MODELING ECOLOGICAL NICHE FOR Swietenia macrophylla King., IN THE BRAZILIAN AMAZON.
Brazilian Mahogany; Geographic distribution; Deforestation; Species conservation
Habitat degradation and fragmentation are considered serious threats to biodiversity in the Amazon. These losses alter the structural integrity and functioning of ecosystems. Due to intensive exploitation, many natural populations of Brazilian mahogany (Swietenia macrophylla King.) have been suppressed or had their stock drastically reduced, especially in the Brazilian Amazon. Considering the importance of species conservation, techniques of potential species distribution can serve as a basis for decision making regarding definition of conservation areas. Thus, this work aimed to predict areas of ecological niche for S. macrophylla, in the geographical space of the Brazilian Amazon. The real occurrence points of the species were obtained in the databases of the Global Biodiversity Information Facility - GBIF and the RadamBrasil Project with occurrence data for South and Central America. The statistical program R was used to exclude points of occurrence with no consistent information. A total of 138 predictors with climatic, topographic and soil property characterization values were used, to which, Principal Component Analysis (PCA) was applied. The distribution modeling was performed in the statistical program R-3.6.2, based on a function for creating ecological niche models “ENMTML”, using four algorithms. The Consensus Map (Ensemble) was synthesized from the set of predictions based on the first 14 axes of the main components of the generated models. The processed output image was cropped to the limits of the geographic area of the Brazilian Amazon. The delineations of the area of actual occurrence of mahogany, inferred by Lamb (1966) and Barros et al. (1992), for the Brazilian Amazon, were compared to the area defined by the consensus model as an ecological niche of the species, in order to verify the percentage of modeled area existing in the area classified by the authors. The binary map was superimposed by the shapefile of accumulated deforestation area in the Brazilian Amazon from the National Institute for Space Research (INPE), in the years 2008 to 2019, for subtracting deforested areas. The area described was calculated from the modeling as a niche of the species, occurring in Conservation Units (UC), from the database of the Chico Mendes Institute for Biodiversity Conservation (ICMBio) and the I3Geo portal of the Ministry of the Environment (MMA), at the State and Federal levels in the Amazon biome. As a result, we had a total of approximately 2,395,593.72 km² of ecological niche area for the species. The overlapping of the ecological niche area for S. macrophylla, corresponded to 65.25% of the area demarcated by Lamb and about 81.56% of Barros et al delimitation for the area classified as high volume occurrence of mahogany in the Brazilian Amazon. Deforestation occurring in the area modeled as an ecological mahogany niche, was approximately 2.07% of the total predicted by the model. The deforestation incident in areas of State and Federal Conservation Units, revealed loss of ecological niche areas with possible occurrence of Brazilian mahogany. Therefore, the present study was developed in an attempt to update the geographical limits of possible occurrence of mahogany and to help improve public policies aimed at environmental conservation of the Amazonian flora, giving the main focus to Brazilian mahogany.