scholarly journals Influence of Harvest on the Dynamics of Populations with Age and Sex Structures

2018 ◽  
Vol 13 (1) ◽  
pp. 270-289 ◽  
Author(s):  
O.L. Revutskaya ◽  
G.P. Neverova ◽  
E.Ya. Frisman
Keyword(s):  
Self Regulation ◽  
Pair Formation ◽  
Population Models ◽  
Structured Populations ◽  
Population Fluctuations ◽  
Structured Population Models ◽  
Mechanisms Of Formation ◽  
System Nonlinearity ◽  
Harvesting Intensity ◽  
Mating Function

The paper investigates influence of sex- and age-specific harvest on the dynamics of structured populations based on the mathematical model with discrete time. We assume birth rate depends on the population sex ratio and is described by the modified harmonic mating function with switching. The population size is regulated by decreasing juvenile survival rate with growth of sex-age class sizes. The aim is to study the mechanisms of formation and evolution of dynamic modes for the exploited structured population models due to harvesting intensity. Conditions for sustainable development of the exploited population are received. Dynamic modes of the population models are studied. Influence of birth, survival, and self-regulation rates, the formation process of the mating pairs, and sex- and age-specific harvest on transitions between different dynamic modes are investigated. Sex-specific harvest of mature females or males will change the pair formation if the sex class, whose number of individuals is more, is exploited. Depending on values of the population parameters, the sex- and age-specific harvest (juveniles, mature females or males) can result in both damping of the oscillations, which stabilizes population dynamics, and the oscillation appearance, including two-year or quasiperiodic population fluctuations. The model of exploited population reveals the phenomenon of multistability, which is typical for a population without harvesting. The multistability is the result of complex bifurcations occurring due to both the system nonlinearity and the changing pair formation principle.

Demographic processes in socially structured populations

2021 ◽  
pp. 341-350
Author(s):  
Maria Paniw ◽  
Gabriele Cozzi ◽  
Stefan Sommer ◽  
Arpat Ozgul
Keyword(s):  
Population Dynamics ◽  
Social Groups ◽  
Population Models ◽  
Structured Populations ◽  
Model Complexity ◽  
Vital Rates ◽  
Integral Projection Model ◽  
Projection Model ◽  
Structured Population Models ◽  
Structured Population

In socially structured animal populations, vital rates such as survival and reproduction, are affected by complex interactions among individuals of different social ranks and among social groups. Due to this complexity, mechanistic approaches to model vital rates may be preferred over commonly used structured population models. However, mechanistic approaches come at a cost of increased modelling complexity, computational requirements, and reliance on simulated metrics, while structured population models are analytically tractable. This chapter compares different approaches to modelling population dynamics of socially structured populations. It first simulates individual-based data based on the life cycle of a hypothetical cooperative breeder and then projects population dynamics using a matrix population model (MPM), an integral projection model (IPM), and an individual-based model (IBM). The authors demonstrate that, when projecting population size or structure, the relatively simpler MPM can outperform both the IPM and IBM. However, mechanistic details parametrised in the more complex IBM are required to accurately project interactions within social groups. The R scripts in this chapter provide a roadmap to both simulate data that best describe a socially structured system and assess the level of model complexity needed to capture the dynamics of the system.

scholarly journals On the formulation and analysis of general deterministic structured population models

2001 ◽  
Vol 43 (2) ◽  
pp. 157-189 ◽  
Author(s):  
O. Diekmann ◽  
M. Gyllenberg ◽  
H. Huang ◽  
M. Kirkilionis ◽  
J.A.J. Metz ◽  
...  
Keyword(s):  
Population Models ◽  
Structured Population Models ◽  
Structured Population

scholarly journals Splitting-particle methods for structured population models: Convergence and applications

2014 ◽  
Vol 24 (11) ◽  
pp. 2171-2197 ◽  
Author(s):  
J. A. Carrillo ◽  
P. Gwiazda ◽  
A. Ulikowska
Keyword(s):  
Numerical Scheme ◽  
Order Of Convergence ◽  
Operator Splitting ◽  
Population Models ◽  
Particle Simulation ◽  
Particle Methods ◽  
Test Cases ◽  
Structured Population Models ◽  
Convergence Error ◽  
Structured Population

We propose a new numerical scheme designed for a wide class of structured population models based on the idea of operator splitting and particle approximations. This scheme is related to the Escalator Boxcar Train (EBT) method commonly used in biology, which is in essence an analogue of particle methods used in physics. Our method exploits the split-up technique, thanks to which the transport step and the nonlocal integral terms in the equation can be separately considered. The order of convergence of the proposed method is obtained in the natural space of finite non-negative Radon measures equipped with the flat metric. This convergence is studied even adding reconstruction and approximation steps in the particle simulation to keep the number of approximation particles under control. We validate our scheme in several test cases showing the theoretical convergence error. Finally, we use the scheme in situations in which the EBT method does not apply showing the flexibility of this new method to cope with the different terms in general structured population models.

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