Tecomella undulata under threat: The impact of climate change on the distribution of a valuable tree species using a machine learning model

PLOS One | https://doi.org/10.1371/journal.pone.0326609 July 9, 2025 14 / 18 temperatures by late May (Bio9 > 27) also lower habitat quality, causing fruit drop. Leaf drop in winter (Delfard) relates to low temperatures (Bio8). In contrast, summer leaf drop (Shahnia, Moghdan) is likely due to high temperatures (Bio9) and aridity causing moisture stress. Preference for moderate seasonal temperature variation (Bio4) is consistent with leaf retention in winter and summer, avoiding extreme cold or heat. Comparison with other studies The present study, focusing on the impacts of climate change on T. undulata distribution in Iran, identified temperature seasonality (Bio4), mean temperature of the wettest quarter (Bio8), and precipitation seasonality (Bio15) as the primary drivers. This emphasis on temperature aligns with the findings of Arshad et al [18], who also highlighted the importance of Bio8 and Bio9 (mean temperature of the driest quarter) for the species in Pakistan. However, our study diverges by emphasizing precipitation seasonality, suggesting a greater sensitivity of T. undulata in Iran to fluctuations in rainfall patterns. Mathur and Mathur [15], conducting a global assessment, identified November wind speed and isothermality (Bio3) as the principal factors influencing the species’ distribution, alongside precipitation of the wettest quarter (Bio16) and mean temperature of the warmest quarter (Bio10). However, the inclusion of wind speed in their model underscores the potential

impact of additional climatic factors at a global scale, which was not used in our regional study. Mathur and Mathur [14], focusing on India, also emphasized the role of temperature and precipitation, particularly annual precipitation and maximum temperature of warmest month. Precipitation seasonality was identified as the third most important variable for both current conditions and the 2070 projections, which aligns with the findings of our study. This further supports the critical role of these factors in shaping T. undulata’s distribution. However, their study also con- sidered soil properties, habitat heterogeneity indices, and land-use land cover, revealing a facilitative rather than limiting effect of these non-climatic variables on the species’ distribution in India. These discrepancies in variable importance and the inclusion of unique factors in each study highlight the influence of specific environmental contexts and habitat characteristics on T. undulata’s distribution across different regions and scales. The variation in methodological approaches, such as the use of Shared Socioeconomic Pathways (SSPs) in our study versus Representative Concentration Pathways (RCPs) in Arshad et al [18], and the incorporation of ensemble modeling in Mathur and Mathur [15], further contributes to the observed differences. Our national-scale analysis provides a broad overview of T. undulata’s climate-driven suitability, but finer-scale regional variations and microclimates, not fully captured at our 1 km² resolution, influence local presence. Factors like slope,

aspect, soil, and water availability can create more or less favorable microclimates within generally suitable regions, potentially forming refugia. Future research with finer-resolution data is needed to understand these microclimatic influences. While our study provides a robust assessment of T. undulata’s vulnerability to climate change in Iran, it is crucial to acknowledge that the species’ response might vary across its range due to local adaptations and environmental heteroge- neity. Future studies incorporating a wider range of predictors, including biotic interactions and disturbance regimes, could enhance our understanding of the species’ ecological niche and inform more targeted conservation strategies. Addition- ally, long-term monitoring and experimental studies are needed to validate the model predictions and assess the species adaptive capacity in the face of ongoing climate change. Conservation strategies for T. undulata in a changing environment Evidence strongly suggests that T. undulata is projected to face a constricting range in Iran due to climate change, with significant implications for its conservation status. The spatiotemporal dynamics observed in T. undulata highlight the broader need for robust predictive models to inform adaptive management strategies under climate change. Consider- ing these factors, targeted conservation strategies can be developed. Areas featuring moderate seasonal temperature