CONICET | Buscador de Institutos y Recursos Humanos

We aimed at exploring how the presences of monospecific patches of alien trees, may affect litter decomposition at Cordoba Chaquean mountain woodlands, by changes in litter quality and leaves attributes. We compared the decomposability of litter from native woodlands with that of monoespecific forests of the most important woody invaders of the region: Ligustrum lucidum, Gleditsia triacanthos and Pinnus elliottii. We measured litter decomposability of compound litter samples (litter mixtures) from each forest type, as well as leaf litter decomposability of the thirty most representative native and alien plants, through a simultaneous incubation in a purpose-built decomposition bed. Decomposability of species and forest mixtures were associated to green leaf features (specific leaf area, leaf tensile strength and leaf water content) and litter chemical quality (carbon, nitrogen and non-labile compounds content), respectively. Decomposability did not differ between individual native and alien species, but there where significant differences between forests potential decomposition when considering species weighted input. In general, decomposability values where highest in the native woodland, intermediate in Ligustrum and Gleditsia forests and lowest in the Pinnus forest. This general pattern was observed when analyzing (1) litter mixtures (2) dominant tree species of each type of forest, and (3) plot weighted decomposability. We suggest that, inferring the impact of alien species on ecosystem process, without considering their relative abundance in the community might lead to erroneous conclusions. In chaquean woodlands, invaders, which differ from natives in leaf and litter attributes, might strongly impact on ecosystem decomposition, when they dominate the vegetation.