1
|
Mendez AH, Yu C, Smith LB. Controlling the input: How one-year-old infants sustain visual attention. Dev Sci 2024; 27:e13445. [PMID: 37665124 DOI: 10.1111/desc.13445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 08/01/2023] [Accepted: 08/18/2023] [Indexed: 09/05/2023]
Abstract
Traditionally, the exogenous control of gaze by external saliencies and the endogenous control of gaze by knowledge and context have been viewed as competing systems, with late infancy seen as a period of strengthening top-down control over the vagaries of the input. Here we found that one-year-old infants control sustained attention through head movements that increase the visibility of the attended object. Freely moving one-year-old infants (n = 45) wore head-mounted eye trackers and head motion sensors while exploring sets of toys of the same physical size. The visual size of the objects, a well-documented salience, varied naturally with the infant's moment-to-moment posture and head movements. Sustained attention to an object was characterized by the tight control of head movements that created and then stabilized a visual size advantage for the attended object for sustained attention. The findings show collaboration between exogenous and endogenous attentional systems and suggest new hypotheses about the development of sustained visual attention.
Collapse
Affiliation(s)
- Andres H Mendez
- CICEA, Universidad de la República, Montevideo, Uruguay
- Institut de Neurociencies, Universitat de Barcelona, Barcelona, Spain
| | - Chen Yu
- Department of Psychology, University of Texas, Austin, Texas, USA
| | - Linda B Smith
- Psychological and Brain Sciences, Indiana Unversity, Bloomington, Indiana, USA
| |
Collapse
|
2
|
Gilson AR, McQuaid C. Top-down versus bottom-up: Grazing and upwelling regime alter patterns of primary productivity in a warm-temperate system. Ecology 2023; 104:e4180. [PMID: 37784259 DOI: 10.1002/ecy.4180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 07/21/2023] [Accepted: 08/25/2023] [Indexed: 10/04/2023]
Abstract
Community structure is driven by the interaction of physical processes and biological interactions that can vary across environmental gradients and the strength of top-down control is expected to vary along gradients of primary productivity. In coastal marine systems, upwelling drives regional resource availability through the bottom-up effect of nutrient subsidies. This alters rates of primary production and is expected to alter algae-herbivore interactions in rocky intertidal habitats. Despite the potential for upwelling to alter these interactions, the interaction of upwelling and grazing pressure is poorly understood, particularly for warm-temperate systems. Using in situ herbivore exclusion experiments replicated across multiple upwelling regimes, we investigated the effects of both grazing pressure, upwelling, and their interactions on the sessile invertebrate community and biomass of macroalgal communities in a warm-temperate system. The sessile invertebrate cover showed indirect effects of grazing, being consistently low where algal biomass was high at upwelling sites and at nonupwelling sites when grazers were excluded. The macroalgal cover was greater at upwelling sites when grazers were excluded and there was a strong effect of succession throughout the experimental period. Grazing effects were greater at upwelling sites, particularly during winter months. There was a nonsignificant trend toward greater grazing pressure on early than later successional stages. Our results show that the positive bottom-up effects of nutrient supply on algal production do not overwhelm top-down control in this warm-temperate system but do have knock-on consequences for invertebrates that compete with macroalgae for space. We speculate that global increases in air and sea surface temperatures in warm-temperate systems will promote top-down effects in upwelling regions by increasing herbivore metabolic and growth rates.
Collapse
Affiliation(s)
- Abby R Gilson
- Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa
| | - Christopher McQuaid
- Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa
| |
Collapse
|
3
|
Dubey A, Markowitz DA, Pesaran B. Top-down control of exogenous attentional selection is mediated by beta coherence in prefrontal cortex. Neuron 2023; 111:3321-3334.e5. [PMID: 37499660 PMCID: PMC10935562 DOI: 10.1016/j.neuron.2023.06.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 11/30/2022] [Accepted: 06/26/2023] [Indexed: 07/29/2023]
Abstract
Salience-driven exogenous and goal-driven endogenous attentional selection are two distinct forms of attention that guide selection of task-irrelevant and task-relevant targets in primates. Top-down attentional control mechanisms enable selection of the task-relevant target by limiting the influence of sensory information. Although the lateral prefrontal cortex (LPFC) is known to mediate top-down control, the neuronal mechanisms of top-down control of attentional selection are poorly understood. Here, we trained two rhesus monkeys on a two-target, free-choice luminance-reward selection task. We demonstrate that visual-movement (VM) neurons and nonvisual neurons or movement neurons encode exogenous and endogenous selection. We then show that coherent beta activity selectively modulates mechanisms of exogenous selection specifically during conflict and consequently may support top-down control. These results reveal the VM-neuron-specific network mechanisms of attentional selection and suggest a functional role for beta-frequency coherent neural dynamics in the modulation of sensory communication channels for the top-down control of attentional selection.
Collapse
Affiliation(s)
- Agrita Dubey
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - David A Markowitz
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - Bijan Pesaran
- Center for Neural Science, New York University, New York, NY 10003, USA; Departments of Neurosurgery, Neuroscience, and Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
4
|
Lagasse E, Levin M. Future medicine: from molecular pathways to the collective intelligence of the body. Trends Mol Med 2023; 29:687-710. [PMID: 37481382 PMCID: PMC10527237 DOI: 10.1016/j.molmed.2023.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/24/2023]
Abstract
The remarkable anatomical homeostasis exhibited by complex living organisms suggests that they are inherently reprogrammable information-processing systems that offer numerous interfaces to their physiological and anatomical problem-solving capacities. We briefly review data suggesting that the multiscale competency of living forms affords a new path for biomedicine that exploits the innate collective intelligence of tissues and organs. The concept of tissue-level allostatic goal-directedness is already bearing fruit in clinical practice. We sketch a roadmap towards 'somatic psychiatry' by using advances in bioelectricity and behavioral neuroscience to design methods that induce self-repair of structure and function. Relaxing the assumption that cellular control mechanisms are static, exploiting powerful concepts from cybernetics, behavioral science, and developmental biology may spark definitive solutions to current biomedical challenges.
Collapse
Affiliation(s)
- Eric Lagasse
- McGowan Institute for Regenerative Medicine and Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, MA, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
| |
Collapse
|
5
|
Stenson AR, Whitney P, Hinson JM, Hansen DA, Lawrence-Sidebottom D, Skeiky L, Riedy SM, Kurinec CA, Van Dongen HPA. Effects of total sleep deprivation on components of top-down attentional control using a flexible attentional control task. J Sleep Res 2023; 32:e13744. [PMID: 36205178 DOI: 10.1111/jsr.13744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/28/2022] [Accepted: 09/19/2022] [Indexed: 11/30/2022]
Abstract
Sleep deprivation consistently decreases vigilant attention, which can lead to difficulty in performing a variety of cognitive tasks. However, sleep-deprived individuals may be able to compensate for degraded vigilant attention by means of top-down attentional control. We employed a novel task to measure the degree to which individuals overcome impairments in vigilant attention by using top-down attentional control, the Flexible Attentional Control Task (FACT). The FACT is a two-choice task that has trials with valid, invalid, and neutral cues, along with an unexpected switch in the probability of cue validity about halfway in the task. The task provides indices that isolate performance components reflecting vigilant attention and top-down attentional control. Twelve healthy young adults completed an in-laboratory study. After a baseline day, the subjects underwent 39 hours of total sleep deprivation (TSD), followed by a recovery day. The FACT was administered at 03:00, 11:00, and 19:00 during sleep deprivation (TSD condition) and at 11:00 and 19:00 after baseline sleep and at 11:00 after recovery sleep (rested condition). When rested, the subjects demonstrated both facilitation and interference effects on cued trials. While sleep deprived, the subjects showed vigilant attention deficits on neutral cue trials, and an impaired ability to reduce these deficits by using predictive contextual cues. Our results indicate that the FACT can dissociate vigilant attention from top-down attentional control. Furthermore, they show that during sleep deprivation, contextual cues help individuals to compensate partially for impairments in vigilant attention, but the effectiveness of top-down attentional control is diminished.
Collapse
Affiliation(s)
- Anthony R Stenson
- Department of Psychology, Washington State University, Pullman, Washington, USA
| | - Paul Whitney
- Department of Psychology, Washington State University, Pullman, Washington, USA.,Sleep and Performance Research Center, Washington State University, Spokane, Washington, USA
| | - John M Hinson
- Department of Psychology, Washington State University, Pullman, Washington, USA.,Sleep and Performance Research Center, Washington State University, Spokane, Washington, USA
| | - Devon A Hansen
- Sleep and Performance Research Center, Washington State University, Spokane, Washington, USA.,Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
| | | | - Lillian Skeiky
- Sleep and Performance Research Center, Washington State University, Spokane, Washington, USA.,Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
| | - Samantha M Riedy
- Sleep and Performance Research Center, Washington State University, Spokane, Washington, USA
| | - Courtney A Kurinec
- Department of Psychology, Washington State University, Pullman, Washington, USA.,Sleep and Performance Research Center, Washington State University, Spokane, Washington, USA
| | - Hans P A Van Dongen
- Sleep and Performance Research Center, Washington State University, Spokane, Washington, USA.,Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
| |
Collapse
|
6
|
Frith CD. EXPRESS: Consciousness, (meta)Cognition, and Culture. Q J Exp Psychol (Hove) 2023:17470218231164502. [PMID: 36880665 DOI: 10.1177/17470218231164502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Our conscious experience is determined by a combination of top-down processes (e.g., prior beliefs) and bottom-up processes (e.g., sensations). The balance between these two processes depends on estimates of their reliability (precision), so that the estimate considered more reliable is given more weight. We can modify these estimates at the metacognitive level, changing the relative weights of priors and sensations. This enables us, for example, to direct our attention to weak stimuli. But there is cost to this malleability. For example, excessive weighting of top-down processes, as in schizophrenia, can lead to perceiving things that are not there and believing things that are not true.It is only at the top of the brain's cognitive hierarchy that metacognitive control becomes conscious. At this level, our beliefs concern complex, abstract entities with which we have limited direct experience. Estimates of the precision of such beliefs are more uncertain and more malleable. However, at this level we don't need to rely on our own limited experience. We can rely instead on the experiences of others. Explicit metacognition plays a unique role, enabling us to share our experiences. We acquire our beliefs about the world from our immediate social group and from our wider culture. And the same sources provide us with better estimates of the precision of these beliefs. Our confidence in our high-level beliefs is heavily influenced by culture at the expense of direct experience.
Collapse
Affiliation(s)
- Chris D Frith
- Wellcome Centre for Human Neuroimaging at UCL Institute of Philosophy, School of Advanced Study, University of London4919
| |
Collapse
|
7
|
Kempel A, Allan E, Gossner MM, Jochum M, Grace JB, Wardle DA. From bottom-up to top-down control of invertebrate herbivores in a retrogressive chronosequence. Ecol Lett 2023; 26:411-424. [PMID: 36688259 DOI: 10.1111/ele.14161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 01/24/2023]
Abstract
In the long-term absence of disturbance, ecosystems often enter a decline or retrogressive phase which leads to reductions in primary productivity, plant biomass, nutrient cycling and foliar quality. However, the consequences of ecosystem retrogression for higher trophic levels such as herbivores and predators, are less clear. Using a post-fire forested island-chronosequence across which retrogression occurs, we provide evidence that nutrient availability strongly controls invertebrate herbivore biomass when predators are few, but that there is a switch from bottom-up to top-down control when predators are common. This trophic flip in herbivore control probably arises because invertebrate predators respond to alternative energy channels from the adjacent aquatic matrix, which were independent of terrestrial plant biomass. Our results suggest that effects of nutrient limitation resulting from ecosystem retrogression on trophic cascades are modified by nutrient-independent variation in predator abundance, and this calls for a more holistic approach to trophic ecology to better understand herbivore effects on plant communities.
Collapse
Affiliation(s)
- Anne Kempel
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.,WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland.,Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Davos, Switzerland.,University of Bern, Institute of Plant Sciences, Bern, Switzerland
| | - Eric Allan
- University of Bern, Institute of Plant Sciences, Bern, Switzerland
| | - Martin M Gossner
- Forest Entomology, WSL Swiss Federal Research Institute, Birmensdorf, Switzerland.,ETH Zurich, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, Zurich, Switzerland
| | - Malte Jochum
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Leipzig University, Institute of Biology, Leipzig, Germany
| | | | - David A Wardle
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.,Nanyang Technological University, Asian School of the Environment, Singapore, Singapore
| |
Collapse
|
8
|
Dubey A, Markowitz DA, Pesaran B. Top-down control of exogenous attentional selection is mediated by beta coherence in prefrontal cortex. bioRxiv 2023:2023.01.11.523664. [PMID: 36711697 PMCID: PMC9882082 DOI: 10.1101/2023.01.11.523664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Salience-driven exogenous and goal-driven endogenous attentional selection are two distinct forms of attention that guide selection of task-irrelevant and task-relevant targets in primates. During conflict i.e, when salience and goal each favor the selection of different targets, endogenous selection of the task-relevant target relies on top-down control. Top-down attentional control mechanisms enable selection of the task-relevant target by limiting the influence of sensory information. Although the lateral prefrontal cortex (LPFC) is known to mediate top-down control, the neuronal mechanisms of top-down control of attentional selection are poorly understood. Here, using a two-target free-choice luminance-reward selection task, we demonstrate that visual-movement neurons and not visual neurons or movement neurons encode exogenous and endogenous selection. We then show that coherent-beta activity selectively modulates mechanisms of exogenous selection specifically during conflict and consequently may support top-down control. These results reveal the VM-neuron-specific network mechanisms of attentional selection and suggest a functional role for beta-frequency coherent neural dynamics in the modulation of sensory communication channels for the top-down control of attentional selection.
