Dealing with Deer
Nature out of balance
The sika deer (Cervus nippon) used to graze in the Minami Alps at elevations of 2,000 to 2,500 meters, descending to lower elevations in winter. Starting in the late 1990s, however, the deer began to venture above 2,500 meters into the very highest reaches of the mountains in the summer and autumn. Their 1,100-meter range of elevational movement is not seen in any other deer population in the world.
The motivation for venturing higher is simple enough: the deer are looking for food. Rising population numbers mean that their traditional grazing grounds lower down the mountain no longer provide enough to eat. What, then, is behind this increase in deer? Multiple long-term factors are at work. First, the Japanese wolf, the sika deer’s natural predator, went extinct in the early twentieth century. Then, in the 1980s, the number of hunters began to decline due to changing lifestyles and rural depopulation. Depopulation in turn has left more abandoned farmland for the deer to graze on. At the same time, reduced snowfall as a result of global warming enables more fawns to survive the winter and grow to adulthood.
Visitors to the Minami Alps will probably come upon deer-damaged trees with their bark stripped off—either eaten, or rubbed off by the antlers of male deer. The most serious deer-inflicted damage, however, is to the alpine meadows where they eat the flowers in bud. Since 2011, the Ministry of the Environment has been fencing in the meadows from June to October to keep the deer out and protect the flowers.