Presentation Information
[POS-42]Discrete time population dynamics model for exploitative
competition between native and alien predators
*Akshat Goyal1 (1. Tohoku University (Japan))
Keywords:
Population dynamics,Invasion,Prey predator
Today numerous species are experiencing habitat shifts potentially driven by climate change. Invasion of
an alien predator species into a native prey-predator system could lead to substantial ecological conse-
quences. In this research we present a discrete-time population dynamics model to analyze exploitative
competition between native and alien predators sharing a common prey. The study investigates the
conditions under which an alien predator can successfully invade a native predator-prey system, the per-
sistence of both predators, and the consequences of their interactions.
The three-species system is governed by the following set of difference equations:
Hn+1 = e−α1Pn {r0 /(1 + e−α1Qn Hn/β)} e−α2Qn Hn ;
Pn+1 = ρ1(1 −e−α1Pn ) {r0 /(1 + e−α1Qn Hn/β)} e−α2Qn Hn ;
Qn+1 = ρ2(1 −e−α2Qn )Hn ,
where Hn , Pn and Qn are the host, and two predator populations respectively at time step n. Parame-
ters α1 and α2 are the coefficients for the successful predation by predator species P and Q respectively.
r0 is the supremum for the expected number of host’s offsprings produced by an adult prey. β is the
coefficient of the strength of intraspecific density effect on the prey reproduction. The larger β means the
weaker sensitivity of prey reproduction to the density effect. In the other sense, it indexes the strength
of prey’s intraspecific competition. Its larger value means the weaker intraspecific competition affecting
the reproduction rate. ρ1 and ρ2 are the expected number of predator offsprings born per prey consumed
by P and Q respectively. We here assume that the predator species P and Q attempt to predate on the
prey at different life stages, at juvenile stage and adult stage respectively.
an alien predator species into a native prey-predator system could lead to substantial ecological conse-
quences. In this research we present a discrete-time population dynamics model to analyze exploitative
competition between native and alien predators sharing a common prey. The study investigates the
conditions under which an alien predator can successfully invade a native predator-prey system, the per-
sistence of both predators, and the consequences of their interactions.
The three-species system is governed by the following set of difference equations:
Hn+1 = e−α1Pn {r0 /(1 + e−α1Qn Hn/β)} e−α2Qn Hn ;
Pn+1 = ρ1(1 −e−α1Pn ) {r0 /(1 + e−α1Qn Hn/β)} e−α2Qn Hn ;
Qn+1 = ρ2(1 −e−α2Qn )Hn ,
where Hn , Pn and Qn are the host, and two predator populations respectively at time step n. Parame-
ters α1 and α2 are the coefficients for the successful predation by predator species P and Q respectively.
r0 is the supremum for the expected number of host’s offsprings produced by an adult prey. β is the
coefficient of the strength of intraspecific density effect on the prey reproduction. The larger β means the
weaker sensitivity of prey reproduction to the density effect. In the other sense, it indexes the strength
of prey’s intraspecific competition. Its larger value means the weaker intraspecific competition affecting
the reproduction rate. ρ1 and ρ2 are the expected number of predator offsprings born per prey consumed
by P and Q respectively. We here assume that the predator species P and Q attempt to predate on the
prey at different life stages, at juvenile stage and adult stage respectively.