Variação espaço-temporal da cobertura de vegetação da caatinga, usando o índices de vegetação normalizada (NDVI)

Abstract

It is evident that climate change is altering ecosystems on a global scale. In recent decades, there has been an increase in the melting of the polar ice caps and snowy peaks in the mountain chains, as well as the increase in temperature, water shortages and the risk of extinction in several organisms, resulting at the same time in a risk increase of food security for the people. In Brazil, effects of climate change are already observed in some regions, some effects are increase of torrential rain in areas where rainfall was very low, as well as the rainfall decrease elsewhere. Similarly, the Brazilian biomes are subject not merely to climate change, but also to anthropogenic changes, such as deforestation, that compromises the existence of these Biomes. The Caatinga biome for example, face increasingly prolonged droughts, strong anthropic pressures and weak environmental policies. All those factors threaten the conservation of this biome that is unique in Brazil. The present study aims to seek to demonstrate the high value that conservation units have against extreme climatic events in the Caatinga. For this, NDVI monthly values were used, as well as precipitation and vector data (Shapefile) of deforestation (IBAMA) and the Conservation Units (MMA). In the Chapter, we analyze which is the relation between NDVI monthly values and precipitation in areas with deforestation and conservation units, using a generalized linear model (GLM). The results showed that: i) there is a strong relationship between monthly NDVI, precipitation and conservation units (Estimate = -0.019, SE = 0.004, p-value = <0.001), ii) it also show that the conservation units play an important role in the events of extreme drought in the Caatinga vegetation.