Faculty of 1000 evaluation for Species interactions and a chain of indirect effects driven by reduced precipitation.

Abstract Mammalian spatial and temporal activity patterns can vary depending on foraging behavior or the perception of predation or competition risk among species. These behaviors may in turn be altered by human influences such as defaunation. Herein, we evaluate whether frugivores avoid areas with high visitation rates by potential predators or competitors, and whether this avoidance changes in areas with different degrees of defaunation. We installed 189 cameras under fruit trees in six areas of the Atlantic Forest, Brazil, that differ in the abundance of top predators and large frugivores. Small predators and small frugivores were more frequent at night while large frugivores were more frequent during the day, but small frugivores visited and spent less time at fruiting trees on brighter nights, unlike large predators and large frugivores. Small frugivores also were less frequent in areas with high visitation by large frugivores and more frequent in highly defaunated areas. Our results suggest that the dynamics among mammalian functional groups varied according to diel patterns, potential competitors, and defaunation. We highlight the importance of understanding how species interactions are changing in areas exposed to strong human impacts to mitigate the indirect effects of defaunation.

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Analysis of adaptive foraging in an intraguild predation system

Web Ecology ◽

10.5194/we-4-1-2003 ◽

2003 ◽

Vol 4 (1) ◽

pp. 1-6 ◽

Cited By ~ 12

Author(s):

T. Okuyama ◽

R. L. Ruyle

Keyword(s):

Foraging Behavior ◽

Adaptive Behavior ◽

Intraguild Predation ◽

Indirect Effects ◽

Species Interactions ◽

Community Dynamics ◽

Antipredator Behavior ◽

Density Dependent ◽

Top Predators ◽

Adaptive Foraging

Abstract. An intraguild predation (IGP) system with adaptive foraging behavior was analyzed using a simple mathematical model. The main aim was to explore how the adaptive behavior affects species interactions as well as how such interactions derived from adaptive behavior affect community stability. The focal system contained top predators, intermediate predators, and basal prey. Intermediate predators exhibit antipredator behavior and balance costs (e.g. perceived predation risk) and benefits (e.g. resource intake) to determine their foraging effort. Density-dependent foraging behavior with the unique connectance of the IGP food web created unusual species interactions. Notably, increased prey density can transmit negative indirect effects to top predators while increased top predator density transmits positive indirect effects to prey population. The nature of these interactions is density-dependent. The results suggest that both IGP (as opposed to linear food chain) and adaptive foraging behaviors may strongly influence community dynamics due to emergent interactions among direct effects and indirect effects. Furthermore, the adaptive foraging of intermediate predators may stabilize the community as a whole.

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The role of indirect effects in coevolution as mutualism transitions into antagonism

10.1101/2021.11.22.469544 ◽

2021 ◽

Author(s):

Fernando Pedraza ◽

Hanlun Liu ◽

Klementyna A. Gawecka ◽

Jordi Bascompte

Keyword(s):

Global Change ◽

Evolutionary Theory ◽

Indirect Effects ◽

Species Interactions ◽

Antagonistic Selection ◽

Combine Network ◽

Mutualistic Networks ◽

Interaction Types ◽

Tight Integration

Species interactions have evolved from antagonistic to mutualistic and back several times throughout life's history. Yet, it is unclear how changes in the type of interaction between species alter the coevolutionary dynamics of entire communities. This is a pressing matter, as transitions from mutualisms to antagonisms may be becoming more common with human-induced global change. Here, we combine network and evolutionary theory to simulate how shifts in interaction types alter the coevolution of empirical communities. We show that as mutualistic networks shift to antagonistic, selection imposed by direct partners begins to outweigh that imposed by indirect partners. This weakening of indirect effects is associated with communities losing their tight integration of traits and increasing their rate of adaptation. The above changes are more pronounced when specialist consumers are the first species to switch to antagonism. A shift in the outcome of species' interactions may therefore reverberate across communities and alter the direction and speed of coevolution.

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Relationship Between Psychological Empowerment and the Retention Intention of Kindergarten Teachers: A Chain Intermediary Effect Analysis

Frontiers in Psychology ◽

10.3389/fpsyg.2021.601992 ◽

2021 ◽

Vol 12 ◽

Author(s):

Lina Ma ◽

Fusheng Zhou ◽

Haidan Liu

Keyword(s):

Indirect Effects ◽

Psychological Capital ◽

Psychological Empowerment ◽

Mainland China ◽

Job Involvement ◽

Kindergarten Teachers ◽

Effect Analysis ◽

Internal Mechanism ◽

A Chain ◽

The Relationship

Objective: To investigate the relationship between psychological empowerment, psychological capital, job involvement, and the retention intention of kindergarten teachers in mainland China and the internal mechanism of action.Methods: A total of 554 kindergarten teachers were investigated by scales for psychological empowerment, psychological capital, job involvement, and retention intention.Results: (1) Psychological empowerment was positively correlated with psychological capital and job involvement. Psychological capital was positively correlated with job involvement. Psychological empowerment, psychological capital, and job involvement were significantly and positively correlated with retention intention. (2) Psychological empowerment influences kindergarten teachers' retention intention mainly through three indirect effects: the single intermediary effects of psychological capital and job involvement and the chain intermediary effect of psychological capital → job involvement.Conclusion: Psychological empowerment can not only indirectly predict the retention intention of kindergarten teachers through the single intermediary effects of psychological capital and job involvement, but also indirectly predict the retention intention of kindergarten teachers through the chain intermediary effect of psychological capital and job involvement.

