Areas of high conservation priority for threatened terrestrial vertebrates are governed by novel ecological conditions

Matthew Roy Kerr , Anna M Behrend, Mia K Hoffmann, Jonas Trepel, Felix Riede, Alejandro Ordonez, Jens-Christian Svenning

Over half of the terrestrial biosphere is exposed to highly novel conditions that differ from the historical state, resulting from anthropogenic pressures such as climate change, floristic disruption, and defaunation. Highly novel conditions result in unpredictable biodiversity outcomes, impacting the effectiveness of conservation and restoration actions and the ability for threatened species to persist. Here, we quantify the extent to which areas of high conservation priority intersect areas of high ecological novelty, focusing on the distribution of threatened terrestrial vertebrates. We use two proxies for global conservation and restoration priorities, the IUCN Red List and the recent LIFE metric, to identify areas where management actions would have the most effect. We then performed overlay analyses calculating the spatial co-occurrence between these proxies and recent global data on novelty exposure. Species-rich areas of high conservation and restoration value were exposed to highly novel conditions across all regions, but were concentrated in the tropics, with Southeast Asia showing the highest novelty exposure. Birds exhibited the greatest spatial exposure, whereas amphibians had the highest number of threatened species experiencing highly novel conditions. Climatic novelty emerged as the dominant driver underlying hotspots of threatened species exposed to novelty; how-ever, amphibians were disproportionately exposed to floristic disruption. Finally, we detected strong spatial overlap between areas where conservation and restoration would have the highest impact, concentrated across the tropics. Our results demonstrate that global conservation and restoration efforts are already governed by novel conditions across most of the biosphere, underscoring the need for adaptive management informed by ecological novelty.