Protected areas are effective at conserving carbon sink capacity even in fire-prone terrestrial ecosystems

Abstract Recent studies have claimed that protected areas (PAs) in fire-prone landscapes may undermine forest carbon conservation by creating high fuel load concentrations, challenging the role of PA expansion as a climate change mitigation strategy. We tested this hypothesis using above-ground biomass trends from 2017 to 2024 across Spain, a region experiencing intensifying drought and extreme events as well as increasing wildfire pressure. Using statistical matching techniques that control for initial biomass conditions and climate exposure, we compared live biomass carbon conservation performance between PAs and non-PAs. PAs significantly outperformed non-PA counterparts, showing better live biomass carbon conservation in 70% of biomass-matched comparisons and maintaining this advantage in 59% of climate-controlled comparisons-representing a statistically significant 9% advantage over the null hypothesis. We find that most strict PAs (National Parks) have an enhanced effectiveness, showing better performance in carbon conservation in 85% of biomass-controlled and 68% of climate-controlled matches, respectively. This advantage demonstrates that protection status itself, not merely favorable location, can drive enhanced carbon conservation. Our results provide empirical support for PA expansion as an effective climate change mitigation strategy.