During the last decades, the earth's vegetation cover has been greatly affected by
anthropic action, affecting not only the quality of human life, but also the characteristics of the
ecosystem. Vegetation dynamics and changes in vegetation cover can influence several
environmental aspects, and especially the hydrological processes of a basin, in addition to
influencing water availability. The state of Tocantins stands out for having great potential for
agriculture due to the existence of fertile land and water availability. As a result, the growth of
agricultural activities in Tocantins became a highlight in Brazil. In this sense, applications of
digital image processing techniques and analysis of spatial metrics are important sources of
useful information to monitor the use of forest cover, estimating how much these generated
impacts affect biodiversity. This work sought to apply these techniques to understand the
structural and temporal dynamics of the landscape in the sub-basin of the Javaés River, which
is located in the southwest region of the state of Tocantins. To carry out the land cover
classification process, satellite images from the LANDSAT series were used for the years 2000,
2010 and 2020. From the images of each period, mosaics and clippings were generated using
the QGIS software. The selection of spatial metrics was based on ecological precepts according
to Metzger and the data were processed in the ArcGis program. In the first two years, the
changes were not very significant visually when compared to the year 2020, where there was a
significant reduction in native vegetation, mainly around the watercourses, some stretches
basically did not show a spectral response from the water, probably due to the siltation process,
and possibly causing the increase of sandbanks. With regard to the landscape metrics applied,
an increase of 26.57% of anthropized areas was observed in the period of 20 years, a reduction
of 35.31% of the natural vegetation of the sub-basin, and a reduction of 41.91% in the class of
water/wetlands. Thus, it is concluded that the increase in anthropized areas to the detriment of
native vegetation, due to the advance of pasture and agriculture areas, caused an increase in the
number of vegetation fragments and consequently a reduction in the areas of this class.
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