Complexidade estrutural, composição de espécies e traços funcionais de comunidades lenhosas ao longo de gradientes sucessionais em duas formações tropicais secas no Brasil

Abstract

Tropical dry woodlands, such as the Cerrado and Caatinga, exhibit high biological diversity and play an essential role in maintaining ecosystem services. Despite this, these forests have historically been neglected in terms of research and conservation, undergoing intense changes in their original cover. In Brazil, the Cerrado sensu stricto and tropical dry forests (TDFs) coexist in transition regions, such as northern Minas Gerais, offering unique opportunities to investigate their successional trajectories. Therefore, the objective of this study was to evaluate changes in the structure and floristic composition of woody communities along chronosequences in the Cerrado and TDF, by selecting areas that represent the different stages of succession. Nine 20 x 50 m plots were allocated in each environment, three of which represented each successional stage. All woody individuals with a DBH ≥ 5 cm were considered, marked in the field with an enumerated aluminum plate, and identified to the species level. A total of 1,300 individuals of 84 species belonging to 31 botanical families were recorded in the Cerrado, and 881 individuals of 75 species belonging to 23 families in the TDF. The most representative family was Fabaceae for all three successional stages in both formations. Astronium urundeuva (Aroeira-do sertão) dominated the entire successional gradient of the TDF, with a significant difference in the number of individuals compared to the other species. The Cerrado, in turn, showed a shift in the most abundant species across the gradient and a better distribution of the number of individuals among the species found. Contrary to expectations, the floristic composition between stages was similar in both formations, which can be attributed to the regrowth of late species at the beginning of regeneration. Finally, an increase in community complexity was observed with succession in both environments, especially for the basal area in the TDF and richness in the Cerrado.