Cascading effects of a top predator on intraspecific competition at intermediate and basal trophic levels

AbstractCascading effects of high trophic levels onto lower trophic levels have been documented in many ecosystems. Some studies also show evidence of extended trophic cascades, in which guilds dependent on lower trophic levels, but uninvolved in the trophic cascade themselves, are affected by the trophic cascade due to their dependence on lower trophic levels. Top-down effects of large mammals on plants could lead to a variety of extended trophic cascades on the many guilds dependent on plants, such as pollinators. In this study, floral-visitor and floral abundances and assemblages were quantified within a series of 1-ha manipulations of large-mammalian herbivore density in an African savanna. Top-down effects of large mammals on the composition of flowers available for floral visitors are first shown, using regressions of herbivore activity on metrics of floral and floral-visitor assemblages. An extended trophic cascade is also shown: the floral assemblage further altered the assemblage of floral visitors, according to a variety of approaches, including a structural equation modelling approach (model with an extended trophic cascade was supported over a model without, AICc weight = 0.984). Our study provides support for extended trophic cascades affecting floral visitors, suggesting that trophic cascades can have impacts throughout entire communities.

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Trophic cascades alter eco-evolutionary dynamics and body size evolution

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.0526 ◽

2020 ◽

Vol 287 (1938) ◽

pp. 20200526

Author(s):

Thomas M. Luhring ◽

John P. DeLong

Keyword(s):

Body Mass ◽

Trophic Level ◽

Evolutionary Dynamics ◽

Trophic Cascades ◽

Trophic Levels ◽

Chain Model ◽

Top Predator ◽

Predator Prey ◽

Top Predators ◽

Time Changes

Trait evolution in predator–prey systems can feed back to the dynamics of interacting species as well as cascade to impact the dynamics of indirectly linked species (eco-evolutionary trophic cascades; EETCs). A key mediator of trophic cascades is body mass, as it both strongly influences and evolves in response to predator–prey interactions. Here, we use Gillespie eco-evolutionary models to explore EETCs resulting from top predator loss and mediated by body mass evolution. Our four-trophic-level food chain model uses allometric scaling to link body mass to different functions (ecological pleiotropy) and is realistically parameterized from the FORAGE database to mimic the parameter space of a typical freshwater system. To track real-time changes in selective pressures, we also calculated fitness gradients for each trophic level. As predicted, top predator loss generated alternating shifts in abundance across trophic levels, and, depending on the nature and strength in changes to fitness gradients, also altered trajectories of body mass evolution. Although more distantly linked, changes in the abundance of top predators still affected the eco-evolutionary dynamics of the basal producers, in part because of their relatively short generation times. Overall, our results suggest that impacts on top predators can set off transient EETCs with the potential for widespread indirect impacts on food webs.

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Giving-up diversity (GUDiv): top-down effects of foraging decisions on local, landscape and regional biodiversity of resources

10.22541/au.161113483.38126576/v1 ◽

2021 ◽

Author(s):

Jana Eccard ◽

Clara Ferreira ◽

Andres Peredo Arce ◽

Melanie Dammhahn

Keyword(s):

Foraging Behaviour ◽

Functional Trait ◽

Spatial Diversity ◽

Trophic Levels ◽

Community Effects ◽

Wild Rodents ◽

Cascading Effects ◽

Predation Effects ◽

Novel Concept ◽

Adaptive Foraging

Foraging by consumers has direct effects on the community of their resource species, and may serve as a biotic filtering mechanism of diversity. Determinants of foraging behaviour may thus have cascading effects on abundance, diversity, and functional trait composition of the resource community. Here we propose giving-up diversity (GUDiv) as a novel concept and simple measure to quantify community effects of foraging at multiple spatial diversity scales. GUDiv provides a framework linking theories of adaptive foraging behaviour with community ecology. In experimental resource landscapes we showcase effects of patch residency of foraging wild rodents on α-GUDiv, ß-GUDiv and γ- GUDiv, and on functional trait composition of resources. Using GUDiv allows for prediction-based investigation of cascading indirect predation effects (ecology of fear) across multiple trophic levels, of feedbacks between functional trait composition of resource and consumer communities, and of effects of inter-individual differences among foragers on the diversity of resource communities.

