Officials fret over ballooning deer population in Oze National Park

by Daisuke Tanaka

Kyodo

A surge in the Japanese deer population in Oze National Park has led to the depletion of rare marshland plants such as the white arum, or Asian skunk cabbage, which has made the park a popular destination for hikers.

Earlier this summer, the skunk cabbage colony along the Shimono-ohori River, one of the best locations for taking photos, showed signs of damage from deer. There was also visible damage to plants near a section of boardwalk in the Ryugu Crossroad section of the park.

“It’s a shame that the most popular spot in this park has been damaged,” said Kazuo Matsuura, the 74-year-old chairman of a local mountain guides association in Katashina, Gunma Prefecture.

“No damage had been seen in the area along the Shimono-ohori River before,” Matsuura said. “Deer seem to change their habitat every year.”

Deer were first seen in the park, which straddles Fukushima, Tochigi, Gunma and Niigata prefectures, in the mid-1990s, according to Matsuura and the Gunma Prefectural Government.

Every spring, deer come from the Nikko area in Tochigi, on the east side of the park, after the snow melts.

The population has apparently ballooned because deer have few natural predators and hunters in the area are aging and on the decline.

The damage to local plants became more pronounced around 2009, according to the local government. They stomp on the marsh and rub their bodies on the ground to wipe mites off, which damages the surrounding plants.

Both the Environment Ministry and the Gunma Prefectural Government installed deer traps in the park, catching 148 in the spring and fall of 2013, and 152 this spring alone.

Since many of those captured were pregnant females, traps had some effect in controlling the population, according to an official with the prefectural government.

However, not everyone thinks the deer pose a major problem. One hiker said they “don’t actually feel that the damage is so severe.”

Sumio Hagiwara, the 60-year-old owner of a mountain lodge near the Ryugu Crossroad, said he believes the damage has declined compared to previous years “and that is probably because of the (local government’s) trapping.”

The Gunma Prefectural Government official said “we have no idea how many deer we need to capture, and we just need to keep hunting them.”