Status of phosphorus in the rain forest ecosystem of Mt. Pangasugan, Leyte, Philippines

Author(s): Janice P. Susaya1 and Victor B. Asio1,2


Phosphorus (P) is generally considered to be the most limiting mineral nutrient in tropical soils. This study was conducted to determine the amounts of Pin various components of the rainforest ecosystem. Composite samples of rocks, soil, stream sediments, stream water, rainwater, leaves of dominant vegetation, forest litter, wood and moss were randomly collected from a portion of the rain forest in Mt. Pangasugan, Leyte, Philippines. Samples were analyzed for their total P contents.
Findings revealed that P concentration varied substantially in the various ecosystem components evaluated. Higher P concentrations were found in the biosystem components particularly in the leaves of the vegetation than in the geosystem components. The P concentrations decreased in the following order: fresh leaves > moss > litter > soil > sediment >rock > wood > stream water > rainwater. Trace amount of P is brought into the ecosystem by rain. On the other hand, considerable amounts of P are found in the stream water and stream sediments which represent P losses from the rainforest ecosystem. This substantial loss of P is attributed to human disturbance in the forest ecosystem.

Keywords : phosphorus status, rain forest ecosystem, nutrient cycling

Full PDF :