Collapse
Affiliation(s)
- Agrita Dubey
- Center for Neural Science, New York University, New York 10003
- Department of Neurosurgery, University of Pennsylvania, Philadelphia 19104
| | | | - Bijan Pesaran
- Center for Neural Science, New York University, New York 10003
- Department of Neurosurgery, University of Pennsylvania, Philadelphia 19104
- Department of Neuroscience, University of Pennsylvania, Philadelphia 19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia 19104
| |
Collapse
|
9
|
Abstract
Nature and culture work together to shape who we are. We are embedded in culture and are profoundly influenced by what those around us say and do. The interface between minds occurs at the level of explicit metacognition, which is at the top of our brain's control hierarchy. But how do our brains do this?
Collapse
Affiliation(s)
- Chris D Frith
- Institute of Philosophy, School of Advanced Study, University of London, Senate House, Malet Street, London WC1E 7HU, UK; Wellcome Centre for Human Neuroimaging, University College London, 12 Queen Square, London WC1N 3AR, UK
| | - Uta Frith
- Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N 3AZ, UK.
| |
Collapse
|
10
|
Neidel V, Sint D, Wallinger C, Traugott M. RNA allows identifying the consumption of carrion prey. Mol Ecol Resour 2022; 22:2662-2671. [PMID: 35668675 PMCID: PMC9541938 DOI: 10.1111/1755-0998.13659] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 05/05/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022]
Abstract
Facultative scavenging by predatory carnivores is a prevalent but frequently underestimated feeding strategy. DNA‐based methods for diet analysis, however, do not allow to distinguish between scavenging and predation, thus, the significance of scavenging on population dynamics and resource partitioning is widely unknown. Here, we present a methodological innovation to differentiate between scavenging and fresh prey consumption using prey RNA as a target molecule. We hypothesized that the rapid post‐mortem breakdown of RNA in prey tissue should lead to a significantly lower detection probability of prey RNA than DNA when carrion rather than fresh prey is consumed. To test this hypothesis, ground beetles (Pseudoophonus rufipes [De Geer]) were offered either fresh or 1‐day‐old dead Drosophila melanogaster fruit flies (carrion). The detectability of prey RNA and DNA in the beetles' regurgitates was assessed with diagnostic Drosophila‐specific RT‐PCR and PCR assays at 0, 6, 12, 24 and 48 h post‐feeding. After fresh fly consumption, prey RNA and DNA were detectable equally well at all times. When carrion prey was consumed, the detection strength of prey RNA immediately after feeding was significantly lower than that of prey DNA and reached zero in most samples within 6 h of digestion. Our findings provide evidence that prey RNA allows distinguishing between the consumption of fresh and scavenged prey, thereby overcoming a long‐known weakness of molecular diet analysis. The assessment of prey RNA offers a generally applicable approach for examining the importance of scavenging in food webs to unravel its functional consequences for populations, communities, and ecosystems.
Collapse
Affiliation(s)
- Veronika Neidel
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Daniela Sint
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Corinna Wallinger
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Michael Traugott
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Innsbruck, Austria
| |
Collapse
|
11
|
Malik R, Li Y, Schamiloglu S, Sohal VS. Top-down control of hippocampal signal-to-noise by prefrontal long-range inhibition. Cell 2022; 185:1602-1617.e17. [PMID: 35487191 PMCID: PMC10027400 DOI: 10.1016/j.cell.2022.04.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 11/15/2021] [Accepted: 03/31/2022] [Indexed: 02/07/2023]
Abstract
Prefrontal cortex (PFC) is postulated to exert "top-down control" on information processing throughout the brain to promote specific behaviors. However, pathways mediating top-down control remain poorly understood. In particular, knowledge about direct prefrontal connections that might facilitate top-down control of hippocampal information processing remains sparse. Here we describe monosynaptic long-range GABAergic projections from PFC to hippocampus. These preferentially inhibit vasoactive intestinal polypeptide-expressing interneurons, which are known to disinhibit hippocampal microcircuits. Indeed, stimulating prefrontal-hippocampal GABAergic projections increases hippocampal feedforward inhibition and reduces hippocampal activity in vivo. The net effect of these actions is to specifically enhance the signal-to-noise ratio for hippocampal encoding of object locations and augment object-induced increases in spatial information. Correspondingly, activating or inhibiting these projections promotes or suppresses object exploration, respectively. Together, these results elucidate a top-down prefrontal pathway in which long-range GABAergic projections target disinhibitory microcircuits, thereby enhancing signals and network dynamics underlying exploratory behavior.
Collapse
Affiliation(s)
- Ruchi Malik
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA
| | - Yi Li
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA
| | - Selin Schamiloglu
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA
| | - Vikaas S Sohal
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA.
| |
Collapse
|
12
|
Bogdziewicz M, Kuijper D, Zwolak R, Churski M, Jędrzejewska B, Wysocka-Fijorek E, Gazda A, Miścicki S, Podgórski T. Emerging infectious disease triggered a trophic cascade and enhanced recruitment of a masting tree. Proc Biol Sci 2022; 289:20212636. [PMID: 35232238 PMCID: PMC8889186 DOI: 10.1098/rspb.2021.2636] [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] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
There are several mechanisms that allow plants to temporarily escape from top-down control. One of them is trophic cascades triggered by top predators or pathogens. Another is satiation of consumers by mast seeding. These two mechanisms have traditionally been studied in separation. However, their combined action may have a greater effect on plant release than either process alone. In 2015, an outbreak of a disease (African swine fever, ASF) caused a crash in wild boar (Sus scrofa) abundance in Białowieża Primeval Forest. Wild boar are important consumers of acorns and are difficult to satiate relative to less mobile granivores. We hypothesized that the joint action of the ASF outbreak and masting would enhance regeneration of oaks (Quercus robur). Data from ungulate exclosures demonstrated that ASF led to reduction in acorn predation. Tree seedling data indicated that oak recruitment increased twofold relative to pre-epidemic period. Our results showed that perturbations caused by wildlife disease travel through food webs and influence forest dynamics. The outbreak of ASF acted synergistically with masting and removed herbivore top-down control of oaks by mobile consumers. This illustrates that the ASF epidemic that currently occurs across Europe can have broad effects on forest dynamics.
Collapse
Affiliation(s)
- Michał Bogdziewicz
- Department of Systematic Zoology, Faculty of Biology, Adam Mickiewicz University in Poznań, Ulica Uniwersytetu Poznańskiego 6, Poznań 61-614, Poland.,INRAE, LESSEM, University Grenoble Alpes, 2 rue de la Papeterie, BP 76, Saint-Martin-d'Hères 38400, France
| | - Dries Kuijper
- Mammal Research Institute, Polish Academy of Sciences, Ul. Stoczek 1, 17-230 Białowieża, Poland
| | - Rafał Zwolak
- Department of Systematic Zoology, Faculty of Biology, Adam Mickiewicz University in Poznań, Ulica Uniwersytetu Poznańskiego 6, Poznań 61-614, Poland
| | - Marcin Churski
- Mammal Research Institute, Polish Academy of Sciences, Ul. Stoczek 1, 17-230 Białowieża, Poland
| | - Bogumiła Jędrzejewska
- Mammal Research Institute, Polish Academy of Sciences, Ul. Stoczek 1, 17-230 Białowieża, Poland
| | - Emilia Wysocka-Fijorek
- Department of Forest Resources Management, Forest Research Institute-Sękocin Stary, ul. Braci Leśnej 3, 05-090 Raszyn, Poland
| | - Anna Gazda
- Department of Forest Biodiversity, Faculty of Forestry, University of Agriculture, al. 29 Listopada 46, 31-425 Kraków, Poland
| | - Stanisław Miścicki
- Department of Forest Management Planning, Dendrometry and Forest Economics, Institute of Forests Sciences, Warsaw University of Life Sciences (SGGW), Nowoursynowska Str. 159, Warszawa 02-776, Poland
| | - Tomasz Podgórski
- Mammal Research Institute, Polish Academy of Sciences, Ul. Stoczek 1, 17-230 Białowieża, Poland.,Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Kamýcká 129, 165 00 Prague, Czech Republic
| |
Collapse
|
13
|
Otsuka S, Nakagawa S, Furukawa S. Expectations of the timing and intensity of a stimulus propagate to the auditory periphery through the medial olivocochlear reflex. Cereb Cortex 2022; 32:5121-5131. [PMID: 35094068 PMCID: PMC9667176 DOI: 10.1093/cercor/bhac002] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 12/27/2022] Open
Abstract
Expectations concerning the timing of a stimulus enhance attention at the time at which the event occurs, which confers significant sensory and behavioral benefits. Herein, we show that temporal expectations modulate even the sensory transduction in the auditory periphery via the descending pathway. We measured the medial olivocochlear reflex (MOCR), a sound-activated efferent feedback that controls outer hair cell motility and optimizes the dynamic range of the sensory system. MOCR was noninvasively assessed using otoacoustic emissions. We found that the MOCR was enhanced by a visual cue presented at a fixed interval before a sound but was unaffected if the interval was changing between trials. The MOCR was also observed to be stronger when the learned timing expectation matched with the timing of the sound but remained unvaried when these two factors did not match. This implies that the MOCR can be voluntarily controlled in a stimulus- and goal-directed manner. Moreover, we found that the MOCR was enhanced by the expectation of a strong but not a weak, sound intensity. This asymmetrical enhancement could facilitate antimasking and noise protective effects without disrupting the detection of faint signals. Therefore, the descending pathway conveys temporal and intensity expectations to modulate auditory processing.
Collapse
Affiliation(s)
- Sho Otsuka
- Address correspondence to Sho Otsuka, Center for Frontier Medical Engineering, Chiba University, 1-33 Yayoicho, Inageku, Chiba 263-8522, Japan.
| | - Seiji Nakagawa
- Center for Frontier Medical Engineering, Chiba University, Chiba, Japan
| | - Shigeto Furukawa
- NTT Communication Science Laboratoires, NTT Corporation, Kanagawa, Japan
| |
Collapse
|
14
|
Xu X, Zhang Y, Li S, Chen H, Liu M, Li B, Nie M. Native herbivores indirectly facilitate the growth of invasive Spartina in a eutrophic saltmarsh. Ecology 2021; 103:e3610. [PMID: 34923622 DOI: 10.1002/ecy.3610] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/21/2021] [Accepted: 10/07/2021] [Indexed: 11/07/2022]
Abstract
Current theory (e.g., consumer-controlled theory) predicts that nutrient enrichment typically amplifies herbivory and thereby suppresses the growth and expansion of invasive plants. Herbivores can facilitate plant regrowth in the native community by stimulating complementary growth or ameliorating habitat conditions (e.g., by increasing soil oxygen and nutrient availability), but whether they have similar positive effects on invasive plants, especially under nutrient enrichment, remains unknown. Using a field nitrogen (N)-enrichment X crab exclusion experiment, we evaluated and compared the effects of both N enrichment and crab herbivory on the growth performance of a global invasive cordgrass, Spartina alterniflora, and a co-occurring native plant, Phragmites australis. We found that crabs consistently suppressed P. australis by decreasing density and aboveground biomass regardless of N enrichment. In contrast, for S. alterniflora, the negative effects of crabs under ambient N were replaced by positive effects under N enrichment, with crabs stimulating complementary increases in density and aboveground biomass. The differing effects between the N treatments were driven by crab burrowing activity, which increased soil N availability, and the nutrient-use efficiency of S. alterniflora. Our findings reveal that native herbivores can have opposing effects on native and invasive plants, which broadens our understanding of how exotic plants can achieve dominance in a changing world. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Xiao Xu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai, China
| | - Yan Zhang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai, China
| | - Songshuo Li
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai, China
| | - Hongyang Chen
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai, China
| | - Mu Liu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai, China
| | - Bo Li
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai, China
| | - Ming Nie
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai, China
| |
Collapse
|
15
|
Curveira-Santos G, Gigliotti L, Silva AP, Sutherland C, Foord S, Santos-Reis M, Swanepoel LH. Broad aggressive interactions among African carnivores suggest intraguild killing is driven by more than competition. Ecology 2021; 103:e03600. [PMID: 34816428 DOI: 10.1002/ecy.3600] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 02/03/2021] [Revised: 07/01/2021] [Accepted: 09/16/2021] [Indexed: 11/10/2022]
Abstract
Theory on intraguild killing (IGK) is central to mammalian carnivore community ecology and top-down ecosystem regulation. Yet, the cryptic nature of IGK hinders empirical evaluations. Using a novel data source - online photographs of interspecific aggression between African carnivores - we revisited existing predictions about the extent and drivers of IGK. Compared with seminal reviews, our constructed IGK network yielded 10 more species and nearly twice as many interactions. The extent of interactions increased 37% when considering intraguild aggression (direct attack) as a precursor of killing events. We show that IGK occurs over a wider range of body-mass ratios than predicted by standing competition-based views, with highly asymmetrical interactions being pervasive. Evidence that large species, particularly hypercarnivore felids, target sympatric carnivores with a wide range of body sizes suggests that current IGK theory is incomplete, underestimating alternative competition pathways and the role of predatory and incidental killing. Our findings reinforce the potential for IGK-mediated cascades in species-rich assemblages and community-wide suppressive effects of large carnivores.
