Exotic species as modifiers of ecosystem process: litter decomposition in secondary forest invaded by Ligustrum lucidum

ARAGÓN ROXANA; FERNANDEZ ROMINA; AYUP MARTA; MONTTI LÍA

Mar del Plata

Conferencia; 2nd World Conference on Biological Invasions and Ecosystem Functioning (BIOLIEF); 2011

GRIETA

Decomposition represents a major flux of carbon and it is a key process for nutrient cycling that, in turn, controls plant productivity. Quantifying litter decomposition is an important aspect for evaluating ecosystem functioning. Exotic species have been show to affect richness and abundance of native, modify environmental variables, an in addition; they often have distinct structural and functional traits. As a consequence, exotic may modify litter quality and environmental conditions, altering decomposition rates. This research investigated the role that Ligustrum lucidum, as Asian tree, may play in litter decomposition in secondary forests of Yungas in Tucumán, Argentina. We performed a litter-bag experiment and incubated litter of 5 species (3 native and 2 exotics: Morus sp. and Ligustrum) in native and Ligustrum-dominated forest patches. We recorded litter decay along 4 dates during a year, and environment and structural plant variables. We found that that invaded forest are drier and hotter than native’s. The two exotic species represent the represented the extremes in specific leaf area, and Morus had the minor tensile strength. Overall, litter decomposition of the 5 species did not differ between invaded and native parches, but the there was significant different among species. The two exotics and Rapanea laetevirens (a native tree) had a faster decay than the two other natives. There was also tendency for all species to decompose slower in invaded patches, but this trend was opposite for Ligustrum litter. Exploring other characteristics, such as litter chemical composition, or activity of soil decomposers may help to explain our results