Abstract
Reed communities in the kitakami river mouth were changed by the 2011 earthquake off the pacific coast of Tohoku. GPS vegetation survey, aerial photo image analysis, cross-section surveying data analysis, and so on were carried out in September 2012, 2013 in order to examine decay factors and recovery factors. Main findings are as follows : 1) Total area of reed communities between river mouth and 9.0 km from the river mouth were 102.3 ha (left bank 66.4 ha, central shoal 21.0 ha, right bank 14.1 ha) in September 2008, however they decreaed to 33.6 ha (left bank 27.8 ha, central shoal 4.7 ha, right bank 1.1 ha) in July 2012 due to the 2011 earthquake. 2) Most reed communities disappeared on the ground lower than T.P. -60 cm. 3) Total area of reed communites in October 2013 recovered from 33.6 ha (one and a half years after the earthquake) to 36.6 ha (two and a half years after the earthquake). Especially, it was occurred on the ground higher than T.P. 16 cm. 4) Total 111 plant species were observed in the reed communities. Many alien plant species were observed at the survey lines 9.0 km and 14.2 km.
