Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

When and where to protect forests


Ongoing deforestation poses a major threat to biodiversity1,2. With limited resources and imminent threats, deciding when as well as where to conserve is a fundamental question. Here we use a dynamic optimization approach to identify an optimal sequence for the conservation of plant species in 458 forested ecoregions globally over the next 50 years. The optimization approach includes species richness in each forested ecoregion, complementarity of species across ecoregions, costs of conservation that rise with cumulative protection in an ecoregion, the existing degree of protection, the rate of deforestation and the potential for reforestation in each ecoregion. The optimal conservation strategy for this formulation initially targets a small number of ecoregions where further deforestation leads to large reductions in species and where the costs of conservation are low. In later years, conservation efforts spread to more ecoregions, and invest in both expanded protection of primary forest and reforestation. The largest gains in species conservation come in Melanesia, South and Southeast Asia, the Anatolian peninsula, northern South America and Central America. The results highlight the potentially large gains in conservation that can be made with carefully targeted investments.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Forested ecoregions with conservation spending resulting in additional species protection over the 50-year planning horizon with an annual budget of US $1 billion.
Fig. 2: Optimal conservation strategy: determinants and comparison with heuristics.

Similar content being viewed by others

Data availability

Data used for the analysis in this paper can be found at Zenodo: data are provided with this paper.

Code availability

Code for this paper can be found at Zenodo: data are provided with this paper.


  1. Newbold, T. et al. Global effects of land use on local terrestrial biodiversity. Nature 520, 45–50 (2015).

    Article  ADS  CAS  Google Scholar 

  2. Díaz, S. et al. Pervasive human-driven decline of life on earth points to the need for transformative change. Science 366, eaax3100 (2019).

    Article  Google Scholar 

  3. United Nations Food and Agriculture Organization (FAO). State of the World’s Forests 2022: Forest Pathways for Green Recovery and Building Inclusive, Resilient and Sustainable Economies (FAO, 2022).

  4. Williams, M. Deforesting the Earth: From Prehistory to Global Crisis (University of Chicago Press, 2003).

  5. Laurence, W. F. et al. Averting biodiversity collapse in tropical forest protected areas. Nature 489, 290–294 (2012).

    Article  ADS  Google Scholar 

  6. UNEP-WCMC and IUCN. Protected Planet: The World Database on Protected Areas (WDPA) (2020).

  7. Convention on Biological Diversity. First Draft of the Post-2020 Global Biodiversity Framework (2021).

  8. Wilson, E. O. Half-Earth: Our Planet’s Fight for Life (Liveright Publishing Company, 2016).

  9. Joppa, L. N. & Pfaff, A. High and far: biases in the location of protected areas. PLoS One 4, e8273 (2009).

    Article  ADS  Google Scholar 

  10. Sarkar, S. et al. Biodiversity conservation planning tools: present status and challenges for the future. Annu. Rev. Environ. Resour. 31, 123–159 (2006).

    Article  Google Scholar 

  11. Naidoo, R. et al. Integrating economic costs into conservation planning. Trends Ecol. Evol. 21, 681–687 (2006).

    Article  Google Scholar 

  12. Ando, A., Camm, J., Polasky, S. & Solow, A. Species distributions, land values, and efficient conservation. Science 279, 2126–2128 (1998).

    Article  ADS  CAS  Google Scholar 

  13. Meir, E., Andelman, S. & Possingham, H. P. Does conservation planning matter in a dynamic and uncertain world? Ecol. Lett. 7, 615–622 (2004).

    Article  Google Scholar 

  14. Costello, C. & Polasky, S. Dynamic reserve site selection. Resour. Energy Econ. 26, 157–174 (2004).

    Article  Google Scholar 

  15. The Nature Conservancy. Terrestrial Ecoregions (2008).

  16. Hansen, M. C. et al. High-resolution global maps of 21st-century forest cover change. Science 342, 850–853 (2013).

    Article  ADS  CAS  Google Scholar 

  17. Kummu, M., Taka, M. & Guillaume, J. Gridded global datasets for gross domestic product and human development index over 1990–2015. Sci. Data 5, 180004 (2018).

    Article  Google Scholar 

  18. Kier, G. et al. Global patterns of plant diversity and floristic knowledge. J. Biogeogr. 32, 1107–1116 (2005).

    Article  Google Scholar 

  19. Tilman, D., Reich, P. B. & Isbell, F. Biodiversity impacts ecosystem productivity as much as resources, disturbance or herbivory. Proc. Natl Acad. Sci. USA 109, 10394–10397 (2012).

    Article  ADS  CAS  Google Scholar 

  20. Thompson, I., Mackey, B., McNulty, S. & Mosseler, A. Forest Resilience, Biodiversity, and Climate Change CBD Technical Series No. 43 (Secretariat of the Convention on Biological Diversity, 2009).

  21. Butsic, V., Lewis, D. J. & Radeloff, V. C. Reserve selection with land market feedbacks. J. Environ. Manag. 114, 276–284 (2013).

    Article  Google Scholar 

  22. Wilson, K. A., McBride, M. F., Bode, M. & Possingham, H. P. Prioritizing global conservation efforts. Nature 440, 337–340 (2006).

    Article  ADS  CAS  Google Scholar 

  23. McBride, M. F., Wilson, K. A., Bode, M. & Possingham, H. P. Incorporating the effects of socioeconomic uncertainty into priority setting for conservation investment. Conserv. Biol. 21, 1463–1474 (2007).

    Article  Google Scholar 

  24. Bode, M., Wilson, K., McBride, M. & Possingham, H. P. Optimal dynamic allocation of conservation funding among priority regions. Bull. Math. Biol. 70, 2039–2054 (2008).

