Woody vegetation in Atlantic Forest inselbergs: floristic similarity, patterns of richness, pollination/dispersal syndromes, and influence of climatic variables

Abstract Forest ecosystems established on developed soils occupy the most significant territorial extension in the Atlantic Forest and are historically the most studied environments in this domain. However, woody vegetation on granitoid rock outcrops (inselbergs) has been historically neglected. The objective of this study was to analyze the composition of the woody flora of inselbergs in the Monumento Natural do Maciço das Andorinhas (MONAMA), a southern region of Espírito Santo state, and evaluate its similarity with other inselbergs studied in southeastern Brazil. Based on field expeditions and literature data, we recorded a total of 27 species, 25 genera, and 16 families. The families Fabaceae and Myrtaceae, along with the genus Eugenia, were the richest in species diversity. The predominant pollination and dispersal syndromes were entomophily and zoochory, respectively. Furthermore, Erythroxylum deciduum, Ficus cyclophylla, Pseudobombax petropolitanum, Trigoniodendron spiritusanctense, and Wunderlichia azulensis are listed as endangered species. Pseudobombax petropolitanum, Tabebuia reticulata and Wunderlichia azulensis are endemic to inselbergs of the Atlantic Forest. Species endemic to the Atlantic Forest and species with wide geographic distribution across Brazilian phytogeographical domains predominated. Regarding environmental variables, the CCA indicated a strong correlation between woody species and elevation, maximum temperature of the warmest month, mean diurnal range, and precipitation in the driest month. MONAMA has more species shared with inselbergs in southern Espírito Santo due to geographic distance. This study provides an essential contribution to the knowledge of the woody vegetation of inselbergs, which has been historically neglected in the Atlantic Forest domain.