Quanto cabe de riqueza florística em parques urbanos? A diversidade vegetal e os conflitos socioambientais em áreas verdes públicas da cidade de Fortaleza, Ceará

Abstract

Urban expansion over recent centuries and the way cities are organized have resulted in an increasing concentration of the human population in urban centers. Fortaleza has lost a large portion of its vegetation cover throughout its expansion, with approximately 83.7% of its area lacking native vegetation. Urban parks are green areas, characterized by a predominance of natural attributes and vegetation cover, and they play important ecological and social roles. Despite these benefits, several challenges exist in the coexistence between cities and natural environments, which primarily affect both the environment and the population. This study aimed to present an overview of the floristic richness recorded in 24 urban parks in Fortaleza, distinguishing native from exotic species, using rarefaction to estimate the total botanical richness of the parks, and identifying the main socio-environmental conflicts present in each one. The floristic inventory of each park was conducted by the Fortaleza Municipal Secretariat of Urbanism and Environment (SEUMA) through field surveys using the walking method, in which the author participated as an assistant in part of the field activities. Species were identified and photographically recorded, as were the socio-environmental conflicts, and socio-environmental diagnoses for each of the 24 parks were subsequently made available, from which the flora and conflict data used in this study were obtained. The software EstimateS was used for rarefaction analyses, along with the ICE, Chao 2, Jackknife 2, and Bootstrap estimators for expected species richness, while QGIS 3.22.4 was used for map production. A total of 534 species were recorded across the 24 urban parks, of which 205 were exotic, 99 native to Brazil, and 228 native to the state of Ceará. Among the species found in common in more than 19 parks, six were native and ten were exotic. The presence of three species classified as “Vulnerable”, two as “Endangered”, and one as “Near Threatened” was identified. The rarefaction curve did not reach an asymptote, and the Chao 2 estimator proved to be the most accurate for estimating the asymptotic species richness of the 24 parks. A total of 23 different socio-environmental conflicts were identified, with the most prevalent being exotic/invasive species, improper disposal of solid waste, and irregular discharge of effluents, which were present in nearly all parks. Therefore, the implementation of more effective management practices in these green spaces is essential, as well as replacing and reducing the cultivation of exotic species, especially invasive ones, by prioritizing the planting of native species in urban parks, in addition to integrating the population with the city’s green areas through environmental education and strengthening monitoring and enforcement in urban park areas.