The minimum land areas required for maximizing biodiversity conservation

The Kunming-Montreal Global Biodiversity Framework has established an ambitious target to expand protected areas and reverse the tide of biodiversity loss. However, such expansion entails significant financial and temporal costs. Consequently, identifying the most critical areas for biodiversity conservation has become a vital task for nations. This study developed a Biodiversity Conservation Priority Index (BCPI) through Multi-Criteria Decision Analysis framework, to determine the minimum land area necessary for maximizing biodiversity conservation efforts. Taking the Qinghai-Tibet Plateau (QTP) in China as a case study, we compiled distribution data for 2151 species, including 204 endangered species along with 14 climate and human activity factors, and three habitat indices to develop over 50 conservation scenarios. These scenarios aim to identify the minimum critical areas for biodiversity conservation (MCABC). The results show that the MCABC covers only 17.6 % of the QTP but shelters habitats for 96.1 % of endangered species and 97.2 % of all species. However, more than two-thirds of the MCABC are not covered by protected areas (PAs) or wilderness areas (WAs). Moreover, PAs are found to be less effective in protecting the MCABC compared to WAs. Lastly, under multiple SSP scenarios by 2100, the MCABC is expected to face primary threats from climate change, affecting 47.7 % to 84.6 % of the area, with more severe impacts anticipated in the southern and central QTP. This research addresses the challenge of optimizing biodiversity conservation at the minimum land cost and robustly supports the development of actions and strategies for achieving biodiversity goals.