Comparison of nutrient balance between a tropical lowland forest and a tropical montane forest in Malaysian Borneo

To compare nutrient balances between lowland and montane tropical forests, water samples were collected for chemical analyses and hydrological observations over a 3-year period in Tower Large watershed in Lambir Hills National Park (LT; tropical lowland forest) and Mempening watershed in Kinabalu Park (KM; tropical montane forest) in Malaysian Borneo. We estimated the annual input flux by rainfall (AIF_T), annual input flux by throughfall (AIF_T) and annual output flux (AOF) of nutrients in these watersheds. The greatest difference in nutrient balance between LT and KM was manifested in the S0_4-S balance. Although no distinct difference in the AIF_R and AIF_Tof S0_4-S was detected between KM and LT, the mean AOF of S04-S in LTwas 65 times larger than that in KM. The AOF of S04-S was higher than the AIF_R and AIF_T in LT, where as the AOF of S04-S was lower than the AIF_R and AIF_T in KM. No distinct differences in inorganic N balance were detected between LT and KM. The large differences in the AOFs of Na, K, Mg and Ca between KM and LT may be explained by the supply of each element in LT from chemical weathering of the bedrock.