Collapse
Affiliation(s)
- Gonçalo Curveira-Santos
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Laura Gigliotti
- Department of Forestry and Environmental Conservation, Clemson University, Clemson, South Carolina, USA.,Department of Ecosystem Science, Policy, and Management, University of California Berkeley, Berkeley, California, USA
| | - André P Silva
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.,Department of Ecology and Genetics, Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Chris Sutherland
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, Massachusetts, USA.,Centre for Research into Ecological and Environmental Modelling, University of St Andrews, St Andrews, UK
| | - Stefan Foord
- Department of Zoology, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, South Africa
| | - Margarida Santos-Reis
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Lourens H Swanepoel
- Department of Zoology, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, South Africa.,African Institute for Conservation Ecology, Levubu, South Africa
| |
Collapse
|
16
|
Fecskeová LK, Piwosz K, Šantić D, Šestanović S, Tomaš AV, Hanusová M, Šolić M, Koblížek M. Lineage-Specific Growth Curves Document Large Differences in Response of Individual Groups of Marine Bacteria to the Top-Down and Bottom-Up Controls. mSystems 2021; 6:e0093421. [PMID: 34581594 DOI: 10.1128/mSystems.00934-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Marine bacterioplankton represent a diverse assembly of species differing largely in their abundance, physiology, metabolic activity, and role in microbial food webs. To analyze their sensitivity to bottom-up and top-down controls, we performed a manipulation experiment where grazers were removed, with or without the addition of phosphate. Using amplicon-reads normalization by internal standard (ARNIS), we reconstructed growth curves for almost 300 individual phylotypes. Grazer removal caused a rapid growth of most bacterial groups, which grew at rates of 0.6 to 3.5 day−1, with the highest rates (>4 day−1) recorded among Rhodobacteraceae, Oceanospirillales, Alteromonadaceae, and Arcobacteraceae. Based on their growth response, the phylotypes were divided into three basic groups. Most of the phylotypes responded positively to both grazer removal as well as phosphate addition. The second group (containing, e.g., Rhodobacterales and Rhizobiales) responded to the grazer removal but not to the phosphate addition. Finally, some clades, such as SAR11 and Flavobacteriaceae, responded only to phosphate amendment but not to grazer removal. Our results show large differences in bacterial responses to experimental manipulations at the phylotype level and document different life strategies of marine bacterioplankton. In addition, growth curves of 130 phylogroups of aerobic anoxygenic phototrophs were reconstructed based on changes of the functional pufM gene. The use of functional genes together with rRNA genes may significantly expand the scientific potential of the ARNIS technique. IMPORTANCE Growth is one of the main manifestations of life. It is assumed generally that bacterial growth is constrained mostly by nutrient availability (bottom-up control) and grazing (top-down control). Since marine bacteria represent a very diverse assembly of species with different metabolic properties, their growth characteristics also largely differ accordingly. Currently, the growth of marine microorganisms is typically evaluated using microscopy in combination with fluorescence in situ hybridization (FISH). However, these laborious techniques are limited in their throughput and taxonomical resolution. Therefore, we combined a classical manipulation experiment with next-generation sequencing to resolve the growth dynamics of almost 300 bacterial phylogroups in the coastal Adriatic Sea. The analysis documented that most of the phylogroups responded positively to both grazer removal and phosphate addition. We observed significant differences in growth kinetics among closely related species, which could not be distinguished by the classical FISH technique.
Collapse
|
17
|
Rakowski CJ, Farrior CE, Manning SR, Leibold MA. Predator complementarity dampens variability of phytoplankton biomass in a diversity-stability trophic cascade. Ecology 2021; 102:e03534. [PMID: 34496044 DOI: 10.1002/ecy.3534] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 06/15/2021] [Accepted: 07/08/2021] [Indexed: 11/11/2022]
Abstract
Trophic cascades - indirect effects of predators that propagate down through food webs - have been extensively documented in many ecosystem types. It has also been shown that predator diversity can mediate these trophic cascades and, separately, that herbivore biomass can influence the stability of primary producers. However, whether predator diversity can cause cascading effects on the stability of lower trophic levels has not yet been studied. We conducted a laboratory microcosm experiment and a field mesocosm experiment manipulating the presence and coexistence of two heteropteran predators and measuring their effects on zooplankton herbivores and phytoplankton basal resources. We predicted that if the predators partitioned their zooplankton prey, for example by size, then the co-presence of the predators would reduce zooplankton prey mass and lead to (1) increased biomass of, and (2) decreased temporal variability of phytoplankton basal resources. We present evidence that the predators partitioned their zooplankton prey, leading to a synergistic suppression of zooplankton. In turn, this enhanced zooplankton suppression led to only a weak, non-significant increase in the central tendency of phytoplankton biomass, but significantly reduced its variability. Our results demonstrate that predator diversity may indirectly stabilize basal resource biomass via a "diversity-stability trophic cascade," seemingly dependent on predator complementarity, even when there is no significant classic trophic cascade altering the central tendency of biomass. Therefore predator diversity, especially if correlated with diversity of prey use, could play a role in regulating ecosystem stability. This link between predator diversity and producer stability has implications for conservation and for potential biological control methods to improve crop yield reliability.
Collapse
Affiliation(s)
- Chase J Rakowski
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, 78712, USA
| | - Caroline E Farrior
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, 78712, USA
| | - Schonna R Manning
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, 78712, USA
| | - Mathew A Leibold
- Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| |
Collapse
|
18
|
Landolfi A, Prowe AEF, Pahlow M, Somes CJ, Chien CT, Schartau M, Koeve W, Oschlies A. Can Top-Down Controls Expand the Ecological Niche of Marine N 2 Fixers? Front Microbiol 2021; 12:690200. [PMID: 34489886 PMCID: PMC8416505 DOI: 10.3389/fmicb.2021.690200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 04/02/2021] [Accepted: 07/05/2021] [Indexed: 01/12/2023] Open
Abstract
The ability of marine diazotrophs to fix dinitrogen gas (N2) is one of the most influential yet enigmatic processes in the ocean. With their activity diazotrophs support biological production by fixing about 100–200 Tg N/year and turning otherwise unavailable dinitrogen into bioavailable nitrogen (N), an essential limiting nutrient. Despite their important role, the factors that control the distribution of diazotrophs and their ability to fix N2 are not fully elucidated. We discuss insights that can be gained from the emerging picture of a wide geographical distribution of marine diazotrophs and provide a critical assessment of environmental (bottom-up) versus trophic (top-down) controls. We expand a simplified theoretical framework to understand how top-down control affects competition for resources that determine ecological niches. Selective mortality, mediated by grazing or viral-lysis, on non-fixing phytoplankton is identified as a critical process that can broaden the ability of diazotrophs to compete for resources in top-down controlled systems and explain an expanded ecological niche for diazotrophs. Our simplified analysis predicts a larger importance of top-down control on competition patterns as resource levels increase. As grazing controls the faster growing phytoplankton, coexistence of the slower growing diazotrophs can be established. However, these predictions require corroboration by experimental and field data, together with the identification of specific traits of organisms and associated trade-offs related to selective top-down control. Elucidation of these factors could greatly improve our predictive capability for patterns and rates of marine N2 fixation. The susceptibility of this key biogeochemical process to future changes may not only be determined by changes in environmental conditions but also via changes in the ecological interactions.
Collapse
Affiliation(s)
- Angela Landolfi
- Institute of Marine Sciences, National Research Council, Rome, Italy.,Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - A E Friederike Prowe
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Markus Pahlow
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Christopher J Somes
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Chia-Te Chien
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Markus Schartau
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Wolfgang Koeve
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Andreas Oschlies
- Marine Biogeochemistry, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| |
Collapse
|
19
|
Perez‐Alvarez R, Grab H, Polyakov A, Poveda K. Landscape composition mediates the relationship between predator body size and pest control. Ecol Appl 2021; 31:e02365. [PMID: 33938606 PMCID: PMC8459275 DOI: 10.1002/eap.2365] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/04/2021] [Indexed: 06/12/2023]
Abstract
Understanding the mechanisms contributing to positive relationships between predator diversity and natural pest control is fundamental to inform more effective management practices to support sustainable crop production. Predator body size can provide important insights to better understand and predict such predator-pest interactions. Yet, most studies exploring the link between predator body size and pest control have been conducted in species-poor communities under controlled environmental conditions, limiting our ability to generalize this relationship across heterogeneous landscapes. Using the community of naturally occurring ground beetles in cabbage fields, we examined how landscape composition (percent cropland) influences the size structure (mean, variance, and skewness of body size distribution) of predator communities and the subsequent effects on pest control. We found that predator communities shifted their size distribution toward larger body sizes in agriculturally dominated landscapes. This pattern arose from increasing numerical dominance of a few large-bodied species rather than an aggregated response across the community. Such landscape-driven changes in community size structure led to concomitant impacts on pest control, as the mean body size of predators was positively related to predation rates. Notably, the magnitude of pest control depended not only on the size of the dominant predators but was also strongly determined by the relative proportion of small vs. large-bodied species (i.e., skewness). Predation rates were higher in predator assemblages with even representation of small and large-bodied species relative to communities dominated by either large or small-bodied predators. Landscape composition may therefore modulate the relationship between predator body size and pest control by influencing the body size distribution of co-occurring species. Our study highlights the need to consider agricultural practices that not only boost effective predators, but also sustain a predator assemblage with a diverse set of traits to maximize overall pest control.
Collapse
Affiliation(s)
- Ricardo Perez‐Alvarez
- Department of EntomologyCornell UniversityIthacaNew York14853USA
- Zoological BiodiversityInstitute of GeobotanyLeibniz University of HannoverHannover30167Germany
| | - Heather Grab
- Department of EntomologyCornell UniversityIthacaNew York14853USA
- School of Integrative Plant ScienceCornell UniversityIthacaNew York14853USA
| | - Anthony Polyakov
- Department of EntomologyCornell UniversityIthacaNew York14853USA
| | - Katja Poveda
- Department of EntomologyCornell UniversityIthacaNew York14853USA
| |
Collapse
|
20
|
Abstract
The role of cascades in natural communities has been extensively studied, but interactions between trophic and facilitation cascades are unexplored. In the White Sea (65°N) shallow subtidal, bivalve primary facilitators provide hard substrate for secondary facilitator barnacles, that, in turn, provide substrate for conspecifics, ascidians, red algae and multiple associated organisms, composing a multi-level facilitation cascade. Previous research revealed that predation by the whelk Boreotrophon clathratus accounts for ~7% of adult barnacle mortality. Low whelk abundance limits their effect, with barnacles living on conspecifics several times more vulnerable to predation than those living on primary substrate. Trophic cascades can selectively shield foundation species from consumers, and hence may affect the structure and length of facilitation cascades. We tested the hypothesis that low abundance of the whelks results from mesopredator predation on their juveniles. Depending on the magnitude of the effect, this would mean that a trophic cascade controls the abundance of barnacles on all substrates or only barnacles living on conspecifics. We also suggested that barnacles on primary substrates and conspecifics facilitate different dependent assemblages. We manipulated the presence of crab and shrimp mesopredators in field caging experiments to assess their effect on whelk recruitment. In a field survey, we compared the assemblages of sessile macrobenthic organisms associated with barnacles living on different substrates. Caging experiments evidenced that crab and shrimp mesopredators reduce whelk recruitment by 4.6 times. Field data showed that barnacles on primary substrate and on conspecifics promote different dependent assemblages including secondary facilitator ascidians. Although mesopredators do not shield barnacles from elimination, their absence would restrict them from living on conspecifics. Barnacles on conspecifics are functionally different from barnacles on primary substrate, and can be considered a separate level of the facilitation cascade. Trophic cascades thus can generate community-wide effects on facilitation cascades by affecting their structure and possibly length.
