Environmental fragility and vegetation cover dynamics in the Lapa Grande State Park, MG, Brazil.

The environmental fragility analysis evaluates the susceptibility of an environment to degradation. Thus, the goals of this work are to analyze and map the environmental fragility of the Lapa Grande State Park (PELG), Brazil, and its buffer zone (ZA) and also quantify the changes in the vegetation cover before and after the implementation of the PELG. The environmental fragility was evaluated through multicriteria analysis using the factors: slope, geology, pedology and land use and land cover. The changes in the high vigor vegetation cover were determined from the normalized difference vegetation index (NDVI) for 1996, 2006 and 2016. It was verified that the central-east and northeast regions of the PELG presented the greatest environmental fragilities in 1996, and significant reductions in the areas with high and very high fragility were observed in 2006 and 2016 due to the increase in the vegetation cover after the implementation of the PELG, which was more expressive in the park area than in the ZA. The increase of 20.7% of 2006 to 2016 in the vegetation with greater vigor, proved the importance of the creation of a conservation unit.

Development of an annual drought classification system based on drought severity indexes.

In order to characterize the occurrence and intensity of droughts in the Doce River Basin, as well as to develop a system for its classification, four different drought indexes were evaluated: Percent of Normal Precipitation (PNP), Deciles Method (DM), Rainfall Anomaly Index (RAI) and Standardized Precipitation Index (SPI). The indices were calculated annually, based on precipitation data from 89 rainfall stations of the Brazilian National Water Agency (ANA). Nine analysis units (AUs) were determined in the basin and the Thiessen Polygons method was used to obtain the average precipitation in the respective drainage areas. The indices were calculated for each AU and then related to the drought intensity classes. An overall classification of the indices was proposed for the drought classification system for a 30-year base period, from 1985 to 2015. The most critical hydrological years of the Doce River Basin in relation to the drought were 1994/1995, 2000/2001 and 2014/2015, the latter being the most critical of the last 30 years. The results show that the annual drought classification system proved to be efficient in the identification of events, allowing to verify that the Doce River Basin presents a severe climatic drought condition, on average, every seven years.