Large amounts of agricultural conversion remain the primary driver of wetland loss and degradation, especially in Asia. Meanwhile, a certain type of rice cultivation, along with sustainable farming practices, can deliver human-made wetlands that provide multiple ecosystem functions similar to those provided by natural wetlands. This study aims to determine which factors, and appropriate policy interventions, can improve both agroecosystems and wetland ecosystems such as to beneﬁt both society and environment. The case in Korea showed insufﬁcient development in relevant policy and uncooperative responses from some of stakeholders. Through the precedent in Japan, this study found that the case in Korea can overcome recent issues through the development of an agri-environmental scheme, collaborative effort from diverse stakeholders, and most of all, change of perception about human-made wetland. This work may contribute to delivering useful suggestions in social, economic, and environmental terms through expanding sustainable rice farming within human-made wetlands in Asia.
Approximately 100 years ago, contaminated water from the Ashio Copper Mine in Japan spilled out frequently during ﬂoods and caused the detrimental effects on surrounding areas. Currently, situations of the heavy metal contamination have been improved due to the recent activities of the government, NPOs and citizen volunteers. However, high amount of heavy metals can be still detected and effects of these heavy metals on organisms are still not clear around the Watarase Retarding Basin. In this study, we investigated the effects of heavy metals on the microbial compositions in the Watarase Retarding Basin. Measurement of heavy metals extracted from the soils sampled at different spots demonstrated that the soil from the previously contaminated spot showed higher level of various heavy metals compared to other spots. In addition, in this spot, soil bacterial composition was changed drastically, indicating that the bacterial communities were affected by the presence of heavy metals in
the soil. Especially, Acidobacteria which was reported to exist in chemically polluted areas was abundant. It should
be the ﬁrst report that revealed the effects of heavy metals on microorganisms in the Watarase Retarding Basin.