Balancing Fire Regimes and Population Dynamics for the Conservation of a Microendemic Lizard From a Biodiversity Hotspot

ABSTRACT Understanding how fire regimes influence population processes is critical for conserving biodiversity in fire‐prone ecosystems, particularly for microendemic species with restricted distributions. Fire effects on wildlife are often inferred from abundance alone, potentially obscuring life‐stage–specific demographic mechanisms that determine population persistence. We investigated how variation in fire regimes shapes demographic performance in Ameivula jalapensis , a microendemic lizard from the Brazilian Cerrado. Using complementary sampling designs, we combined mark‐recapture and Bayesian hierarchical models to investigate whether more severe fire regimes and recently burned areas enhance survival, recruitment, abundance, and body condition (P1), increase the number of smaller individuals in the size structure (P2), and maintain a balanced 1:1 sex ratio (P3). We also incorporated vegetation structure, microclimate, and ecophysiological parameters to identify mechanistic links between fire regimes and population responses. Ecophysiological parameters, particularly locomotor performance and hours of activity mediated by microclimatic temperatures, were key predictors of demographic patterns. Although detection‐corrected abundance, survival, and recruitment did not vary across fire regimes, severe regimes were associated with higher adult body condition and activity (partially supporting P1), while size structure shifted toward larger individuals (contradicting P2), and sex ratio remained stable (supporting P3). Because juveniles were disproportionately associated with microhabitats offering temperatures close to their locomotor optimum (which are less available under severe fire regimes), these patterns suggest a potential demographic trade‐off between adult performance and juvenile success. These results indicate that fire regimes act as environmental filters, benefiting resilient adults while potentially constraining recruitment through microclimatic pathways. Our findings underscore the importance of landscape heterogeneity: frequent fires create open habitats favorable to adults, but less‐severely burned or unburned areas remain essential for recruitment. More broadly, we demonstrate how integrating demography and physiology can uncover life‐stage–specific responses to disturbance, providing a transferable framework for conserving cryptic, low‐detectability species in fire‐managed ecosystems.