The Effect of Tsunami in 2004 on Mangrove Forests, Nias Island, Indonesia

The earthquake and tsunami that devastated coastal area in Nanggroe Aceh Darussalam Province and North Sumatra Province,especially Nias Island on December 26,2004,caused damage to most mangrove and coastal forests in the areas.Before the 2004 tsunami,there is no report or publication about mangrove and coastal vegetation in Nias Island.The aims of this research were to describe the mangrove forests and coastal vegetation after tsunami disaster and to learn the ecological functions of mangrove forests and coastal vegetation on shore protection.Field surveys,in eastern,northern and western coast of Nias Island within 10 days of the middle weeks in March 2005 and in southern coast of Nias Island within 6 days of the first 2 weeks in November 2006 after the 2004 tsunami,were conducted.Our research results showed that dense mangrove forests and coastal vegetation had been proven to be effective on protecting coastal area from the tsunami,while heavy damage occurred in the areas that have degraded mangrove and coastal forests.Therefore,mangrove forests play an important role on shore protection,and this protection depends on the quality of the mangrove habitats.It should be noted that degraded habitats or habitats with mangrove associate species instead of true mangrove species do not provide adequate protection.

The Current Status of Riparian Vegetation along Bank of Kelantan River after the Worst Flood for Decades

Undeniably Kelantan is one of the east coast states of Malaysia,which has faced yearly flooding catastrophe especially during north-east-monsoon season.The aims of this study are to record the land uses from upstream to downstream of Kelantan River basin,and to record the riparian vegetation that are resistance and susceptible to flood situations in affected areas along the bank of Kelantan River after December 2014 when the worst flood was recorded for decades.A serial of surveys were conducted at 9 sampling sites(S1 to S9)from the upstream to the downstream in the basin.The massive clearing in the forest in the basin particularly in the upper streams was a serious problem.Heavy loads of sedimentations greatly affected the hydrological system of Kelantan River.There were 64 plant species were recorded in this study.Most sampling sites were submerged and most of the riparian plants survived although the flood levels reached 10 m.On the other hand,some commercial tree species such as Elaeis guenensis,Lansium parasiticum and Nephelium lappaceum could not thrive in flooding conditions.It should be noted that the populations of noxious,such as Mimosa pigra and Piper aduncum had colonized most parts of riparian zones.Perhaps due to the disturbances of catchment and riparian vegetations,the river water regimes have been transformed.Therefore,the ecological assessments and socio-economic approaches were recommended in order to mitigate the flood situation.