Bark stripping by sika deer on veitch fir related to stand age, bark nutrition, and season in northern Mount Fuji district, central Japan

摘要

We carried out this study to clarify the relationships between the seasonal changes of bark stripping and food quality, and between bark-stripping intensity and bark nutrition with age of veitch fir (Abies veitchii) by sika deer (Cervus nippori) in the northern Mount Fuji district, from June 2000 to July 2003. We found that sika deer gnawed and ate all of the bark stripped, and a seasonal change in bark stripping occurred from December to May or June with a peak in March-April. The stripping period largely overlapped with the periods of low food availability and poor food nutrition (indicated by fecal chemical component index) of sika deer, from January to April. Both bark nutritional quality and bark-stripping intensity related to stand age and tree size of veitch fir negatively. Consequently, bark-stripping intensity related to bark nutritional quality positively. February is the worst forage period in terms of both quantity (due to deep snow) and quality (indicated by fecal chemical components).There was a time lag of 1 to 2 months in the peak of bark stripping in March-April when compared with the poor forage period in February. This time lag may suggest that sika deer need more nutritious and easily digested food from March due to increasednutrient demands that result from depleted body condition in both sexes, gestation of pregnant females, and the recovery of active metabolism.