Collapse
Affiliation(s)
- Eugeniy Yakovis
- Invertebrate Zoology Department, St.-Petersburg State University, Petersburg, Russia
| | - Anna Artemieva
- Invertebrate Zoology Department, St.-Petersburg State University, Petersburg, Russia
| |
Collapse
|
21
|
Hungate BA, Marks JC, Power ME, Schwartz E, van Groenigen KJ, Blazewicz SJ, Chuckran P, Dijkstra P, Finley BK, Firestone MK, Foley M, Greenlon A, Hayer M, Hofmockel KS, Koch BJ, Mack MC, Mau RL, Miller SN, Morrissey EM, Propster JR, Purcell AM, Sieradzki E, Starr EP, Stone BWG, Terrer C, Pett-Ridge J. The Functional Significance of Bacterial Predators. mBio 2021; 12:e00466-21. [PMID: 33906922 PMCID: PMC8092244 DOI: 10.1128/mbio.00466-21] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
Abstract
Predation structures food webs, influences energy flow, and alters rates and pathways of nutrient cycling through ecosystems, effects that are well documented for macroscopic predators. In the microbial world, predatory bacteria are common, yet little is known about their rates of growth and roles in energy flows through microbial food webs, in part because these are difficult to quantify. Here, we show that growth and carbon uptake were higher in predatory bacteria compared to nonpredatory bacteria, a finding across 15 sites, synthesizing 82 experiments and over 100,000 taxon-specific measurements of element flow into newly synthesized bacterial DNA. Obligate predatory bacteria grew 36% faster and assimilated carbon at rates 211% higher than nonpredatory bacteria. These differences were less pronounced for facultative predators (6% higher growth rates, 17% higher carbon assimilation rates), though high growth and carbon assimilation rates were observed for some facultative predators, such as members of the genera Lysobacter and Cytophaga, both capable of gliding motility and wolf-pack hunting behavior. Added carbon substrates disproportionately stimulated growth of obligate predators, with responses 63% higher than those of nonpredators for the Bdellovibrionales and 81% higher for the Vampirovibrionales, whereas responses of facultative predators to substrate addition were no different from those of nonpredators. This finding supports the ecological theory that higher productivity increases predator control of lower trophic levels. These findings also indicate that the functional significance of bacterial predators increases with energy flow and that predatory bacteria influence element flow through microbial food webs.IMPORTANCE The word "predator" may conjure images of leopards killing and eating impala on the African savannah or of great white sharks attacking elephant seals off the coast of California. But microorganisms are also predators, including bacteria that kill and eat other bacteria. While predatory bacteria have been found in many environments, it has been challenging to document their importance in nature. This study quantified the growth of predatory and nonpredatory bacteria in soils (and one stream) by tracking isotopically labeled substrates into newly synthesized DNA. Predatory bacteria were more active than nonpredators, and obligate predators, such as Bdellovibrionales and Vampirovibrionales, increased in growth rate in response to added substrates at the base of the food chain, strong evidence of trophic control. This work provides quantitative measures of predator activity and suggests that predatory bacteria-along with protists, nematodes, and phages-are active and important in microbial food webs.
Collapse
Affiliation(s)
- Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Jane C Marks
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Mary E Power
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Kees Jan van Groenigen
- Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Steven J Blazewicz
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Peter Chuckran
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Brianna K Finley
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Mary K Firestone
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA
| | - Megan Foley
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Alex Greenlon
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | - Kirsten S Hofmockel
- Pacific Northwest National Laboratory, Richland, Washington, USA
- Department of Agronomy, Iowa State University, Ames, Iowa, USA
| | - Benjamin J Koch
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Michelle C Mack
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Rebecca L Mau
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Samantha N Miller
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | - Ember M Morrissey
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Jeffrey R Propster
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Alicia M Purcell
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Ella Sieradzki
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA
| | - Evan P Starr
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Bram W G Stone
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona, USA
| | - César Terrer
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, USA
| |
Collapse
|
22
|
Abstract
Climate warming and biological invasions are key drivers of biodiversity change. Their combined effects on ecological communities remain largely unexplored. We investigated the direct and indirect influences of temperature on invasion success, and their synergistic effects on community structure and dynamics. Using size-structured food web models, we found that higher temperatures increased invasion success. The direct physiological effects of temperature on invasions were minimal in comparison with indirect effects mediated by changes on food web structure and stability. Warmer communities with less connectivity, shortened food chains and reduced temporal variability were more susceptible to invasions. The directionality and magnitude of invasions effects on food webs varied across temperature regimes. When invaded, warmer communities became smaller, more connected and with more predator species than their colder counterparts. They were also less stable and their species more abundant. Considering food web structure is crucial to predict invasion success and its impacts along temperature gradients.
Collapse
Affiliation(s)
- Arnaud Sentis
- Centre for Biodiversity Theory and Modelling, Theoretical and Experimental Ecology Station, CNRS, 2 route du CNRS, 09200 Moulis, France,INRAE, Aix-Marseille University, UMR RECOVER, 3275 route Cézanne, 13182 Aix-en-Provence, France
| | - Jose M. Montoya
- Centre for Biodiversity Theory and Modelling, Theoretical and Experimental Ecology Station, CNRS, 2 route du CNRS, 09200 Moulis, France
| | - Miguel Lurgi
- Centre for Biodiversity Theory and Modelling, Theoretical and Experimental Ecology Station, CNRS, 2 route du CNRS, 09200 Moulis, France,Department of Biosciences, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| |
Collapse
|
23
|
Husain L, Berggren N, Remington A, Forster S. Intact Goal-Driven Attentional Capture in Autistic Adults. J Cogn 2021; 4:23. [PMID: 33817551 PMCID: PMC7996432 DOI: 10.5334/joc.156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/08/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Autistic individuals have been found to show increased distractibility by salient irrelevant information, yet reduced distractibility by information of personal motivational salience. Here we tested whether these prior discrepancies reflect differences in the automatic guidance of attention by top-down goals. METHODS Autistic (self-reported diagnoses, confirmed with scores on the Social Responsiveness Scale) and non-autistic adults, without intellectual disability (IQ > 80 on Wechsler Abbreviated Scale of Intelligence), searched for a color-defined target object (e.g., red) among irrelevant color objects. Spatially uninformative cues, matching either the target color or a nontarget/irrelevant color, were presented prior to each display. RESULTS Replicating previous work, only target color cues reliably captured attention, delaying responses when invalidly versus validly predicting target location. Crucially, this capture was robust for both autistic and neurotypical participants, as confirmed by Bayesian analysis. Limitations: While well powered for our research questions, our sample size precluded investigation of the automatic guidance of attention in a diverse group of autistic people (e.g. those with a range of cognitive abilities). CONCLUSIONS Our findings imply that key mechanisms underlying the automatic implementation of top-down attentional goals are intact in autism, challenging theories of reduced top-down control.
Collapse
Affiliation(s)
- Layal Husain
- Centre for Research in Autism and Education, Department of Psychology and Human Development, UCL Institute of Education, University College London, UK
| | - Nick Berggren
- Department of Psychological Sciences, Birkbeck College, University of London, UK
| | - Anna Remington
- Centre for Research in Autism and Education, Department of Psychology and Human Development, UCL Institute of Education, University College London, UK
| | | |
Collapse
|
24
|
Pastor V, Medina JH. Medial prefrontal cortical control of reward- and aversion-based behavioral output: Bottom-up modulation. Eur J Neurosci 2021; 53:3039-3062. [PMID: 33660363 DOI: 10.1111/ejn.15168] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/15/2021] [Accepted: 02/24/2021] [Indexed: 12/22/2022]
Abstract
How does the brain guide our actions? This is a complex issue, where the medial prefrontal cortex (mPFC) plays a crucial role. The mPFC is essential for cognitive flexibility and decision making. These functions are related to reward- and aversion-based learning, which ultimately drive behavior. Though, cortical projections and modulatory systems that may regulate those processes in the mPFC are less understood. How does the mPFC regulate approach-avoidance behavior in the case of conflicting aversive and appetitive stimuli? This is likely dependent on the bottom-up neuromodulation of the mPFC projection neurons. In this review, we integrate behavioral-, pharmacological-, and viral-based circuit manipulation data showing the involvement of mPFC dopaminergic, noradrenergic, cholinergic, and serotoninergic inputs in reward and aversion processing. Given that an incorrect balance of reward and aversion value could be a key problem in mental diseases such as substance use disorders, we discuss outstanding questions for future research on the role of mPFC modulation in reward and aversion.
Collapse
Affiliation(s)
- Verónica Pastor
- CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis" (IBCN), Buenos Aires, Argentina.,Universidad de Buenos Aires, Facultad de Medicina, Departamento de Ciencias Fisiológicas, Buenos Aires, Argentina
| | - Jorge Horacio Medina
- CONICET-Universidad de Buenos Aires, Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis" (IBCN), Buenos Aires, Argentina.,Instituto Tecnológico de Buenos Aires (ITBA), Buenos Aires, Argentina
| |
Collapse
|
25
|
Wollrab S, Izmest'yeva Любовь Р Изместьева L, Hampton SE, Silow Евгений А Зилов EA, Litchman E, Klausmeier CA. Climate Change-Driven Regime Shifts in a Planktonic Food Web. Am Nat 2021; 197:281-295. [PMID: 33625965 DOI: 10.1086/712813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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
AbstractPredicting how food webs will respond to global environmental change is difficult because of the complex interplay between the abiotic forcing and biotic interactions. Mechanistic models of species interactions in seasonal environments can help understand the effects of global change in different ecosystems. Seasonally ice-covered lakes are warming faster than many other ecosystems and undergoing pronounced food web changes, making the need to forecast those changes especially urgent. Using a seasonally forced food web model with a generalist zooplankton grazer and competing cold-adapted winter and warm-adapted summer phytoplankton, we show that with declining ice cover, the food web moves through different dynamic regimes, from annual to biennial cycles, with decreasing and then disappearing winter phytoplankton blooms and a shift of maximum biomass to summer season. Interestingly, when predator-prey interactions were not included, a declining ice cover did not cause regime shifts, suggesting that both are needed for regime transitions. A cluster analysis of long-term data from Lake Baikal, Siberia, supports the model results, revealing a change from regularly occurring winter blooms of endemic diatoms to less frequent winter bloom years with decreasing ice cover. Together, the results show that even gradual environmental change, such as declining ice cover duration, may cause discontinuous or abrupt transitions between dynamic regimes in food webs.
Collapse
|
26
|
Totah NK, Logothetis NK, Eschenko O. Synchronous spiking associated with prefrontal high γ oscillations evokes a 5-Hz rhythmic modulation of spiking in locus coeruleus. J Neurophysiol 2021; 125:1191-1201. [PMID: 33566743 DOI: 10.1152/jn.00677.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The brainstem noradrenergic locus coeruleus (LC) is reciprocally connected with the prefrontal cortex (PFC). Coupling between LC spiking and the depolarizing phase of slow (1-2 Hz) waves in PFC field potentials during sleep and anesthesia suggests that LC drives cortical state transition. Reciprocal LC-PFC connectivity should also allow interactions in the opposing (top-down) direction, but prior work has only studied prefrontal control over LC activity using electrical or optogenetic stimulation. Here, we describe the physiological characteristics of spontaneously occurring top-down LC-PFC interactions. We recorded LC multiunit activity (MUA) simultaneously with PFC single-unit and local field potential (LFP) activity in urethane-anesthetized rats. We observed cross-regional coupling between the phase of 5-Hz oscillations in LC-MUA and the power of PFC LFP 60-200 Hz high γ (hγ). Transient increases in PFC hγ power preceded peaks in the 5-Hz LC-MUA oscillation. Analysis of cross-regional transfer entropy demonstrated that the PFC hγ transients were predictive of a transient increase in LC-MUA. An ∼29 ms delay between these signals was consistent with the conduction velocity from the PFC to the LC. Finally, we showed that PFC hγ transients are associated with synchronized spiking of a subset (27%) of PFC single units. Our data suggest that PFC hγ transients may indicate the timing of the top-down excitatory input to LC, at least under conditions when LC neuronal population activity fluctuates rhythmically at 5 Hz. Synchronized PFC neuronal spiking that occurs during hγ transients may provide a previously unknown mode of top-down control over the LC.NEW & NOTEWORTHY The prefrontal cortex (PFC) is thought to control activity in the noradrenergic locus coeruleus (LC). Prior anatomical and prefrontal stimulation studies demonstrated the potential for PFC-LC interactions; however, it is unknown what types of PFC activity affect the LC. Here, we show that transient increases in PFC high γ power and associated changes in PFC unit-pair synchrony are a potential sign of top-down control over the LC.
