Análise das mudanças no uso e cobertura da terra na Bacia hidrográfica do Rio Maxaranguape - RN (1985 - 2020)

Abstract

The present monograph has as its central issue the analysis of the changes in land use and land cover in the Maxaranguape River Hydrographic Basin (MRHB) in the state of Rio Grande do Norte. The overall objective of this research is to analyze such changes over 35 years (1985-2020). The total area of the basin in question is 1,010.2 km2 and corresponds to about 1.9% of the state territory, with the Maxaranguape River as its main watercourse. To this end, geoprocessing techniques were used, making use of geospatial analysis in Geographic Information Systems (GIS) environment. Land use and land cover maps were made for the years 1985, 2002 and 2020; satellite images from the LANDSAT-TM mission, specifically from series 5, were used to compose mosaics of the study area for the years 1985 and 2002. For the year 2020 satellite images from the SENTINEL-02B-MSI series were used. These images were acquired and filtered in order to remove cloud cover using the Google Earth Engine (GEE) platform. In addition, we used the satellite image RAPIDEYE, acquired from the portal of the company PLANET, to validate the land use and land cover map of 2020. After performing these procedures, the following classes were obtained as a result of the classification: 1) Agriculture, 2) Water, 3) Intermittent Humid Area, 4) Deforested Area, 5) Dunes, 6) Urban Stain, 7) Anthropic Occupation Mosaic, 8) Pastures, 9) Central Pivot and 10) Vegetation. Of these, the class that suffered the greatest reduction in total area (166 km² from 1985 to 2020) was Vegetation. Those with the largest area increase, in turn, were the Agriculture and Pastures classes (98 and 52.5 km² from 1985 to 2020, respectively). However, proportionally to its original size, the Dunes class lost the most absolute area (58% of its total area from 1985 to 2020). On the other hand, in the same proportional measure to its original size, the Urban Spread class was the one that observed the greatest growth (258% of its total area from 1985 to 2020). The total area for each class observed in the year 2020 is as follows: Agriculture 176 km², Water 4.5 km², Wetland intermittent area 1.0 km², Deforested area 7.0 km², Dunes 1.8 km², Urban Plot 4.2 km², Anthropic Occupation Mosaic 38.3 km², Pastures 129.4 km², Central Pivot 6.9 km² and Vegetation 631.1 km². Thus, it was found in this research a significant increase in anthropic action (agriculture, pastures and urban sprawl) to the detriment of natural areas (vegetation and dunes) during the time period observed. Nevertheless, vegetation continues to be the class of greatest territorial extension in the MHRB.