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Cascading Effects of Moth Outbreaks on Subarctic Soil Food Webs

10.21203/rs.3.rs-228461/v1 ◽

2021 ◽

Author(s):

Irene Calderón-Sanou ◽

Tamara Münkemüller ◽

Lucie Zinger ◽

Heidy Schimann ◽

Nigel Gilles Yoccoz ◽

...

Keyword(s):

Food Webs ◽

Large Scale ◽

Trophic Levels ◽

Trophic Groups ◽

Holistic View ◽

Cascading Effects ◽

Soil Food Webs ◽

Network Analyses ◽

Northern Fennoscandia ◽

Belowground Diversity

Abstract The increasing severity and frequency of natural disturbances requires a better understanding of their effects on all compartments of biodiversity. In Northern Fennoscandia, recent large-scale moth outbreaks have led to an abrupt change in plant communities from birch forests dominated by dwarf shrubs to grass-dominated systems. However, the indirect effects on the belowground compartment remained unclear. Here, we combined eDNA survey of multiple trophic groups with network analyses to demonstrate that moth defoliation has far-reaching consequences on soil food webs. Following this disturbance, diversity and relative abundance of certain trophic groups declined (e.g. ectomycorrhizal fungi) while many others profited (e.g. bacterivores, omnivores) making soil food webs more diverse and structurally different. Overall, the direct and indirect consequences of moth outbreaks increased belowground diversity at different trophic levels. Our results highlight that a holistic view of ecosystems improves our understanding of cascading effects of major disturbances on soil food webs.

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Study on autonomous and nonautonomous version of a food chain model with intraspecific competition in top predator

Mathematical Methods in the Applied Sciences ◽

10.1002/mma.6109 ◽

2019 ◽

Vol 43 (6) ◽

pp. 3167-3184 ◽

Cited By ~ 4

Author(s):

Jyotirmoy Roy ◽

Shariful Alam

Keyword(s):

Food Chain ◽

Intraspecific Competition ◽

Chain Model ◽

Top Predator ◽

Food Chain Model

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The impacts of new street light technologies: experimentally testing the effects on bats of changing from low-pressure sodium to white metal halide

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2014.0127 ◽

2015 ◽

Vol 370 (1667) ◽

pp. 20140127 ◽

Cited By ~ 33

Author(s):

Emma Louise Stone ◽

Andrew Wakefield ◽

Stephen Harris ◽

Gareth Jones

Keyword(s):

Low Pressure ◽

Global Scale ◽

County Council ◽

Metal Halide ◽

Trophic Levels ◽

Mercury Vapour ◽

Cascading Effects ◽

Significant Difference ◽

Wide Scale ◽

Species Specific

Artificial light at night is a major feature of anthropogenic global change and is increasingly recognized as affecting biodiversity, often negatively. On a global scale, newer technology white lights are replacing orange sodium lights to reduce energy waste. In 2009, Cornwall County Council (UK) commenced replacement of existing low-pressure sodium (LPS) high intensity discharge (HID) street lights with new Phillips CosmoPolis white ceramic metal halide street lights to reduce energy wastage. This changeover provided a unique collaborative opportunity to implement a before-after-control-impact field experiment to investigate the ecological effects of newly installed broad spectrum light technologies. Activity of the bat species Pipistrellus pipistrellus , P. pygmaeus and Nyctalus/Eptesicus spp. was significantly higher at metal halide than LPS lights, as found in other studies of bat activity at old technology (i.e. mercury vapour) white light types. No significant difference was found in feeding attempts per bat pass between light types, though more passes overall were recorded at metal halide lights. Species-specific attraction of bats to the metal halide lights could have cascading effects at lower trophic levels. We highlight the need for further research on possible ecosystem-level effects of light technologies before they are installed on a wide scale.

