Effect of perturbation in stabilizing metapopulations
Student name: Ms Pratha Sah
Guide: Dr Joachim Schmerbeck
Year of completion: 2011
Host Organisation: Indian Institute of Scientific Education and Research (IISER)
Supervisor (Host Organisation): Dr Sutirth Dey
Abstract: In this study we present a simulation analysis of effect of perturbation and migration in
stabilizing metapopulations governed by the Ricker model. We found that theoretically these
controllers attained metapopulation stability over a much wider range of migration rate vs.
intrinsic growth rate parameter space than an unperturbed system. We propose two methods of
perturbation to achieve metapopulation stability; limiter control and delayed feedback control.
We also present a preliminary empirical verification of effect of limiter controller in stabilizing
laboratory metapopulations of the common fruitfly D. melanogaster. Recent theoretical
researches on animal populations have seen an increased interest in the concept of
metapopulation, dynamic consequences of migration among local populations, conditions for
synchrony (or asynchrony) between subpopulations as well as conditions for metapopulation
stability of species with unstable local populations. Low, intermediate, and high migration rates
have been shown to lead to complex, stable, and unstable dynamics, respectively in a system
containing two subpopulations. A large number of theoretical studies also predict that the
dynamics of metapopulation can be altered by constant perturbations to local population size.
Our analysis involved assessment of the effect of external perturbation coupled with low and high
level of migration on the metapopulation stability, using a modified version of Ricker model
which incorporates biologically realistic conditions of stochasticity, extinction and integerization
of population numbers. If the strategy of local perturbation to gain metapopulation stability
work, such perturbations could prove to be a useful tool in future for managing fragmented and
unstable populations.
Keywords: Metapopulation dynamics; Metapopulation stability; Asynchrony; Limiter Control;
Delayed Feedback Control
