An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm

Abstract

We assess progress toward the protection of 50% of the terrestrial biosphere to address the species-extinction crisis and conserve a global ecological heritage for future generations. Using a map of Earth's 846 terrestrial ecoregions, we show that 98 ecoregions (12%) exceed Half Protected; 313 ecoregions (37%) fall short of Half Protected but have sufficient unaltered habitat remaining to reach the target; and 207 ecoregions (24%) are in peril, where an average of only 4% of natural habitat remains. We propose a Global Deal for Nature-a companion to the Paris Climate Deal-to promote increased habitat protection and restoration, national- and ecoregion-scale conservation strategies, and the empowerment of indigenous peoples to protect their sovereign lands. The goal of such an accord would be to protect half the terrestrial realm by 2050 to halt the extinction crisis while sustaining human livelihoods.

Keywords: Aichi target 11; Nature Needs Half; ecoregions; global biodiversity conservation strategies; protected areas.

Figure 1.

The 846 global ecoregions that comprise Ecoregions2017^©Resolve nested within 14 terrestrial biomes. An interactive map is available at ecoregions2017.appspot.com. (A companion biome map is presented in supplemental appendix S1, supplemental figure S1).

Figure 2.

The protection statuses of ecoregions of the world. This map shows the high levels of habitat remaining in some of the most species-rich areas on Earth, including the Brazilian Amazon, the Congo basin, and the islands of Indonesia. Although enough habitat remains for nearly half of the ecoregions to exceed 50% protected in the coming decades, much of this forest is still unprotected, and just under 50% of ecoregions have adequate conservation plans in place to keep remaining forests intact (supplemental appendix S3). The numbers in parentheses for each category represent the entire number of ecoregions found in each category. The ecoregion protection categories are defined as the following: Half Protected, more than 50% protected; Nature Could Reach Half, less than 50% of the total ecoregion area is protected, but the sum of the total ecoregion protected and unprotected natural habitat remaining is more than 50%; Nature Could Recover, the sum of the amount of natural habitat remaining and the amount of the total ecoregion that is protected is less than 50% but more than 20%; Nature Imperiled, the sum of the amount of natural habitat remaining and the amount of the total ecoregion that is protected is less than or equal to 20%.

Figure 3.

The proportion of biodiversity goals addressed within available conservation plans for all 846 ecoregions, distributed across the four protection-status categories. The colors represent the percentage of conservation strategies addressed within each protection-status category: 0 goals addressed, red; 1 goal addressed, yellow; 2 goals addressed, orange; 3 goals addressed, light green; 4 goals addressed, dark green. For a detailed list of conservation strategies and sources, see supplemental appendix S3.

Figure 4.

a–c. Ecoregion conservation planning in three developing countries: (a) Namibia uses communal conservation areas to extend protection beyond protected areas and cover a diverse set of ecoregions, (b) Nepal uses a mixture of protected areas and conservation landscapes to protect along north–south and east–west gradients, and (c) Bhutan uses protected areas combined with biological corridors to provide connectivity between protected areas and across ecoregions.