تاکسونومی و بیوسیستماتیک (May 2022)
Flora, Life Form, and Chorology of Plants in Highlands of South Mashhad
Abstract
AbstractIn the present field study, the flora, life form, and chorology of plants were identified in the highlands of south Mashhad (Iran). The area was approximately 4351 hectares and the altitude varied from 1000-1520 m above sea level. The plant species were identified and their chorology, life form, endemism, and rarity were determined through laboratory examinations and botany reference books. We identified 259 plant species belonging to 190 genera and 47 families. The dominance of therophytes and hemichryptophytes (79.5%) life forms indicated the specific flora of mountainous regions and the cold and aridclimates. Irano-Turanian and multi-regional were the most dominant Chorotypes that were referred to in the long history of disturbance in the dry climate of Khorassan. In terms of conservational classifications, 6 species were identified as vulnerable, 11 species as lower risk, and 3 species as threatened; 13 species were endemic to Iran and/or Khorassan-Kopet Dagh floristic province.IntroductionSince the vegetation of each region is very important in evaluating the current situation and predicting the future, the basis of the management and protection programs of natural resources of each region is the identification of the vegetation and the study of the geographical distribution of the plants in that region. For this purpose, identifying the plants of an area allows quick access to specific species at a certain time and place. Identifying the genetic power of plants as well as the by-products of natural resource fields, including medicinal plants, could provide industrial and basic use of them and help to determine the country's vegetation. Materials and MethodsIn order to identify the plants in the south and west highlands of Mashhad, during regular visits from spring to autumn in the growing seasons, plants of the area were collected and pressed. At the same time as sampling, the life form of each species was noted. The plant samples were identified using Flora Iranica, Color Flora of Iran, and Flora of Iran. In order to determine the life forms of plants, the Raunkiaer's Life form System was used. The chorotype of plant species was determined according to the information related to the distribution areas of species in existing floras and articles based on the groups of plant geography areas. FindingsA total of 259 plant species were identified belonging to 190 genera and 47 families. The most frequent plant family was Asteraceae. The results showed that therophytes with 109 species are the most important life forms in the study area, and then hemicryptophytes with 97 species have the largest number of species. Irano-Turanian was the most dominant Chorotypes. In terms of conservational classifications of the IUCN, 6 species were identified as vulnerable, 11 species as lower risk, 1 species as data deficient, 4 species as least concern, and 3 species as threatened. Discussion of Results and Conclusions The reason for the relative abundance of species belonging to the Asteraceae family can be attributed to the high diversity of its species in the country and the evolution of this family, which has increased its distribution power, and the special morphological, anatomical, and physiological characteristics of this family, including high adaptability of plants in this family due to unfavorable ecological conditions such as mountainous and dry areas of Irano-Turanian region, producing small seeds and equipped with different propagation factors, the presence of blades and thorns and secondary metabolites in some genera belonging to this family cause an increase in the number of species of this family. The existence of a large number of Poaceae family species in the region is of particular importance in terms of fodder value and soil protection. Due to the placement of the terminal bud in the plant species of this family on the soil surface, the damage caused by destructive factors such as livestock grazing is far less and this factor, along with the abundance of small seeds in this family, can be one of the most important factors of the high distribution and diversity of the species of this family.The presence of many species of the genus Astragalus with different biological forms in the region (12 species) indicates the cold, high, and semi-arid conditions in this region. In this study, 13 species were endemic to Iran’s floristic province (10 species of them are endemic to Khorassan-Kopet Dagh floristic province). Most of the endemic species of the study area have a hemicryptophyte life form. Based on the results of the investigation of the life forms, therophytes and hemicryptophytes respectively have the highest percentage of life forms in the study area. The life form shows the taxonomic characteristics and adaptation of plants to environmental conditions, so the flora is very rich in annual plants. The dominance of therophytes can be referred to the simultaneous effects of disturbance on the flora of this region and the dry climate. Disturbance factors were from livestock grazing for many years and human activities due to the easy access to the area as a result of the proximity to the urban area and green belt of Mashhad and the easy access of tourists to this area and the planting of non-native trees and shrubs. Obviously, we can still see virgin places in terms of vegetation in some difficult parts of the region. Hemicryptophytes are the second life form and the abundance of this group of plants is due to their adaptation to the cold, semi-arid, and mountainous climatic conditions, which indicates high areas and the preservation of soil moisture due to snow melting during the growing season. Also, the abundance of hemicryptophytes is due to spending the cold season by the renewing buds in this group of plants on the soil surface. The dominance of therophytes and hemichryptophytes life forms indicated the specific flora of mountainous regions and the cold and aridclimates, and the dominance of Irano-Turanian elements also confirms this. Considering that the studied area has a very large percentage of Irano-Turanian and multi-regional elements, it has important genetic reserves.
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