Invasive plant species in natural and agricultural ecosystems of Khorasan provinces and global climate change

As a result of its climatic diversity and extensive agricultural and pasture lands, the Northeast of Iran (Khorasan Provinces) enjoys good conditions for the distribution of alien species as invasive plants. These species have created a variety of problems in the region over the last few years. The purpose of this study was to assess invasive plant species in the three Provinces of Khorasan in Iran. Data on species presence, abundance and status were derived from the local literature, expert knowledge and field investigations. For assessment of the region’s present flora, we used the information from the herbarium of Ferdowsi University in Mashhad and documents related to regional plant flora over the past thirty years. For each of the species, their life form, taxonomic family and geographic distribution were determined. In total, 114 species from 74 genera and 32 families were recorded as invasive plants. Considering the total pool of invaders, 82.43% were dicotyledons (with 61 genera) and the rest were monocotyledons. Among all the species, thirteen were selected as the most important invasive plants in the agricultural ecosystems and twenty-one as important in the natural ecosystems. The families with the most invasive species were Asteraceae with 12 species (10.61%), Poaceae with seven species (6.19%) and Lamiaceae with five species (4.42%). The highest number of species in different genera belonged to Tamarix with eight species and Bromus with four species.