Network stability of bryophyte-diazotrophic metacommunity in tropical fragmented forests

The size and connectivity of habitat patches are key factors determining ecological and evolutionary processes. Globally, forest fragmentation has extensively reconfigured spatial landscapes, yielding profound and enduring impacts on biodiversity. In the Amazon Forest, widespread deforestation has led to a rapid decline in biodiversity across the whole biome. Epiphyllous bryophytes form abundant and diverse communities in tropical forests, yet highly sensitive to environmental change. This makes them a good study system and environmental indicators to understand biodiversity dynamics associated with habitat loss. This project employs a comprehensive approach, integrating genomics and bioinformatics tools, to characterize the host genotype and nitrogen-fixing microbiota (diazotrophic) of two prevalent epiphyllous bryophyte species. Our investigation delves into the intricate interplay between abiotic factors (habitat size, connectivity, and quality) and biotic factors (species identity and host genotype) on plant-microbe associations within the context of forest fragmentation pressure. Observations from the study species reveal that populations genotypes diverged in 1- and 10-ha fragments (Genetic drift), when compared to populations in 100-ha fragments and continuous forests. Notably, only one species displayed reduced genetic diversity in 1- and 10-ha fragments. Additionally, both species in 1-ha fragments exhibited a decrease in nitrogen-fixing bacteria species and a shift in their composition. At a broader scale, our findings underscore the significant impact of fragmentation at the plant population genomics and their associated microbiota within the Amazon, one of the Earth's most biodiverse terrestrial ecosystems. This integrative approach illustrates the profound effects of habitat disturbance on a plant species' ability to sustain its beneficial associated microbiota.