Collaborative Research: RAPID: Emergency Recovery of Madagascar's Last Rainforest Megafauna

Madagascar experienced one of the most dramatic episodes of vertebrate extinction in recent Earth history, with giant lemurs, elephant birds, dwarf hippopotamuses, giant tortoises, and other endemic species all disappearing abruptly within the last one to three thousand years. Despite decades of research, scientists still do not fully understand why these extinctions occurred or whether some species survived longer within some isolated habitats than previously recognized. Recent discoveries of exceptionally well-preserved fossil deposits in caves within Ranomafana National Park present a rare opportunity to recover irreplaceable scientific evidence before the deposits are degraded by natural erosion and increasing human disturbance. This RAPID project will preserve and study these unique fossil and environmental archives to better understand how biodiversity responds to environmental change and human activities over time. By combining expertise in paleontology, ancient DNA, and geoscience, the project will generate new knowledge about the processes that shape extinction and ecosystem resilience in one of the world's most important biodiversity hotspots. The research will strengthen long-standing collaborations among U.S. and Malagasy institutions, provide training opportunities for students and early-career scientists, expand research capacity through partnerships with the University of Antananarivo and Centre ValBio, and produce openly accessible datasets for future research. This collaborative RAPID project will investigate newly discovered fossil-bearing cave deposits in the Ranomafana rainforest to reconstruct the evolutionary history, chronology, and ecological context of Madagascar's late surviving megafauna. The project will test hypotheses concerning the persistence, genetic diversity, and extinction dynamics of dwarf hippopotamuses and associated vertebrate communities within humid forest ecosystems that are poorly represented in the subfossil record. Field investigations will include systematic excavation, stratigraphic documentation, sedimentological analyses, and targeted recovery of vertebrate fossils and environmental samples. Fossils and sediments will be analyzed using radiocarbon dating, stable isotope analyses, ancient DNA, sedimentary environmental DNA (eDNA), and comparative morphological approaches to establish species identities, population relationships, dietary ecology, and the timing of extinction. Paleoenvironmental reconstruction will integrate geochronological, geochemical, and genomic datasets to evaluate ecological change through time and assess the relative roles of climatic variability and human activities in shaping rainforest ecosystems. The resulting multidisciplinary datasets will provide the first comprehensive genomic and paleoecological assessment of rainforest megafaunal persistence in southeastern Madagascar and establish an essential scientific foundation for future research on extinction processes, tropical ecosystem resilience, and conservation genomics. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.