Effects of multiple ecological factors on the body mass of small rodents in a forest ecosystem

Abstract

The body mass of animals is directly or indirectly affected by multiple ecological factors. However, the effects of ecological factors on the body mass are controversial, and a comprehensive study dealing diverse ecological factors is rare. This study was performed to determine the effects of ecological factors on the body mass of small rodents in a natural deciduous forest located on Mt Gariwang, Pyeongchang and Jeongseon, South Korea from May 2019 to October 2020. We classified ecological factors into topographic, climatic, cover and demographic factors. Three forest-dwelling small rodent species, striped field mouse Apodemus agrarius, Korean field mouse A. peninsulae and red-backed vole Myodes regulus, were captured using the capture–mark–recapture method. The findings showed that the body mass of three rodent species was not regulated by topographic factors. In addition, a high ambient temperature resulted in a heavy body mass for A. agrarius and A. peninsulae, and the A. agrarius body mass was negatively affected by extreme rainfall. The body mass of each rodent species had a specific response to the cover factors: ground vegetation, understory vegetation or downed trees. The three species showed sexual dimorphism and two Apodemus species competed each other. This study reveals that ecological factors affecting body mass differ among species. Our findings contribute to enhancing the understanding of variation in the body mass of animals, particularly small rodents, in response to diverse ecological factors.