Evaluating the dual effects of 1,399 protected areas in China leveraging propensity score matching and difference in differences methods

Protected areas (PAs) are central to global biodiversity conservation, yet existing assessments of PAs’ effects typically address ecological and environmental (eco-environmental) or socioeconomic outcomes separately, limiting the ability to identify synergies and trade-offs between them. This study develops a unified counterfactual framework, integrating propensity score matching with difference in differences (PSM-DID) and a nine-category composite classification, to jointly evaluate both dimensions across 1,399 PAs at 4 administrative levels in China from 2000 to 2020. Results indicated that socioeconomic indicators responded more readily to PA establishment than eco-environmental ones, among which GDP tended to decline while nighttime light increased. Eco-environmental indicators exhibited several statistically significant outcomes, yet their practical magnitudes were generally small. The dual-dimensional classification reveals that simultaneous gains remained uncommon among PAs (less than 10%), with systematic variation across administrative levels and regions. This study provides evidence-informed directions for differentiated PA governance in China.