TAXONOMIC STRUCTURE OF THE ALGAL FLORA OF IRAN

Algal floristic work carried out in Iran between 1853 and 1981 have been reviewed and compared with the results obtained in a series of recent studies (2000-2007). Algal samples for the recent studies were collected mainly from different inland aquatic habitats. On the basis of data from published and the recent studies, the systematic list of algae shows the occurrence of 1304 species and 1559 infra-specific taxa in Iran. However, 1213 species (1443 infra-specific taxa) revealed from the recent studies included 812 species (979 infra-specific taxa) as new reports for Iran (63% of the total species recorded). Analysis on taxonomic structure of algal flora of Iran testifies its richness. The basic parameters of a regular diversification of flora, values of genera quotient, spectra of leading taxa confirm that the highest percentage is contributed by Bacillariophyta (43%) of the total number of specific and infra-specific taxa followed by Chlorophyta (25%), Cyanophyta (15%) and Euglenophyta (8%). On an interrelation among divisions of algae, the algal flora of Iran appeared to be closer to that of Turkmenistan. Introduction Preserving biological diversity needs research on species richness of certain taxonomic groups in different administrative and natural territories. So far, the algal diversity of Iran has been investigated very insufficiently. According to Compere (1981) L. Rabenhorst (1853) reported first several species of freshwater diatoms (Bacillariophyta) from South Persia, Iran but without mentioning habitats. In 1842, soil samples were collected by Kotschy from the territories between Percipolis, Shiraz and Bushehr which cover modern provinces, namely Fars, Esfahan, Bahtiaria and Cheharmehal, Busher. Later Ehrenberg studied them and revealed 45 species of algae (Ehrenberg, 1854), out of which, 29 species became valid. In 1899, J.B. Petersen identified 8 species of algae studying samples collected by O. Paulsen from the Purlieus of Tehran (Petersen, 1930). Later on, D.A. Tarnogradskiy collected 9 samples from the Anzali Swamp in November 1922 and Woronichin (1925) published 13 species of algae from those collections. The first remarkable studies on the algal flora of Iran by Löffler (1959, 1961) appeared 100 years after the very first report by Rabenhorst (l.c.). The works of Löffler can be considered as the first authentic study on the algal flora of Iran. Later on, Hirano (1973) and Wasylik (1975) reported 406 infra-specific taxa. From the soil algae of Sahara-Gobi desert area, 29 species from the arid soils have been mentioned for Iran (Novichkova-Ivanova, 1980). 1 E-mail: zareidarki@iaufala.ac.ir; zarei@mail.ru


Introduction
Preserving biological diversity needs research on species richness of certain taxonomic groups in different administrative and natural territories.So far, the algal diversity of Iran has been investigated very insufficiently.According to Compere (1981) L. Rabenhorst (1853) reported first several species of freshwater diatoms (Bacillariophyta) from South Persia, Iran but without mentioning habitats.In 1842, soil samples were collected by Kotschy from the territories between Percipolis, Shiraz and Bushehr which cover modern provinces, namely Fars, Esfahan, Bahtiaria and Cheharmehal, Busher.Later Ehrenberg studied them and revealed 45 species of algae (Ehrenberg, 1854), out of which, 29 species became valid.In 1899, J.B. Petersen identified 8 species of algae studying samples collected by O. Paulsen from the Purlieus of Tehran (Petersen, 1930).Later on, D.A. Tarnogradskiy collected 9 samples from the Anzali Swamp in November 1922 and Woronichin (1925) published 13 species of algae from those collections.
The first remarkable studies on the algal flora of Iran by Löffler (1959Löffler ( , 1961) appeared 100 years after the very first report by Rabenhorst (l.c.).The works of Löffler can be considered as the first authentic study on the algal flora of Iran.Later on, Hirano (1973) and Wasylik (1975) reported 406 infra-specific taxa.From the soil algae of Sahara-Gobi desert area, 29 species from the arid soils have been mentioned for Iran (Novichkova-Ivanova, 1980).
In autumn of 1972, the Belgian multi-purpose expedition investigated deserts of the central, eastern and middle Iran, mainly Dašt-e Kavir, Dašt-e Lut and hollow Jazmuriyãn.Botanist of the above-mentioned expedition J. Leonard collected samples of algae, which became a subject of study in P. Compere's work (Compere, 1981).The samples of algae were collected from 21 different places and about 300 species and varieties were presented.Of these 66% was diatom, 17% green and 14% blue-green algae.Two species of diatom Nitzschia curvata Compere, N. iranica Compere and one form Navicula egregia Hust.fa.elongata Compere were described as new to science (Compere, 1981).Till 2000, an estimated 580 algal taxa were known from Iran.
The present paper attempts to analyze the taxonomic structure of algal flora of Iran based upon published information starting from L. Rabenhorst to P. Compere (1853Compere ( -1981) ) and also data obtained from recent studies based upon samples collected between 2000 and 2007 by the author.The algal flora of Georgia (Chkhaidze, 1987), Turkmenistan (Kogan, 1973), Central Asia (Muzafarov, 1965), Vietnam (Tien, 1982) and Ukraine (Wasser and Tsarenko, 2000;Tsarenko and Petlevanniy, 2001) were also compared with that of Iran.

