Securing Nature's Contributions to People requires at least 20%–25% (semi-)natural habitat in human-modified landscapes

The cascading effects of biodiversity decline on human well-being present a pressing challenge for sustainable development. Conservation efforts often prioritize safeguarding specific species, habitats, or intact ecosystems but overlook biodiversity's fundamental role in providing Nature's Contributions to People (NCP) in human-modified landscapes. Here, we systematically review 154 peer-reviewed studies to estimate the minimum levels of (semi-)natural habitat quantity, quality, and spatial configuration needed in human-modified landscapes to secure functional integrity essential for sustaining NCP provision. We find that the provision of multiple NCP is threatened when (semi-)natural habitat in the landscape falls below an area of 20%–25% for each km2. Five NCP almost completely disappear below a level of 10% habitat. The exact quantity, quality, and spatial configuration of habitat required depends on local context and specific NCP. Today, about two-thirds of human-modified lands have insufficient (semi-)natural habitat, requiring action for NCP regeneration. Our findings serve as a generic guideline to target conservation actions outside natural areas. © 2023 The Authors

This work is part of the Earth Commission, which is hosted by Future Earth and is the science component of the Global Commons Alliance. The Global Commons Alliance is a sponsored project of Rockefeller Philanthropy Advisors, with support from Oak Foundation, MAVA, Porticus, Gordon and Betty Moore Foundation, Tiina and Antti Herlin Foundation, William and Flora Hewlett Foundation, Generation Foundation, and the Global Environment Facility. The Earth Commission is also supported by the Global Challenges Foundation and Frontiers Research Foundation. Individual researchers were supported by the European Research Council grant on Climate Change and Fossil Fuel (project number 101020082) (J.G.) and the Open Society Foundations (J.F.A.). F.D.C. received additional support from the Food System Economics Commission and PHV from the NatureConnect project funded by the European Commission Horizon Europe program. F.D.C., S.J., and N.E.C. acknowledge funding support from the OneCGIAR NEXUS Gains initiative, Realizing Multiple Benefits Across Water, Energy, Food and Ecosystems (Forests, Biodiversity). I.C.M. acknowledges the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) financial support awarded within the Heisenberg program (grant no. ME 4156/5-1). We also acknowledge Nuno Martins Migueis Garcia for his invaluable assistance with the spatial analysis and data repository