The research addresses the urgent need to reconcile global commitments to conservation, climate action, and sustainable development, acknowledging the complex interplay of synergies and trade-offs among these objectives. The accelerating transformation of ecosystems, exacerbated by climate change, is causing widespread biodiversity loss and negatively impacting nature’s contributions to people (NCP). While economic development has improved living standards for many, the loss of NCP has detrimental effects on millions. International agreements, such as the Kunming-Montreal Global Biodiversity Framework and proposals like “Half-Earth,” aim to address this by effectively conserving significant portions of land and water. However, the challenge lies in coordinating conservation efforts with the need for food, energy, and livelihood security, requiring careful planning to avoid conflicts between development and conservation objectives. This study uses spatial analysis to map areas crucial for both NCP and biodiversity, also considering development potential across various sectors to pinpoint potential conflicts and inform policy decisions.

The introduction cites several key papers and reports that form the basis of the study's context. These include research on the pervasive decline of life on Earth, global trends in nature's contributions to people, the Kunming-Montreal Global Biodiversity Framework, the “America the Beautiful” initiative, and proposals for conserving 50% of the Earth's land area. The literature establishes the interconnectedness of biodiversity, climate change, and sustainable development goals and highlights the need for coordinated planning to avoid conflicts between conservation and development. Previous studies on the sufficiency of the global protected area (PA) network for biodiversity are mentioned, emphasizing the novelty of this study in jointly assessing the sufficiency of the PA network for NCP and species.

The study employs a global analysis to prioritize areas for effective NCP and species conservation, focusing on terrestrial areas. Ten important NCP were considered, including vulnerable terrestrial ecosystem carbon storage (a global benefit) and nine NCP with local or regional benefits (coastal risk reduction, flood regulation, sediment retention, nitrogen retention, crop pollination, fodder production, fuel wood production, timber production, and access to nature). These NCP were mapped using various datasets and models, including InVEST and Co$ting Nature. Biodiversity was assessed using species area of habitat (AOH) data for 26,709 terrestrial vertebrate species. Spatial optimization techniques (linear programming) were utilized to identify areas that simultaneously maximize NCP provision and meet minimum representation targets for species. The analysis also incorporated estimates of development potential across major sectors (agriculture, renewable energy, mining, oil and gas, urban expansion), to reveal potential conflicts between conservation and development objectives. The World Database on Protected Areas (WDPA) and other effective area-based conservation measures (OECM) were incorporated to evaluate the extent to which existing conservation efforts could meet the identified targets. The methodology involved multiple optimization scenarios, including one where existing PAs and OECMs were locked in, and another that focused solely on NCP. Different spatial resolutions were also tested to evaluate the impact on results. The study used various publicly available datasets to map the NCP and development pressures, with specific sources detailed in supplementary materials.

The study's key finding is that conserving approximately 44% of the global land area (excluding Antarctica) could provide 90% of current levels of NCP and meet minimum representation targets for 26,709 terrestrial vertebrate species, if spatially optimized. This finding supports both the 30% target under the Global Biodiversity Framework and the “Half-Earth” proposals. Including existing PAs and OECMs increased the required land area to 49%. Prioritizing solely for NCP, without species targets, reduced the required area to 36%. The spatial distribution of prioritized areas varied based on the inclusion of species targets; including species targets identified sparsely vegetated arid regions and northern latitudes as important for biodiversity despite their lower levels of the modeled NCP. Overlapping high development potential with prioritized areas for NCP and species reveals potential conflicts; 37% of prioritized areas have high development potential across multiple sectors. Significant overlaps exist for renewable energy, agriculture, mining, and oil and gas development. The study identifies specific biomes and countries with particularly high overlaps between prioritized areas and high development potential. Spatial analysis at different resolutions indicates that coarser resolutions require more land area to achieve targets. Only 18% of the prioritized areas are currently protected, indicating a substantial need for additional conservation or sustainable management efforts.

The findings lend strong support to global conservation targets (30% and 50%) and highlight opportunities for synergy between maintaining NCP and biodiversity. The significant overlap between conservation priorities and areas with high development potential underscores the crucial need for integrated planning to avoid conflicts. The study acknowledges that the identified areas represent a best-case scenario of internationally coordinated conservation efforts and that the estimates of required land area are likely conservative due to various challenges in optimizing conservation actions. The results also suggest that while expanding protected areas is beneficial, it alone will not suffice to meet targets for both NCP and species representation. The study emphasizes the need for incorporating local-scale information, considering conservation feasibility, and respecting local perspectives and sovereignty in implementing conservation strategies. Sustainable management practices, such as payments for ecosystem services (PES), are highlighted as crucial for conserving NCP and biodiversity outside of strictly protected areas.

This study provides a crucial framework for identifying global priorities for conservation and sustainable use investments, emphasizing the importance of considering both nature’s contributions to people and biodiversity. The findings support ambitious conservation targets and highlight potential conflicts with development. Future research should focus on incorporating finer-scale data, addressing computational limitations to achieve higher resolution analyses, and integrating projected future demands for NCP and species responses to climate change.

The study acknowledges several limitations. Computational constraints limited the spatial resolution of the analysis, potentially affecting the accuracy of fine-scale patterns and priorities. Data limitations for both NCP and biodiversity might underestimate the true extent of natural ecosystems needed. The development pressure maps may not perfectly predict future development patterns due to fluctuating demands and policies. The lack of a contiguous criterion in the optimization resulted in prioritized areas that are not always contiguous, requiring further planning for implementation. The study’s species targets are minimum targets, neglecting elements such as connectivity and ecological interactions.