scholarly journals Coexistence of complete competitors with fitness inequality

2017 ◽  
Author(s):  
Lev Kalmykov ◽  
Vyacheslav Kalmykov
Keyword(s):  
Competitive Exclusion ◽  
Initial Conditions ◽  
Exclusion Principle ◽  
Single Individual ◽  
Competing Species ◽  
Competitive Exclusion Principle ◽  
Trade Offs ◽  
Initial Stage ◽  
Initial Location ◽  
Rigorous Model

There was a long standing contradiction between formulations of the competitive exclusion principle and natural species richness, which is known as the biodiversity paradox. Here we investigate a role of fitness differences in coexistence of two completely competing species using individual-based cellular automata. According to the classical formulations of the competitive exclusion principle such coexistence is impossible. Earlier we found that coexistence of complete competitors is possible with a 100% difference in fitness, but only under certain initial conditions. Here we verify a hypothesis that completely competing species may coexist with less than 100% difference in fitness regardless of different initial location of competing individuals in the ecosystem. We have found a new fact that two aggressively propagating complete competitors can stably coexist in one limited, stable and homogeneous habitat, when one species has some advantage in fitness over the other and all other characteristics of the species are equal, in particular any trade-offs and cooperations are absent. This fact is established theoretically on the rigorous model. The found competitive coexistence occurred regardless of the initial location of individuals in the ecosystem. When colonization of free habitat started from a single individual of each species, then the complete competitors coexisted up to 31% of their difference in fitness. And when on initial stage half of the territory was probabilistically occupied, the complete competitors coexisted up to 22% of their difference in fitness. These results additionally support our reformulation of the competitive exclusion principle, which we consider as resolving of the biodiversity paradox.

scholarly journals Axiomatic-deductive theory of competition of complete competitors: coexistence, exclusion and neutrality in one model

2020 ◽  
Author(s):  
Lev V. Kalmykov ◽  
Vyacheslav L. Kalmykov
Keyword(s):  
Artificial Intelligence ◽  
Competitive Exclusion ◽  
Ecosystem Dynamics ◽  
Exclusion Principle ◽  
Single Individual ◽  
Competing Species ◽  
Competitive Exclusion Principle ◽  
Cooperative Effects ◽  
Initial Location ◽  
Individual Based Modeling

AbstractBackgroundThe long-standing contradiction between formulations of the competitive exclusion principle and natural diversity of trophically similar species is known as the biodiversity paradox. Earlier we found that coexistence of complete competitors is possible despite 100% difference in competitiveness, but only under certain conditions – at their moderate propagation and at the particular initial location of individuals. Here we verify a hypothesis that completely competing species with aggressive propagation may coexist with less than 100% difference in competitiveness regardless of random initial location of competing individuals in ecosystem.MethodsWe investigate a role of competitiveness differences in coexistence of two completely competing species by individual-based modeling based on a transparent artificial intelligence. We propose and investigate an individual-based model of ecosystem dynamics supplemented by a probabilistic determination of the competitiveness of competing individuals without cooperative effects and with cooperative effects based on the numerical superiority of individuals of the species.ResultsWe have found that two aggressively propagating complete competitors can stably coexist, despite one species has some advantage in competitiveness over the other and all other characteristics of the species are equal. The found competitive coexistence occurred regardless of the initial random location of individuals in the ecosystem. When colonization of a free habitat started from a single individual of each species, then the complete competitors coexisted up to 31% of their difference in competitiveness. And when on initial stage half of the territory was probabilistically occupied, the complete competitors coexisted up to 22% of their difference in competitiveness. In the experiments with cooperative dependence on the numerical superiority of individuals of the species complete competitors stably co-existed despite 10% difference in basic competitiveness.DiscussionThe results additionally support our earlier reformulation of the competitive exclusion principle. Besides that, we revealed classical cases of competitive exclusion and “neutrality”. Our approach unifies models of competitive exclusion (“niche”), neutrality and coexistence of complete competitors in one theory. Our individual-based modeling of a complex system based on a transparent artificial intelligence opens up great prospects for a variety of theoretical and applied fields.

How can inter-specific interferences explain coexistence or confirm the competitive exclusion principle in a chemostat?

