Impact of Flood on Dynamics of Mimosa pigra Populations in Affected Kelantan River Basin
Kelantan is one of the east coast states of Malaysia, which has faced yearly flooding catastropheespecially during north-east-monsoon season. Most of the land use from upstream to downstreamof Kelantan River Basin was affected after December 2014 when the worst flood was recorded fordecades. Due to the immense flood, Mimosa pigra is spreading forming dense thickets belt alongthe riparian vegetation area. It has transformed the river water regime. M. pigra is identified as theworst invasive species in Malaysia and caused massive threat to riverine ecosystem. It’sconsidered to be a colonizer of mainly wetland and seasonally flooded areas. The dispersalprocess by which this rapid colonization was achieved has yet to be fully documented. The studywas done in three sampling areas along Kelantan river basin (upstream, downstream, outfall)focusing on the distribution of M. pigra after the recent flood. Based on Landsat TM imageclassification analysis and ground thruting, result showed 60% (upstream), 40% (downstream)and 70% (outfall) of accuracy assessment respectively. For each of the 30 sampled point (a 7.5mradius circle), M. pigra has covered an average of 23.04% of the area with a total of 2,309.58m2/ha.