Contrasting effects of fire on reproductive structures: prescribed burns advance and extend flowering but reduce fruiting of Macairea radula (Bonpl.) DC (Melastomataceae) in the Brazilian Cerrado

Abstract

Abstract Fire triggers flowering, stimulating and advancing flower production and, consequently, fruiting in some plants of the Cerrado , the Brazilian savanna. Integrated Fire Management (IFM) has been applied in several protected areas in the Cerrado to simulate natural fire regimes. However, its effects on both flowering and fruiting patterns remain underexplored. This study evaluated the impact of IFM on the phenology and abundance of flowers and fruits of Macairea radula , an abundant shrub that produces large quantities of flowers. Sampling was conducted monthly for 12 months in both unburned and low-intensity prescribed-burned areas. Our findings highlight the complex interactions between fire and plants. Prescribed fire anticipated and extended flowering, indicating that M. radula is fire-stimulated but not fire-dependent. However, fire reduced both the fruiting period and fruit abundance, suggesting an effect on initial reproductive stages that did not lead to increased fruit availability over time. These findings underscore the need to monitor phenological processes beyond flowering. Species-specific assessments are essential for understanding the full impact of IFM on plant reproductive strategies and for guiding fire management in fire-prone biodiversity hotspots. From a management perspective, our results also indicate that adjusting the timing of prescribed fires to avoid periods of high reproductive sensitivity may substantially mitigate negative effects on plant reproductive success without compromising the benefits of low-intensity burns.