Plant Species with Extremely Small Populations (PSESP) is a conservation concept that emerged in China in 2005. Species qualify if there are < 5,000 mature individuals in the wild and < 500 individuals in each population. To date, c. 100 such species have been effectively conserved and their habitats incorporated in China's Ecological Conservation Red Lines scheme, which prohibits or limits human impact in areas of ecological importance such as nature reserves, wetlands and public forests. After nearly 2 decades, the implementation and achievements of both regional and national PSESP conservation programmes has led to a broader recognition of this concept.

During 15–29 July 2023, supported by the Key Research and Development Programme of Yunnan Province (202103AL140002), the first International Training Course on Conservation and Utilization Techniques of PSESP was offered at Kunming Institute of Botany, Chinese Academy of Sciences, Kunming. The 20 participants came from Azerbaijan, Bangladesh, Brunei, India, Indonesia, Laos, Myanmar, Nepal, Pakistan, the Philippines, Uzbekistan and Viet Nam. During the 5-day indoor session, techniques, case analysis and theory of the PSESP conservation system were introduced. In the subsequent field session, the participants visited the Western Yunnan Provincial PSESP ex situ and near situ conservation garden, in situ conservation sites, and reinforced and reintroduced populations of Acer yangbiense, Firmiana major and Poncirus polyandra in Yunlong, Yuanmou and Fumin counties, respectively, in Yunnan. The implementation and challenges of these conservation programmes were discussed with the participants.

Transplanting Firmiana major at its reintroduction site, Fuming County, Yunnan Province, China, in July 2023. Photo: the authors.

The training course achieved its aims to introduce and share knowledge and information about the PSESP programme and to demonstrate how its innovative approaches and strategies could be tailored and adopted to local conservation efforts across Asia.