Fire regimes play a pivotal role in shaping the structure and function of biotic communities in fire-adapted ecosystems. While fire is well recognized as a driver of plant diversity, the effects of fire regimes on belowground microbial diversity, plant-microbe interactions, and post-fire recovery patterns remain comparatively understudied. This dissertation addresses these gaps by examining how two long-term prescribed fire regimes, annual (1-year fire return interval) and maintenance (1-3-year fire return interval), influence plant communities, soil bacterial and fungal assemblages, plant-soil feedbacks, and post-fire successional trajectories in a longleaf pine-wiregrass savanna. We found that frequent annual fires reduced plant richness and diversity, depleted soil phosphorus, and homogenized fungal communities, indicating that highly frequent prescribed burning may undermine resilience in this ecosystem. Plant-soil feedback experiments revealed that recurrent annual fire likely promoted antagonistic soil biota that inhibited the dominant graminoid in our study, which may have potential complications for future restoration efforts for the species. Moreover, plant and soil microbial communities exhibited divergent recovery trajectories, with both compositional and richness patterns strongly shaped by fire legacy. Annual fire regimes delayed fungal recovery, increased bacterial richness, decreased plant richness, and slowed depth-dependent recovery for fungi, whereas maintenance regimes promoted stronger recovery and greater overall biodiversity retention. Together, these findings underscore that fire regimes fundamentally govern community composition, recovery trajectories, and the long-term stability and function of ecosystems. This work highlights the importance of fire management strategies that account for both above and belowground responses, and the cumulative impacts of repeated burns on ecosystem resilience.