Collapse
Affiliation(s)
- Nelson K Totah
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Nikos K Logothetis
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester, United Kingdom
| | - Oxana Eschenko
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| |
Collapse
|
27
|
Bertoni S, Franceschini S, Puccio G, Mancarella M, Gori S, Facoetti A. Action Video Games Enhance Attentional Control and Phonological Decoding in Children with Developmental Dyslexia. Brain Sci 2021; 11:171. [PMID: 33572998 PMCID: PMC7911052 DOI: 10.3390/brainsci11020171] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [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: 11/20/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 01/06/2023] Open
Abstract
Reading acquisition is extremely difficult for about 5% of children because they are affected by a heritable neurobiological disorder called developmental dyslexia (DD). Intervention studies can be used to investigate the causal role of neurocognitive deficits in DD. Recently, it has been proposed that action video games (AVGs)-enhancing attentional control-could improve perception and working memory as well as reading skills. In a partial crossover intervention study, we investigated the effect of AVG and non-AVG training on attentional control using a conjunction visual search task in children with DD. We also measured the non-alphanumeric rapid automatized naming (RAN), phonological decoding and word reading before and after AVG and non-AVG training. After both video game training sessions no effect was found in non-alphanumeric RAN and in word reading performance. However, after only 12 h of AVG training the attentional control was improved (i.e., the set-size slopes were flatter in visual search) and phonological decoding speed was accelerated. Crucially, attentional control and phonological decoding speed were increased only in DD children whose video game score was highly efficient after the AVG training. We demonstrated that only an efficient AVG training induces a plasticity of the fronto-parietal attentional control linked to a selective phonological decoding improvement in children with DD.
Collapse
Affiliation(s)
- Sara Bertoni
- Department of Human and Social Sciences, University of Bergamo, 24129 Bergamo, Italy;
- Department of General Psychology, University of Padova, 35122 Padova, Italy; (S.F.); (G.P.); (M.M.); (A.F.)
| | - Sandro Franceschini
- Department of General Psychology, University of Padova, 35122 Padova, Italy; (S.F.); (G.P.); (M.M.); (A.F.)
| | - Giovanna Puccio
- Department of General Psychology, University of Padova, 35122 Padova, Italy; (S.F.); (G.P.); (M.M.); (A.F.)
| | - Martina Mancarella
- Department of General Psychology, University of Padova, 35122 Padova, Italy; (S.F.); (G.P.); (M.M.); (A.F.)
- Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Simone Gori
- Department of Human and Social Sciences, University of Bergamo, 24129 Bergamo, Italy;
| | - Andrea Facoetti
- Department of General Psychology, University of Padova, 35122 Padova, Italy; (S.F.); (G.P.); (M.M.); (A.F.)
| |
Collapse
|
28
|
Frank SM, Bründl S, Frank UI, Sasaki Y, Greenlee MW, Watanabe T. Fundamental Differences in Visual Perceptual Learning between Children and Adults. Curr Biol 2021; 31:427-432.e5. [PMID: 33212018 DOI: 10.1016/j.cub.2020.10.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 09/21/2020] [Accepted: 10/15/2020] [Indexed: 11/23/2022]
Abstract
It has remained uncertain whether the mechanisms of visual perceptual learning (VPL)1-4 remain stable across the lifespan or undergo developmental changes. This uncertainty largely originates from missing results about the mechanisms of VPL in healthy children. We here investigated the mechanisms of task-irrelevant VPL in healthy elementary school age children (7-10 years old) and compared their results to healthy young adults (18-31 years old). Subjects performed a rapid-serial-visual-presentation (RSVP) task at central fixation over the course of several daily sessions while coherent motion was merely exposed as a task-irrelevant feature in the visual periphery either at threshold or suprathreshold levels for coherent motion detection. As a result of this repeated exposure, children and adults both showed enhanced discrimination performance for the threshold task-irrelevant feature as in previous studies with adults.5-8 However, adults demonstrated a decreased performance for the suprathreshold task-irrelevant feature whereas children increased performance. One possible explanation for this difference is that children cannot effectively suppress salient task-irrelevant features because of weaker selective attention ability compared to that of adults.9-11 However, our results revealed to the contrary that children with stronger selective attention ability, as measured by the useful field of view (UFOV) test, showed greater increases in performance for the suprathreshold task-irrelevant feature. Together, these results suggest that the mechanisms of VPL change dramatically from childhood to adulthood due to a change in the way learners handle salient task-irrelevant features.
Collapse
|
29
|
Chaguaceda F, Scharnweber K, Dalman E, Tranvik LJ, Eklöv P. Short-term apparent mutualism drives responses of aquatic prey to increasing productivity. J Anim Ecol 2020; 90:834-845. [PMID: 33340096 PMCID: PMC8048462 DOI: 10.1111/1365-2656.13413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 02/26/2020] [Accepted: 11/16/2020] [Indexed: 11/29/2022]
Abstract
According to apparent competition theory, sharing a predator should cause indirect interactions among prey that can affect the structure and the dynamics of natural communities. Though shifts in prey dominance and predator resource use along environmental gradients are rather common, empirical evidence on the role of indirect prey-prey interactions through shared predation particularly with increasing productivity, is still scarce. In an 8-week lake mesocosm experiment, we manipulated both the addition of inorganic nutrients and the presence of generalist fish predators (crucian carp, Carassius carassius L.), to test for the effects of indirect interactions through shared predation along a productivity gradient. We found that apparent mutualism (indirect positive interaction) between benthic and pelagic prey strongly affected short-term responses of aquatic food webs to increasing productivity in the presence of a generalist fish. Increasing productivity favoured the relative abundance of benthic prey, following trends in natural productive lake systems. This led to a shift in fish selectivity from pelagic to benthic prey driven by changes in fish behaviour, which resulted in apparent mutualism due to the lower and delayed top-down control of pelagic prey at increasing productivity. Our results show empirical evidence that the coupling of multiple production pathways can lead to strong indirect interactions through shared predation, whereby prey dynamics on short time-scales are highly dependent on the foraging behaviour of generalist predators. This mechanism may play an important role in short-term responses of food webs across environmental gradients.
Collapse
Affiliation(s)
- Fernando Chaguaceda
- Department of Ecology and Genetics; Limnology, Uppsala University, Uppsala, Sweden
| | - Kristin Scharnweber
- Department of Ecology and Genetics; Limnology, Uppsala University, Uppsala, Sweden
| | - Erik Dalman
- Department of Ecology and Genetics; Limnology, Uppsala University, Uppsala, Sweden
| | - Lars J Tranvik
- Department of Ecology and Genetics; Limnology, Uppsala University, Uppsala, Sweden
| | - Peter Eklöv
- Department of Ecology and Genetics; Limnology, Uppsala University, Uppsala, Sweden
| |
Collapse
|
30
|
Zheng Q, Lin W, Wang Y, Xu D, Liu Y, Jiao N. Top-down controls on nutrient cycling and population dynamics in a model estuarine photoautotroph-heterotroph co-culture system. Mol Ecol 2020; 30:592-607. [PMID: 33226689 DOI: 10.1111/mec.15750] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/05/2020] [Accepted: 11/19/2020] [Indexed: 11/29/2022]
Abstract
Viral lysis and protistan grazing are thought to be the major processes leading to microbial mortality in aquatic environments and thus regulate community diversity and biogeochemical cycling characteristics. Here, we studied nutrient cycling and bacterial responses to cyanophage-mediated photoautotroph lysis and ciliate predation in a model Synechococcus-heterotroph co-culture system. Both viral lysis and Euplotes grazing facilitated the transformation of organic carbon from biomass to dissolved organic matter with convention efficiencies of 20%-26%. The accumulation of ammonium after the addition of phages and ciliates suggested the importance of recycled NH4 + occurred in the interactions between Synechococcus growth and heterotrophic bacterial metabolism of photosynthate. The slower efficiency of P mineralization compared to N (primarily ammonium) indicated that P-containing organic matter was primarily integrated into bacterial biomass rather than being remineralized into inorganic phosphate under C-rich conditions. In the cyanophage addition treatment, both Fluviicola and Alteromonas exhibited rapid positive responses to Synechococcus lysing, while Marivita exhibited an apparent negative response. Further, the addition of Euplotes altered the incubation system from a Synechococcus-driven phycosphere to a ciliate-remodelled zoosphere that primarily constituted grazing-resistant bacteria and Euplotes symbionts. Top-down controls increased co-culture system diversity and resulted in a preference for free-living lifestyles of dominant populations, which was accompanied by the transfer of matter and energy. Our results indicate top-down control was particularly important for organic matter redistribution and inorganic nutrient regeneration between photoautotrophs and heterotrophs, and altered bacterial lifestyles. This study consequently sheds light on marine biogeochemical cycling and the interaction networks within these dynamic ecosystems.
Collapse
Affiliation(s)
- Qiang Zheng
- State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen, People's Republic of China.,Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, People's Republic of China
| | - Wenxin Lin
- State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen, People's Republic of China.,Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, People's Republic of China
| | - Yu Wang
- State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen, People's Republic of China.,Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, People's Republic of China
| | - Dapeng Xu
- State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen, People's Republic of China.,Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, People's Republic of China
| | - Yanting Liu
- State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen, People's Republic of China.,Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, People's Republic of China
| | - Nianzhi Jiao
- State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiamen, People's Republic of China.,Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, People's Republic of China
| |
Collapse
|
31
|
Chollet S, Maillard M, Schörghuber J, Grayston SJ, Martin JL. Deer slow down litter decomposition by reducing litter quality in a temperate forest. Ecology 2020; 102:e03235. [PMID: 33098575 DOI: 10.1002/ecy.3235] [Citation(s) in RCA: 4] [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: 10/24/2019] [Revised: 06/22/2020] [Accepted: 08/24/2020] [Indexed: 11/05/2022]
Abstract
Litter decomposition is a key process that allows the recycling of nutrients within ecosystems. In temperate forests, the role of large herbivores in litter decomposition remains a subject of debate. To address this question, we used two litterbag experiments in a quasiexperimental situation resulting from the introduction of Sitka black-tailed deer Odocoileus hemionus sitkensis on forested islands of Haida Gwaii (Canada). We investigated the two main pathways by which deer could modify litter decomposition: change in litter quality and modification of decomposer communities. We found that deer presence significantly reduced litter mass loss after 1 yr, mainly through a reduction in litter quality. This mass loss reflected a 30 and 28% lower loss of carbon (C) and nitrogen (N), respectively. The presence of deer also reduced the ability of decomposers to break down carbon, but not nitrogen. Indeed, litter placed on an island with deer lost 5% less carbon after 1 yr of decomposition than did litter decomposing on an island without deer. This loss in ability to decompose litter in the presence of deer was outweighed by the differences in mass loss associated with the effect of deer on litter quality. Additional effects of feces deposition by deer on the decomposition process were also significant but minor. These results suggest that the effects dramatic continental-scale increases in deer populations may have on broad-scale patterns of C and N cycling deserve closer attention.
Collapse
Affiliation(s)
- Simon Chollet
- Univ Rennes, Université de Rennes 1, CNRS, ECOBIO [(Ecosystems-Biodiversity-Evolution)] - UMR 6553, Campus de Beaulieu, 263 avenue du Général Leclerc, F-35042, Rennes, France
| | - Morgane Maillard
- Centre d'Écologie Fonctionnelle et Évolutive, UMR 5175, CNRS-Université de Montpellier-Université Paul Valéry-EPHE-IRD, 1919 route de Mende, F-34293, Montpellier, France.,Department of Forest and Conservation Sciences Vancouver, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Juliane Schörghuber
- Research Group on Introduced Species, British Columbia, Queen Charlotte, V0T 1S0, Canada
| | - Sue J Grayston
- Department of Forest and Conservation Sciences Vancouver, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Jean-Louis Martin
- Centre d'Écologie Fonctionnelle et Évolutive, UMR 5175, CNRS-Université de Montpellier-Université Paul Valéry-EPHE-IRD, 1919 route de Mende, F-34293, Montpellier, France
| |
Collapse
|
32
|
Sabbagh EI, Huete-Stauffer TM, Calleja MLL, Silva L, Viegas M, Morán XAG. Weekly variations of viruses and heterotrophic nanoflagellates and their potential impact on bacterioplankton in shallow waters of the central Red Sea. FEMS Microbiol Ecol 2020; 96:5800985. [PMID: 32149360 PMCID: PMC7104677 DOI: 10.1093/femsec/fiaa033] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [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: 07/31/2019] [Accepted: 03/08/2020] [Indexed: 11/14/2022] Open
Abstract
Bacterioplankton play a pivotal role in marine ecosystems. However, their temporal dynamics and underlying control mechanisms are poorly understood in tropical regions such as the Red Sea. Here, we assessed the impact of bottom-up (resource availability) and top-down (viruses and heterotrophic nanoflagellates) controls on bacterioplankton abundances by weekly sampling a coastal central Red Sea site in 2017. We monitored microbial abundances by flow cytometry together with a set of environmental variables including temperature, salinity, dissolved organic and inorganic nutrients and chlorophyll a. We distinguished five groups of heterotrophic bacteria depending on their physiological properties relative nucleic acid content, membrane integrity and cell-specific respiratory activity, two groups of Synechococcus cyanobacteria and three groups of viruses. Viruses controlled heterotrophic bacteria for most of the year, as supported by a negative correlation between their respective abundances and a positive one between bacterial mortality rates and mean viral abundances. On the contrary, heterotrophic nanoflagellates abundance covaried with that of heterotrophic bacteria. Heterotrophic nanoflagellates showed preference for larger bacteria from both the high and low nucleic acid content groups. Our results demonstrate that top-down control is fundamental in keeping heterotrophic bacterioplankton abundances low (< 5 × 10 5 cells mL−1) in Red Sea coastal waters.
