Role of interspecific competition in the coexistence of <i>Apodemus argenteus</i> and <i>A. speciosus</i> (Rodentia: Muridae)

Abstract

Abstract Reciprocal‐removal experiments with two replicates were conducted to test for the role of interspecific competition in the coexistence of Apodemus argenteus and A. speciosus . Population density, rate of appearance of new (unmarked) individuals, reproduction, survival rate and habitat use were monitored during pre‐ and removal periods. In both removal experiments, the removal of A. argenteus had little effect on A. speciosus , while that of A. speciosus affected several population characteristics of A. argenteus . Namely, the removal of A. speciosus shifted the distribution of A. argenteus to the habitat with a denser shrub cover in one experiment. Also, the removal increased the population densities and appearance rates of new individuals of A. argenteus in another experiment. Interspecific interactions between the two species appeared to be a one‐way action from A. speciosus to A. argenteus . In removal periods in both experiments, the rates of appearance of new individuals in each species were the highest on the grid where that species was removed. These results suggest that, though interspecific competition occurred between the two species, intraspecific competition had greater effects than interspecific competition on the abundance and habitat use of A. argenteus and A. speciosus . This implies that the fundamental niches of A. argenteus and A. speciosus differ potentially, which may play an important role in the coexistence of the two species.