A study recently published earlier in 2022 in the journal Nature shows that the conservation impact of protected areas, such as national parks, on species greatly varies according to the way that they are managed. The study led by the universities of Exeter and Cambridge examined the impact of 1,500 protected areas (in 68 countries) on more than 27,000 waterbird populations. The study compared waterbird population trends in protected areas before management control with trends afterwards and compared the trends of similar waterbird populations inside and outside protected areas.