Linking hydrologic regime, rainfall and leaf litter fall in a riverine forest within the Ramsar Site Humedales Chaco (Argentina).

CASCO, S.L.; GALASSI, M.E.; MARI, E.K.A.; POI, A.S.G.; NEIFF, J.J.

Milwaukee

Encuentro; Annual Meeting de la Society of Freshwater Science; 2015

Society of Freshwater Science

We analyze the pattern of leaf litterfall and the breakdown rate in a mixed gallery forest that covers the levees of the Paraná River oxbow lake. Litter fall was collected biweekly for four year that represents different rainfall and hydrologic regime of the Paraná River including flood and prolonged drought. Litter bags were incubated on the forest floor during flooding conditions and dry conditions and in the oxbow lake. Our results suggest that with the increasing severity of the dry season and decreasing hydrologic connectivity, the annual leaf litterfall increases, whereas its seasonal pattern does not change. Regardless of the seasonal pattern of rainfall and hydrological regime in each study period, leaf fall occurred throughout the year. Leaves decomposed fastest in oxbow lake, and the leaf breakdown on the forest floor was slower during flooding conditions than in dry conditions. Regular floods are natural occurrences that not affect the leaf production of the mixed forest and the leaf processing depends on the oxygen concentrations. Prolonged droughts led to high annual leaf production, which is mainly processed within this forest.