Comparative analysis of leaf-litter decomposition from the native Pouteria salicifolia and the exotic invasive Ligustrum lucidum in a lowland stream (Buenos Aires, Argentina).

Abstract: We compared loss in leaf mass and chemical changes (concentrations of carbon, nitrogen, phosphorous, acid detergent fiber, lignin and phenolic compounds) during the decay of submersed leaf-litter of the native Poute­ria salicifolia and the exotic invasive Ligustrum lucidum , in a lowland stream of Buenos Aires (Argentina). Leaf input of L. lucidum was greater than that of P. salicifolia . In addition, leaves of L. lucidum decomposed more rapidly than those of P. salicifolia , which appear to be related to leaf chemistry, i.e. initial content of carbon, phosphorous, acid detergent fiber, lignin and phenolic compounds and the microbial colonizationgreatest . Differences in leaf chemistry and in the contribution of each plant species to litter changed the quality and quantity of organic matter entering the stream, and therefore influenced differently the process of decomposition. Consequently, we expect that these changes might alter nutrient cycles and food web dynamics. Key words: