Okunoshima Island in Hiroshima Prefecture is known as "Rabbit Island" because it is home to hundreds of European rabbits, and it has become a popular tourist destination. European rabbits are an introduced species originally from Europe, and their population on the island is maintained by the food provided by tourists.
Wild boars have been observed preying on live rabbits on this island. Until now, it was thought that wild boars only ate rabbits to utilize their carcasses. However, there have been previous sightings of wild boars preying on healthy rabbits on Okunoshima Island, suggesting that this type of predation may be a recurring issue.
Why are cases that overturn conventional views occurring on Okunoshima Island? A research team led by Professor Shingo Kaneko of Fukushima University, along with Associate Professor Asami Ogura of Kure National College of Technology, who is familiar with the local situation, and picture book author Eri Kondo, investigated the factors behind these occurrences.
The behavior of the wild boars is thought to be influenced by several factors, including the fact that a large number of rabbits live on the island, depending on the food provided by tourists, that the wild boars utilize the leftover food from the rabbits, and that the numerous rabbit carcasses also serve as a food source for the wild boars.
Furthermore, this case is pointed out to be more than just a record of unusual animal behavior. What is happening on Okunoshima Island suggests that feeding by tourists is having an indirect impact on the ecosystem. In fact, due to large-scale and poorly managed feeding that depends on the number of tourists, the number of rabbits on Okunoshima Island exceeds the vegetation's capacity, and branches and leaves within the rabbits' reach (the rabbit line) are being lost. When there are fewer tourists, food resources on the island become scarce, and evidence of rabbits gnawing on poisonous plants has also been observed.
Okunoshima is a national park and a historical island with war relics such as the remains of a poison gas manufacturing facility and gun emplacements. The predation of rabbits by wild boars on Okunoshima is considered to offer important insights into rethinking wildlife feeding management practices in order to promote sustainable tourism and biodiversity conservation.
Paper information: [Journal of Ecotourism] Wild boar predation on feral rabbits in a tourist-fed island population: ecological and management implications from Okunoshima Island, Japan
