Responsive strategies of three sympatric small rodents to the altitudinal effects on microhabitats

This study evaluated the effects of altitudinal gradients on small-rodent populations and microhabitat conditions. We selected three altitudinal bands: lowland, mid-land, and highland. We captured three small-rodent species, the striped field mouse (Apodemus agrarius), the Korean field mouse (A. peninsulae), and the red-backed vole (Myodes regulus). A. agrarius preferred microhabitats with dense ground vegetation and sparse mid-story vegetation, basal area, downed trees, and stone coverage. A. peninsulae utilized ground vegetation, overstory vegetation, and downed trees. M. regulus occupied microhabitats with abundant stone coverage and little ground vegetation coverage. Ground vegetation coverage was higher in the mid-land. The lowland was characterized by high understory vegetation, bulky downed trees, and high stone coverage. A. agrarius mostly occupied the mid-land, whereas A. peninsulae and M. regulus mainly inhabited the lowland. Our results show that each small-rodent species had its own strategy for utilizing the key habitat factors in altitudinally affected microhabitats and for reducing competition among the populations. This finding contributes to improving knowledge of the ecological altitudinal features of microhabitat conditions, as well as the altitudinal distributions and abundances of three small-rodent species.