Floristic, structural, successional and phylogenetic disparities in a mosaic of adjacent forest physiognomies in the Atlantic Forest

Abstract Tropical forests are structured as complex mosaics shaped by disturbance regimes and edaphic filters, yet distinguishing between successional dynamics and edaphic climax vegetation remains a challenge for forest ecology and conservation. This study examines the floristic composition, phytosociological attributes, successional stage, and phylogenetic diversity of three adjacent forest environments within Cantareira State Park, southeastern Brazil, one of the largest remnants of Atlantic Forest. Across 0.525 ha, we sampled 768 individuals, representing 92 species, 65 genera, and 42 families. Species richness was highest in environments B and C (56 species each) and lowest in A (42 species). Tree ferns (Cyathea phalerata and Dicksonia sellowiana) dominated the waterlogged environment A, while environment B was characterized by early secondary canopy trees and shade-tolerant understory species, and environment C by late secondary species such as Ocotea catharinensis and Micropholis crassipedicellata. Clustering analyses integrating floristic, structural, successional, and phylogenetic data revealed that environment C was consistently distinct, whereas A and B showed partial overlap due to shared edaphic conditions. Successional classification indicated apparent differences among environments, but the presence of mature forest indicators, including well-developed tree ferns and late secondary species, suggests that all three environments represent stable, mature forests shaped by contrasting soil and drainage conditions. These findings highlight the importance of recognizing edaphic climax communities within forest mosaics and caution against relying solely on successional stage classifications in conservation planning. Misinterpretation of structurally simple yet mature forests may bias management decisions and reduce protection under current legislation. Competing Interest Statement The authors have declared no competing interest.