Protected areas are a key component of global conservation, and the world is aiming to increase protected areas to cover 30% of land and water through the 30 × 30 Initiative under the Post-2020 Global Biodiversity Framework. However, factors affecting their success or failure in regard to promoting mammal population recovery are not well studied, particularly using quantitative approaches comparing across diverse taxa, biomes, and countries. To better understand how protected areas contribute to mammalian recovery, we conducted an analysis of 2706 mammal populations both inside and outside of protected areas worldwide. We calculated the annual percent change of mammal populations within and outside of terrestrial protected areas and examined the relationship between the percent change and a suite of human and natural characteristics including biome, region, International Union for Conservation of Nature (IUCN) protected area category, IUCN Red List classification, and taxonomic order. Our results show that overall mammal populations inside and outside of protected areas are relatively stable. It appears that Threatened mammals are doing better inside of protected areas than outside, whereas the opposite is true for species of least concern and Near Threatened species. We also found significant population increases in protected areas classified as category III and significant population decreases in protected and unprotected areas throughout Oceania. Our results demonstrate that terrestrial protected areas can be an important approach for mammalian recovery and conservation.

保护区是全球保护的重要组成部分，世界的目标是通过2020年后全球生物多样性框架下的30×30倡议，将保护区扩大到覆盖土地和水域的30%。然而，影响其在促进哺乳动物种群恢复方面成功或失败的因素尚未得到充分研究，特别是使用定量方法对不同类群、生物群落和国家进行比较。为了更好地了解保护区如何促进哺乳动物的恢复，我们对全球保护区内外的 2706 个哺乳动物种群进行了分析。我们计算了陆地保护区内外哺乳动物种群的年度百分比变化，并研究了百分比变化与一系列人类和自然特征之间的关系，包括生物群落、区域、国际自然保护联盟 (IUCN) 保护区类别、 IUCN 红色名录分类和分类顺序。我们的结果表明保护区内外的总体哺乳动物种群相对稳定。受威胁的哺乳动物在保护区内的情况似乎比在保护区外的情况要好，而最不受关注的物种和近危物种的情况则相反。我们还发现，整个大洋洲第三类保护区的人口显着增加，而保护区和非保护区的人口显着减少。我们的结果表明，陆地保护区可以成为哺乳动物恢复和保护的重要方法。