Severe fire regimes select for highly resilient populations in ectotherms

Abstract Understanding species’ responses to environmental change is crucial for mitigating human-induced disturbances. Here, we test hypotheses regarding how three essential components of demographic resilience (compensation, resistance, and recovery) co-vary along the distinct life histories of three lizard species exposed to variable, prescribed fire regimes. Using a Bayesian hierarchical framework, we parameterize stochastic Integral Projection Models with 14 years of individual-level data from five sites in Brazilian savannas, each historically subjected to different fire regimes. Our findings reveal that severe fire regimes reduce populations’ resistance, compensation, or recovery abilities. Additionally, we identify generation time and reproductive output as predictors of resilience trends across fire regimes and climate. Our analyses demonstrate that the probability and quantity of monthly reproduction are the proximal drivers of demographic resilience across the three species. We emphasize how reproductive constraints, such as viviparity and fixed clutch sizes, significantly impact the ability of ectothermic populations to resist to and benefit from disturbances, underscoring their relevance in conservation assessments.