Knowing how many wild animals have lived in the past is important for understanding the true nature of natural ecosystems and the nature of biodiversity.In addition, in the case of animals that require management, it is necessary information to consider the appropriate number of animals.It was known from the text left by explorer Matsuura Takeshiro and others that many Yezo deer lived in Hokkaido at the beginning of the Meiji era, but in detail how many lived there. I didn't know.

　Professor Agetsuma simply calculates the number of deer that must live in order to achieve the number of deer caught every year for the 1873 years from 1882 to 10 in the early days of Hokkaido development. Invented.According to this, it was found that in 1873, at least 35 to 47 sika deer lived.
Furthermore, when this value was corrected by the ratio of the number of deer caught and the number of inhabitants in recent years, it was found that the number of deer inhabitants in 1873 was about 50 to 70, which was about the same as in recent years.

　In Hokkaido at that time, the natural enemy of deer, the wolf, was alive and well, and due to the harsh climatic conditions before global warming progressed, it is estimated that the mortality rate of deer was higher than it is now.Nevertheless, this result, which showed that the same number of deer as in recent years, when the deer problem has become more serious, inhabited at the beginning of the development, is a consideration for the conservation of the ecosystem peculiar to Hokkaido and the management of the deer population. Has an important meaning.

Paper information:[PLOS ONE] A simple method for calculating minimum estimates of previous population sizes of wildlife from hunting records