Government administered protected areas (PAs) have dominated conservation strategies, discourse, and research, yet private actors are increasingly managing land for conservation. Little is known about the social and environmental outcomes of these privately protected areas (PPAs). We searched the global literature in English on PPAs and their environmental and social outcomes and identified 412 articles suitable for inclusion. Research on PPAs was geographically skewed; more studies occurred in the United States. Environmental outcomes of PPAs were mostly positive (89%), but social outcomes of PPAs were reported less (12% of all studies), and these outcomes were more mixed (65% positive). Private protected areas increased the number or extent of ecosystems, ecoregions, or species covered by PAs (representativeness) and PA network connectivity and effectively reduced deforestation and restored degraded lands. Few PPA owners reported negative social outcomes, experienced improved social capital, increased property value, or a reduction in taxes. Local communities benefited from increased employment, training, and community-wide development (e.g., building of schools), but they reported reduced social capital and no significant difference to household income. The causal mechanisms through which PPAs influence social and environmental outcomes remain unclear, as does how political, economic, and social contexts shape these mechanisms. Future research should widen the geographical scope and diversify the types of PPAs studied and focus on determining the casual mechanisms through which PPA outcomes occur in different contexts. We propose an assessment framework that could be adopted to facilitate this process.

中文翻译：

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私人保护区的保护和社会成果

政府管理的保护区 (PA) 主导了保护战略、讨论和研究，但私人参与者越来越多地管理土地以进行保护。人们对这些私人保护区 (PPA) 的社会和环境成果知之甚少。我们检索了关于 PPA 及其环境和社会成果的全球英文文献，并确定了 412 篇适合纳入的文章。对购电协议的研究在地理上是倾斜的；更多的研究发生在美国。PPA 的环境结果大多是积极的 (89%)，但 PPA 的社会结果报告较少（占所有研究的 12%），而且这些结果更加复杂（65% 是积极的）。私人保护区增加了生态系统、生态区、或保护区覆盖的物种（代表性）和保护区网络连通性，并有效减少森林砍伐和恢复退化土地。很少有 PPA 所有者报告负面的社会结果，经历了社会资本的改善、财产价值的增加或税收的减少。当地社区受益于就业、培训和社区范围发展（例如，学校建设）的增加，但他们报告说社会资本减少，家庭收入没有显着差异。PPA 影响社会和环境结果的因果机制尚不清楚，政治、经济和社会背景如何塑造这些机制也是如此。未来的研究应扩大地理范围，使研究的 PPA 类型多样化，并重点确定 PPA 结果在不同背景下发生的偶然机制。我们提出了一个评估框架，可以用来促进这个过程。