Descomposición de materia orgánica en ríos andinos: efectos del cambio de uso de suelo y de la calidad de la hojarasca

Abstract

Leaf litter breakdown is an ecological indicator of stream ecosystem functioning that can be altered by human activities. This study evaluates the effect of different land use practices and litter type on breakdown rates. A leaf litter bag assay was used to estimate the breakdown rates in nine streams with different land use cover (native forest, pastures, forest-pasture) using two types of native leaf litter (Alnus acuminata and Croton rimbachii) and one exotic one (Eucalyptus globulus). Coarse and fine mesh sizes were used for the leaf litter bag assay. Breakdown rates were slower in pasture streams than in forest-pasture and in forest streams. Breakdown rates were similar between both types of native leaf litter and both were higher than exotic one. Our results suggest that land use change can reduce the processing of organic matter, and that introduction of exotic plants along the riparian margins can alter the leaf litter dynamics in Andean streams.