    Article  MathSciNet  Google Scholar 

  25. Pouzols, F. M. et al. Global protected area expansion is compromised by projected land-use and parochialism. Nature 516, 383–386 (2014).

    Article  ADS  Google Scholar 

  26. Pollock, L. J., Thuiller, W. & Jetz, W. Large conservation gains possible for global biodiversity facets. Nature 546, 141–144 (2017).

    Article  ADS  CAS  Google Scholar 

  27. Dinerstein, E. et al. A ‘Global Safety Net’ to reverse biodiversity loss and stabilize Earth’s climate. Sci. Adv. 6, eabb2824 (2020).

    Article  ADS  Google Scholar 

  28. Jung, M. et al. Areas of global importance for conserving terrestrial biodiversity, carbon and water. Nat. Ecol. Evol. 5, 1499–1509 (2021).

    Article  Google Scholar 

  29. Polasky, S. et al. Where to put things? Spatial land management to sustain biodiversity and economic returns. Biol. Conserv. 141, 1505–1524 (2008).

    Article  Google Scholar 

  30. Lennox, G. D., Fargione, J., Spector, S., Williams, G. & Armsworth, P. The value of flexibility in conservation financing. Conserv. Biol. 31, 666–674 (2016).

    Article  Google Scholar 

  31. Drechsler, M. & Wätzold, F. Biodiversity conservation in a dynamic world may lead to inefficiencies due to lock-in effects and path dependence. Ecol. Econ. 173, 106652 (2020).

    Article  Google Scholar 

  32. Boulton, C. A., Lenton, T. M. & Boers, N. Pronounced loss of Amazon rainforest resilience since the early 2000s. Nat. Clim. Chang. 12, 271–278 (2022).

    Article  ADS  Google Scholar 

  33. Lomolino, M. V. Ecology’s most general, yet protean pattern: the species‐area relationship. J. Biogeogr. 27, 17–26 (2000).

    Article  Google Scholar 

  34. Drake, J. & Griffen, B. Early warning signals of extinction in deteriorating environments. Nature 467, 456–459 (2010).

    Article  ADS  CAS  Google Scholar 

  35. Grantham, H. et al. Anthropogenic modification of forests means only 40% of remaining forests have high ecosystem integrity. Nat. Commun. 1, 5978 (2020).

    Article  ADS  Google Scholar 

  36. Naidoo, R. & Iwamura, T. Global-scale mapping of economic benefits from agricultural land: Implications for conservation priorities. Biol. Conserv. 140, 40–49 (2007).

    Article  Google Scholar 

  37. UNEP-FAO. United Nations Decade on Ecosystem Restoration 2021–2030 (2021).

  38. UN Climate Change Conference. Glasgow Leaders’ Declaration on Forests and Land Use (2021)

  39. UN Climate Change Conference. The Global Forest Finance Pledge (2021).

  40. Convention on Biological Diversity. Preparations for the Post-2020 Biodiversity Framework (2021)

  41. Deutz, A. et al. Financing Nature: Closing the Global Biodiversity Financing Gap (The Paulson Institute, The Nature Conservancy, and the Cornell Atkinson Center for Sustainability, 2020).

  42. Griscom, B. W. et al. Natural climate solutions. Proc. Natl Acad. Sci. USA 114, 11645–11650 (2017).

    Article  ADS  CAS  Google Scholar 

  43. Guerry, A. D. et al. Natural capital and ecosystem services informing decisions: from promise to practice. Proc. Natl Acad. Sci. USA 112, 7348–7355 (2015).

    CAS  Google Scholar 

  44. Leclère, D. et al. Bending the curve of terrestrial biodiversity needs an integrated strategy. Nature 585, 551–556 (2020).

    Article  ADS  Google Scholar 

  45. Wintle, B. A. et al. Spending to save: what will it cost to halt Australia’s extinction crisis? Conserv. Lett. 12, e12682 (2019).

    Article  Google Scholar 

  46. Ostrom, E. Governing the Commons: The Evolution of Institutions for Collective Action (Cambridge University Press, 1990)

  47. WWF et al. The State Of Indigenous Peoples' and Local Communities’ Lands and Territories (2021) .

  48. Chaplin-Kramer, R. et al. Conservation needs to integrate knowledge across scales. Nat. Ecol. Evol. 6, 118–119 (2022).

    Article  Google Scholar 

  49. IUCN. Spatial Data Download: Terrestrial Mammals. IUCN Red List (2021).

  50. Abay, K. A., Chamberlin, J. & Berhane, G. Are land rental markets responding to rising population pressures and land scarcity in sub-Saharan Africa? Land Use Policy 101, 105139 (2021).

    Article  Google Scholar 

Download references


We thank P. Armsworth, M. Burgman and members of his laboratory group, J. Fargione, E. Game, K. Helmstedt and G. Iacona for their comments on the manuscript; S. Andelman, J. Bielecki, M. Bode and H. Possingham for early discussions and development of the ideas; and J. Smith for help on addressing species complementarity.

Author information

Authors and Affiliations



S.P. conceived the original idea. All authors devised the theoretical method and application. I.L. and S.J.M. collected and analysed the data and S.J.M. performed the numerical optimizations. All authors wrote the manuscript and participated in in the discussion and interpretation of the results, and the determination of the conclusions.

Corresponding author

Correspondence to Ian H. Luby.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature thanks Ian Bateman, Laura Pollock, Henrique Pereira and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

This file contains Supplementary Sections 1-6; Supplementary Figures; Supplementary Tables and Supplementary References.

Reporting Summary

Peer Review File

Source data

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Luby, I.H., Miller, S.J. & Polasky, S. When and where to protect forests. Nature 609, 89–93 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing Anthropocene

Sign up for the Nature Briefing: Anthropocene newsletter — what matters in anthropocene research, free to your inbox weekly.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing: Anthropocene