| 要旨トップ | 目次 | 日本生態学会第66回全国大会 (2019年3月、神戸) 講演要旨
ESJ66 Abstract


一般講演(口頭発表) G01-06  (Oral presentation)

Assessing extent of forest disturbances by tropical cyclones on Sundarbans Mangrove Forests using 30-year Landsat images

*Mohammad shamim hasan MANDAL, Tetsuro Hosaka(IDEC, Hiroshima Univ.)

Frequent cyclones may be one of the driving factors of forest dynamics in the Sundarbans, the largest mangrove forest in the world. Yet, few studies have quantified the extent of forest disturbance caused by cyclones and demonstrated the relationship between the extent of disturbance and characteristics of cyclone. We focused on 21 cyclones during 1988-2016 and assessed changes in normalized difference vegetation index (NDVI) before and after the cyclones using Google Earth Engine (GEE) and Landsat imagery. The percentage of disturbed forest area varied 0.5-24.1%. Eighteen of the 21 cyclones affected less than 10% of forest area in Sundarbans while cyclone Sidr in 2007 and a cyclone in 1988 affected 24.1% and 20.4%, respectively. Wind speed of cyclones significantly correlated with the forest disturbances, while minimum distance between cyclone path and center of Sundarbans was marginally significant, and water level of rivers on the day of cyclone landfall was not significant. Our piecewise regression analysis suggested that wind speed had a breakpoint at 101.9 km/hr, below which wind speed had no effect on the level of disturbance. Thus, it suggests that only major cyclones occurring about every 10 years may cause a substantial disturbance on the Sundarbans.


日本生態学会