Shifting distribution patterns of an endemic conifer species in the Himalayan region under climate change: Past, present, and future

Species with narrow ranges, particularly rare and endangered ones, are more vulnerable to rapid climate change. The endangered Pinaceae species Picea smithiana (Wall.) Boiss. (P. smithiana), endemic to the Himalayan region, is of significant economic and ecological importance. Understanding how its distribution responds to climate change is crucial for effective biodiversity conservation. Our research integrates three species distribution models, i.e. MaxEnt, Random Forest, and Support Vector Machine, to predict the suitable habitat of P. smithiana in the past, present, and future, and to analyze changes in their spatial distribution patterns. Our study also interprets its geographical distribution patterns through an analysis of multiple environmental factors within its suitable habitat. Our results indicate that, since the last glacial maximum, the suitable habitat of P. smithiana has been shifting towards high latitudes and altitudes, corresponding with its cold tolerance traits. Besides the Himalayan region, suitable habitat of P. smithiana were also predicted in Southwest China, despite a lack of observed occurrences, suggesting possible speciation events linked to the uplift of the Qinghai−Tibetan Plateau. Our study warns that the actual distribution of P. smithiana might be more pessimistic than predictions indicate, with protected areas encompassing less than 27 % of its suitable habitat. This highlights the critical need for intensified conservation and management measures to secure the long-term persistence of P. smithiana.