Coastal vegetation on the shingle spits of southwestern Japan
The coastal vegetation on shingle spits was studied in southwestern Japan. Shingle spits are sand and/or gravel banks deposited from wave action near marine coast lines, usually forming extensions of beaches into open water. The vegetation differs on the inner and the outer sides of these spits. On the inner side, salt marsh communities and semi-mangroves are characteristically found. Differences in the vegetation are more pronounced on the larger spits because of the greater wave action there and its associated ground conditions. Soil profiles were investigated and particle size analyses were made at five points on both sides of one of the spits. The quantity of the fine fraction is greater at points on the inner than on the outer sides. It is suggested that coastal currents play a primary role not only in controlling edaphic factors but also in dispersing the seeds of the coastal vegetation on shingle spits.