Post-fire recovery in fire-sensitive tropical forests: the role of habitat loss and resilience thresholds

Fire is a major driver of ecological change in tropical forests, yet the combined effects of fire history and habitat loss on frugivorous birds and post-fire vegetation recovery remain poorly understood. We evaluated how fire severity, extent, and frequency-together with forest cover-shape frugivore abundance and influence short-term (≤ 10 years) forest resilience in the Cantareira-Mantiqueira Corridor, southeastern Brazil. Using frugivore surveys conducted at fixed points across 15 landscapes, combined with satellite-derived fire metrics and kNDVI-based estimates of engineering resilience, we applied a set of hypothesis-driven Generalized Linear Models and segmented regressions. Fire characteristics alone did not explain frugivore abundance; however, a strong interaction between fire severity and forest cover revealed that forest cover buffered fire impacts under a low severity but failed under high-severity conditions, leading to marked declines in frugivore abundance. Forest recovery was primarily governed by fire characteristics rather than by frugivore abundance. Fire extent showed a linear negative effect on kNDVI trend, while fire frequency displayed nonlinear behavior, with a threshold near three fire events beyond which recovery became highly variable and unpredictable. Together, these findings provide evidence that fire and habitat loss interact to shape frugivore communities, and that repeated burning can push fire-sensitive tropical forests toward resilience thresholds. Effective conservation and restoration strategies must therefore integrate both fire prevention and habitat maintenance to safeguard ecosystem recovery.