Topography and land use history of habitat for brackish water submerged plants that emerged and disappeared after the 2011 tsunami disaster: The case of Nono-shima Island (Miyagi Prefecture, Japan)

Abstract

Many endangered hygrophytes and hydrophytes appeared in habitats created by the tsunami disaster following the 2011 Tohoku Earthquake and subsequently disappeared following the reconstruction work. We surveyed the aquatic flora of a small wetland on Nono-shima Island, Miyagi Prefecture, Japan, in 2015 that had been disturbed by the 2011 Tohoku Earthquake and tsunami. Four brackish water submerged vascular plant species and one charalean alga were recorded. The brackish water submerged macrophyte species diversity of this wetland was higher than that of salt marshes in Japan. As shown by aerial photographs and satellite images, this wetland is behind a beach ridge and was a paddy field or fallow land for at least 50 years before the tsunami. There was insufficient time to consider conservation plans for the rare species that emerged after the disaster because of the rapid reconstruction of infrastructure required in the disaster-stricken areas. To provide information for species conservation rapidly, it may be effective to predict the emergence of species from buried soil seeds using land use history and topographical information.