Collapse
Affiliation(s)
- Eman I Sabbagh
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, Thuwal, Kingdom of Saudi Arabia
| | - Tamara M Huete-Stauffer
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, Thuwal, Kingdom of Saudi Arabia
| | - Maria L L Calleja
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, Thuwal, Kingdom of Saudi Arabia.,Max Planck Institute for Chemistry, Hahn-Meitner Weg 1, 55128 Mainz, Germany
| | - Luis Silva
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, Thuwal, Kingdom of Saudi Arabia
| | - Miguel Viegas
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, Thuwal, Kingdom of Saudi Arabia
| | - Xosé Anxelu G Morán
- King Abdullah University of Science and Technology (KAUST), Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, Thuwal, Kingdom of Saudi Arabia
| |
Collapse
|
33
|
He Q, Li H, Xu C, Sun Q, Bertness MD, Fang C, Li B, Silliman BR. Consumer regulation of the carbon cycle in coastal wetland ecosystems. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190451. [PMID: 33131445 DOI: 10.1098/rstb.2019.0451] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 01/25/2023] Open
Abstract
Despite escalating anthropogenic alteration of food webs, how the carbon cycle in ecosystems is regulated by food web processes remains poorly understood. We quantitatively synthesize the effects of consumers (herbivores, omnivores and carnivores) on the carbon cycle of coastal wetland ecosystems, 'blue carbon' ecosystems that store the greatest amount of carbon per unit area among all ecosystems. Our results reveal that consumers strongly affect many processes of the carbon cycle. Herbivores, for example, generally reduce carbon absorption and carbon stocks (e.g. aboveground plant carbon by 53% and aboveground net primary production by 23%) but may promote some carbon emission processes (e.g. litter decomposition by 32%). The average strengths of these effects are comparable with, or even times higher than, changes driven by temperature, precipitation, nitrogen input, CO2 concentration, and plant invasions. Furthermore, consumer effects appear to be stronger on aboveground than belowground carbon processes and vary markedly with trophic level, body size, thermal regulation strategy and feeding type. Despite important knowledge gaps, our results highlight the powerful impacts of consumers on the carbon cycle and call for the incorporation of consumer control into Earth system models that predict anthropogenic climate change and into management strategies of Earth's carbon stocks. This article is part of the theme issue 'Integrative research perspectives on marine conservation'.
Collapse
Affiliation(s)
- Qiang He
- Coastal Ecology Lab, MOE Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200438, People's Republic of China
| | - Haoran Li
- Coastal Ecology Lab, MOE Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200438, People's Republic of China
| | - Changlin Xu
- Coastal Ecology Lab, MOE Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200438, People's Republic of China
| | - Qingyan Sun
- Coastal Ecology Lab, MOE Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200438, People's Republic of China
| | - Mark D Bertness
- Department of Ecology and Evolutionary Biology, Brown University, 80 Waterman Street, Providence, RI 02516, USA
| | - Changming Fang
- Coastal Ecology Lab, MOE Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200438, People's Republic of China
| | - Bo Li
- Coastal Ecology Lab, MOE Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200438, People's Republic of China
| | - Brian R Silliman
- Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, 135 Duke Marine Lab Road, Beaufort, NC 28516, USA
| |
Collapse
|
34
|
Hsieh SS, Chueh TY, Morris TP, Kao SC, Westfall DR, Raine LB, Hopman RJ, Pontifex MB, Castelli DM, Kramer AF, Hillman CH. Greater childhood cardiorespiratory fitness is associated with better top-down cognitive control: A midfrontal theta oscillation study. Psychophysiology 2020; 57:e13678. [PMID: 32877574 DOI: 10.1111/psyp.13678] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/09/2020] [Accepted: 08/06/2020] [Indexed: 11/28/2022]
Abstract
The aim of the current study was to examine the association between cardiorespiratory fitness and electroencephalogram-based neural oscillations, using midfrontal theta, during an inhibitory control task in children. One-hundred seventy-one school-aged children (mean age = 8.9 ± 0.6 years; 46% girls) were recruited. Cardiorespiratory fitness was assessed by a test of maximal oxygen consumption (VO2peak ) while inhibitory control performance was measured via a modified flanker task with an electroencephalogram. Behavioral findings demonstrated that higher cardiorespiratory fitness was associated with higher response accuracy regardless of task difficulty as well as lower response variability during trials with lower cognitive demand. Neuroelectric outcomes revealed that higher cardiorespiratory fitness was correlated with smaller modulation of theta (4-7 Hz) oscillatory power regardless of task difficulty. Collectively, the current findings indicate that higher cardiorespiratory fitness is associated with better performance on a task that modulates inhibitory control, signified by higher, and more stable, task performance. More importantly, higher childhood cardiorespiratory fitness is associated with better top-down control and cortical communication, as reflected by midfrontal theta. Such findings support the critical role of cardiorespiratory fitness in brain health during childhood.
Collapse
Affiliation(s)
- Shu-Shih Hsieh
- Department of Psychology, Northeastern University, Boston, MA, USA
| | - Ting-Yu Chueh
- Department Physical Education, National Taiwan Normal University, Taipei, Taiwan
| | - Timothy P Morris
- Department of Psychology, Northeastern University, Boston, MA, USA
| | - Shih-Chun Kao
- Department of Health and Kinesiology, Purdue University, West Lafayette, IN, USA
| | | | - Lauren B Raine
- Department of Psychology, Northeastern University, Boston, MA, USA
| | - Rachel J Hopman
- Department of Psychology, Northeastern University, Boston, MA, USA
| | - Matthew B Pontifex
- Department of Kinesiology, Michigan State University, East Lansing, MI, USA
| | - Darla M Castelli
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA
| | - Arthur F Kramer
- Department of Psychology, Northeastern University, Boston, MA, USA.,Beckman Institute, University of Illinois, Urbana, IL, USA
| | - Charles H Hillman
- Department of Psychology, Northeastern University, Boston, MA, USA.,Department of Physical Therapy, Movement, and Rehabilitation Sciences, Northeastern University, Boston, MA, USA
| |
Collapse
|
35
|
Yates L, Hobson H. Continuing to look in the mirror: A review of neuroscientific evidence for the broken mirror hypothesis, EP-M model and STORM model of autism spectrum conditions. Autism 2020; 24:1945-1959. [PMID: 32668956 PMCID: PMC7539595 DOI: 10.1177/1362361320936945] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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] [Indexed: 11/23/2022]
Abstract
The mirror neuron system has been argued to be a key brain system responsible for action understanding and imitation. Subsequently, mirror neuron system dysfunction has therefore been proposed to explain the social deficits manifested within autism spectrum condition, an approach referred to as the broken mirror hypothesis. Despite excitement surrounding this hypothesis, extensive research has produced insufficient evidence to support the broken mirror hypothesis in its pure form, and instead two alternative models have been formulated: EP-M model and the social top-down response modulation (STORM) model. All models suggest some dysfunction regarding the mirror neuron system in autism spectrum condition, be that within the mirror neuron system itself or systems that regulate the mirror neuron system. This literature review compares these three models in regard to recent neuroscientific investigations. This review concludes that there is insufficient support for the broken mirror hypothesis, but converging evidence supports an integrated EP-M and STORM model.
Collapse
|
36
|
Maksimenko VA, Kuc A, Frolov NS, Khramova MV, Pisarchik AN, Hramov AE. Dissociating Cognitive Processes During Ambiguous Information Processing in Perceptual Decision-Making. Front Behav Neurosci 2020; 14:95. [PMID: 32754018 PMCID: PMC7370842 DOI: 10.3389/fnbeh.2020.00095] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [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: 12/11/2019] [Accepted: 05/20/2020] [Indexed: 12/25/2022] Open
Abstract
Decision-making requires the accumulation of sensory evidence. However, in everyday life, sensory information is often ambiguous and contains decision-irrelevant features. This means that the brain must disambiguate sensory input and extract decision-relevant features. Sensory information processing and decision-making represent two subsequent stages of the perceptual decision-making process. While sensory processing relies on occipito-parietal neuronal activity during the earlier time window, decision-making lasts for a prolonged time, involving parietal and frontal areas. Although perceptual decision-making is being actively studied, its neuronal mechanisms under ambiguous sensory evidence lack detailed consideration. Here, we analyzed the brain activity of subjects accomplishing a perceptual decision-making task involving the classification of ambiguous stimuli. We demonstrated that ambiguity induced high frontal θ-band power for 0.15 s post-stimulus onset, indicating increased reliance on top-down processes, such as expectations and memory. Ambiguous processing also caused high occipito-parietal β-band power for 0.2 s and high fronto-parietal β-power for 0.35–0.42 s post-stimulus onset. We supposed that the former component reflected the disambiguation process while the latter reflected the decision-making phase. Our findings complemented existing knowledge about ambiguous perception by providing additional information regarding the temporal discrepancy between the different cognitive processes during perceptual decision-making.
Collapse
Affiliation(s)
- Vladimir A Maksimenko
- Institute of Information Technologies, Mathematics and Mechanics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Center for Technologies in Robotics and Mechatronics Component, Innopolis University, Innopolis, Russia
| | - Alexander Kuc
- Center for Technologies in Robotics and Mechatronics Component, Innopolis University, Innopolis, Russia
| | - Nikita S Frolov
- Center for Technologies in Robotics and Mechatronics Component, Innopolis University, Innopolis, Russia
| | - Marina V Khramova
- Faculty of Information Technologies, Saratov State University, Saratov, Russia
| | - Alexander N Pisarchik
- Center for Technologies in Robotics and Mechatronics Component, Innopolis University, Innopolis, Russia.,Center for Biomedical Technology, Technical University of Madrid, Madrid, Spain
| | - Alexander E Hramov
- Center for Technologies in Robotics and Mechatronics Component, Innopolis University, Innopolis, Russia
| |
Collapse
|
37
|
Senzaki M, Kadoya T, Francis CD. Direct and indirect effects of noise pollution alter biological communities in and near noise-exposed environments. Proc Biol Sci 2020; 287:20200176. [PMID: 32183626 DOI: 10.1098/rspb.2020.0176] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Noise pollution is pervasive across every ecosystem on Earth. Although decades of research have documented a variety of negative impacts of noise to organisms, key gaps remain, such as how noise affects different taxa within a biological community and how effects of noise propagate across space. We experimentally applied traffic noise pollution to multiple roadless areas and quantified the impacts of noise on birds, grasshoppers and odonates. We show that acoustically oriented birds have reduced species richness and abundance and different community compositions in experimentally noise-exposed areas relative to comparable quiet locations. We also found both acoustically oriented grasshoppers and odonates without acoustic receptors to have reduced species richness and/or abundance in relatively quiet areas that abut noise-exposed areas. These results suggest that noise pollution not only affects acoustically oriented animals, but that noise may reverberate through biological communities through indirect effects to those with no clear links to the acoustic realm, even in adjacent quiet environments.
Collapse
Affiliation(s)
- Masayuki Senzaki
- Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Onogawa 16-2, Tsukuba City, Ibaraki 305-8506, Japan.,Faculty of Environmental Earth Science, Hokkaido University, Nishi 5, Kita 10, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Taku Kadoya
- Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Onogawa 16-2, Tsukuba City, Ibaraki 305-8506, Japan
| | - Clinton D Francis
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| |
Collapse
|
38
|
Abstract
Disturbances associated with agricultural intensification reduce our ability to achieve sustainable crop production. These disturbances stem from crop-management tactics and can leave crop fields more vulnerable to insect outbreaks, in part because natural-enemy communities often tend to be more susceptible to disturbance than herbivorous pests. Recent research has explored practices that conserve natural-enemy communities and reduce pest outbreaks, revealing that different components of agroecosystems can influence natural-enemy populations. In this review, we consider a range of disturbances that influence pest control provided by natural enemies and how conservation practices can mitigate or counteract disturbance. We use four case studies to illustrate how conservation and disturbance mitigation increase the potential for biological control and provide co-benefits for the broader agroecosystem. To facilitate the adoption of conservation practices that improve top-down control across significant areas of the landscape, these practices will need to provide multifunctional benefits, but should be implemented with natural enemies explicitly in mind.
