Floristic composition and phytogeographical spectrum of Pistacia vera L. woodland remnants in northeastern Iran

The xerophilic woodlands of wild pistachio Pistacia vera L. remnants occur as several isolated stands in Central Asia. The Kopet Dagh mountain range, northeastern Iran, is the westernmost distribution range of wild pistachio. In this research, we present the annotated checklist of vascular plants of two remnants of P. vera woodlands along the Iran-Turkmenistan borders. We provide the life-forms, phytogeographical spectrum, endemism and conservation status of the flora. The field surveys were conducted through several field collection efforts during 2018-2020. A map showing the boundaries of the woodlands was prepared. We recorded 348 plant species distributed in 214 genera and 48 families. The richest families were Asteraceae (33 genera with 59 species), Poaceae (22 with 41), Brassicaceae (24 with 28) and Fabaceae (11 with 27), and the two richest genera were Astragalus (ten species) and Galium (nine species). The dominant life-forms were therophytes (54%) and hemicryptophytes (24%), which confirm a xeric climate condition. Irano-Turanian elements (195 species, 56%) were the most common plants, followed by bi-regional (21%) elements. Based on our samplings, the Khorassan-Kopet Dagh endemics represented only four percent of the flora. We recorded 34 endemics/sub-endemics of plants, eight of which were categorized as threatened or near-threatened. The results indicated the important role of pistachio remnant woodlands in plant biodiversity and conservation biogeography of northeastern Iran.