Modelagem de nicho ecológico de Aldina heterophylla Spruce ex Benth, Mezilaurus itauba (Meisn.) Taub. ex Mez. e Virola surinamensis (Rol.) Warb.: impactos ambientais e conservação na Amazônia

Abstract

Tropical rainforests are distributed globally along the equator and have a hot and humid climate. However, this humidity is not constant and equal throughout the Amazon basin. This, along with other environmental factors such as geomorphology, geology, and local variations, results in different types of vegetation, from open forests such as campinaranas and savannas to densely forested areas such as terra firme forests and floodplain vegetation such as várzea and igapó. Terra firme forests occupy a large area, approximately 80% of the Amazon basin. Floodplain forests, which are periodically flooded during river floods, occupy approximately 10% of the Amazon biome. Aldina heterophylla Spruce ex Benth., popularly known as macucú, belongs to the Fabaceae family and has a distribution practically restricted to campinarana areas. Mezilaurus itauba (Meisn.) Taub. ex Mez. (Lauraceae) is popularly known as louro-itaúba, itaúba, itaúba-abacate, and itaúba-amarela and grows in dryland forests, igapós, and floodplain forests. Virola surinamensis (Rol.) Warb (Myristicaceae), known as ucuúba, is a predominant species in flooded areas, especially igapós. These species are listed as vulnerable and endangered. Ecological niche modeling is a widely used practice to infer the geographic distribution of species from observed and estimated data, using environmental variables as predictors. Occurrence data were extracted from the Species Link website database and REFLORA herbaria. These data were processed in a spreadsheet, filtered and standardized by species, and subsequently applied to modeling programs with algorithms to produce final maps. This research used climate data from the WordClim research platform as a reference for the modeling. Among the variables tested, the most important were temperature seasonality and the average temperature in the wettest quarter (°C) for macromodeling, while altitude was the most important for micromodeling. For the future, reductions in potential occurrence areas were estimated for all three species, reaching at least 37% for the least pessimistic scenario, with the largest habitat losses, around 61.5%, in the projections for the most pessimistic scenarios. The comparative maps show greater comparative accuracy compared to the occurrence points in R Studio, as Open Modeler presented overestimated results. However, they followed the same trend, with a progressive reduction in potential areas, which increased according to the period and the projections used. Government protection measures, such as the demarcation of protected areas such as Indigenous Lands and Conservation Units, are of great importance because they create legal barriers that, together with monitoring and enforcement, are vital to guaranteeing habitats and the survival of the aforementioned species and other threatened species in the Amazon Biome. Other ways are the use of species in silvicultural and agroforestry techniques, which function as propagation of species in projects to recover degraded and altered areas, contributing to the forest's carbon absorption capacity and resulting in the reduction of greenhouse gases.