Iwasa M.A., Takahashi M. 2021. Soil hardness of burrows related to the usage frequencies of the lesser Japanese mole, Mogera imaizumii (Talpidae) // Russian J. Theriol. Vol.20. No.2. P.129–135 [in English].
Masahiro A. Iwasa [email@example.com], Mao Takahashi, College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-0880, Japan.
ABSTRACT. The soil hardness inside burrows was studied in the lesser Japanese mole, Mogera imaizumii, to evaluate differences in the hardness of the ground surface, sidewalls, and bottoms of regular burrows (high usage frequency, Rb) and temporary burrows (low usage frequency, Tb). We analyzed usage frequency at 68 burrow points by setting snare-type tube traps, which triggered responses by the moles, at each burrow point to record the usage of moles without capturing them. These burrow points were classified as Rb or Tb based on the presence or absence of a response, respectively, sixteen hours after being set; 20 burrow points were identified as Rb, and 48 were identified as Tb. No differences in the frequencies of Rb and Tb were observed relation to the depth, which is related to the vertical gradient of hardness. In addition, newly detected burrows were more frequently found to be Tb than in Rb during early spring to summer, which seems to be related to mole dispersal. Moreover, we measured the soil hardness of the ground surface, sidewalls, and bottoms of the burrows at the 68 burrow points. On comparisons of the relationships between the soil hardness and the burrow usage frequency, we found that the bottoms were significantly harder in Rb than in Tb. Therefore, the hardness of the bottom soil in Rb is considered to have been caused by the frequent treading of mole movements.
KEY WORDS: Mogera imaizumii, burrow, soil hardness, usage frequency.