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Overlooked risks and opportunities in groundwatersheds of the world’s protected areas


Protected areas are a key tool for conserving biodiversity, sustaining ecosystem services and improving human well-being. Global initiatives that aim to expand and connect protected areas generally focus on controlling ‘above ground’ impacts such as land use, overlooking the potential for human actions in adjacent areas to affect protected areas through groundwater flow. Here we assess the potential extent of these impacts by mapping the groundwatersheds of the world’s protected areas. We find that 85% of protected areas with groundwater-dependent ecosystems have groundwatersheds that are underprotected, meaning that some portion of the groundwatershed lies outside of the protected area. Half of all protected areas have a groundwatershed with a spatial extent that lies mostly (at least 50%) outside of the protected area’s boundary. These findings highlight a widespread potential risk to protected areas from activities affecting groundwater outside protected areas, underscoring the need for groundwatershed-based conservation and management measures. Delineating groundwatersheds can catalyse needed discussions about protected area connectivity and robustness, and groundwatershed conservation and management can help protect groundwater-dependent ecosystems from external threats.

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Fig. 1: GDEs and protected areas.
Fig. 2: Overview of groundwatersheds and our application of groundwatersheds in this study.
Fig. 3: Mapping the groundwatersheds of the world’s protected areas.
Fig. 4: Implications of groundwatersheds for conservation initiatives.

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Data availability

This study uses data from multiple open-access datasets. Source data are documented in Supplementary Table 1 and can be downloaded from the persistent web-links provided. Data produced in this study, including the GDE map, groundwatershed extents and protected area metrics have been deposited on Borealis, the Canadian Dataverse Repository (

Code availability

Code used to produce all results in this study is available at All analyses were conducted using the R project for statistical computing44. R packages necessary for analysis and visualization include: terra45, gdalUtilities46, rasterDT47, whitebox48, tmap49, rnaturalearth50, ggplot251, scico52,53 and MetBrewer54. Composite figures were assembled in Affinity Designer (


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Figure 2 was produced by the authors with support from L. Bueno and S. Lopez by adapting vector graphics by artists ‘brgxfx’ and ‘freepik’, accessed on the graphic repository Freepik (; artists T. Saxby, J. Hawkey and J. C. Fisher, accessed on the Integration and Application Network ( under CC BY-SA 4.0; and artist A. Coquet, accessed on The Noun Project ( under CC BY-NC-ND 2.0.

X.H. was supported by an Alexander Graham Bell Canada Graduate Scholarship from the Natural Sciences and Engineering Research Council (NSERC) of Canada. A.H. was supported by the German Research Foundation DFG (HA 8113/1-1).

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The study was conceived by S.Z., T.G. A.H. and F.J. The methods were developed by T.G., X.H., S.Z., A.H., F.J. and D.S. Analysis was performed by X.H. Figures were developed by X.H., T.G. and D.S. Paper writing was led by X.H., T.G. and D.S. with input from all authors. All authors, X.H., T.G., S.Z., D.S., M.M.R., K.V., R.A., A.H. and F.J., discussed the results and edited the paper at multiple stages.

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Correspondence to Xander Huggins.

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Nature Sustainability thanks Arnout van Soesbergen, Anthony Kendall and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Texts 1 and 2, Figs. 1–9 and Tables 1–3.

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Huggins, X., Gleeson, T., Serrano, D. et al. Overlooked risks and opportunities in groundwatersheds of the world’s protected areas. Nat Sustain 6, 855–864 (2023).

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