Quanto sobra de verde em uma metrópole? Um estudo sobre a cobertura vegetal e corredores ecológicos em Fortaleza, Ceará.

Abstract

The coexistence between human beings and natural ecosystems has become increasingly conflicting and studying this relationship is a central object of study for environmental sciences. The present work aimed to map the approximate extent of the different types of natural vegetation, calculate how much of each type was left and evaluate the possibility of tracing urban ecological corridors between the remnants of vegetation, in the municipality of Fortaleza, Ceará. For that, GIS techniques such as geoprocessing and remote sensing were used, using the free software QGIS. From the analysis of the different geomorphological units of the municipality, it was possible to infer with reasonable certainty the phytoecological units originally present in the municipality. We also calculated vegetation cover (VCI) and green areas (GAI) indices for each neighborhood. Finally, from the Conservation Units that exist in Fortaleza and the green environments, we modeled routes that could potentially be planned to shelter ecological corridors in the urban fabric. From the analysis of land use and cover, it was concluded that approximately 83% of the territory has already been modified by deforestation and the consolidation of urban areas and that less than 17% of the area of the municipality still harbors native vegetation. The environments with the least area lost were dry forest (85% of remaining areas) and mangroves (75% of remaining areas), and the ones that lost the most area were the crystalline caatinga (4% of remaining areas) and the vegetation of the coastal tablelands (9% of remaining areas). The indexes showed very low results, the VCI was approximately equal to 13 m²/inhabitant and the GAI was approximately equal to 2 m²/inhabitant. In total, 13 ecological corridors were modeled connecting Cocó State Park to other conservation units and urban parks. The city of Fortaleza has serious problems regarding its growth process, since, in general, all the environments identified here are under threat from real estate developments and the city has only a small fraction of remaining areas, which suffer from a series of of impacts and need expansion and ecological restoration. In addition to making it clear that the city's green infrastructure is not being efficient. In view of this, the implementation of ecological corridors is an intervention proposal with social and ecological gains, and depends on the good management and planning of conservation units, urban parks, squares and the road network. With focused actions, the city's green infrastructure can expand its function of safeguarding native vegetation and conserving urban biodiversity.