How does predation affect competition

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Primary Literature 1. MacArthur R Species packing and competitive equilibrium for many species. Theor Popul Biol —11 Google Scholar. MacArthur RH Geographical ecology: patterns in the distribution of species. Tilman D Resource competition and community structure.

Grubb PJ The maintenance of species-richness in plant communities: the importance of the regeneration niche. Biol Rev — Google Scholar. Harper JL Population biology of plants. Academic, London Google Scholar. Connolly SR, Roughgarden J Theory of marine communities: competition, predation, and recruitment-dependent interaction strength. Ecol Monogr — Google Scholar. Bioscience — Google Scholar. Birch LC The meanings of competition. Am Nat —18 Google Scholar.

Schoener TW Field experiments on interspecific competition. Am Nat — Google Scholar. Dayan T, Simberloff D Ecological and community-wide character displacement: the next generation.

Ecol Lett — Google Scholar. Chesson P Quantifying and testing species coexistence mechanisms. Ecology — Google Scholar. Chesson P Mechanisms of maintenance of species diversity. Nature — Google Scholar. Holt RD Predation, apparent competition, and the structure of prey communities. Theor Popul Biol — Google Scholar. Nicholson AJ The role of competition in determining animal populations. Roughgarden J Community structure and assembly. Holt RD Spatial heterogeneity, indirect interactions, and the coexistence of prey species.

Chesson P, Huntly N Temporal hierarchies of variation and the maintenance of diversity. Plant Species Biol — Google Scholar. Kang Y, Chesson P Relative nonlinearity and permanence. Theor Popul Biol —35 Google Scholar. Abrams PA High competition with low similarity and low competition with high similarity: exploitative and apparent competition in consumer-resource systems. Abrams PA, Rueffler C Coexistence and limiting similarity of consumer species competing for a linear array of resources.

Hardin G The competitive exclusion principle. Science — Google Scholar. Schoener TW Resource partitioning in ecological communities. Science —39 Google Scholar. Tilman D Plant strategies and the dynamics and structure of plant communities.

Hubbell SP The unified neutral theory of biodiversity and biogeography. Purves DW, Pacala SW Ecological drift in niche-structured communities: neutral pattern does not imply neutral process.

J Theor Biol — Google Scholar. Chesson P, Huntly N The roles of harsh and fluctuating conditions in the dynamics of ecological communities. In summary, we demonstrate that predation and, to a lesser extent, competition, have strong top-down effects structuring a guild of Neotropical amphibian larvae and their trophic status.

Predation and competition differentially altered growth, survival and the trophic niches of multiple amphibian species, with potential downstream ramifications for resource assimilation and energy flow between aquatic and terrestrial habitats. Longer-term studies of trophic alterations and structure in aquatic communities are needed to clarify the ecological consequences and cascading effects of amphibian losses in food webs across the world, given that they are the most endangered group of vertebrates Stuart et al.

JT and IG-M conceived the study and designed the experiment. RA and JT setup the mesocosms and collected the animals. RA conducted the experiment and collected the data. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

We also thank the unconditional help in the field and experimental work from H. Lee, G. Toral, K. Warkentin, T. Hammer, P. Marting, U. Somjee, I. Hoffmann, and any others who passed by and gave a hand. The mesocosm array was made possible by an NSF grant to K. Warkentin and J.

Ackerly, D. Community assembly, niche conservatism, and adaptive evolution in changing environments. Plant Sci. Agrawal, A. Phenotypic plasticity in the interactions and evolution of species. Science , — Alford, R. McDiarmid and R. Altig Chicago: University of Chicago Press , — Google Scholar.

Altig, R. What do tadpoles really eat? Assessing the trophic status of an understudied and imperiled group of consumers in freshwater habitats. Alzmann, N. Arribas, R. Ecological consequences of amphibian larvae and their native and alien predators on the community structure of temporary ponds. Stable isotopes reveal trophic partitioning and trophic plasticity of a larval amphibian guild.

Atwood, T. Competitive displacement alters top-down effects on carbon dioxide concentrations in a freshwater ecosystem. Oecologia , — Azevedo-Ramos, C. Predation as the key factor structuring tadpole assemblages in a savanna area in Central Amazonia.

Copeia 1, 22— Benjamini, Y. Controlling the false discovery rate: a practical and powerful approach to multiple testing. B 57, — Berg, M. Temporal and spatial variability in soil food web structure. Oikos , — Bolnick, D. Resource competition modifies the strength of trait-mediated predator-prey interactions. Ecology 86, — Bowes, R. Brodin, T. Effects of predator-induced thinning and activity changes on life history in a damselfly. Caut, S. Plastic changes in tadpole trophic ecology revealed by stable isotope analysis.

