Abstract
We reviewed the characteristics of the paddy field ecosystem and how and why it has deteriorated fields in recent decades from the viewpoint of Ecological Engineering for paddy. Considering the range of some animal activity and material flow in the ecosystem, the paddy field ecosystem is easily comprehensible if we treat it as large scale. Mosaic structure, hierarchic structure and aquatic network are spatial characterization of the ecosystem. These contribute to the biodiversity conservatory. Agricultural infrastructure development is one of the factors behind degradation of the paddy ecosystem. The project has disturbed paddy ecosystems to exceed the possibility of restoration, affecting the environmental element in the canal that has included water velocity, water depth, canal section, bottom material and vegetation. It might cause catastrophic shift of paddy field ecosystems. The model of the ecosystem shall be established in preservation of paddy ecosystem to re-create physical dimension of structures with imitation of structure, function, diversity and dynamics. The master plan for environmental improvement in the rural area must be prepared to be a temporal and spatial ecosystem model. Nature regeneration must be promoted hence.
