The Potential and Problems of Agricultural Ecosystems for Birds in Japan

抄録

 Japanese rural landscapes have been home of many species of birds, ranging from forest birds to waterbirds. Recent changes in Japanese farmland, especially in rice fields, may have affected populations of these birds, as in Europe. We reviewed information on the status of farmland birds and case studies on bird-agriculture interactions in Japan. Although some farmland birds such as geese that once declined seriously are now recovering, others, especially those that live exclusively in rural areas but do not depend on agricultural crops for food, are facing new threats from recent changes in agriculture. Improvement of rice fields has caused a decline in aquatic animals and hence in their predator, the intermediate egret Egretta intermedia, which was the commonest heron until the 1960s. The decrease in nesting woods and abandonment of rice fields are serious threats to the gray-faced buzzard-eagle Butastur indicus, which is the umbrella species in the "SATOYAMA" landscapes. On the other hand, several studies have shown that fallow farmland can be useful for birds if appropriately managed. More studies are needed to seek the coexistence of agricultural production and wildlife with minimum costs. Potential research areas are : 1) relationships between birds and habitat heterogeneity at different spatial scales, 2) use of birds as environmental indicators at the regional scale, and 3) farming structures and practices that benefit birds and other organisms.