Collapse
Affiliation(s)
- John F Tooker
- Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA;
| | - Matthew E O'Neal
- Department of Entomology, Iowa State University, Ames, Iowa 50011, USA;
| | | |
Collapse
|
39
|
Gutierrez M, Berggren N. Anticipation of aversive threat potentiates task-irrelevant attentional capture. Cogn Emot 2019; 34:1036-1043. [PMID: 31878835 DOI: 10.1080/02699931.2019.1706448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Anxiety is believed to have a disruptive effect on attentional control, supported by evidence of increased distractibility among high trait anxious individuals. However, how feelings of current anxious apprehension influence selective attention is less well-understood. The present study examined this by assessing attentional capture by a novel distractor within a visual search task. Participants searched an array of coloured objects for a shape-defined target, while attempting to ignore a colour singleton distractor presented on half of the trials. To induce apprehension, participants completed the task in some blocks with a low probability threat of loud aversive sounds being presented. We found significantly increased distractibility within the threat condition when noise was anticipated but not played, as reflected by a larger distractor presence cost to reaction times. The finding that apprehension potentiates task-irrelevant attentional capture suggests a generalised role of anxious emotion in increasing distractibility.
Collapse
Affiliation(s)
- Monica Gutierrez
- Department of Psychological Sciences, Birkbeck College, University of London, London, UK
| | - Nick Berggren
- Department of Psychological Sciences, Birkbeck College, University of London, London, UK
| |
Collapse
|
40
|
Bauer CCC, Whitfield-Gabrieli S, Díaz JL, Pasaye EH, Barrios FA. From State-to-Trait Meditation: Reconfiguration of Central Executive and Default Mode Networks. eNeuro 2019; 6:ENEURO. [PMID: 31694816 DOI: 10.1523/ENEURO.0335-18.2019] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 12/17/2022] Open
Abstract
While brain default mode network (DMN) activation in human subjects has been associated with mind wandering, meditation practice has been found to suppress it and to increase psychological well-being. In addition to DMN activity reduction, experienced meditators (EMs) during meditation practice show an increased connectivity between the DMN and the central executive network (CEN). While brain default mode network (DMN) activation in human subjects has been associated with mind wandering, meditation practice has been found to suppress it and to increase psychological well-being. In addition to DMN activity reduction, experienced meditators (EMs) during meditation practice show an increased connectivity between the DMN and the central executive network (CEN). However, the gradual change between DMN and CEN configuration from pre-meditation, during meditation, and post-meditation is unknown. Here, we investigated the change in DMN and CEN configuration by means of brain activity and functional connectivity (FC) analyses in EMs across three back-to-back functional magnetic resonance imaging (fMRI) scans: pre-meditation baseline (trait), meditation (state), and post-meditation (state-to-trait). Pre-meditation baseline group comparison was also performed between EMs and healthy controls (HCs). Meditation trait was characterized by a significant reduction in activity and FC within DMN and increased anticorrelations between DMN and CEN. Conversely, meditation state and meditation state-to-trait periods showed increased activity and FC within the DMN and between DMN and CEN. However, the latter anticorrelations were only present in EMs with limited practice. The interactions between networks during these states by means of positive diametric activity (PDA) of the fractional amplitude of low-frequency fluctuations (fALFFs) defined as CEN fALFF¯ − DMN fALFF¯ revealed no trait differences but significant increases during meditation state that persisted in meditation state-to-trait. The gradual reconfiguration in DMN and CEN suggest a neural mechanism by which the CEN negatively regulates the DMN and is probably responsible for the long-term trait changes seen in meditators and reported psychological well-being.
Collapse
|
41
|
Hood GR, Comerford M, Weaver AK, Morton PM, Egan SP. Human-mediated disturbance in multitrophic interactions results in outbreak levels of North America's most venomous caterpillar. Biol Lett 2019; 15:20190470. [PMID: 31480937 DOI: 10.1098/rsbl.2019.0470] [Citation(s) in RCA: 5] [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] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Anthropogenic environmental change is predicted to disrupt multitrophic interactions, which may have drastic consequences for population-level processes. Here, we investigate how a large-scale human-mediated disturbance affects the abundance of North America's most venomous caterpillar species, Megalopyge opercularis. Specifically, we used a natural experiment where netting was deployed to cover the entire canopies of a subset of mature southern live oak trees (Quercus virginiana) to exclude urban pest birds (grackles and pigeons), throughout an 8.1 km2 area encompassing a medical centre in Houston, Texas. We used this experimental exclusion to test the following hypothesis: release from avian predators increases caterpillar abundance to outbreak levels, which increases the risk to human health. Results from a multi-year survey show that caterpillar abundance increased, on average, more than 7300% on netted versus non-netted trees. Thus, increases in caterpillar abundance due to anthropogenic enemy release increase human exposure to this venomous pest, and should be considered a health threat in the area. This study emphasizes the unforeseen consequences of ecological disturbance for species interactions and highlights the importance of considering ecology in urban planning.
Collapse
Affiliation(s)
- Glen R Hood
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.,Department of Biosciences, Rice University, Houston, TX 77005, USA
| | | | - Amanda K Weaver
- Department of Biosciences, Rice University, Houston, TX 77005, USA
| | - Patricia M Morton
- Department of Sociology, Wayne State University, Detroit, MI 48202, USA
| | - Scott P Egan
- Department of Biosciences, Rice University, Houston, TX 77005, USA
| |
Collapse
|
42
|
Melguizo-Ruiz N, Jiménez-Navarro G, De Mas E, Pato J, Scheu S, Austin AT, Wise DH, Moya-Laraño J. Field exclusion of large soil predators impacts lower trophic levels and decreases leaf-litter decomposition in dry forests. J Anim Ecol 2019; 89:334-346. [PMID: 31494934 DOI: 10.1111/1365-2656.13101] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [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: 01/17/2019] [Accepted: 09/04/2019] [Indexed: 11/28/2022]
Abstract
Shifts in densities of apex predators may indirectly affect fundamental ecosystem processes, such as decomposition, by altering patterns of cascading effects propagating through lower trophic levels. These top-down effects may interact with anthropogenic impacts, such as climate change, in largely unknown ways. We investigated how changes in densities of large predatory arthropods in forest leaf-litter communities altered lower trophic levels and litter decomposition. We conducted our experiment in soil communities that had experienced different levels of long-term average precipitation. We hypothesized that altering abundances of apex predators would have stronger effects on soil communities inhabiting dry forests, due to lower secondary productivity and greater resource overexploitation by lower trophic levels compared to wet forests. We experimentally manipulated abundances of the largest arthropod predators (apex predators) in field mesocosms replicated in the leaf-litter community of Iberian beech forests that differed in long-term mean annual precipitation by 25% (three dry forests with MAP < 1,250 mm and four wet forests with MAP > 1,400 mm). After one year, we assessed abundances of soil fauna in lower trophic levels and indirect impacts on leaf-litter decomposition using litter of understorey hazel, Corylus avellana. Reducing densities of large predators had a consistently negative effect on final abundances of the different trophic groups and several taxa within each group. Moreover, large predatory arthropods strongly impacted litter decomposition, and their effect interacted with the long-term annual rainfall experienced by the soil community. In the dry forests, a 50% reduction in the densities of apex predators was associated with a 50% reduction in decomposition. In wet forests, the same reduction in densities of apex soil predators did not alter the rate of litter decomposition. Our results suggest that predators may facilitate lower trophic levels by indirectly reducing competition and resource overexploitation, cascading effects that may be more pronounced in drier forests where conditions have selected for greater competitive ability and more rapid resource utilization. These findings thus provide insights into the functioning of soil invertebrate communities and their role in decomposition, as well as potential consequences of soil community responses to climate change.
Collapse
Affiliation(s)
- Nereida Melguizo-Ruiz
- Estación Experimental de Zonas Áridas, Functional and Evolutionary Ecology, Consejo Superior de Investigaciones Científicas (CSIC), Almería, Spain.,Research Unit of Biodiversity (UO/CSIC/PA), Oviedo University, Mieres, Spain.,CIBIO/InBio Research Center in Biodiversity and Genetic Resources, Évora, Portugal
| | - Gerardo Jiménez-Navarro
- Estación Experimental de Zonas Áridas, Functional and Evolutionary Ecology, Consejo Superior de Investigaciones Científicas (CSIC), Almería, Spain.,CIBIO/InBio Research Center in Biodiversity and Genetic Resources, Évora, Portugal
| | - Eva De Mas
- Estación Experimental de Zonas Áridas, Functional and Evolutionary Ecology, Consejo Superior de Investigaciones Científicas (CSIC), Almería, Spain
| | - Joaquina Pato
- Research Unit of Biodiversity (UO/CSIC/PA), Oviedo University, Mieres, Spain
| | - Stefan Scheu
- J.F. Blumenbach Institute of Zoology and Anthropology, Animal Ecology, University of Göttingen, Göttingen, Germany.,Centre of Biodiversity and Sustainable Land Use, University of Göttingen, Göttingen, Germany
| | - Amy T Austin
- Facultad de Agronomía, Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - David H Wise
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Jordi Moya-Laraño
- Estación Experimental de Zonas Áridas, Functional and Evolutionary Ecology, Consejo Superior de Investigaciones Científicas (CSIC), Almería, Spain
| |
Collapse
|
43
|
Abstract
Representations of visual objects in working memory (WM) can be part-based or object-based, and we investigated whether this is determined by top-down control processes. Lateralised change detection tasks were employed where sample objects on one task-relevant side had to be memorized. Contralateral delay activity (CDA) components were measured during the retention period as electrophysiological markers of WM maintenance processes. In two critical task conditions, sample displays contained objects composed of two vertically aligned shapes. In the Parts task, test displays contained a single shape that had to be matched with either of the two sample shapes, encouraging the storage of part-based WM representations. In the Whole task, compound-shape objects shown at test had to be matched with memorized compound objects, which should facilitate the formation of object-based integrated WM representations. CDA amplitudes were significantly larger in the Parts task than in the Whole task, indicative of differences in effective WM load. This suggests that the two individual shapes were represented separately in the Parts task, whereas a single compound object was maintained in the Whole task. These results provide new evidence that changes in task goals can result in qualitative differences in the way that identical visual stimuli are represented in WM.
Collapse
Affiliation(s)
- Cody W McCants
- Department of Psychological Sciences, Birkbeck, University of London, London, UK
| | - Tobias Katus
- Department of Psychological Sciences, Birkbeck, University of London, London, UK
| | - Martin Eimer
- Department of Psychological Sciences, Birkbeck, University of London, London, UK
| |
Collapse
|
44
|
Bansal S, Robinson BM, Leonard CJ, Hahn B, Luck SJ, Gold JM. Failures in top-down control in schizophrenia revealed by patterns of saccadic eye movements. J Abnorm Psychol 2019; 128:415-422. [PMID: 31192637 PMCID: PMC6640840 DOI: 10.1037/abn0000442] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Successful execution of many behavioral goals relies on well-organized patterns of saccadic eye movements, and in complex tasks, these patterns can reveal the component processes underlying task performance. The present study examined the pattern of eye movements in a visual search task to provide evidence of attentional control impairments in people with schizophrenia (PSZ). We tested PSZ(N = 38) and nonpsychiatric control subjects (NCS, N = 35) in a task that was designed to stress top-down control by pitting task goals against bottom-up salience. Participants searched for either a low-contrast (nonsalient) or a high-contrast (salient) target among low- and high-contrast distractors. By examining fixations of the low- and high-contrast items, we evaluated the ability of PSZ and NCS to focus on low-salience targets and filter out high-salience distractors (or vice versa). When participants searched for a salient target, both groups successfully focused on relevant, high-contrast stimuli and filtered out target-mismatched, low-contrast stimuli. However, when searching for a nonsalient target, PSZ were impaired at efficiently suppressing high-contrast (salient) distractors. Specifically, PSZ were more likely than NCS to fixate and revisit salient distractors, and they dwelled on these items longer than did NCS. The results provide direct evidence that PSZ are impaired in their ability to utilize top-down goals to overcome the prepotent tendency to focus attention on irrelevant but highly salient information. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Collapse
Affiliation(s)
- Sonia Bansal
- University of Maryland School of Medicine, Maryland
Psychiatric Research Center
| | | | | | - Britta Hahn
- University of Maryland School of Medicine, Maryland
Psychiatric Research Center
| | - Steven J. Luck
- Center for Mind & Brain and Department of Psychology,
University of California, Davis
| | - James M. Gold
- University of Maryland School of Medicine, Maryland
Psychiatric Research Center
| |
Collapse
|
45
|
Nakajima M, Schmitt LI, Halassa MM. Prefrontal Cortex Regulates Sensory Filtering through a Basal Ganglia-to-Thalamus Pathway. Neuron 2019; 103:445-458.e10. [PMID: 31202541 DOI: 10.1016/j.neuron.2019.05.026] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/01/2019] [Accepted: 05/15/2019] [Indexed: 02/06/2023]
Abstract
To make adaptive decisions, organisms must appropriately filter sensory inputs, augmenting relevant signals and suppressing noise. The prefrontal cortex (PFC) partly implements this process by regulating thalamic activity through modality-specific thalamic reticular nucleus (TRN) subnetworks. However, because the PFC does not directly project to sensory TRN subnetworks, the circuitry underlying this process had been unknown. Here, using anatomical tracing, functional manipulations, and optical identification of PFC projection neurons, we find that the PFC regulates sensory thalamic activity through a basal ganglia (BG) pathway. Engagement of this PFC-BG-thalamus pathway enables selection between vision and audition by primarily suppressing the distracting modality. This pathway also enhances sensory discrimination and is used for goal-directed background noise suppression. Overall, our results identify a new pathway for attentional filtering and reveal its multiple roles in sensory processing on the basis of internal goals.
