PARENT SESSION
Poster Session #27: Nutrient Cycling I.
Tuesday, August 6. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC
122
Elemental fluxes en litterfall in riparian montane forest of the San Alberto cathment, Andean Amazon Basin (nutrient cycling).
Nuņez, Fabiola*,1, Reynel, Carlos, Mc Clain, Michael, 1 Universidad Nacional Agraria La Molina, Lima, Lima, Peru
ABSTRACT- Nutrient cycling in Amazon montane cloud forests is expected to differ greatly from that in adjoining lowland forests because of pronounced structural, floristic, and climatic differences. In this study we investigated fluxes of mass and nutrients in litterfall of mature and secondary montane cloud forest at approximately 2400 masl in the Peruvian Amazon. Litter was collected in 26 x 1m2 traps during the dry and rainy seasons of 2001. Leaves made up 70% (by weight) of the litter; they were separated according to family. Woody material made up 15%, reproductive parts made up 5%, and unclassified material made up 10%. The most common families of trees contributing to litterfall were Euphorbiaceae, Melastomataceae, Poaceae, Chloranthaceae, Solanaceae, Asteraceae; within these families the most common genera were Croton, Miconia, Hedyosmun, Cestrum. The results of this study, which are currently being generated, build upon previous work that found an average litter production rate of 6.6 Mg/ha/yr. In these comparable samples, leaf litterfall nutrient concentrations averaged 17 mg N g-1, 1.6 mg P g-1, and 7.6 mg K g-1. Total nutrient fluxes were 117 kgN ha-1, 10.2 kgP ha-1, and 48.5 kgK ha-1. Total mass of litterfall and nutrient fluxes in litterfall in this forest are high relative to other montane forest systems. In fact, these values are comparable with fluxes in lowland Amazon forest. The data accumulating in this study challenge the commonly held notion that nutrient cycling is reduced in montane cloud forest, at least along the litterfall pathway. We evaluate possible explanations for these findings including excess nutrient availability in soils relative to physical limitations on forest production.
KEY WORDS: Yanachaga, Litterfall, Nutrients, Forest