Abstract: The study area (Mirabad) is located between 36°, 55’ to 37° north latitude and 45°, 05' to 55°,44' east longitude in west Azerbaijan province. In this study, Flora of this region was determined by using available references. We encountered 192 species that belongs to 126 genera and 41 families. The largest family of region is Asteraceae with 31 sp. and the largest Genera is Astragalus with 7 sp. The main life forms are: Hemicryptophyte with 30.2% and Therophyte with 28.1%. The most extended chorotype with 62.5% is related to: Irano_ Turanian.
INTRODUCTION
The diversity of plant life is an essential underpinning of most of our terrestrial ecosystems. Humans and most other animals are almost totally dependent on plants, directly or indirectly. Another important role of plant life is the provision of ecosystem services the protection of watersheds, stabilization of slopes, improvement of soils, moderation of climate and the provision of a habitat for much of our wild fauna.
While it is generally accepted today that the conservation of all biodiversity should be our goal, understanding the natural distribution of plants (Floristic studies) is central to conserving biodiversity and managing ecosystems for long-term viability and sustainability. Iran is a country with high divers climate and topography, which leads to diversity in natural and biological resources. Therefore, for management in order to conservation of this diversity, prevention from destruction of habitats, determining the native, resistant and endangered species and supporting them, recognition of medicinal plants for proper use of them, Floristic studies is necessary. Nowadays, many studies in this field have been doing by researchers, such as: plant species of Vanak-Semirom-Isfahan (Parishani, 2003); Floristic study of Palangdarreh-Qom (Mirzaei, 2001); Floristic study of Dalamper-West Azerbaijan (Shaikhi, 2005); Floristic study of National park of Urmia Lake (Biabani, 2000); Floristic study of Ghasemeloo (Shohada) Valley, forest reservoir (Malekmohammady, 2006). While this sort of studies is very useful for planning with refer to protection, reclamation and management of valuable species, present study was done in Mirabad region in 2005-2006.
MATERIALS AND METHODS
The study was conducted at Mirabad region during the growing season of 2005 and 2006. This region is located between 36°, 55’ to 37° north latitude and 45°, 05' to 55°, 44' east longitude in northwest of Iran in west Azerbaijan province. Minimum altitude of region is 1600 m in Chamdrud and black river and maximum altitude is 2800 m in Shatar Mountain.
In this investigation, plant specimens were collected in different seasons. The samples were transferred to the herbarium and were pressed and recognized according to the Flora of Iran; Assadi (1988-2002), Flora of Iran; Rechinger (1963-2000), Flora of Iran; Parsa (1943-1950), Flora of Turkey; Davis (1965-1988), Colored Flora; Ghahreman (1975-2000), Astragalus communities of Iran; Masoumiramak (1986-2000) and Flora of Iran; Mobayen (1980-1996). In this manner geographical plant distribution also determined according these Flora. Determining the life form was done by Raunckier's classification (Raunchier, 1934), Iran's endemic species determined according to Red data book of Iran (Jalili and Jamzad, 1999) and then floristic list of this region provided in this study.
RESULTS
The results of study show that about 192 species belong to 126 genera and 41
families have been recognized.
| Table 1: | Frequency of species in family |
| Table 2: | Frequency of species in genus |
| Table 3: | Life form spectrum of species in Mirabad |
| Th: Therophyte, He: Hemicryptophyte, Ch: Chamaephyte, Ph: Phanerophyte, Cr: Cryptophyte | |
| Table 4: | The phytocorya distribution of species in Miarabad |
| IT: Irano-Turanian, ES: Euro-Siberian, Med: Mediterranean, Endm: Endemic | |
| Table 5: | Floristic list of Mirabad region |
The biggest family of the region is Asteraceae with 31 sp. Fabaceae with 27 sp., Rosaceae with 24 sp. and Poaceae with 23 sp. are in the next order (Table 1).
Among the existing genera there are 79 genera with one sp., 35 genera with 2 sp., 8 genera with 3 sp. and 3 genera with 4 sp. and 1 genus with 7 sp. Astragalus with 7 species is biggest genera (Table 2).
The life form spectrum of plant species are as fallow: He: 30.2%, Th: 28.1%, Ph: 17.7%, Ch: 12.5%, Cr: 22% (Table 3).
The phytocorya distribution of species is as follow: IT: 62.5%; IT, ES: 21.35%; ES: 6.78%; Endm: 4.68%; IT, Med: 2.6%; ES, Med: 1.57%; Med: 0.52% (Table 4). Floristic list of Mirabad region is provided in Table 5.
DISCUSSION
It is concluded from the results of the study that the study area is very rich with refer to plant diversity. The existence 41 families, 126 genera and 192 species support this conclusion.
Among all plants He with 30.2% is dominant and Th with 28.1% is in the next order. In fact life forms of the plants indicate the possibility of adaptation of plants to environmental factors especially climatic condition. According to Dr. Mobayen (1980-1996), the frequency of He is due to cold and temperate climate and the frequency of Th plants is due to Mediterranean climate. On the whole the frequency of He and Th among the plants of the region shows that the effect from two types of climate-Mediterranean and cold temperate- affected them.
Hemicryptophyte adapted to condition of area. They adapted and developed themselves to area by using different ways such as: reserving water, using ground water, reducing their water need by loosing their leaves and reduction of vegetative growth.
Therophyte adapted to the dryness of the region and shortage rainfall. Because these plants spend vegetative period in the form of seed (Asri, 2003).
Dominance of Hemicryptophyte and Therophyte clearly indicate the adaptation of these plants to aridity of area.
The low percentage of Cryptophyte, Champhyte, Phanerophyte shows that they are not adapted to existence climate and edaphical situations. Each plant species has it’s special ecological area with a known tolerance to life conditions of area. There fore, the geographical distribution of plant species depending on life conditions of area and adaptation of plants to area (Asri, 2003).
Astragalus diversity with its 7 species in this area, which is mountainous, shows that Astragalus has adapted to the mountainous conditions.
The photocopy distribution of plants reflects the climate conditions. Considering to this fact that 65.25% plant species in a region are IT elements, so we can conclude that this region belong to IT. IT (the Irano-Touranian region) is characterized by low rainfall and a long dry season.
The existence endemic species indicate diversity in Iran climate. The study area is under different conserving strategies including: protected area and non-protected area, additionally, with refer to conserving policies the protected area has the better situation.
The existence of Asteraceae family with large diversity is the result of destruction in some portions of this region. It is experiencly understood that the increasing of the number of some plant families including compositae accompanied with destruction in area; (Vakili et al., 2001; Archibold, 1995). Significantly the presence of these species: Stachys inflate, Teucrium polium, Teucrium orientale and Euphorbia spp. Is indication of destruction in no protected portions of this region. (Moaffarian, 2000). According to rich biodiversity of study area, which resulted from floristic study, it is quite possible to concentrate the improving practices and reclamate to area again.