Effect of water purification by water plants was investigated at a river in Shizuoka Prefecture, Japan. Among the plants, Zizania latifornia Turcz was dominant in biomass. Significant effect of exclusion of nitrogenus and phosphorus ingredients was confirmed.

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In this Paper、a method of river improvement planning to preserve or restore riverside willow trees is cleared. The Points are following: 1.Confirming of changing water channel for long term, 2.Analyzing flood flow situation for all seasons, 3.Confirming of mapping riverside willow trees, 4.Confirming of heights of land into minute detail, 5.Examining the factors.

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Now restoration and creation about a community of riparian vegetation is done for a biodiversity conservation. The large sized riparian vegetation like Phragmites australis (Cav.） Trin. ex Steud. and Typha latifolia Linn. attract attention for objective community, but they have strong propagative power, which is fair that cover surface of the water make into a bush. And labor becomes necessary for maintain the reasonable scale about riparian vegetation community. I take up and investigate Carex thunbergii Steud. that middle size riparian vegetation as one of a solution of it. A result is as follows. 1)The root system of Carex tunbergii concentrate in the surface layer about 10cm and makes rootmat. 2)The maximum depth of the water for Carex tunbergii is about 20cm. 3)Cutting down management in summer season expect hold down height of a plant, and maintain a green of plant in late autumn. By the above, Carex tunbergii is suitable for small-middle scale riparian revegetation for the purpose of scenery.

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Since the 1960’s, numerous land consolidation projects have been performed in rural areas of Japan. Dual-purpose canals around paddy fields have been changed to irrigation through pipes and drainage by means of concrete canals, and many functions for fish habitat have also been degraded in the canals. To clarify environment factors required for restoration of fish habitat, we investigated the relationship between morphological and physical environment properties and fish distribution of dual-purpose and drainage canals in the Shitada・gawa River basin (C.A. 10km²) in Chiba Prefecture. From July 2002 to December 2003, we surveyed materials, substrate, water width, depth, flow condition vegetation, etc. in canals, and collected fish with electric shockers and hand nets at monthly intervals. The sampled field data were analyzed statistically, yielding the following results. First, structural barriers appear to limit species richness. The fish species found in canals are dependent on the height of drops at the canal junctions with the Shitada・gawa River. Where the drops disturbed continuation of the water level, there were only a few species in the canals as most fish could not ascend large drops. Second, water quality appears to limit the numbers of fish using the canals. Loach were collected in the most of canals. The density of the loach population decreased in the drainage canals into which gray water flowed, and it is suggested that habitat with sand and vegetation, which were observed in the dual-purpose canal, was suitable to loach.

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The objective of this paper is to clarify the significance of interaction between the ecological environment and living things in environmental education and environmental restoration. We would like to consider the following themes: environment and living things, environment and human recognition of environment, the goals of environmental education and objectives of environmental restoration. We will examine I. Prigogine’s theory of dissipative structures and J. J. Gibson's concept of affordance to comprehend the mechanism of self-organization in the natural environment and perception of animals and humans, so that we can integrate them with human recognition, which is inclined to be anthropocentric according to the theories of I. Kant and W. James, in order to make causes of environmental destruction clear. Lastly, we will consider the essence of education itself and environmental education, and then propose suggestions for the goals of environmental education and objectives of environmental restoration.

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There is concern that the biodiversity are effected by alien plants. But in Japan, a few practicable studies are available. This paper reviews recent overseas studies about concepts of invasion of plants, weed risk assessment systems and management methods of invasive plants.

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Recently, there are a lot of construction projects considering the natural environment. Because, in the construction project, it is requested to maintain and to create the natural environment, along with the enforcement of the Environmental Impact Assessment Law. The project of a medium-small scale is familiar development for the resident. However, this law is not applied to the medium-small scale project. The natural environment in the project region is greatly affected by the medium-small scale development. Therefore, it is necessary to establish a concrete method of evaluating these projects. In this paper, the concept of the environmental reconstruction which considers the idea of an omniscape geology different from the viewpoint of large-scale development is described. And, a concrete technique of the investigation and evaluation in the omniscape geology is examined.

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Eco-mixed Seeding and Planting Method, the technical skill to introduce diverse native species distributed around the site by seeding and planting seedlings, was developed in order to regenerate forests close to natural composition of tree species and their gene pool, through natural selection. In the former experiments, mainly introduced plants by direct seeding, light seeds, most of which was born by pioneer trees, could not survive. Therefore, we developed the technique to plant several seedlings (1 or 2 years old) by pots and the mulching technique using macadam and wood chips to prevent the obstructions against the survival of the seeds and seedlings, as drying, erosion and invasion of herbage. In accordance with the application of public involvement on regeneration of nature-rich forests, we clarified the possibility to save the cost for planting and maintenance and to increase public interests.

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Prior to 1960, Can Gio mangrove forest in Vietnam covered area of 40,000ha; the canopy was dense, with trees over 20m tall. During the 1970’s, the forest suffered almost complete destruction. Can Gio mangrove reforestation work has continued consistently from 1968 to the present day. After 30 years of rehabilitation and development by the hard efforts of Ho Chi Minh City government and people, the forest become the largest replaced mangrove areas in Vietnam. This significant fact led to its recognition by the MAB/UNESCO Committee on January 21, 2000, as a Mangrove Biosphere Reserve.

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[in Japanese]

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