30% land conservation and climate action reduces tropical extinction risk by more than 50%

Abstract

Limiting climate change to less than 2°C is the focus of international policy under the climate convention (UNFCCC), and is essential to preventing extinctions, a focus of the Convention on Biological Diversity (CBD). The post‐2020 biodiversity framework drafted by the CBD proposes conserving 30% of both land and oceans by 2030. However, the combined impact on extinction risk of species from limiting climate change and increasing the extent of protected and conserved areas has not been assessed. Here we create conservation spatial plans to minimize extinction risk in the tropics using data on 289 219 species and modeling two future greenhouse gas concentration pathways (RCP2.6 and 8.5) while varying the extent of terrestrial protected land and conserved areas from <17% to 50%. We find that limiting climate change to 2°C and conserving 30% of terrestrial area could more than halve aggregate extinction risk compared with uncontrolled climate change and no increase in conserved area.

Designing optimal human‐modified landscapes for forest biodiversity conservation

“…A recent study modelling 289 219 species indicates that preserving 30% of terrestrial ecosystems can reduce extinction risk by more than 50% (Hannah et al . 2020). Yet, extinction risk decreases with increasing area conserved (Hannah et al .…”

“…Yet, extinction risk decreases with increasing area conserved (Hannah et al . 2020). Furthermore, density estimates and population viability analyses are inherently uncertain (Pe’er et al .…”

“…Such a degree of protection has been achieved in several regions (Hannah et al . 2020), and has proven to be highly successful for biodiversity conservation (see case studies in https://natureneedshalf.org/). In particular, it allows for the protection of very large amounts of forest in some areas, sufficient to maintain species that cannot persist in human‐dominated landscapes.…”

“…This should improve the fate of forest species (Hannah et al . 2020). However, forest species within reserves are also influenced by their surrounding landscape, because human‐caused disturbances (e.g.…”

Climate change promotes transitions to tall evergreen vegetation in tropical Asia

“…Many protected areas are under pressure by increasing human population and land use intensities in neighbouring buffer zones, or by changes in their protection status (Symes, Rao, Mascia, & Carrasco, 2016). Hannah et al (2020) showed that species extinction risk in the tropics could be halved if 30% of the land surface height, determine habitat suitability for animals (Smit & Prins, 2015;Tews et al, 2004) and link different trophic levels via biotic interaction networks (Schleuning et al, 2016;Walther, 2010). Vegetation structure and canopy characteristics also influence the near-surface microclimatic conditions, as well as albedo, surface roughness and partitioning of energy into sensible and latent heat fluxes (Bonan, 2008;Ozanne et al, 2003).…”