Shared predation and its impact on two sympatric rodent species. Adding to nature’s complexity

Abstract

I used a theoretical model with different predatory preference relationships but with no direct competition. Simulated time series were statistically analysed to evaluate changes in rodent dynamics, with respect to periodicity, synchrony, amplitude and symmetry. The study found that shared predation could mediate a relationship between the two rodents to some extent. Periodicity increased on average for both species but decreased in the scenarios were the predator response was very rapid for the alternative prey. When this was applied to the main prey, extinction occurred. Synchrony was at its strongest when there was a slight preference for the lemming and amplitude showed very little variation but increased when the rodents were coupled in the more complex model. There was no consistent pattern concerning changes in symmetry but a tendency towards higher asymmetry when there was a very high preference for main prey.