Habitat suitability dynamics of Myrtus communis L. in Iran under climate change: a MaxEnt modeling approach

Introduction: Myrtle (Myrtus communis L.) is an evergreen shrub native to Iran, recognized for its valuable compounds utilized in the pharmaceutical and food industries. It thrives in arid and semi-arid regions and plays a significant role in enhancing urban green spaces, beautifying environments, and restoring ecosystems. Unfortunately, wild myrtle populations are declining due to overharvesting and their vulnerability to climate change. As a result, the future suitability of their habitats is uncertain. Therefore, understanding how climate change affects the distribution of this species is essential for effective conservation planning.

 Methods: Species Distribution Models (SDMs) were employed to predict current species distributions and potential changes under two future climate scenarios, SSP2-4.5 and SSP5-8.5, for the 2050s. The MaxEnt model was optimized using the ENMeval package, which adjusted the Regularization Multiplier (RM) and Feature Class Combinations (FC) parameters.

Results: The model with FC = LQHP and RM = 1.5 achieved a mean validation AUC of 0.868 ± 0.056, a low omission rate (OR10 = 0.105), and a True Skill Statistic (TSS) of 0.727, indicating good predictive performance for the distribution of M. communis. The primary environmental factors affecting the distribution of M. communis, based on permutation importance, are slope (55.2%), Bio15 (15.5%), and elevation (13.1%). Under current climate conditions, M. communis occupies an area of 355,138.97 km². Future scenarios (SSP245 and SSP585) predict reductions to 296,643.27 km² and 285,063.60 km², corresponding to losses of 16.47% and 19.73%, respectively.

 Conclusions: These findings underscore the importance of conserving, restoring, and sustainably utilizing M. communis. They provide a scientific basis for effective management and long-term preservation of this species in Iran.