Frequência e severidade de queimadas frente aos eventos ENOS e AMO desde 2003 até 2014 na Gran Sabana- Parque Nacional Canaima-Venezuela

Abstract

The Canaima National Park (PNC) is located in the southeast of Venezuela and its foundation was promoted to the conservation of the Bacía of the Río Caroní, where are the sources of the main rivers that feed the Hydroelectric Central Simón Bolívar (Guri Dam) which provides approximately 72% of the National hydroelectric energy. In the eastern sector of the PNC if located the region of GS, which has the highest number of visitors for tourism and has the largest population of indigenous Pemón residents within a protected area in Venezuela, which use the fire as part of their culture. The last decades has reported an increase frequency of climatic anomalies and fires at Gran Sabana (GS), which has been appointed by the managers as the main agents in the reduction of the supply of water at the Guri dam. Therefore, the objective of this work is to evaluate the frequency and severity of bushfires that occurred in the GS PNC between 2003 and 2014 in relation to extreme weather events as ENSO (El Niño-La Niña/Southern Oscillation) and AMO (Multidecadal Atlantic Oscillation) and the dynamics of the vegetation. Were used data from the sources of heat, rainfall data, satellite imagery, and data from the anomalies in Sea Surface temperatures (SST) in the Pacific Ocean. Estimated: Pearson correlation (r) between fire frequencies VS. the SST anomalies; (r) anomalies in rainfall for each season VS SST: anomalies, normalized Index Burned (INQ), vegetation index (NDVI), Normalized Differentiates amount and extent of burned scars; and changes in land cover. It was found that: AMO in its warm phase, affects insignificantly the population of the ITCZ and changes the cell Hadley increasing precipitation in GS; anomalies positive phase/negative ENSO alter insignificantly the cell Walker, inhibiting/promoting rainfall and an increase/decrease in the length of dry periods in GS; ENSO negative phase and AMO warm phase simultaneously encourage an increase in rainfall volumes in GS; prolonged droughts contribute to the degradation of arboreal systems, the expansion of herbaceous systems and increases the frequency of fires; AMO, La Niña , or both, contribute to the growth of shrubs systems and to a lesser extent, to the recovery of arboreal systems; the distribution of burned scars is strongly associated with changes in cultural patterns of livelihood of the local population. It is concluded that the severity and frequency of fires in the Gran Sabana is a multifactorial process and multiscale that happen as a product of sync ecosystem factors (vegetation), social (proximity to population centers) and climate (ENSO and AMO).