Connecting Tree Diversity to Bacterial Community Composition in the Atlantic Forest

The Brazilian Atlantic Forest, a key global biodiversity hotspot, is crucial for climate regulation and water resource preservation. Understanding the importance of this native tropical forest to soil microbial biodiversity is essential for maintaining its ecosystem services and guiding forest management. To evaluate the interrelationship between the tree species and soil bacterial diversity from the Brazilian Atlantic Forest, in this study, soil samples were sampled from 21 plots distributed over an altitude gradient of 100 to 800 meters. Our results indicated that native vegetation cover is decisive for soil microbial biodiversity. Trees species diversity explained 54% of the total bacteria variance at the phylum level and 24% at the ASV level. Of the 72 tree species identified, Senegalia recurva, Araucaria angustifolia, Styrax acuminatus, Ilex paraguaiensis, Eugenia subterminalis, and Pisonia ambigua acted as keystone species in driving microbial abundance, strongly correlating with 7.44% of soil bacterial diversity. In addition, functional metagenomic prediction analysis showed these 6 species as the main trees correlated with the microbial biogeochemical cycles of carbon, nitrogen, sulfur, and phosphorus. These results reinforce the complexity of the interactions responsible for the ecosystem services provided by tropical forests and highlight the relevance of some native trees in maintaining soil microbial diversity to conserve ecosystem health. By identifying the main tree species in the Atlantic Forest that support microbial biodiversity and drive nutrient cycling, future research can be guided, as well as reforestation strategies for this important biome.