Prediction the climate change effects on the potential spatial distribution Onosma sabalanica Ponert. and Onosma cornuta H. Riedl. (Boraginaceae Juss.) in climatic units of Iran

The climate change is the greatest environmental challenge facing the world today. The prediction of the effect of climate change on the distribution of sensitive and valuable plant species is considered important in the management and conservation of them. Onosma L. as a very rich taxa from Lithospermeae Dumort. tribe in Boraginaceae family including 52 species in Iran wich more than half of them are endemic to Iran. The Onosma sabalanica Ponert. and Onosma cornuta H. Riedl. are the rare and endemic species of Onosma L. in Iran. Objective of the present study was to predict the effects of the climate change on the spatial distribution of these plants at future. In this regard, with using species distribution model's tool (SDM), different algorithms (GLM, GAM, GBM, RF, CTA, FDA, MARS, ANN, SRE) in different optimistic (RCP2.6) and pessimistic (RCP8.5) scenarios predicted the future spatial distribution of this species for 2050 by an ensemble model in R statistical software. The results showed that the performance of all models based on TSS index was excellent and modeling of the distribution of the species had been done with high statistical reliability. The results also represented that the distribution of these species in both optimistic and pessimistic scenarios of 2050 had been significantly reduced which requires to apply strategies for protecting of this valuable plants.