Abstract
A camera-trap survey with an automatic infrared sensor camera was conducted from 2008 to 2017 in Yokohama Nature Sanctuary as part of a medium and large-sized mammal survey of the “Monitoring Sites 1000 Satoyama” project. The changes in the animals and diel activities over 10 years were analyzed.
1 There were 3 species of native animals (Racoon Dog, Japanese Hare, Japanese Weasel) and 1 genus of mice (Large Japanese Field Mouse or Small Japanese Field Mouse), 3 introduced species (Formosan Squirrel, Raccoon, Masked Civet) and 2 other species (cat, dog) that were photographed. Also 16 species of birds photographed including 2 species of introduced birds (Chinese Bamboo Partridge, Chinese Hwamei).
2 Declining trends were seen in Japanese Hare (about 30% decrease), Formosan Squirrel (about 20% decrease), Masked Civet (about 10% decrease), Racoon (about 10% before capture, about 20% after capture) . Increasing trends were seen in Racoon Dogs (about 20% increase), mice (about 15%), cats (about 15%) and Chinese Hwamei (about 70%)
3 Species with the same trend of increase/decrease as the entire country were the decline of Japanese Hare and an increase in Racoon Dog and Chinese Hwamei. Masked Civet and Raccoon showed an increase nationwide but a decrease at the Yokohama Nature Sanctuary.
4 Diel activity show that Raccoon Dogs, mice, Masked Civet and Raccoon are nocturnal with over 90% of photographs being at night. And diel activities show that Formosan Squirrel, Chinese bamboo partridge and Chinese Hwamei were photographed about 100% during the day. Japanese hare and stray/feral cats were active both day and night (the ratio of night time photography was about 50%).
