New research shows that private protected areas help conserve underrepresented biomes and highly threatened regions. Researchers have assessed 17,561 privately protected areas in 15 countries across five continents. Their findings reveal that compared to state protected areas, PPAs are twice as likely to be in areas with the greatest human disturbance, such as regions used for agriculture and mining. They are three times more likely to be in biomes with almost no established conservation reserves and protect 1.2% of key biodiversity areas.