Abstract
We examined vegetation changes in 2014 and 2019 in the back swamps of the coastal area of Sendai City, Miyagi Prefecture, Japan that were disturbed in the tsunami and ground subsidence caused by the 2011 off the Pacific coast of Tohoku Earthquake. We established a total of 131 quadrats and conducted vegetation surveys at the same site in July-August 2014 and August-September 2019 and analyzed them using two way indicator species analysis (TWINSPAN) classification and detrended correspondence analysis (DCA) ordination. We examined the relationship between plant community types and ground height using a vegetation map of drone imagery taken in 2019. In many quadrats, wetland plant communities changed to inland plant communities in 2014 and 2019. In addition, even among plant communities of the same habitat type, such as wetland and inland, the dominant species tended to change from Juncus krameri to Typha domingensis and from Miscanthus sinensis to Pinus spp. These vegetation changes were likely caused by a combination of soil drying due to the uplift of the ground and the passage of time following the disturbance caused by the earthquake. Namely, it is considered that the vegetation succession such as the distribution of species with larger individual size and the expansion of the leaf group is progressing. Wetland plant communities were distributed on low ground of 40 cm or less and occupied about 20 % of the study site area in 2019, and these habitats were generally on a downward trend.
