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

The body mass of animals is directly or indirectly affected by multiple
ecological factors. However, the effects of ecological factors on body
mass are controversial, and a comprehensive study dealing with 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 with 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.