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Privately protected areas increase global protected area coverage and connectivity


Privately protected areas (PPAs) are increasing in number and extent. Yet, we know little about their contribution to conservation and how this compares to other forms of protected area (PA). We address this gap by assessing the contribution of 17,561 PPAs to the coverage, complementarity and connectivity of existing PA networks in 15 countries across 5 continents. We find that PPAs (1) are three times more likely to be in biomes with <10% of their area protected than are other PA governance types and twice as likely to be in areas with the greatest human disturbance; (2) that they protect a further 1.2% of key biodiversity areas; (3) that they account for 3.4% of land under protection; and (4) that they increase PA network connectivity by 7.05%. Our results demonstrate the unique and significant contributions that PPAs can make to the conservation estate and that PPAs deserve more attention, recognition and resources for better design and implementation.

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Fig. 1: Proportion of each biome protection level protected by PA governance types.
Fig. 2: Proportion of each terrestrial biome protected by protected areas.
Fig. 3: Complementarity of PPAs to other governance types in protecting terrestrial biomes.
Fig. 4: Proportion of each HF category protected by PA governance types.

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Data availability

All data used in this manuscript are openly available online. Protected areas boundaries are available from The WWF ecoregions layer is available from The Global Human Footprint Dataset v.3 (2009) is available from KBAs are available on request by filling out a form found at Source data are provided with this paper.

Code availability

The R script used to rotate and move polygons can be found at The R script for random placement of PPAs can be found at


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This research was supported by the Economic and Social Research Council through the White Rose Doctoral Training Programme. We would like to thank R. Rigby for the building of the model for random placement. This paper is dedicated to the memory of E. Corcuera Vliegenthart, who did so much for PPAs.

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Authors and Affiliations



R.P. designed the study, conducted the analysis and wrote the first draft of the manuscript. GH. and J.A.O. contributed substantially to the design of the study, as well as drafting and revisions of the manuscript.

Corresponding author

Correspondence to Rachel Palfrey.

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The authors declare no competing interests.

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Nature Ecology & Evolution thanks Jonas Geldmann and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

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Source data

Source Data Fig. 1

Data used to create Fig. 1—display of what proportion of diff gov types protect biomes with low, medium or high representation.

Source Data Fig. 2

Data used to create Fig. 2—proportion of biome protected by each PA gov type.

Source Data Fig. 3

Data used to create Fig. 3—complementarity.

Source Data Fig. 4

Data used to create Fig. 4—Proportion of Human Footprint category in each gov type.

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Palfrey, R., Oldekop, J.A. & Holmes, G. Privately protected areas increase global protected area coverage and connectivity. Nat Ecol Evol 6, 730–737 (2022).

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