Oecologia , 95— Chase, J. The interaction between predation and competition: a review and synthesis. Claessen, D. The impact of size-dependent predation on population dynamics and individual life history. Ecology 83, — Corbet, P. A Biology of Dragonflies.

London: Witherby. Costa, Z. Interspecific differences in the direct and indirect effects of two neotropical hylid tadpoles on primary producers and zooplankton. Biotropica 45, — Prey subsidy or predator cue? Direct and indirect effects of caged predators on aquatic consumers and resources. DeNiro, M. Influence of diet on the distribution of nitrogen isotopes in animals. Acta 45, — Fry, B. Stable Isotope Ecology. Springer: New York, NY. Overfishing of small pelagic fishes increases trophic overlap between immature and mature striped dolphins in the Mediterranean Sea.

Gomez-Mestre, I. Geographic variation in asymmetric competition: a case study with two larval anuran species. Evolution of adaptive plasticity: risk-sensitive hatching in neotropical leaf-breeding treefrogs. Gonzalez, S. Interactions between competition and predation shape early growth and survival of two neotropical hylid tadpoles.

Biotropica 43, — Gurevitch, J. The interaction between competition and predation: a meta-analysis of field experiments. Hammill, E. Predation threat alters composition and functioning of bromeliad ecosystems. Ecosystems 18, — Hero, A. Antipredator defenses influence the distribution of amphibian prey species in the central amazon rain forest. Biotropica 33, — Kilham, S. Challenges for interpreting stable isotope fractionation of carbon and nitrogen in tropical aquatic ecosystems.

Verhandlungen Int. Vereinigung Limnol. Kozak, K. Phylogeny, ecology, and the origins of climate—richness relationships. Ecology 93, — Layman, C. Applying stable isotopes to examine food-web structure: an overview of analytical tools. Legendre, P. Analyzing beta diversity: partitioning the spatial variation of community composition data. Levin, D. Flowering-time plasticity facilitates niche shifts in adjacent populations.

New Phytol. Lima, S. Nonlethal effects in the ecology of predator-prey interactions - What are the ecological effects of anti-predator decision-making? Bioscience 48, 25— Mahato, M. North Am. McIntyre, P. Effects of behavioral and morphological plasticity on risk of predation in a Neotropical tadpole. Morin, P. Predation, competition, and the composition of larval anuran guilds.

Morlon, H. Effects of trophic similarity on community composition. Mowles, S. Susceptibility to predation affects trait-mediated indirect interactions by reversing interspecific competition. Newsome, S.

A niche for isotopic ecology. Nystrom, P. The influence of multiple introduced predators on a littoral pond community. Ecology 82, — CrossRef Full Text. Paine, R. Food web complexity and species diversity. Pascual, M. Oxford: Oxford University Press. Peacor, S. Behavioural response of bullfrog tadpoles to chemical cues of predation risk are affected by cue age and water source.

Hydrobiologia , 39— Peterson, B. Stable isotopes in ecosystem studies. Pimm, S. Food Webs. Dordrecht: Springer. Post, D. Using stable isotopes to estimate trophic position: models, methods, and assumptions. Intraspecific variation in a predator affects community structure and cascading trophic interactions.

Performance of the prey species in resource competition and predation environments. In both panels letters a , b or c indicate subsets that are statistically not different from each other.

Grazing resistance, as with population growth rates, was different among species and rank among species depended on the resource concentration Figure 1 B; species identity: F 3. The grazing resistance of S. In intermediate and high resource concentrations, S. The total number of prey individuals was lower when predators were present in all resource concentrations and each concentration produced low, intermediate and high population densities Figure 2 ; predator treatment: F 1.

Predator population density was lower in low resource concentrations compared to intermediate and high resource concentrations Figure 2 ; resource treatment: F 2. Furthermore, predator population density declined over time in all resource concentrations time: F 1. The effects of experimental treatments resource enrichment and predation on community composition and population densities over time. Vertical bars indicate species proportions in the prey community over time.

Horizontal lines represent the total number of individuals in the prey community circles, total number of prey individuals in the prey community and T. The effects of predation on prey community composition differed along the resource concentration axis.

The proportion of N. In intermediate resource concentrations, the proportions of all species were different from each other; the proportion of N. The proportion of B. Competition for shared resources and predation are usually among the most important factors driving prey community dynamics [ 20 ].

To investigate the effects of these two factors on community dynamics after a resource pulse, we conducted a microbial microcosm experiment where we manipulated the intensity of resource competition with resource pulse concentration as well as the presence of predation. In order to predict and understand the outcome of community dynamics, we measured growth and defense related traits of each prey species prior to the long-term experiment.

