Relação entre as mudanças de uso e cobertura de terra e as queimadas em florestas de Miombo, Gurué, Moçambique

Abstract

Despite having a high forest cover, Mozambique has high rates of deforestation and forest degradation. Fire plays an important role in miombo woodlands, where it constitutes one of the first steps in the deforestation process. The district of Gurué, with a high population density and agricultural production, is a good example of the pressures faced by the country’s forests. The District of Gurué has had a reduction in its woodlands in the last few years. This study presents the land use and land cover (LULC) change for Gurué between 2000 and 2015 and the role fire plays in those changes. The study was conducted using remote sensing techniques and field data. A supervised classification of LULC was conducted, with a maximum likelihood algorithm, using Landsat images. Changes in a vegetation index were also analysed. The fire regime was studied using two MODIS sensor products: active fires and burned area. Temporal and spatial distribution of fires was analysed. The LULC classification accuracy was 80.3, 79.0 and 77.6% for 2000, 2005 and 2015 respectively. The deforestation rate in the district between 2000 and 2015 was 29.9 km 2 /year. The vegetation index indicated an overall decrease in plant biomass. Fire were more frequent in western and southern Gurué. Fire occurrence was independent of LULC class, and fire frequency was not correlated with changes in LULC or plant biomass reduction. Fires in Gurué appear to be a tool in LULC change, rather than a driver of deforestation and forest degradation