Collapse
|
46
|
LeCraw RM, Srivastava DS. Biogeographic context dependence of trophic cascade strength in bromeliad food webs. Ecology 2019; 100:e02692. [PMID: 30868556 DOI: 10.1002/ecy.2692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 10/02/2018] [Revised: 01/30/2019] [Accepted: 02/19/2019] [Indexed: 01/17/2023]
Abstract
Ecosystem functions and the biomass of lower trophic levels are frequently controlled by predators. The strength of top-down control in these trophic cascades can be affected by the identity and diversity of predators, prey, and resources, as well as environmental conditions such as temperature, moisture, and nutrient loading, which can all impact interaction strength between trophic levels. Few studies have been able to replicate a complete community over a large geographic area to compare the full trophic cascade in a manipulative experiment. Here, we identify geographic dependency in trophic cascade strength, and the driving factors and specific mechanisms behind it, by combining geographically replicated experiments with a novel approach of community analogues of common garden and transplant experiments. We studied a predator-detritivore-detritus food web in bromeliads in Puerto Rico, Costa Rica, and Brazil. We found that interaction strengths between resources, consumers, and predators were strongly site-specific, but the exact mechanism differed between trophic levels. Large bodied predators created strong interaction strengths between predator and consumer trophic levels, reducing consumer abundance regardless of the geographic location, whereas small-bodied predators created weak interactions with no impact on consumer abundances in any site. In contrast, the interaction strength between consumers and resources varied among sites, depending on the dominant species of leaf detritus. More labile leaf species in Costa Rica created a strong consumer-resource interaction and therefore strong trophic cascade, whereas tougher leaf species in Brazil created a weak consumer-resource interaction, and an overall weaker trophic cascade. Our study highlights the importance of replicating experiments over geographic scales to understand general patterns of ecological processes.
Collapse
Affiliation(s)
- Robin M LeCraw
- Department of Zoology & Biodiversity Research Centre, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T1Z4, Canada
| | - Diane S Srivastava
- Department of Zoology & Biodiversity Research Centre, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T1Z4, Canada
| |
Collapse
|
47
|
Simonsen A, Fusaroli R, Skewes JC, Roepstorff A, Campbell-Meiklejohn D, Mors O, Bliksted V. Enhanced Automatic Action Imitation and Intact Imitation-Inhibition in Schizophrenia. Schizophr Bull 2019; 45:87-95. [PMID: 29474687 PMCID: PMC6293210 DOI: 10.1093/schbul/sby006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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] [Indexed: 12/29/2022]
Abstract
Imitation plays a key role in social learning and in facilitating social interactions and likely constitutes a basic building block of social cognition that supports higher-level social abilities. Recent findings suggest that patients with schizophrenia have imitation impairments that could contribute to the social impairments associated with the disorder. However, extant studies have specifically assessed voluntary imitation or automatic imitation of emotional stimuli without controlling for potential confounders. The imitation impairments seen might therefore be secondary to other cognitive, motoric, or emotional deficits associated with the disorder. To overcome this issue, we used an automatic imitation paradigm with nonemotional stimuli to assess automatic imitation and the top-down modulation of imitation where participants were required to lift one of 2 fingers according to a number shown on the screen while observing the same or the other finger movement. In addition, we used a control task with a visual cue in place of a moving finger, to isolate the effect of observing finger movement from other visual cueing effects. Data from 33 patients (31 medicated) and 40 matched healthy controls were analyzed. Patients displayed enhanced imitation and intact top-down modulation of imitation. The enhanced imitation seen in patients may have been medication induced as larger effects were seen in patients receiving higher antipsychotic doses. In sum, we did not find an imitation impairment in schizophrenia. The results suggest that previous findings of impaired imitation in schizophrenia might have been due to other cognitive, motoric, and/or emotional deficits.
Collapse
Affiliation(s)
- Arndis Simonsen
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark,The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus, Denmark,The Interacting Minds Centre, School of Culture and Society, Aarhus University, Aarhus, Denmark,Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus, Denmark,The Psychiatric Centre, Landssjúkrahúsið, National Hospital of the Faroe Islands, Tórshavn, Faroe Islands,Ílegusavnið, The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands,To whom correspondence should be addressed; Psychosis Research Unit, The Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH), Aarhus University Hospital, Risskov (AUHR), Skovagervej 2, 8240 Risskov, Denmark; tel: +45-29425875, fax: +45-78471609, e-mail:
| | - Riccardo Fusaroli
- The Interacting Minds Centre, School of Culture and Society, Aarhus University, Aarhus, Denmark
| | - Joshua Charles Skewes
- The Interacting Minds Centre, School of Culture and Society, Aarhus University, Aarhus, Denmark
| | - Andreas Roepstorff
- The Interacting Minds Centre, School of Culture and Society, Aarhus University, Aarhus, Denmark,Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus, Denmark
| | | | - Ole Mors
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark,The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus, Denmark
| | - Vibeke Bliksted
- Psychosis Research Unit, Aarhus University Hospital, Risskov, Denmark,The Interacting Minds Centre, School of Culture and Society, Aarhus University, Aarhus, Denmark,Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus, Denmark
| |
Collapse
|
48
|
He Q, Silliman BR, van de Koppel J, Cui B. Weather fluctuations affect the impact of consumers on vegetation recovery following a catastrophic die-off. Ecology 2018; 100:e02559. [PMID: 30411780 DOI: 10.1002/ecy.2559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 02/11/2018] [Revised: 08/08/2018] [Accepted: 10/11/2018] [Indexed: 11/10/2022]
Abstract
Prolonged droughts exacerbated by climate change have been widely documented to interact with consumers to decimate vegetation in many ecosystems. Although climate change is increasing within-year variation in precipitation and temperature, how weather fluctuations affect the impact of consumers on vegetation processes remains poorly understood. In a salt marsh that has recently experienced drought-associated vegetation die-off, we investigated how top-down control of plant recovery by a prominent salt marsh grazer varies with weather. Our results showed that grazing-driven plant mortality varied strongly with weather in spring, with intense grazing occurring during cool, wet days immediately following rain. Intense grazing on cool, wet days across the generally dry spring season had a strong impact that eliminated plant seedlings that could otherwise have become tolerant of grazing in the following summer, thereby restricting vegetation recovery and contributing to the persistence of an unvegetated salt barren state. Thus, weather fluctuations can modulate the impact of consumers on vegetation recovery, a fundamental process underlying the fate of ecosystems after disturbances. A multi-timescale perspective on top-down control that combines the impact of short-term fluctuations in weather and that of long-term variation in mean climate can not only help understand ecosystem dynamics in an increasingly variable climate, but may also inform conservation strategies or recovery plans for ecosystems that are already lost to climate change.
Collapse
Affiliation(s)
- Qiang He
- Coastal Ecology Lab, MOE Key Laboratory of Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai, 200438, China.,Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, 135 Duke Marine Lab Road, Beaufort, North Carolina, 28516, USA
| | - Brian R Silliman
- Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, 135 Duke Marine Lab Road, Beaufort, North Carolina, 28516, USA
| | - Johan van de Koppel
- Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ), 4401NT 7, Yerseke, The Netherlands.,Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9700 CC, Groningen, The Netherlands
| | - Baoshan Cui
- School of Environment, State Key Laboratory of Water Environment Simulation, Beijing Normal University, Beijing, 100875, China
| |
Collapse
|
49
|
Atwood TB, Hammill E. The Importance of Marine Predators in the Provisioning of Ecosystem Services by Coastal Plant Communities. Front Plant Sci 2018; 9:1289. [PMID: 30233626 PMCID: PMC6129962 DOI: 10.3389/fpls.2018.01289] [Citation(s) in RCA: 2] [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] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 08/16/2018] [Indexed: 06/08/2023]
Abstract
Food web theory predicts that current global declines in marine predators could generate unwanted consequences for many marine ecosystems. In coastal plant communities (kelp, seagrass, mangroves, and salt marsh), several studies have documented the far-reaching effects of changing predator populations. Across coastal ecosystems, the loss of marine predators appears to negatively affect coastal plant communities and the ecosystem services they provide. Here, we discuss some of the documented and suspected effects of predators on coastal protection, carbon sequestration, and the stability and resilience of coastal plant communities. In addition, we present a meta-analysis to assess the strength and direction of trophic cascades in kelp forests, seagrasses, salt marshes, and mangroves. We demonstrate that the strength and direction of trophic cascades varied across ecosystem types, with predators having a large positive effect on plants in salt marshes, a moderate positive effect on plants in kelp and mangroves, and no effect on plants in seagrasses. Our analysis also identified that there is a paucity of literature on trophic cascades for all four coastal plant systems, but especially seagrass and mangroves. Our results demonstrate the crucial role of predators in maintaining coastal ecosystem services, but also highlights the need for further research before large-scale generalizations about the prevalence, direction, and strength of trophic cascade in coastal plant communities can be made.
Collapse
|
50
|
Pekkanen J, Lappi O, Rinkkala P, Tuhkanen S, Frantsi R, Summala H. A computational model for driver's cognitive state, visual perception and intermittent attention in a distracted car following task. R Soc Open Sci 2018; 5:180194. [PMID: 30839728 PMCID: PMC6170561 DOI: 10.1098/rsos.180194] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 08/10/2018] [Indexed: 06/09/2023]
Abstract
We present a computational model of intermittent visual sampling and locomotor control in a simple yet representative task of a car driver following another vehicle. The model has a number of features that take it beyond the current state of the art in modelling natural tasks, and driving in particular. First, unlike most control theoretical models in vision science and engineering-where control is directly based on observable (optical) variables-actions are based on a temporally enduring internal representation. Second, unlike the more sophisticated engineering driver models based on internal representations, our model explicitly aims to be psychologically plausible, in particular in modelling perceptual processes and their limitations. Third, unlike most psychological models, it is implemented as an actual simulation model capable of full task performance (visual sampling and longitudinal control). The model is developed and validated using a dataset from a simplified car-following experiment (N = 40, in both three-dimensional virtual reality and a real instrumented vehicle). The results replicate our previously reported connection between time headway and visual attention. The model reproduces this connection and predicts that it emerges from control of action uncertainty. Implications for traffic psychological models and future developments for psychologically plausible yet computationally rigorous models of full natural task performance are discussed.
Collapse
Affiliation(s)
- Jami Pekkanen
- Cognitive Science, PO Box 9, 00014 University of Helsinki, Finland
- TRUlab, Department of Digital Humanities, PO Box 9, 00014 University of Helsinki, Finland
- Helsinki Center for Digital Humanities (HELDIG), Finland
| | - Otto Lappi
- Cognitive Science, PO Box 9, 00014 University of Helsinki, Finland
- TRUlab, Department of Digital Humanities, PO Box 9, 00014 University of Helsinki, Finland
- Helsinki Center for Digital Humanities (HELDIG), Finland
| | - Paavo Rinkkala
- Cognitive Science, PO Box 9, 00014 University of Helsinki, Finland
- TRUlab, Department of Digital Humanities, PO Box 9, 00014 University of Helsinki, Finland
- Spatial Planning and Transportation Engineering, Department of Built Environment, Aalto University, Finland
| | - Samuel Tuhkanen
- Cognitive Science, PO Box 9, 00014 University of Helsinki, Finland
- TRUlab, Department of Digital Humanities, PO Box 9, 00014 University of Helsinki, Finland
- Helsinki Center for Digital Humanities (HELDIG), Finland
| | - Roosa Frantsi
- Cognitive Science, PO Box 9, 00014 University of Helsinki, Finland
- TRUlab, Department of Digital Humanities, PO Box 9, 00014 University of Helsinki, Finland
- Spatial Planning and Transportation Engineering, Department of Built Environment, Aalto University, Finland
| | - Heikki Summala
- Cognitive Science, PO Box 9, 00014 University of Helsinki, Finland
- TRUlab, Department of Digital Humanities, PO Box 9, 00014 University of Helsinki, Finland
| |
Collapse
|