Habitat quality modelling and effect of climate change on the distribution of Centaurea pabotii in Iran

Climate change resulting from increased greenhouse gases affects the distribution of weeds by commonly expanding and shifting their future distribution. In this study, habitat distribution of Behbahanian Knapweed (Centaurea pabotii) was modelled as an endemic weed of wheat fields in four provinces in the southwest of Iran. Then, the current and the predicted future distributions were compared under two scenarios based on the lowest and highest carbon dioxide emissions. Field survey was carried out during March-May of 2015-2017 to collect presence points of C. pabotii. Habitat modelling was done using MaxEnt software using eight environmental variables and 25 presence points. To predict the future distribution, modelling projection of CCSM4 was performed for the year 2070 under scenarios of representative concentration pathways (RCP) 2.6 and RCP 8.5 using the current and the projected future bioclimatic variables in MaxEnt. Our results revealed that the suitable area of distribution will be approximately doubled in the future for both scenarios and will be shifted to lower latitudes and higher altitudes. Also, in the most western province of the study area, a new isolated and large suitable area will occur in the future. Therefore, it was suspected that this plant will be expanded to the wheat fields of this province. Expanding and shifting in the distribution of C. pabotii should be taken into consideration by agricultural managers in Iran.