scholarly journals Trophic consequences of competitive interactions in freshwater fish: Density dependent effects and impacts of inter‐specific versus intra‐specific competition

2020 ◽  
Author(s):  
Vanessa De Santis ◽  
Catherine Gutmann Roberts ◽  
J. Robert Britton
Keyword(s):  
Freshwater Fish ◽  
Competitive Interactions ◽  
Fish Density ◽  
Density Dependent

The bioenergetics of density-dependent growth in Arctic char (Salvelinus alpinus)

2012 ◽  
Vol 69 (10) ◽  
pp. 1651-1662 ◽  
Author(s):  
Guillaume Guénard ◽  
Daniel Boisclair ◽  
Ola Ugedal ◽  
Torbjørn Forseth ◽  
Ian A. Fleming ◽  
...  
Keyword(s):  
Large Scale ◽  
Salvelinus Alpinus ◽  
Growth Efficiency ◽  
Arctic Char ◽  
Fish Density ◽  
Power Relationship ◽  
Negative Power ◽  
Density Dependent ◽  
Dependent Growth ◽  
Consumption Activity

We explored the mechanisms of density-dependent growth in Arctic char ( Salvelinus alpinus ) by comparing the energetics of growth, consumption, and activity obtained under three replicated density treatments in a large-scale enclosure (90 m2 surface area) experiment. The enclosures permitted the entry of zooplankton and allowed char to feed on the bottom and at the surface of the lake. We found a negative (power) relationship between growth and density. Char consumption rate decreased linearly with increasing density. Growth efficiency was affected by fish density in a similar manner as growth rate. Finally, activity increased with fish density and was particularly high at high densities. Our findings illustrate the complexity of the relationships among consumption, activity, growth rates, and fish density and bring further evidence to the possible involvement of behavioural mechanisms in density-dependent processes, notably by modulating activity costs with density.

Density Dependent Growth and Size Specific Competitive Interactions in Young Fish

Oikos ◽  
1999 ◽  
Vol 86 (2) ◽  
pp. 217 ◽  
Author(s):  
Par Bystrom ◽  
Emili Garcia-Berthou
Keyword(s):  
Competitive Interactions ◽  
Young Fish ◽  
Density Dependent ◽  
Dependent Growth

Competition between native and immigrant Polygonum congeners

1993 ◽  
Vol 71 (7) ◽  
pp. 939-945 ◽  
Author(s):  
B. Collins ◽  
G.R. Wein
Keyword(s):  
Key Words ◽  
Plant Height ◽  
Biomass Allocation ◽  
Seed Set ◽  
Niche Differentiation ◽  
Greenhouse Experiment ◽  
Competitive Interactions ◽  
Mature Plant ◽  
Shared Resources ◽  
Density Dependent

Coexistence of annual herbs Polygonum punctatum, a native, and Polygonum caespitosum, an immigrant, may result from (i) niche differentiation that reduces or avoids competition, (ii) competitive equivalence for shared resources, or (iii) interaction between a strong competitor and a species that tolerates competition. We investigated competitive interactions between the Polygonum congeners in a greenhouse experiment using plants grown from seed to seed set. Thinning profiles of monocultures were density dependent but did not differ between the species in monocultures. Biomass allocation to root, shoot, and racemes was not influenced by competition from conspecifics or congeners. Mature plant height and raceme production of both species were negatively affected by congener density; however, the species were not competitively equivalent. Polygonum caespitosum was suppressed into the shorter heights in mixture pots but produced more racemes at all but the greatest congener densities. Key words: competition, coexistence, annual herbs, immigrant.

Population Dynamics and Stability

2013 ◽  
Author(s):  
Eric Post
Keyword(s):  
Climate Change ◽  
Population Dynamics ◽  
Density Dependence ◽  
Environmental Variation ◽  
External Factors ◽  
Competitive Interactions ◽  
Density Dependent ◽  
Survival And Reproduction ◽  
Dependent Processes

This chapter examines the implications of climate change for population dynamics and stability. Population dynamics, or the variation in abundance of a population through time, can be decomposed into two components: density-dependent and density-independent processes. Density-dependent processes are those involving competitive interactions among members of the same species within the same population that influence survival and reproduction. Density-independent processes are those that do not involve interactions with other members of the same species in the same population but rather owe to external factors such as environmental variation. It is this latter set of processes that has relevance to climate change, though density dependence certainly has a role to play in the response of populations to climate change.

scholarly journals Effects of density dependent larval competition on the life history traits of Aedes aegypti and Aedes albopictus (Diptera: Culicidae)

2017 ◽  
Vol 49 (1) ◽  
pp. 97 ◽  
Author(s):  
Sampa Banerjee ◽  
Soujita Pramanik ◽  
Soumyajit Banerjee ◽  
Goutam K. Saha ◽  
Gautam Aditya
Keyword(s):  
Life History ◽  
Aedes Aegypti ◽  
Life History Traits ◽  
Population Level ◽  
Competitive Interactions ◽  
Pupal Weight ◽  
Larval Competition ◽  
Density Dependent ◽  
Geographical Regions ◽  
F2 Generation

Consequences of larval competition at the population level provide explanation for the differences in relative abundance of <em>Aedes aegypti</em> and <em>Aedes</em> <em>albopictus</em> in different geographical regions. The outcome of competition is assessed through the estimates of the life history traits as a response to varying density and resource available for larval development. In the present study, variations in the life history traits due to density-dependent intra- and inter- specific competition involving <em>A. aegypti</em> and <em>A. albopictus</em> were assessed following the minimalist model. The instar-I larvae (0-day old F2 generation) of both <em>Aedes</em> species were reared to the adult stages using the initial rearing density of 1, 2, 4 and 6 (individuals/10ml) in multiple replicates. The age at pupation, pupal weight, adult weight and adult wing length of the individuals were considered as the response variables and surrogates of estimating the competitive interactions. Density dependent variations in the competitive interactions were evident for both the mosquitoes with reference to the selected life history traits. In <em>A. aegypti,</em> the life history traits varied with the levels of competition, which was not observed for <em>A. albopictus</em>. Although the density levels considered in the present instance were lower than in earlier studies, the observations were similar, with <em>A. albopictus</em> being competitively superior. It appears that irrespective of the density levels, interspecific competition affects <em>A. aegypti</em> and thus may bear population level consequences and overall abundance in the areas where both species are present.

Cascading life-history interactions: alternative density-dependent pathways drive recruitment dynamics in a freshwater fish

Oecologia ◽  
2006 ◽  
Vol 148 (4) ◽  
pp. 573-582 ◽  
Author(s):  
Rena E. Vandenbos ◽  
William M. Tonn ◽  
Shelly M. Boss
Keyword(s):  
Life History ◽  
Freshwater Fish ◽  
Density Dependent
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