Analysis on the effectiveness and impact factors of ex-situ conservation of Pinus squamata, a rare and endangered plant endemic to Yunnan, China

On the background of strengthening global biodiversity conservation, the Kunming Declaration (2021) and the Kunming-Montreal Global Biodiversity Framework (2022) have established a global strategy that integrated both protection and restoration. The Chinese government has responded positively to the international commitments, e.g. listing the rescue of plant species with extremely small populations (PSESP) as a national action priority. Taking Pinus squamata as a case, the study evaluates the effectiveness of its conservation translocation and the mechanisms of environmental impact on its transplantation. The results show that P. squamata had a high transplant survival rate, and there are no significant effects of different protection types and management levels on the survival rate and growth (annual increment of diameter at breast height and tree height). The random forest models have predicted that environmental factors such as annual precipitation and soil total potassium density affect its growth through non-linear threshold effects. Current ex-situ conservation has effectively expanded its population size. But long-term restoration needs to focus on the suitability of translocation site environmental factors and the effective preservation of genetic diversity, as well as to integrate the optimal environmental thresholds of the transplanting site into future conservation plans. The conservation translocation of P. squamata provide a valuable practical experience for the conservation and population reintroduction of PSESP, and indicate its potential value as a plantation tree species.