University of Isfahan Taxonomy and Biosystematics 3115-9001 14 53 2023 01 21 A Floristic Study and Comparison of the Core and Buffer Zones of the Tange-Khoshk Forest Reserve of Semirom in Isfahan Province مطالعۀ فلوریستیک و مقایسۀ دو بخش مرکزی و ضربه‌گیر ذخیره‌گاه جنگلی تنگ‌خشک سمیرم در استان اصفهان 17 48 27089 10.22108/tbj.2022.134846.1211 EN Hadis Asadi Ph. D. Student of Biology, Payame Noor University, Tehran, Iran Maryam Haerinasab Assistant Professor, Department of Biology, Payame Noor University, Tehran, Iran Gholamreza Bakhshi Khaniki Professor, Department of Biology, Payame Noor University, Tehran, Iran Younes Asri Associate Professor, Department of Botany, Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran 0000-0002-4566-1756 Mohabat Nadaf Assistant Professor, Department of Biology, Payame Noor University, Tehran, Iran Journal Article 2022 08 24 In the present study, the flora of the Tange-Khoshk Forest Reserve in Semirom, Isfahan, comprising two zones, the core zone (under protection) and the buffer zone, was investigated to introduce the floristic composition, life forms, and geographical distribution, as well as to understand the effects of exclosure on the vegetation structure. In this region, a total of 194 species belonging to 45 plant genera were identified. The families Asteraceae, Fabaceae, and Poaceae were the most abundant in terms of species count. Regarding life forms, hemicryptophytes were dominant in both the core and buffer zones. The study of the geographical distribution of species revealed that, in both zones, most species belonged to the Irano-Turanian vegetation area. This research demonstrated that the exclosure of the Tange-Khoshk forest reserve has led to an increase in vegetation diversity, particularly marked by the presence of various tree species in the core zone. Introduction In Iran, the primary method of forest protection involves the establishment of reserves. Each forest reserve includes a central part that is fully protected. Surrounding this core zone is a buffer zone where activities such as animal grazing, human interference, and recreational activities are permitted, which in turn contributes to the protection and sustainability of the core zone. The Tange-Khoshk forest reserve, encompassing an area of 6000 hectares, is situated 40 km from Semirom city in the southern part of Isfahan province. This reserve was established in 1372 AH (1993) with the primary aim of preserving the tree species Pistacia atlantica subsp. mutica. In this research, the focus is not only on evaluating the flora, life forms, and chorology of the vegetation but also on investigating the effect of the reserve's establishment on the structure of vegetation in both the core and buffer zones over a span of 28 years. Materials and Methods In the study area, plants were collected and identified using reliable sources, following the APG IV system (2016). The identified specimens were then deposited in the herbarium of the Isfahan Agricultural and Natural Resources Research and Education Center. To classify their life forms, Raunkiaer's (1934) classification system was utilized. Additionally, the Red Data Book of Iran and several authoritative articles were consulted to evaluate endangered species. Furthermore, the chorotype of each species was determined based on their distribution areas in Iran and other countries. This process involved referencing the geographical divisions of Iranian vegetation compiled by Takhtadzhian (1986), Zohary (1973), and Assadi (1986-2018). Results and Discussion Based on the results, the number of species in the core and buffer zones was 182 and 57, respectively, indicating higher species diversity in the core area. When investigating the effect of exclosure on vegetation diversity, assuming that variables affecting plants, such as climate, soil, and slope, remain constant, the differences in species diversity between the core and buffer zones can be attributed to grazing in the buffer area. Among the identified plant species, there were 11 species of trees and shrubs, primarily growing in the core area, which is likely due to the influence of the area's enclosure. In conclusion, it appears that enclosures can have positive effects on soil condition improvement, and consequently, on the establishment and reproduction of vegetation in the unprotected areas of Zagros. In this research, there was a significant difference observed between the presence and absence of tree species inside and outside the reserve. Tree species such as Pistacia atlantica subsp. mutica, Celtis australis subsp. caucasica, Lonicera nummulariifolia, Platanus orientalis, Atraphaxis spinosa, Rhamnus pallasii, Prunus macrocarpa, and Acer monspessulanum were found to grow only in the core zone. However, species like Prunus lycioides, with their long, sharp thorns and rough, dense shapes that protect them from grazing, have been easily established in both regions. Also, the diversity of the Poaceae family was greater in the exclosure region than outside, which can be attributed to the complete vegetative growth of these species due to the creation of desirable conditions, such as the prevention of livestock grazing in the core zone. This factor, combined with the abundance of seeds in this family, can be one of the reasons for the high distribution and diversity of these species throughout the reserve. The abundance of the genus Astragalus, which is specific to the mountainous regions of the Irano-Turanian vegetation area, indicates the cold and semi-arid mountain conditions in the region. The herbaceous species of this genus were more prevalent in the core area, which, due to the palatability of these plants, are most likely grazed by livestock in the buffer zone. Additionally, the comparison of endangered plant species (EN) and plants at lower risk (LR) showed that the number of these species is 13 in the buffer area and 32 in the core zone. It appears that the limited distribution and presence of these species in the buffer zone are due to grazing in this area. This research demonstrated that the buffer zone has been degraded due to factors such as excessive livestock grazing, the presence of agricultural lands on the edge of the reserve, fire, and the harvesting and cutting of trees. These factors have led to the invasion of certain species such as Scariola orientalis, Euphorbia heteradena, and Eremurus spectabilis in some parts of the region. Therefore, significant threats, including road construction and agricultural activities, can lead to the loss of reserves, which serve as the last natural habitats for some endangered species. The study of species endemism revealed that in this region, there are 16 species endemic to Iran, belonging to 9 genera and five families, of which 12 species are relatively vulnerable. Consequently, it can be stated that 25.8% of the total species in Semirom’s Tange-Khoshk forest reserve are endemic, underscoring the necessity for their preservation and further study. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

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