Predicting the potential distribution of Leucomeris decora in Indochina Peninsula and Southwest China under climate change

Leucomeris decora is one of the few arborescent species in the Asteraceae family and an important representative of Asteraceae in the Indochina Peninsula, holding significant scientific value for studies on floristic geography, phylogenetic evolution, and vegetation succession in dry-hot valleys. However, its natural distribution range and potential distribution pattern have not been systematically documented. Based on 62 effective occurrence records and 22 environmental variables, this study identified six core factors through principal component analysis, correlation analysis, and evaluation of contribution rates and permutation importance. MaxEnt parameters were optimized and integrated into the Biomod2 platform to construct an ensemble model comprising 11 algorithms. Potential suitable habitats were simulated under current conditions and four future periods under the SSP2-4.5 and SSP5-8.5 scenarios of the BCC-CSM2-MR climate model, with model performance compared and niche differentiation between Chinese and Thai populations analyzed. Results showed that the Biomod2 ensemble model performed best (weighted mean Kappa = 0.66, TSS = 0.97, AUC = 0.99), exhibiting the highest consistency with the field-observed distribution, and outperformed both the MaxEnt and Domain models. Temperature annual range (Bio7), mean temperature of the coldest quarter (Bio11), precipitation of the warmest quarter (Bio18), and precipitation of the coldest quarter (Bio19) were the dominant climatic factors constraining the distribution; the Chinese population was primarily limited by precipitation, whereas the Thai population was mainly driven by temperature. The two populations exhibited significant niche differentiation (I = 0.43, D = 0.14) and should be considered independent evolutionary significant units. Under both future scenarios, the total suitable habitat area continued to shrink, with the distribution shifting northeastward and gradually diverging into two relatively isolated regions: a southwestern region (border area of Thailand, Myanmar, and Laos) and a northeastern region (border area of Yunnan, Guizhou, and Sichuan, China). The divergence and morphological changes were more pronounced under the high-emission scenario. This study reveals the distributional shift trends and population differentiation patterns of L. decora, and suggests prioritizing conservation strategies based on ensemble model results and strengthening genetic differentiation research, thereby providing a scientific basis for the protection and management of this rare and endangered species.