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Scale-dependent drivers of ungulate patch use along a temporal and spatial gradient of snow depth

Canadian Journal of Zoology ◽

10.1139/z2012-065 ◽

2012 ◽

Vol 90 (8) ◽

pp. 972-983 ◽

Cited By ~ 11

Author(s):

J.C. Witt ◽

C.R. Webster ◽

R.E. Froese ◽

T.D. Drummer ◽

J.A. Vucetich

Keyword(s):

Spatial Scales ◽

Abiotic Factors ◽

Landscape Composition ◽

Trophic Levels ◽

Spatial Gradient ◽

Winter Habitat ◽

Generalist Species ◽

Patch Use ◽

Cascading Effects ◽

Decrease Use

Anthropogenic changes in landscape composition or configuration have the potential to increase the abundance of generalist species, often resulting in cascading effects on other trophic levels and ecosystem function. The selection or utilization of individual patches of habitat, however, may vary in both time and space, as a result of patch and landscape attributes as well as dynamic abiotic factors (i.e., snowfall). We hypothesized that the use of high-quality habitat would be most strongly influenced by snow at local scales and by composition and the configuration of the landscape at greater spatial scales. To test this, we examined white-tailed deer ( Odocoileus virginianus (Zimmermann, 1780)) selection of eastern hemlock ( Tsuga canadensis (L.) Carrière) patches as winter habitat over a 3-year period. Patch-level attributes were poor predictors of patch use in areas with strong gradients in abiotic factors relevant to the energetics of movement or forage acquisition. Additionally, heterogeneity in the greater landscape (3000 m radius buffer) served to increase use, while homogeneity appeared to decrease use. Our results suggest that interactions between deer migratory behavior, interannual variation in winter severity, and landscape context might provide spatial and temporal refugia for hemlock regeneration; a better understanding of which could aide conservation and restoration.

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Effect of an invasive filter-feeder on the zooplankton assemblage in a coastal lagoon

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315415001320 ◽

2015 ◽

Vol 96 (6) ◽

pp. 1201-1210 ◽

Cited By ~ 1

Author(s):

Martin Bruschetti ◽

Tomas Luppi ◽

Oscar Iribarne

Keyword(s):

Phytoplankton Biomass ◽

Food Resource ◽

Zooplankton Community ◽

Grazing Intensity ◽

Trophic Levels ◽

Grazing Impact ◽

Filter Feeder ◽

Cascading Effects ◽

Mesocosm Experiments ◽

The Impact

Depletion of phytoplankton biomass by the introduced reef-forming polychaete Ficopomatus enigmaticus has previously been observed in the Mar Chiquita lagoon (37°40′S 57°23′W; Argentina), but the effect of polychaetes on the higher trophic levels is still unknown. To evaluate the effect of this polychaete on the zooplankton assemblage, replicated mesocosm experiments (N = 10) were performed during spring, summer and winter. Mesocosms with reefs and without reefs were installed and grazing intensity and the effect on the zooplankton assemblage by the polychaetes were assessed. Our results show that the reefs of F. enigmaticus generate minor changes in overall composition of zooplankton assemblage. Although the structure of the zooplankton assemblage was different between seasons, the impact of the reefs was not significant in any of them. There was no relationship between the decline of food resource by grazing and changes in the structure of the zooplankton assemblage. Thus, contrary to our hypothesis, the grazing impact of the invasive polychaete on the biomass of primary producers did not generate cascading effects to higher trophic levels. However, changes in some components of the zooplankton assemblage (e.g. cladocerans) clearly show that the reefs of F. enigmaticus have the potential to affect the structure of the zooplankton community. The lack of data of community composition and abundance of zooplankton before the invasion limits the understanding of how this polychaete might have affected the structure and abundance of the zooplankton of this lagoon. Nevertheless this work suggests that these changes may not be so significant.

