Multiple dimensions of taxonomic tree diversity reveal complementary effects of environmental filtering and land-use legacy in an urban Atlantic Forest

Source abstract

Abstract The Brazilian Atlantic Forest is a highly diverse ecosystem that has been extensively fragmented by human activities, making secondary urban forests important for biodiversity conservation. However, the influence of environmental filtering and land-use legacies on taxonomic diversity during forest regeneration remains poorly understood. We evaluated tree community diversity along environmental gradients under contrasting management histories in an urban secondary forest in Juiz de Fora, Brazil. Three regenerating communities with a common origin as shaded coffee agroforestry systems were sampled: second-growth forest after silvicultural management (SGAM), second-growth forest after enrichment with Euterpe edulis (SGAE), and second-growth forest under natural regeneration (SGA). Phytosociological, topographic, soil, and litter data were analyzed using Hill numbers (q = 0, 1, 2) through iNEXT.3D and iNEXT.beta3D, Principal Component Analysis (PCA), Non-metric Multidimensional Scaling (NMDS), and Generalized Linear Mixed Models. PCA revealed edaphic and elevation gradients, whereas NMDS showed significant differences in species composition. Species richness (q = 0) was highest in SGAE and SGA, while dominance-weighted diversity (q = 1 and 2) was greater in SGAE and SGAM. Species richness increased with elevation, effective cation exchange capacity, sand content, and litter carbon-to-nitrogen ratio, but decreased with clay content, whereas management history showed little influence. In contrast, abundance-weighted diversity was primarily driven by management history, but also increased with litter carbon-to-nitrogen ratio and elevation. These findings indicate that environmental filtering shapes species richness, whereas land-use legacies have persistent effects on community structure, highlighting the importance of multidimensional approaches for evaluating and restoring secondary urban tropical forests.