Perturbações antropogênicas nas últimas décadas no igarapé do Urumari, Santarém, Pará

Abstract

The emergence of spontaneous occupations and land misuse, as well as the inadequate management of water resources, result in numerous problems for the environment and people who live and depend directly or indirectly on it. The research aimed to identify and analyze the spatial and temporal dynamics of land use and land cover changes along the Urumari stream, located in the city of Santarém, Pará, between 1987 and 2018, using digital processing techniques. images and remote sensing. In addition, it sought to investigate the perception of older residents residing along the stream about the possible local processes of environmental degradation, respecting the timeline and comparing this perception with data acquired through geotechnologies. The remote sensing method included on-site visits to strategic points of the main course of the Urumari stream, classification supervised by the Maximum Likelihood algorithm, Landsat 5 TM, Landsat 8 OLI satellite images, and community interviews. Remote sensing data analysis was performed using the QGIS software and its complements. The data collection method for the environmental perception of older residents was based on the Problem-Centered Interview technique, and for the analysis of the interviews, the Collective Subject Discourse (CSD) technique was used. The remote sensing results show the loss of dense vegetation and the considerable increase of the built-up or exposed soil areas. The qualitative data obtained from 31 interviews totaling 27 Central Ideas (IC) and respective speeches. The comparison between the data acquired with the geotechnologies and the perception of the older residents showed the investigated perceptions corroborated the data presented in the georeferencing. Both techniques highlight that, over the last three decades, the studied environment underwent severe changes in its fauna, flora, water flow, as well as in its urban landscape. Thus, we concluded the studied environment has suffered deep human intervention in the last 31 years, without any kind of repair of native vegetation. Finally, it was observed that the investigated environment requires compliance with environmental laws, recovery of degraded areas and, mainly, greater action by the public power.