Based on these measurements, we were able to categorize N. Results from the community experiment support this view: without predators in all resource concentrations and also with predators in low resource concentration, N.

However, predation hindered the dominance of N. See Table 1 for a summary of the results. Temporal changes in resource availability, such as resource pulses, are known to promote species coexistence [ 4 ]. This enhanced diversity is often explained by interspecific differences in the ability to maintain positive growth under low resource conditions and rapid growth when resources are abundant [ 21 — 24 ].

The role of fluctuating resources on species co-existence and community dynamics was tested in a previous study [ 17 ] using the same microbial community as here. The main finding in that study was that S. However, in the Hiltunen et al. A likely reason why S. In the current study, S. Thus, high resource specialists will experience a fitness benefit only for a short period of time and after a while species specialized in the use of low resource concentrations, such as N.

However, we found that in the intermediate and high resource concentrations without predators S. This is a result that cannot be explained with the competitive ability measurements.

One explanation for this change in dominance after 21 days is the change in the resource quality. Pekkonen et al. They found, among other things, that S. To investigate similar questions, Lawrence et al. This approach could also have been useful in our study for investigating qualitative changes in our culture media and explain why S. However, based on data that we have now, we can conclude that in our resource pulse environment, temporal changes in the resource availability might not only have been quantitative but also qualitative.

Even though we do not have direct evidence, this type of complex facilitative interaction could explain why the inferior competitor in low concentrations of fresh growth media could dominate at the end of the experiment when concentrations of the original resources were bound to be extremely low. However, this also makes predicting the competitive outcome based solely on growth rate measurements more challenging.

Predation is generally predicted to have a positive effect on coexistence among prey species when predators prevent the exclusion of more resistant but less competitive prey types [ 6 , 7 , 16 , 26 ].

The community data presented here is a good example of this scenario. Without predators, N. Interestingly, we found an interactive effect between resource concentration and predation treatments so that in low resource environments N. Holt et al.

Our experimental findings described above are consistent with the predictions by Holt et al. We observed, as the theory predicts, a shift in dominance from the superior resource competitor N.

Changes in the relative importance of competition and predation related traits along an enrichment axis might explain this finding in our experiments. When resources are extremely limited, traits related to competitive ability are disproportionally important and the importance of these traits may override any benefits that the higher grazing resistance can provide. Also, the fact that predator population density and, therefore, predation pressure was lower in the low resource environment could have contributed to making competitive ability a more important factor in determining the dominant prey species.

We found that in our experimental bacterial communities, either resource availability or ciliate predation determined the dominant species. This is in line with theoretical predictions [ 1 , 2 , 6 , 7 , 21 , 23 , 26 , 27 ]. In most cases, we were able to predict the identity of the dominant species based on trait characteristics measured prior to the community experiment in single species short-term assays.

We also found that resource concentration and predation treatments strongly interacted so that in low resource environments competitive ability was the main factor determining the community composition. All strains were obtained from the American Type Culture Collection [ 28 ]. The criteria for selecting these three bacterial species included positive growth on both the nutrient broth agar and liquid prey culture medium and that the species were distinguishable based on their colony color and morphology.

Three final concentrations of plant detritus used throughout experiment were 0. As a predator, we used a ciliated protozoa, Tetrahymena thermophila ATCC , which is an asexual strain consisting of only a single mating type and has been widely used in experimental microbial ecology [ 8 , 9 , 17 , 29 — 31 ] T. We conducted a short-term growth and feeding experiment to estimate the competitive ability and grazing resistance of each prey species. As an estimate of competitive ability, we used population growth rate and grazing resistance estimated as biomass reduction by predators.

Measurements were conducted in each of the three resource concentrations low, intermediate and high. Then, the population was allowed to grow for 96 hours and the initial period when resources were not limiting was used to estimate the maximum growth rate see below.

We monitored bacterial biomass optical density for another 96 hours which allowed predators to reach a high density and prey population was simultaneously grazed down. This reduction of prey biomass percent grazed biomass from initial biomass prior to the addition of the predators was then used as an estimate of the grazing resistance. All treatments were replicated nine times. Population growth and predator-induced decline was measured with Bioscreen C spectrophotometer Growth Curves AB Ltd, Finland where optical density of each well was measured at — nm wavelengths at five minute intervals.

Population growth rate was calculated as the slope of the linear regression of natural logarithms of population biomass versus time when the population grew at its maximal rate. This methodology in bacterial trait measurements has been used successfully in previous studies with similar systems see e.

To study community dynamics after a resource pulse, we conducted a factorial microcosm experiment in batch cultures where bacterial communities were cultured in three resource levels low, intermediate and high , with and without predators.

Each treatment was replicated four times.