Integrated conservation of Acer yangbiense: A case study for conservation methods of plant species with extremely small populations

Societal Impact Statement A practical and efficient model is crucial for applying conservation actions to threatened species. Plant Species with Extremely Small Populations (PSESP) is a new concept raised jointly by government and scientists from China, targeted toward funding the urgent rescue of threatened plants. With the cooperation of decision-making departments, scientists, local departments, nongovernment organizations, and local people, we present a case of how the tree species Acer yangbiense was studied and finally rescued. The pipeline and experience in this case will promote the development of the PSESP conservation methods. With only five individuals known for years, the Critically Endangered species Acer yangbiense was listed under the conservation category Plant Species with Extremely Small Populations (PSESP), a concept developed 10 years ago in China, aimed at channeling limited resources to conserve the most threatened plant species. Integrated conservation methods and research were applied to A. yangbiense and introduced in two-time phases upon the discovery of new populations. Being considered one of the most successfully rescued species, A. yangbiense was removed from the second PSESP list issued in 2021 by Yunnan Province, China. The conservation case has become a model, with replicable pipelines, standards, cooperation, and studies to future PSESP conservation actions. Herein, we discuss the significance of work on A. yangbiense for future conservation actions regarding PSESP and other endangered species.