Development of Pteridophyte Community in Levees Protected by Wooden Blocks and its Contribution to Revegetation

Facilitating the establishment of pteridophytes is an important issue in future revegetation activities. In this study, we investigated the species composition and the species richness of pteridophyte communities established in levees around Nagatani dam, Hyogo Prefecture, to gain an understanding of habitat conditions suitable for pteridophytes. The vegetation in the levees in which two types of slope-protection materials, namely, wooden blocks and wire netting, were used was surveyed. The survey results indicated that the number of species of pteridophytes and the coverage of pteridophytes were higher in the levee protected by wooden blocks than in that protected by wire netting. The occurrence frequency of most pteridophytes was also higher in the levee protected by wooden blocks than in that protected by wire netting ; herbaceous seed plants such as roadside weeds, however, were dominant in the levee protected by wire netting and were less abundant in that protected by wooden blocks. The number of species of pteridophytes per unit area was also higher in the levee protected by wooden blocks than in the surrounding secondary vegetation such as pine forests. Moderate moisture and the darkness in the gaps between the wooden blocks, which function as establishment sites for individual plants, are possible factors that promote the development of the pteridophyte community.