The study examines the effectiveness of over 160,000 protected areas (PAs) in resisting habitat loss at different spatial and temporal scales using high-resolution data. Key findings include: 1. **Habitat Loss Across PAs**: Between 2003 and 2019, 1.14 million km² of habitat, equivalent to three times the size of Japan, was altered within protected areas. This loss was primarily due to the expansion of built-up land, cropland, pastureland, and deforestation. 2. **Spatial and Temporal Effectiveness**: Larger and stricter PAs generally had lower rates of habitat loss. While most PAs effectively halted the expansion of built-up areas, they were less successful in preventing deforestation and agricultural conversion. PAs were 33% more effective in reducing habitat loss compared to unprotected areas, but their ability to mitigate nearby human pressures was limited and varied spatially. 3. **Temporal Lag Effects**: There is a significant time lag in the effectiveness of PAs, ranging from 1 to 6 years, depending on the type of habitat loss. For example, PAs were effective in curbing built-up land expansion but less so in preventing cropland and forest loss. 4. **Spatial Variability**: PAs exhibited significant spatial variability in effectiveness, with some areas showing excellent performance while others were ineffective. Factors influencing this variability include the establishment time of PAs, governance type, biodiversity importance, distance to cities, and human footprint. 5. **Policy Implications**: The study suggests that proactive and prompt establishment of PAs is crucial for effective habitat loss mitigation. Tailoring strategies to regional specifics, such as climate, biodiversity, and socioeconomic factors, enhances the effectiveness of PAs. Long-term monitoring and adaptive management are essential to ensure the long-term stability and durability of PAs. 6. **Challenges and Future Directions**: The conflict between conservation and development remains a critical factor affecting the effectiveness of PAs. Sustainable development and harmonious coexistence between humans and nature are essential to reduce the trade-offs between conservation and development. Designing coordinated plans to reduce human demand for resources within PAs is crucial for achieving the post-2020 global biodiversity goals.The study examines the effectiveness of over 160,000 protected areas (PAs) in resisting habitat loss at different spatial and temporal scales using high-resolution data. Key findings include: 1. **Habitat Loss Across PAs**: Between 2003 and 2019, 1.14 million km² of habitat, equivalent to three times the size of Japan, was altered within protected areas. This loss was primarily due to the expansion of built-up land, cropland, pastureland, and deforestation. 2. **Spatial and Temporal Effectiveness**: Larger and stricter PAs generally had lower rates of habitat loss. While most PAs effectively halted the expansion of built-up areas, they were less successful in preventing deforestation and agricultural conversion. PAs were 33% more effective in reducing habitat loss compared to unprotected areas, but their ability to mitigate nearby human pressures was limited and varied spatially. 3. **Temporal Lag Effects**: There is a significant time lag in the effectiveness of PAs, ranging from 1 to 6 years, depending on the type of habitat loss. For example, PAs were effective in curbing built-up land expansion but less so in preventing cropland and forest loss. 4. **Spatial Variability**: PAs exhibited significant spatial variability in effectiveness, with some areas showing excellent performance while others were ineffective. Factors influencing this variability include the establishment time of PAs, governance type, biodiversity importance, distance to cities, and human footprint. 5. **Policy Implications**: The study suggests that proactive and prompt establishment of PAs is crucial for effective habitat loss mitigation. Tailoring strategies to regional specifics, such as climate, biodiversity, and socioeconomic factors, enhances the effectiveness of PAs. Long-term monitoring and adaptive management are essential to ensure the long-term stability and durability of PAs. 6. **Challenges and Future Directions**: The conflict between conservation and development remains a critical factor affecting the effectiveness of PAs. Sustainable development and harmonious coexistence between humans and nature are essential to reduce the trade-offs between conservation and development. Designing coordinated plans to reduce human demand for resources within PAs is crucial for achieving the post-2020 global biodiversity goals.