Conservation Imperatives: securing the last unprotected terrestrial sites harboring irreplaceable biodiversity

Ambitious biodiversity goals to protect 30% or more of the Earth’s surface by 2030 (30x30) require strategic near-term targets. To define areas that must be protected to prevent the most likely and imminent extinctions, we propose Conservation Imperatives—16,825 unprotected sites spanning ~164 Mha of the terrestrial realm that harbor rare and threatened species. We estimate that protecting the Conservation Imperatives would cost approximately US$169 billion (90% probability: US$146—US$228 billion). Globally, 38% of the 16,825 sites are either adjacent to or within 2.5 km of an existing protected area, potentially reducing land acquisition and management costs. These sites should be prioritized for conservation action over the next 5 years as part of a broader strategy to expand the global protected area network. The expansion of global protected areas between 2018 and 2023 incorporated only 7% of sites harboring range-limited and threatened species, highlighting a renewed urgency to conserve these habitats. Permanently protecting only 0.74% of land found in the tropics, where Conservation Imperatives are concentrated, could prevent the majority of predicted near-term extinctions once adequately resourced. We estimate this cost to be from US$29 billion to US$46 billion per year over the next 5 years. Multiple approaches will be required to meet long-term protection goals: providing rights and titles to Indigenous Peoples and Local Communities (IPLCs) conserving traditional lands, government designation of new protected areas on federal and state lands, and land purchase or long-term leasing of privately held lands.

Key points

• There is an urgent need to prioritize the conservation of habitats of rare and threatened species as part of a larger global biodiversity strategy.
• Conservation Imperatives offer a solution to conserving the last unprotected sites harboring rare, range-restricted, and threatened species and should be a central component of the ambitious goals to protect at least 30% of the Earth’s surface by 2030.
• The Conservation Imperatives identified in this study are highly concentrated, requiring only ~164 Mha globally to avoid extinctions; this equates to only 1.22% of the Earth’s entire terrestrial surface and 0.74% of land in the tropics.
• Targeted investments to prevent extinctions in parallel with the conservation of carbon-rich regions are necessary as the world sets about expanding the protected area network from 15.7% today to 30% by 2030.
• Conserving Conservation Imperatives is achievable and affordable, especially in the tropics, as the purchase of the tropical subset of Conservation Imperatives costs about US$169 billion (90% probability: US$146–US$228 billion), or US$34 billion (90% probability: US$29.2–US$45.6 billion) per year over 5 years.
• As Conservation Imperatives represent the most biologically important and threatened places to protect, they can be thought of as “anchor points” to design regional-scale conservation planning efforts under 30×30.