Stable isotope (δ¹⁸O, δD) dataset of soil water, rock fracture water, precipitation, and xylem water in a subtropical karst ecosystem, southwest China (2022–2025)

This dataset provides stable isotope compositions (δ¹⁸O and δD, in ‰) of multiple water sources collected between September 2022 and March 2025 at the Puding Karst Ecosystem Research Station in Guizhou, southwest China (105°42′–105°43′E, 26°14′–26°15′N). The monitored site is a subtropical karst ecosystem characterized by shallow, soil-filled bedrock fractures that play a key role in plant water uptake: Mobile soil water extracted using suction lysimeters at varying depths within the root zone. Bulk soil water obtained from collected soil samples via laboratory extraction. Xylem water from tree branches (xylem tissue only). Rock fracture water extracted from soil-filled fractures in bedrock using suction lysimeters. Precipitation collected using standard rain gauges. The dataset supports ecohydrological analyses of water sources for trees in subtropical karst environments and can be used for isotopic mixing models, source partitioning, and hydrological process studies.