Global dynamic synergies and trade-offs in habitat quality and connectivity for endangered mammals from 2020 to 2100

Land use-driven changes in habitat quality (HQ) and habitat connectivity (HC) have emerged as critical challenges to the survival of endangered species. Previous studies have often overlooked the dynamic synergies or trade-offs between HQ and HC over time. Therefore, this study employed future land-use projections to quantitatively evaluate HQ and HC at multiple time points from 2020 to 2100 under a baseline development scenario. Furthermore, we assessed the temporal shifts in synergies and trade-offs between HQ and HC at a global provincial scale for endangered mammalian species. The results revealed an initial phase of synergistic growth between HQ and HC, presenting a critical window for ecological management interventions. However, as HQ approached a specific threshold, shifts emerged in certain regions: while HQ and HC remained synergistic in North America, Central Africa, Northeast Asia, and Australia, trade-offs became evident in areas such as southwestern South America, the southern Sahara border region, the coastal region of Africa, the southeastern China, and the high-latitude region of northwestern Asia, where improvements in HQ alone failed to effectively enhance HC. Additionally, the trade-off thresholds increased over time, rising by more than 26.46% by 2100 compared with that in 2030, and HC may derive greater benefits from equivalent HQ levels in the future. This study highlights the regional differences in future HQ and HC responses over time, and is expected to provide a scientific foundation for developing targeted conservation strategies. • Evaluates habitat quality (HQ) and connectivity (HC) globally from 2020 to 2100. • Identifies dynamic synergies and trade-offs between HQ and HC across global regions. • Reveals a 26.46% increase in trade-off thresholds for HQ and HC by 2100. • Highlights regional disparities in HQ and HC trends, informing targeted conservation. • Provides a quantitative foundation for improving endangered mammal conservation strategies.