Uma perspectiva histórica e espacial da ocorrência e distribuição de populações de Calophyllum brasiliense Cambess. e Platymiscium ulei Harms no Médio Solimões, Amazonas

Abstract

Historical logging in the Middle Solimões region drastically reduced populations of Calophyllum brasiliense (Jacareúba) and Platymiscium ulei (Macacaúba), creating an urgent need to understand their current spatial arrangements to support management and conservation efforts. This study investigated the occurrence and structure of three Jacareúba populations (JAC1, JAC2, JAC3) and two Macacaúba populations (MAC1, MAC2) in the Mamirauá Sustainable Development Reserve, correlating them with soil physicochemical attributes collected in the field between 2023 and 2025 (with analytical determinations completed in 2026). The methodology integrated geostatistical tools (variography, ordinary kriging, cross-validation) and multivariate analysis (Exploratory Factor Analysis) applied to 313 georeferenced tree specimens and 259 soil samples. Results revealed contrasting post-disturbance trajectories. C. brasiliense maintained, across its clusters, an aggregated spatial pattern with moderate spatial dependence and practical ranges between 274 m and 288 m, demonstrating resilience and autonomous recovery capacity. In contrast, P. ulei exhibited an independent pattern with Pure Nugget Effect in both remaining populations, characterizing severe demographic collapse associated with a potential Allee effect. In MAC1, the species was restricted to an equally random bipolar fertility/acidity gradient (pH, V, H+Al), whereas in MAC2 the abiotic matrix proved chaotic, precluding Factor Analysis (KMO = 0.17). It is concluded that the same historical pressure produced distinct dynamic responses according to the intrinsic vulnerability of each taxon. Passive protection is sufficient for Jacareúba regeneration, whereas Macacaúba requires active enrichment interventions and differentiated silvicultural management.