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Environmentally triggered evolutionary cascade across trophic levels in an experimental phage-bacteria-insect system

10.1101/850248 ◽

2019 ◽

Cited By ~ 1

Author(s):

Matthieu Bruneaux ◽

Roghaieh Ashrafi ◽

Ilkka Kronholm ◽

Anni-Maria Örmälä-Odegrip ◽

Juan A. Galarza ◽

...

Keyword(s):

Environmental Effects ◽

Large Scale ◽

Environmental Changes ◽

Galleria Mellonella ◽

Biotic Interactions ◽

Trophic Levels ◽

Lytic Cycle ◽

Biological Interactions ◽

Insect Host ◽

Cascading Effects

AbstractEnvironmental changes can cause strong cascading effects in species communities due to altered biological interactions between species (Zarnetske et al., 2012). Highly specialized interactions arising from the co-evolution of hosts and parasites, such as bacteria and phages, and short generation times of these species could rapidly lead to considerable evolutionary changes in their biotic interactions (Kerr, 2012; Buck and Ripple, 2017), with potential large-scale ramifications to other trophic levels. Here we report experimental evidence of cascading environmental effects across trophic levels in an experimental system where phage-bacteria coevolution in an abiotically altered environment cascaded on bacterial virulence in an insect host. We found that the lytic cycle of the temperate phage KPS20 induced at low temperatures led to selection in the bacterial host Serratia marcescens that tempered the likelihood of triggering the phage’s lytic cycle. These changes in S. marcescens concomitantly attenuated its virulence in an insect host, Galleria mellonella. In addition, our data suggests that this effect is mediated by mutations and epigenetic modifications of bacterial genes moderating the onset of the temperate phage’s lytic cycle. Given the abundance of temperate phages in bacterial genomes (Canchaya et al., 2003), the sensitivity of the onset of their lytic cycle to environmental conditions (Howard-Varona et al., 2017), and the predominance of environmental change due to climate change, our results warrants attention as a cautionary example of the dangers of predicting environmental effects on species without considering complex biotic interactions.

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Dietary polyunsaturated fatty acid supply improves Daphnia performance during vertical migration

10.1101/586156 ◽

2019 ◽

Author(s):

Jana Isanta Navarro ◽

Matthias Fromherz ◽

Michelle Dietz ◽

Bettina Zeis ◽

Anke Schwarzenberger ◽

...

Keyword(s):

Lipid Peroxidation ◽

Vertical Migration ◽

Temperature Fluctuations ◽

Temperature Acclimation ◽

Trophic Levels ◽

List Type ◽

Dietary Pufa ◽

Pufa Supplementation ◽

Cold Temperatures ◽

Cascading Effects

AbstractDiel vertical migration (DVM) is a common predator avoidance strategy of zooplankton. Migration to deeper water layers during the day to escape visually hunting predators most likely requires physiological adaptations to periodically changing temperatures. Polyunsaturated fatty acids (PUFA) are essential nutrients that play crucial roles in membrane temperature acclimation. Exposure to cold temperatures typically results in an increase in the relative abundance of PUFA in cell membranes and PUFA requirements of Daphnia have been shown to increase with decreasing temperatures.To assess the significance of dietary PUFA for coping with temperature fluctuations experienced during DVM, we reared Daphnia magna at either constantly warm or fluctuating temperatures simulating DVM both with and without dietary PUFA supplementation.We show that the well-known positive effect of dietary eicosapentaenoic acid (EPA) supplementation on offspring production and population growth rates of Daphnia is more pronounced at alternating temperatures than at constantly warm temperatures. Exposure to alternating temperatures caused modification in body PUFA concentrations and, consequently, increased lipid peroxidation. However, detrimental effects of lipid peroxidation were not evident.Our data demonstrate that the capacity to cope with the distinct temperature fluctuations experienced during DVM increases with dietary EPA supplementation, suggesting that an adequate dietary PUFA supply is crucial especially for migrating Daphnia populations. A dietary deficiency in long-chain PUFA may thus severely constrain predator evasion, potentially resulting in increased mortality and cascading effects on lower trophic levels.

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