2018 ◽  
Vol 11 (08) ◽  
pp. 1850111 ◽  
Author(s):  
Miled El Hajji
Keyword(s):  
Competitive Exclusion ◽  
Initial Conditions ◽  
Exclusion Principle ◽  
Initial Condition ◽  
System Of Differential Equations ◽  
Specific Density ◽  
Competitive Exclusion Principle ◽  
Mutualistic Relationship ◽  
Dependent Growth

In this paper, I consider two species feeding on limiting substrate in a chemostat taking into account some possible effects of each species on the other one. System of differential equations is proposed as model of these effects with general inter-specific density-dependent growth rates. Three cases were considered. The first one for a mutual inhibitory relationship where it is proved that at most one species can survive which confirms the competitive exclusion principle. Initial concentrations of species have great importance in determination of which species is the winner. The second one for a food web relationship where it is proved that under general assumptions on the dilution rate, both species persist for any initial conditions. Finally, a third case dealing with an obligate mutualistic relationship was discussed. It is proved that initial condition has a great importance in determination of persistence or extinction of both species.

scholarly journals On a solution of the biodiversity paradox and a competitive coexistence principle

2014 ◽  
Author(s):  
Lev V. Kalmykov ◽  
Vyacheslav L. Kalmykov
Keyword(s):  
Sustainable Development ◽  
Biodiversity Conservation ◽  
Theoretical Basis ◽  
Competitive Exclusion ◽  
Exclusion Principle ◽  
Central Problem ◽  
Competitive Exclusion Principle ◽  
Theoretical Ecology ◽  
Competitive Coexistence ◽  
Trade Offs

The biodiversity paradox is the central problem in theoretical ecology. The paradox consists in the contradiction between the competitive exclusion principle and the observed biodiversity. This contradiction is the key subject of the long-standing and continuing biodiversity debates. The paradox impedes our insights into biodiversity conservation. Previously we proved that due to a soliton-like behaviour of population waves complete competitors can indefinitely coexist in one closed homogeneous habitat on one and the same limiting resource under constant conditions of environment, without any trade-offs and cooperations. As this fact violates the known formulations of the competitive exclusion principle we have reformulated the principle. Here we explain why this reformulation of the principle results in a solution of the biodiversity paradox. In addition, we generalize the competitive exclusion principle. Reasoning by contradiction, we formulate a generalized principle of competitive coexistence. These principles expand theoretical basis for biodiversity conservation and sustainable development.

scholarly journals The Paradox of the Plankton: Coexistence of Structured Microbial Communities

2021 ◽  
Author(s):  
Alberto Scarampi
Keyword(s):  
Competitive Exclusion ◽  
Resource Competition ◽  
Exclusion Principle ◽  
Limited Resources ◽  
Shared Resources ◽  
Competitive Exclusion Principle ◽  
Biophysical Models ◽  
Competition Models ◽  
Model Match ◽  
Trade Offs

In the framework of resource-competition models, it has been argued that the number of species stably coexisting in an ecosystem cannot exceed the number of shared resources. However, plankton seems to be an exception of this so-called "competitive-exclusion principle". In planktic ecosystems, a large number of different species stably coexist in an environment with limited resources. This contradiction between theoretical expectations and empirical observations is often referred to as "The Paradox of the Plankton". This project aims to investigate biophysical models that can account for the large biodiversity observed in real ecosystems in order to resolve this paradox. A model is proposed that combines classical resource competition models, metabolic trade-offs and stochastic ecosystem assembly. Simulations of the model match empirical observations, while relaxing some unrealistic assumptions from previous models.

Ecological Theory and the Superfluous Niche

2019 ◽  
Vol 47 (1) ◽  
pp. 105-123
Author(s):  
James Justus ◽  
Keyword(s):  
Competitive Exclusion ◽  
Ecological Theory ◽  
Character Displacement ◽  
Exclusion Principle ◽  
Limiting Similarity ◽  
Competitive Exclusion Principle ◽  
Ecological Equivalence

Perhaps no concept has been thought more important to ecological theorizing than the niche. Without it, technically sophisticated and well-regarded accounts of character displacement, ecological equivalence, limiting similarity, and others would seemingly never have been developed. The niche is also widely considered the centerpiece of the best candidate for a distinctively ecological law, the competitive exclusion principle. But the incongruous array and imprecise character of proposed definitions of the concept square poorly with its apparent scientific centrality. I argue this definitional diversity and imprecision reflects a problematic conceptual indeterminacy that challenges its putative indispensability in ecology.

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