Litter decomposition: The role of precipitation, solar radiation and the effects of rainfall pattern in a changing climate in an Brazilian Semi-Arid ecosystem
Photodegradation; Caatinga; organic matter ; decay rates; drivers decomposition.
The aim of this thesis is to understand the role of solar radiation and precipitation and their relationship with climate change on the control of decomposition in a Caatinga ecosystem in the Brazilian semiarid region. Through a set of manipulative field experiments, this thesis demonstrates that potodegradation (direct and indirect effects) affected the ecological process of decomposition, with a similar magnitude to the precipitation, in the studied area. We demonstrate an additive role of solar radiation and the precipitation in the control of annual decomposition rates and tends occurrence of synergism between these factors, at least part of the year. The results also prove that reductions in rainfall in climate change scenario for the region are responsible for to generate negative impacts on litter decay rates. We can conclude that the direct and indirect photodegradation ensures the presentation of higher levels and continue the process of decomposition of organic matter in the study area. Finally, this thesis alerts that a possible collapse of the litter decomposition process due to climate change may make vulnerable the functioning of this ecosystem.