Ecological evaluation of cultivating medicinal plants in different rangelands of Lorestan Province

Climate changes and indiscriminate harvesting as well as overgrazing of different Iranian rangelands have caused the destruction and reduction of vegetation in the rangelands. This has been especially severe for medicinal plants, in the last decade. By identifying the plant communities and analyzing the ecological nature of each species, it is possible to plan for optimal management based on ecological principles for the present and the future. Based on the above-mentioned issues, the current research was conducted regarding the ecological evaluation of cultivating medicinal plants in different rangelands of Lorestan Province through analytic hierarchy process (AHP) approach and ArcGIS software in order to restore the rangelands and protect the medicinal plants.

The studied area was the rangelands class 1 of Lorestan Province in the west of Iran. Required data included soil, long-term climatic (1970-2020), and topographic data. Climatic and topographical data were obtained from the WorldClim database. Soil data were gathered by the International Soil Reference and Information Centre (ISRIC). Studied medicinal plants were Asafoetida, Galbanum, Liquorice, Keluss, and Borago Oxtongue flower. The judgment of 15 experts was used for pairwise comparisons and weighting of ecological data for each medicinal plant using the Delphi method, and the weight of each of the options and criteria was calculated in Expert Choice11 software. Then, to match the environmental requirements of the medicinal plants with the characteristics of the rangelands, the natural breaks –(Jenks) classification method was employed in ArcGIS software.

The results showed the major role of annual mean temperature with a weighting coefficient of 0.309 in cultivating medicinal plants, followed by elevation and annual cumulative rainfall (0.212). Also, among the studied factors, the lowest weight belonged to soil organic carbon percentage (0.057). For annual mean temperature, more than 53% of rangelands in Lorestan Province experienced a temperature between 10 and 15 °C. The rangelands received an average of 350 mm. More than 60% of the rangelands were located at an elevation between 2000 and 3000 m. For slope, more than 54% of rangelands had a slope between 25 and 60%. The soil of Lorestan rangelands had a heavy texture, so that more than 75% of the rangelands had clay loam soil texture. More than 59% of the rangelands had soil organic carbon of 2-5%. Also, more than 74% of the rangelands had a pH between 7.7 and 7.9. Also, the rangelands were divided into three classes (very good, good, and medium) in terms of potential and having suitable ecological conditions for growing Asafoetida, Galbanum, Liquorice, Keluss, and Borago Oxtongue flowers. Ninety-eight, 97, and 94% of the rangelands were placed in the very good and good categories for cultivating Asafoetida, Galbanum, and Keluss, respectively. However, these values were 26 and 27% for planting Liquorice and Borago Oxtongue flower, respectively.

Overall, the rangelands of Lorestan Province had a good potential for growing Asafoetida, Galbanum, and Keluss, and they had a medium potential for cultivating Liquorice and Borago Oxtongue flowers. However, the suitability of medicinal plants cultivation varied based on the geographical position of the rangelands, and the recommendation for cultivating each medicinal plant should be considered according to each geographical zone.