Scientists around the world have long debated whether allowing—or encouraging—farmland to revert to nature benefits or harms biodiversity. Recent studies in Japan have virtually all found that the abandonment of small, traditionally managed rice paddies results in less biodiversity among the seminatural grasses and weeds that grow on paddy margins and in the insect populations that depend on that vegetation. Farmers encourage the growth of plants on rice terraces and paddy banks for soil stability but periodically mow the vegetation to keep it in check. Researchers theorize that these plant species evolved over millennia to coexist with traditional agriculture. Some plants are now found only on the margins of rice paddies. Yet farmland abandonment is likely to accelerate as demand for rice drops with the increasing popularity of wheat products and Japan's population ages and shrinks.
Author: Dennis Normile