Decomposition of and nutrient dynamics on leaf litter and roots in Poa ligularis, Nassella tenuis and Amelichloa ambigua en Patagonia.
This project is carried out by researchers of the Dpto. Agronomia, CERZOS- UNS, Ecology Group.SUMMARY: Poa ligularis, Nassella tenuis and A. ambigua are C3, perennial native grasses in arid rangelands of Northwestern Patagonia. They represent late, intermediate or early stages of plant succession, respectively. Domestic livestock shows high selectivity for P. ligularis and N. tenuis, and rejection of A. ambigua. This is associated with a reduction in the abundance of P. ligularis and N. tenuis, and an increase in the abundance of A. ambigua in arid zones, where grazing mismanagement is conducted. If abundance of A. ambigua is greater than that of the other two species, and decomposition and nutrient mineralization are lower in A. ambigua than in P. ligularis and N. tenuis , rates of nutrient cycling can be reduced in the ecosystem. During 2012-2014, above- and belowground (roots) dry weight losses, the effects of UV radiation on the aboveground decomposition rates, and C, N and P concentrations in aboveground litter (blades) and roots of P. ligularis and N. tenuis versus A. ambigua will be determined . Decomposition rates will be related to abiotic (climatic parameters: temperature, moisture, UV radiation) and biotic (degree of activity of microbial decomposers) variables. The soil biological activity will be determined by CO2 release methods, by fluorescein hydrolisis and by the dehydrogenase activity. Species effects will be separated from those of sites by incubating leaf litter and roots of all three species at sites dominated by P. ligularis, N. tenuis and A. ambigua.