Dynamic modes of exploited limited population: results of modeling and numerical study

2016 ◽  
Vol 11 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Г.П. Неверова ◽  
G.P. Neverova
Keyword(s):  
Population Dynamics ◽  
Density Dependence ◽  
Population Size ◽  
Age Structure ◽  
Birth Rate ◽  
Numerical Study ◽  
Dynamic Regime ◽  
Demographic Parameters ◽  
Current Population

The paper investigates the model of population dynamics with age structure and density dependence of birth rate. We consider two situations: 1) the population develops freely and 2) the population is exploited. It was shown that harvesting leads to the stabilization of the dynamics. There is multiregimism, i.e. different dynamic regimes are possible with the same values of demographic parameters. It is shown that even a single harvesting in the current population size could lead to a change of the observed dynamic regime.

scholarly journals Bistability and Bifurcations in Modified Nicholson-Bailey Model with Age-Structure for Prey

2019 ◽  
Vol 14 (1) ◽  
pp. 257-278 ◽  
Author(s):  
O.L. Revutskaya ◽  
M.P. Kulakov ◽  
E.Ya. Frisman
Keyword(s):  
Survival Rate ◽  
Population Size ◽  
Age Structure ◽  
Birth Rate ◽  
System Stability ◽  
Dynamic Mode ◽  
Interacting Species ◽  
Predator Prey Model ◽  
Saddle Node ◽  
Age Dependent

The paper investigates dynamic modes of the predator-prey model with age structure for prey. We use a slight modification of the Nicholson-Bailey model to describe the interaction between predator and prey. We assume the population size is regulated by decreasing juvenile survival rate with growth of age class sizes. Conditions for sustainable coexistence of interacting species are described. It is shown that the coexistence of species becomes possible if there are a transcritical or saddle-node (tangential) bifurcations. Due to the saddle-node bifurcation there is bistability in the system of interacting species: predator either coexists with prey or dies depending on the initial conditions. It is shown that the range of demographic parameters, for which the prey and predator coexist, can significantly increase with growth of survival of adult prey or the proportion of predators born or the prey consumption rate of the predator. We studied the oscillation scenarios of interacting population, influences of reproduction, survival and self-regulation rates of population prey and age-dependent predation as well as variations in the current number on transitions between different dynamic modes. It is shown that an increase in the birth rate of the prey under intraspecific competition can lead to a dynamics destabilization and to oscillations appearance in numbers. Age-dependent predation is shown to be a stabilizing influence. At the same time, with a high birth rate of the prey, the system stability is ensured by the high survival rate of adult prey. It was found that in the model parametric space, both bistability and multistability arises, which are not related to each other. Consequently, even a small variation of the current population size leads to more complex behavior of the interacting species, and can give a significant change in both the observed dynamic mode and the coexistence scenario of the species.

Dynamic Regimes of Local Homogeneous Population with Delayed Density Dependence

2015 ◽  
Vol 10 (2) ◽  
pp. 309-324 ◽  
Author(s):  
Г.П. Неверова ◽  
G.P. Neverova
Keyword(s):  
Population Dynamics ◽  
Density Dependence ◽  
Population Size ◽  
Chaotic Attractor ◽  
Time Lag ◽  
Stable State ◽  
Periodic Oscillations ◽  
Homogeneous Population ◽  
Delayed Density Dependence ◽  
Period 2

It is researched a model of limited homogeneous population size. It is assumed that there is delayed density dependence. It is made the analytical and numerical investigation of the model with different time lag. It is shown there it is the phenomenon of multiregimism. This phenomenon consists in the existence of various dynamic regimes under the same values of parameters. This effect arises in the model that simultaneously possesses several different limit regimes: stable state, regular fluctuations, and chaotic attractor. The research results show if present population dynamics substantially depends on population size of previous years than it is observed quasi-periodic oscillations. Fluctuations with period 2 occur when the growth of population size is regulated by density-dependence in the current year.

scholarly journals Accounting for interspecific competition and age structure in demographic analyses of density dependence improves predictions of fluctuations in population size

2019 ◽  
Vol 22 (5) ◽  
pp. 797-806 ◽  
Author(s):  
Marlène Gamelon ◽  
Stefan J. G. Vriend ◽  
Steinar Engen ◽  
Frank Adriaensen ◽  
André A. Dhondt ◽  
...  
Keyword(s):  
Density Dependence ◽  
Interspecific Competition ◽  
Population Size ◽  
Age Structure

scholarly journals The effect of change in population size on DNA polymorphism.

Genetics ◽  
1989 ◽  
Vol 123 (3) ◽  
pp. 597-601 ◽  
Author(s):  
F Tajima
Keyword(s):  
Population Size ◽  
Dna Sequences ◽  
Dna Polymorphism ◽  
Population Bottleneck ◽  
Expected Number ◽  
Original Population ◽  
Current Population ◽  
Segregating Sites

Abstract The expected number of segregating sites and the expectation of the average number of nucleotide differences among DNA sequences randomly sampled from a population, which is not in equilibrium, have been developed. The results obtained indicate that, in the case where the population size has changed drastically, the number of segregating sites is influenced by the size of the current population more strongly than is the average number of nucleotide differences, while the average number of nucleotide differences is affected by the size of the original population more severely than is the number of segregating sites. The results also indicate that the average number of nucleotide differences is affected by a population bottleneck more strongly than is the number of segregating sites.

scholarly journals Sensitivity analysis of effective population size to demographic parameters in house sparrow populations

2017 ◽  
Vol 26 (9) ◽  
pp. 2449-2465 ◽  
Author(s):  
Marlene Waege Stubberud ◽  
Ane Marlene Myhre ◽  
Håkon Holand ◽  
Thomas Kvalnes ◽  
Thor Harald Ringsby ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Population Size ◽  
Effective Population Size ◽  
House Sparrow ◽  
Demographic Parameters ◽  
Effective Population
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