Climate suitability for the moisture-sensitive conifer species may not be universally declining in a warming world

Amid ongoing and escalating climate change, understanding changes in habitat suitability for forest tree species is crucial for anticipating risks to their growth and ecosystem services. Despite advancements in this area, challenges remain, particularly in addressing spatial and temporal discrepancies in suitability change. This study evaluated habitat suitability changes for Qinghai spruce, a moisture-sensitive conifer species, during the warming period from 1960 to 2020, by integrating species distribution modeling with dendrochronological methods. Maxent model outputs revealed a distinct dipole pattern in habitat suitability changes: an increase in the west (56.2%) and a decrease in the east (43.8%). This dipole pattern was corroborated by the spatial pattern of forest population dynamics, highlighting much higher adult-tree mortality frequency, rate, and density decline in regions with decreased suitability, while showing minimal values in most (3 out of 4) regions with increased suitability. Climate factors and their changes explained 80.9% of the variance in suitability changes. Precipitation change, with a significant positive relationship to suitability changes, contributed the most (54.5%) to this explained variance, followed by post-warming temperature, which contributed 34.3% with a significant negative relationship. Thresholds of +20 mm for precipitation change and 0 °C for post-warming temperature distinguished regions with a high probability of increased suitability from those with a high probability of decreased suitability. This study provides nuanced insights into the responses of moisture-sensitive conifer species to climate change, helping inform and enhance conservation strategies for Qinghai spruce.