As mudanças temporais do uso da terra e da fragmentação florestal provocada pela expansão da monocultura do dendê (Elaeis guineensis Jacq.) em uma bacia hidrográfica no estado do Pará.

Abstract

The microregion of Tomé-Açu, northeastern Pará, is marked by changes in the landscape due to the oil palm boom (Elaeis guineensis Jacq.), A remarkable monoculture that ended up reorganizing the space and territorial dynamics in this part of the Amazon. The Sustainable Palm Oil Production Program (PPSOP), created in 2010, provided for the cultivation of 316 thousand hectares of oil palm planted area by 2019, involving more than 30 municipalities in northeastern Pará. This context offers an opportunity for the landscape of an ancient colonization frontier, shaped with different land use patterns over time, to be analyzed from the perspective of landscape ecology. This work aimed to identify the spatial and temporal patterns of land use changes and the effect of these changes on the structure of the forest landscape in the Mariquita River Basin in the municipality of Tomé-Açu, Pará, on a sixteen-year multitemporal scale. The methodological steps of this research were divided into: (a) image acquisition through the Google Earth Engine (GEE) platform database, (b) image clipping and classification through the ENVI v. 4.5, (c) elaboration of thematic maps of vegetation cover and land use using the ArcMap 10.5 software, (d) analysis of the environmental trajectories of landscape changes, (e) quantification of the remaining forest fragments, (f) analysis of the structure of the landscape through the application of metrics, with the aid of the program Fragstats v. 4.2. Supervised classification (MaxVer) was applied and points were collected in the field for validation. The indices used were: occupied proportion (PLAND), fragment density (PD), medium proximity (PROX-MN), largest spot index (LPI) and connectivity (COHESION). The classification obtained an overall performance of 0.83 for the Kappa index. The agricultural class was the most expressive over the years; unlike the remaining forest, which declined by almost 20%, leading the landscape to a critical state of fragmentation. The trajectories showed that 47.27% of the total area analyzed (765.65 km²) left the forest for oil palm. The basin landscape is dominated by fragments smaller than 0.5 ha, totaling an increase of 12.76% from 2002 to 2018. The area of the largest fragment decreased by 33.29% and the density increased from 6.03 to 28, 62 (number of fragments / 100 ha). The average proximity between the fragments was greater in 2002, differently from 2018, when there was a decrease in the amount of remaining forest, thus causing greater isolation and less habitat. Connectivity has decreased by almost 5% in 16 years, a fact that can be explained by the increased isolation between the fragments and the disappearance of small remnants. It was also found that, even with the decrease in the amount of forest remaining in the study area, the normative instructions deliberated by the PPSOP are being followed within its conformities, since the expansion of oil palm has occurred in areas of agriculture and secondary vegetation. Therefore, the understanding of the temporal and spatial dynamics of fragmentation in the BHRM landscape has contributed to its being considered a (re)formulation with regard to oil palm expansion policies, in a way that considers the landscape as an object of policy and not only issues related to land use and deforestation of areas within properties.