Revegetation of coastal plants damaged by the 2011 Tohoku tsunami

Abstract

We examined the relationship between coastal plants and microtopography damaged by the Tohoku tsunami of 2011 in a sandy beach to coastal forest ecotone in Minami-Gamou region, near Sendai Bay, Japan. We surveyed three transects on sandy beach and one in coastal forest 28 months after the tsunami. Plant composition was similar between the coastal forest and sandy beach, but plant density was significantly higher in the forest than on the beach. Coastal plants likely established in the coastal forest from the seedbank or from rhizomes extending from the beach, as the ground underlying the coastal forest rose after the tsunami. Furthermore, alien herbs and shrubs dominated in the higher elevations of the coastal forest. This suggests that coastal vegetation will develop into forests in the future. Meanwhile, coastal plant diversity was high in the sandy beach depression zone, but this zone will be destroyed by sea wall development. Consequently, it is important to maintain diverse microtopography to conserve coastal plant diversity in this region.