Abstract
Over the past decade the Land Improvement Act has mandated eco-friendly land development practices. Studies of fishes, published mostly in the recent decade, were reviewed based on their method of evaluating current or potential future habitat conditions. Evaluation is an indispensable element for adaptive management. There are some issues in studies of Suitable Index models for HEP, etc. These issues are the tendency for many studies to construct excessively complicated models and to not disclose the details of their models. It is necessary to disclose model details to achieve progress in aggregation of information about models. Understanding the detailed construction of numerous models will enable future model builders to construct better, more complete models. Disjuncture of water areas is also an urgent issue that has motivated research. For that reason real progress has been made in understanding fish migration. As a result studies which evaluate the status rice paddy irrigation networks or lead to such evaluations have recently appeared. At the same time, the spatial scale treated in such studies has broadened. Several issues surrounding evaluation of management benefits considering spatial placement of habitats are described in this review.
