 Exotic forests now cover over 80% of the area which was previously covered by Grasslands.These non-native species now dominate thousands of acres once dominated by native grasses.These extensive wattle plantations are sometimes blamed as the major cause of reduced soil moisture and stream flows across upper Palni catchments, though it is likely that reduced rainfall during the Southwest monsoon period, combined with a pattern of heavy downpours and longer dry spells between rain events in the non-monsoon months is also responsible.