THE PROPOSAL OF ADAPTIVE MANAGEMENT SYSTEM FOR AUTONOMOUS RESTORATION OF ZOSTERA BED BY BACKFILLING

In order to form Zostera beds which are similar to natural beds, we tried to restore self-sustaining Zostera beds without transplantation and seeding by backfilling old navigation channel on the coast of Iwakuni, based on the concept of adaptive management. The obejective of this study is to verify the effectiveness of the proposed adaptive management system for autonomous restoration of Zostera bed by backfilling. This project focused on restoration policy, goals, monitoring and evaluations. Mid-term evaluation was done to judge the imposibility to achieve the goals in third year, and then final evaluation was done to judge the degree of success by comparing with natural beds in fifth year. At the backfilled areas, there are not only optimum conditions for Zostera marina but also flowering shoots and growth of Zostera marina, and Z. marina and Z. japonica showed almost the same changes of natural beds within their ranges. These results suggest that such self-sustaining beds as natural ones were restored by backfilling old navigation channel, and that this adaptive management was effective for autonomous restoration of Zostera bed.