Diversity Conservation Status, and Ecological Characteristics of Endangered Plant Species in Than Sa–Phuong Hoang Nature Reserve, Thai Nguyen Province, Vietnam

This study investigates plant species diversity, regeneration patterns, and the ecological drivers influencing endangered plant species in the Than Sa–Phuong Hoang Nature Reserve, Thai Nguyen Province, Vietnam. Although tropical forest ecosystems in Southeast Asia are known for their high biodiversity, there is still a lack of site-specific studies that integrate species diversity, regeneration dynamics, and environmental drivers at the reserve scale. A total of 15 standard plots (20 × 50 m) were established across three main forest types (limestone forests, soil mountain forests, and transitional forests) to assess species composition, community structure, and regeneration patterns. Multivariate analyses, including principal component analysis (PCA) and cluster analysis, were applied to identify key ecological factors shaping species distribution and regeneration. The results recorded 1234 plant species belonging to 171 families, confirming the high biodiversity of the study area. Regeneration capacity differed significantly among forest types and was strongly influenced by environmental variables such as canopy cover, soil moisture, topography, and human disturbance. Multivariate results revealed clear ecological differentiation among forest types, highlighting the role of environmental filtering in structuring plant communities. The three target species (Curculigo orchioides Gaertn, Parashorea chinensis, and Paphiopedilum hirsutissimum Stein) exhibited strong dependence on stable microhabitat conditions and showed limited regeneration under disturbed environments, indicating high sensitivity to ecological changes and anthropogenic pressure. This study provides new insights into species–environment relationships at a local scale and highlights key ecological drivers of endangered plant distribution and regeneration, contributing to more effective conservation planning and biodiversity management in tropical forest ecosystems.