Confirmed Wild Reproduction and Distribution Records of Palea steindachneri in Northern Vietnam, with Notes on Sympatric Pelodiscus sp. in Dam-Impacted Habitats

Previous studies have consistently reported the detrimental impact of dam construction on natural populations of softshell turtles across East and Southeast Asia, with particularly severe effects on large-bodied species. The Wattle-necked Softshell Turtle (Palea steindachneri), a large-sized and Critically Endangered member of the family Trionychidae, remains poorly documented throughout much of its native range in Southeast Asia. In this study, we present new field data from the Đà River basin in northern Vietnam, encompassing areas both upstream and downstream of the Sơn La Dam. Data were obtained through a combination of direct field observations, camera trap monitoring, and semi-structured interviews with local fishers and traders. Two individuals of P. steindachneri—including a juvenile—were recorded, providing the first confirmed evidence of ongoing natural reproduction in the region. Additionally, we documented 102 individuals of Pelodiscus sp., encompassing all life stages and indicating a stable, reproducing local population. Despite overlapping in macrohabitat use along the river, the two species were spatially segregated, with a minimum interspecific distance of 8.2 km, suggesting broad sympatry without syntopy, potentially due to microhabitat partitioning. These findings underscore the persistence and likely reproductive viability of P. steindachneri in modified riverine systems affected by dams, and have broader conservation implications for other threatened taxa with similar ecologies, such as Rafetus swinhoei. Urgent conservation actions, including habitat protection, community-based monitoring, and strengthened regulation of the wildlife trade, are essential to ensure the survival of remaining wild populations.