.2013.12054.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 07/21/2013] [Indexed: 06/03/2023]
Abstract
The impact of emergent macrophyte species and crepuscular sprinkler disturbance on mosquito abundance over a 2-year period was measured in wetland mesocosms. Mosquito oviposition and abundance of immature mosquitoes and aquatic invertebrates were monitored in monotypic plots of small-stature (height of mature stands <1.5 m) alkali bulrush (Schoenoplectus maritimus) and large-stature (height of mature stands > 2 m) California bulrush (Schoenoplectus californicus) without or with daily sprinkler showers to deter mosquito egg laying. Relative to wetlands without operational sprinklers, oviposition by culicine mosquitoes was reduced by > 99% and immature mosquito abundance was reduced by > 90% by crepuscular sprinkler applications. Mosquito abundance or distribution in wetlands did not differ between the two bulrush species subjected to the sprinkler treatment. Alkali bulrush wetlands without daily sprinkler treatments contained more egg rafts but significantly fewer mosquito larvae than did California bulrush wetlands. Predaceous damselfly naiads were 3-5 times more abundant in alkali bulrush than in California bulrush. Stem density, rate of spread, and autumnal mortality of alkali bulrush were higher than for California bulrush. Replacement of large emergent macrophytes by smaller species may enhance the efficacy of integrated mosquito management programs to reduce mosquito-transmitted disease cycles associated with multipurpose constructed wetlands used worldwide for water reclamation and habitat restoration.
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Affiliation(s)
- David A Popko
- Department of Entomology, University of California, Riverside, CA 92521
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23
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Abstract
Linguistic labels (e.g., "chair") seem to activate visual properties of the objects to which they refer. Here we investigated whether language-based activation of visual representations can affect the ability to simply detect the presence of an object. We used continuous flash suppression to suppress visual awareness of familiar objects while they were continuously presented to one eye. Participants made simple detection decisions, indicating whether they saw any image. Hearing a verbal label before the simple detection task changed performance relative to an uninformative cue baseline. Valid labels improved performance relative to no-label baseline trials. Invalid labels decreased performance. Labels affected both sensitivity (d') and response times. In addition, we found that the effectiveness of labels varied predictably as a function of the match between the shape of the stimulus and the shape denoted by the label. Together, the findings suggest that facilitated detection of invisible objects due to language occurs at a perceptual rather than semantic locus. We hypothesize that when information associated with verbal labels matches stimulus-driven activity, language can provide a boost to perception, propelling an otherwise invisible image into awareness.
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Affiliation(s)
- Gary Lupyan
- University of Wisconsin-Madison, Madison, WI 53706, USA.
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24
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Abstract
Ecological and evolutionary mechanisms are increasingly thought to shape local community dynamics. Here, I evaluate if the local adaptation of a meso-predator to an apex predator alters local food webs. The marbled salamander (Ambystoma opacum) is an apex predator that consumes both the spotted salamander (Ambystoma maculatum) and shared zooplankton prey. Common garden experiments reveal that spotted salamander populations which co-occur with marbled salamanders forage more intensely than those that face other predator species. These foraging differences, in turn, alter the diversity, abundance and composition of zooplankton communities in common garden experiments and natural ponds. Locally adapted spotted salamanders exacerbate prey biomass declines associated with apex predation, but dampen the top-down effects of apex predation on prey diversity. Countergradient selection on foraging explains why locally adapted spotted salamanders exacerbate prey biomass declines. The two salamander species prefer different prey species, which explains why adapted spotted salamanders buffer changes in prey composition owing to apex predation. Results suggest that local adaptation can strongly mediate effects from apex predation on local food webs. Community ecologists might often need to consider the evolutionary history of populations to understand local diversity patterns, food web dynamics, resource gradients and their responses to disturbance.
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Affiliation(s)
- Mark C Urban
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Unit 3043, Storrs, CT 06269, USA.
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25
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Abstract
How does language impact cognition and perception? A growing number of studies show that language, and specifically the practice of labeling, can exert extremely rapid and pervasive effects on putatively non-verbal processes such as categorization, visual discrimination, and even simply detecting the presence of a stimulus. Progress on the empirical front, however, has not been accompanied by progress in understanding the mechanisms by which language affects these processes. One puzzle is how effects of language can be both deep, in the sense of affecting even basic visual processes, and yet vulnerable to manipulations such as verbal interference, which can sometimes nullify effects of language. In this paper, I review some of the evidence for effects of language on cognition and perception, showing that performance on tasks that have been presumed to be non-verbal is rapidly modulated by language. I argue that a clearer understanding of the relationship between language and cognition can be achieved by rejecting the distinction between verbal and non-verbal representations and by adopting a framework in which language modulates ongoing cognitive and perceptual processing in a flexible and task-dependent manner.
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Affiliation(s)
- Gary Lupyan
- Department of Psychology, University of Wisconsin–MadisonMadison, WI, USA
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26
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Romero GQ, Souza JC, Vasconcellos-Neto J. ANTI-HERBIVORE PROTECTION BY MUTUALISTIC SPIDERS AND THE ROLE OF PLANT GLANDULAR TRICHOMES. Ecology 2008; 89:3105-3115. [PMID: 31766796 DOI: 10.1890/08-0267.1] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 03/17/2008] [Indexed: 11/18/2022]
Abstract
Although specific associations between spiders and particular types of plants have been reported for several taxonomic groups, their consequences for spiders and plants are still poorly understood. The most common South American lynx spiders, Peucetia flava and P. rubrolineata, live strictly associated with various plant species that have glandular trichomes. To understand more about these spider-plant relationships, we investigated the influence of the spiders on the fitness of a neotropical glandular shrub (Trichogoniopsis adenantha) and on the arthropod community structure on the plant. We also tested whether glandular hairs provided any benefit to the spiders. Spiders reduced the abundance of several species and guilds of herbivores on the leaves and inflorescences. Consequently, damage to the leaves, capitula, ovaries, corollas, and stigmas caused by leaf-mining and chewing insects, as well as endophagous insects, were strongly reduced in the presence of Peucetia spp. Although the spiders fed on flower visitors, their negative influence on ovary fertilization was only marginally nonsignificant (P = 0.065). Spiders on plants of Trichogoniopsis adenantha that fed on common fruit flies that had died before adhering to the glandular trichomes did not lose body mass. However, those living on plants without stalked glandular trichomes (Melissa officinalis) did not feed on dead flies and lost 13-20% of their biomass. These results indicate that Peucetia spiders are effective plant bodyguards and that when there is limited live prey they may feed on insect carcasses adhered to glandular trichomes. Since several spider species of the genus Peucetia live strictly associated with glandular trichome-bearing plants in neotropical, Neartic, Paleartic, and Afrotropical regions, this type of facultative mutualism involving Peucetia and glandular plants may be common worldwide.
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Affiliation(s)
- Gustavo Q Romero
- Departamento de Zoologia e Botânica, IBILCE, Universidade Estadual Paulista (UNESP), Rua Cristóvão Colombo, 2265, CEP 15054-000, São José do Rio Preto, São Paulo, Brazil
| | - José César Souza
- Departamento de Zoologia e Botânica, IBILCE, Universidade Estadual Paulista (UNESP), Rua Cristóvão Colombo, 2265, CEP 15054-000, São José do Rio Preto, São Paulo, Brazil
| | - João Vasconcellos-Neto
- Departamento de Zoologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, CEP 13083-970, Campinas, São Paulo, Brazil
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