Japan's leech invasion may be an unintended consequence of successful reforestation efforts combined with rural population declines.
"What to make of this leech fest?...Japan's remarkable reforestation record is hardly a new phenomenon. In fact, Japan has reforested itself twice -- once dating back to the 1600s, and again after World War II. Likewise, Japan's demographic woes have been a hot topic for years. Japan's population of 127 million has peaked, and some estimates predict the total will drop to 95 million by 2050.
The most dramatic decline is occurring in rural Japan where the few young people who are actually being born are abandoning the countryside for the city. Which means, according to Asahi Shimbun, that not only are local forests thriving, but that the buffer areas between inhabited regions and the forest are being neglected. The ensuing profusion of weedy growth attracts animals whose numbers are increasing because of hunting restrictions and warm winters. The leeches latch on to the beasties and go for a ride, looking for more fresh meat.
Japan's success at reforestation offers an encouraging model to the rest of the world. Likewise, its imminent population decline suggests that humanity isn't necessarily doomed to perish under the weight of its own numbers. But even so, as a metaphor for the kind of unexpected, and unwelcome, manifestations likely to result from human mismanagement of the world's natural resources, a plague of bloodsucking leeches is not too shabby."