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Indirect effects of timber extraction on plant recruitment and diversity via reductions in abundance of frugivorous spider monkeys

Journal of Tropical Ecology ◽

10.1017/s0266467409990307 ◽

2009 ◽

Vol 26 (1) ◽

pp. 45-52 ◽

Cited By ~ 13

Author(s):

Gabriel Gutiérrez-Granados ◽

Rodolfo Dirzo

Keyword(s):

Indirect Effects ◽

Species Interactions ◽

Spider Monkey ◽

Spider Monkeys ◽

Plant Recruitment ◽

Ecological Processes ◽

Paired Design ◽

The Impact ◽

Understorey Plant ◽

Timber Extraction

Abstract:The ecological effects of logging in the tropics have been analysed largely in terms of its impacts on species diversity and abundance. However, information is very limited regarding the impact of logging on ecological processes such as species interactions. Here we hypothesize that timber extraction per se, that is, in the absence of hunting, affects the abundance of the frugivorous spider monkey, Ateles geoffroyi, and that this has indirect effects on the recruitment of a predominant tree species, Manilkara zapota, and the diversity of the understorey plant community. We compared logged and unlogged sites, using a paired design. In each management condition we conducted line transects and interviews to evaluate spider monkey abundance and game preferences, respectively. Impact on plant recruitment and understorey diversity were evaluated using 2 × 2-m plots (N = 320) established under 40 M. zapota tree crowns. No spider monkeys were recorded in logged sites whereas they were abundant (15 ± 8 individuals per man-km) in unlogged sites. Interviews showed that spider monkeys are not hunted by local inhabitants. Logging was correlated with a reduction of the number of M. zapota fruits used by A. geoffroyi; an increase in the number of sites dominated by M. zapota; and a reduction in understorey plant diversity. Our results suggest that the absence of A. geoffroyi in logged sites can indirectly impact plant recruitment and diversity via the disruption of plant–frugivore interactions. Further work is needed to assess if these effects persist over the long term, to define if logging operations affect the overall diversity of tropical forests.

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An invasive herbivore structures plant competitive dynamics

Biology Letters ◽

10.1098/rsbl.2017.0374 ◽

2017 ◽

Vol 13 (11) ◽

pp. 20170374

Author(s):

Lydia Wong ◽

Tess Nahanni Grainger ◽

Denon Start ◽

Benjamin Gilbert

Keyword(s):

Invasive Species ◽

Indirect Effects ◽

Species Interactions ◽

Native Species ◽

Community Dynamics ◽

Aphid Species ◽

Ecological Communities ◽

Native Plant ◽

Native Communities ◽

Species Invasions

Species interactions are central to our understanding of ecological communities, but may change rapidly with the introduction of invasive species. Invasive species can alter species interactions and community dynamics directly by having larger detrimental effects on some species than others, or indirectly by changing the ways in which native species compete among themselves. We tested the direct and indirect effects of an invasive aphid herbivore on a native aphid species and two host milkweed species. The invasive aphid caused a 10-fold decrease in native aphid populations, and a 30% increase in plant mortality (direct effects). The invasive aphid also increased the strength of interspecific competition between the two native plant hosts (indirect effects). By investigating the role that indirect effects play in shaping species interactions in native communities, our study highlights an understudied component of species invasions.

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Timing and duration of phenological subsidies: toward a mechanistic understanding of impacts on community structure and ecosystem processes in stream food chains

10.1101/768556 ◽

2019 ◽

Author(s):

Gaku Takimoto ◽

Takuya Sato

Keyword(s):

Life History ◽

Indirect Effects ◽

Species Interactions ◽

Community Dynamics ◽

Food Chains ◽

Cascading Effects ◽

Litter Processing ◽

Phenological Changes ◽

Field Manipulation

ABSTRACTPhenological resources are common across many ecological communities, and can strongly affect community dynamics. Recent field manipulation experiments in stream food chains found that seasonal timing and duration of terrestrial prey inputs affected the feeding behavior, growth, and maturation of fish predators, caused predator-mediated indirect effects on aquatic prey, and modified trophic-cascading effects on litter processing. These experiments described impacts of resource phenological changes over a few month period, and long-term impacts of continued changes in resource phenology are unknown. Here we develop a mathematical model to extrapolate long-term predictions about the effects of changes in resource phenology from the results of field manipulation experiments. The model predicts that advanced timing generally decreases aquatic prey and litter processing and prolonged duration will either increase or decrease aquatic prey and litter processing depending on the total amount and pre-disturbed timing and duration of terrestrial prey inputs. Importantly, our modeling approach clarifies the mechanisms by which stage-specific responses of life history processes in fish, such as growth, maturation, and reproduction, respond to phenological changes in terrestrial prey inputs and mediate indirect effects on aquatic prey and litter processing. Stage-specific responses of life history processes are an integral part of the mechanisms with which to predict the consequences of phenological species interactions at the community and ecosystem levels.

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