Yakushima Deer cull

Deer cull planned to save flora

The Yomiuri Shimbun, 13 Oct 2010

The Environment Ministry, the Forestry Agency and local governments are planning a large-scale cull of deer on Yakushima island in Kagoshima Prefecture to counter the threat the animals pose to native plant species.

The growing population of yakushika, a species of deer native to Yakushima, is eating and damaging plants on the island, which is designated a World Natural Heritage site.

Despite culls that have taken place on privately owned land, where the deer have damaged agricultural crops, their population island-wide has continued to increase.

A scientific committee on Yakushima island’s World Heritage areas has been set up by the ministry and other concerned authorities, and an expert panel will soon meet to discuss practical steps towards solving the problem.

No deer-control measures have thus far been taken with regard to the World Heritage areas on the island, which account for about 20 percent of its total area.

The island is famous for its Yakusugi cedar trees, each of which is at least 1,000 years old, and also boasts the tallest mountain in the Kyushu region, the 1,936-meter Mt. Miyanouradake.

The island’s natural environment is characterized by its diverse flora, with species originating from a wide range of climates, from subtropical to subarctic. Many species are native to the island.

But in places where the deer population has increased, the animals’ impact is marked. The number of pteridophytes has drastically decreased and athyrium yakusimense, a native bracken species, is believed to have gone extinct. Phaius flavus Lindl and other orchid species are also now rarely seen.

The Yakushimacho local government has stepped up culling efforts in response to the animals’ damaging local specialty crops, such as ponkan citrus, tankan citrus and tea.

In the first half of this fiscal year, the local government captured about 480 deer. It will likely exceed its annual goal of 700 deer, but animal experts predict culls at that level will not be sufficient to cause the deer population to decline.

Prof. Tetsukazu Yahara, an ecology researcher at Kyushu University, said the increase can be partly attributed to the decline of the forestry industry, which means fewer people live and work in forests and thus fewer deer are hunted.

The abundance of grass along sunny forest roads is another factor, said Yahara, who heads the scientific committee on the island’s World Heritage areas.

The committee’s expert panel comprises five specialists in the field, including Yahara, in addition to representatives of the local community.

The panel is scheduled to hold its first meeting in Kagoshima on Friday.

The panel will divide the island into three areas: a western zone, where deer habitats are the densest; an eastern zone, where damage to plants is becoming increasingly serious; and a southern zone, where there has been no remarkable change.

The panel will decide on the best method and timing for deer culls in each of the three zones, as well as ways to protect plant life from further harm.

Experts reckon the number deers culled annually will be between 1,000 and 2,000.

“Like global warming, the damage is getting worse, and it’ll soon be too late to do anything. The only option is to control the deer population preemptively,” Yahara said.