Overall algal diversity of Iran
Algae from different water bodies of Iran revealed the occurrence of 1213 species and 1443 infra-specific taxa (infra-specific taxa), which included 812 species (979 infraspecific taxa) as new report for Iran (about 63% of the general species diversity).But 91 algal species (116 infra-specific taxa) from the previous studies on the territorial boundary of Iran could not be confirmed in the recent studies.So, by adding 91 species and 116 infra-specific taxa as obtained from the literature survey to the data accumulated in the recent studies, the total number of algal species now reached 1304 (1559 infraspecific taxa) for Iran (Table 1).The algal species of Iran belong to 8 divisions, 15 classes, 37 orders, 96 families and 262 genera (Table 1).Among the divisions, Bacillariophyta is the largest followed by Chlorophyta, Cyanophyta and Euglenophyta.The percentage of each division is given in Table 2.In the following sections, classification of Zerov (1972) is followed.
Euglenophyta is the fourth largest division in Iran in terms of species and infraspecific numbers.In the research conducted during 2000-2007, 121 euglenoid taxa were recorded as new reports.Earlier, four species of euglenoid algae recorded by Wasylik (1975) and Compere (1981) were also found to occur in the present investigation.Altogether 56 species and 58 infra-specific taxa of Xanthophyta have been recorded in the recent studies; but the occurrence of species like Botrydiopsis eriensis Snow, Botryochloris minima Pasch.(Novichkova-Ivanova, 1980) and Vaucheria sessilis (Vauch.)D.C. (Woronichin, 1925) reported in previous studies could not be confirmed.The majority of Xanthophytа representatives was noted seldom, and a few of these species, namely Arachnochloris striata Pasch., Chlorothecium clava Pasch., Stipitococcus apiculatus Prescott and Tetraedriella impressa Pasch., were recorded only in Šãdgãn Pond, and Mohammad ãbãd and Sivand Rivers, and Anzali Swamp, respectively.

Taxonomic quotients
It is known that the factor which testifies connection between number of species, genera and families determines the 'face' of flora with the greatest clarity (Tolmachev, 1974).'Proportions of flora' and generic factor concern to a group of parameters of taxonomic diversity.The s/f (species/families) is estimated as a ratio between the number of species and number of family of a particular group (e.g.class); g/f (genera/families) and s/g (species/genera) are determined in a like manner.Generic factor shows generic richness of algal flora by species and infra-specific taxa.According to some authors, richer floras differ from less rich floras by higher values of these parameters (Shmidt, 1980(Shmidt, , 1984)).Additionally, generic factor is considered as a factor of taxonomic diversity that does not depend on area.
Comparison of genera quotient values among divisions shows that the greatest specific richness is seen in Bacillariophyta followed by Euglenophyta, Cryptophyta and Cyanophyta (Table 1).In spite of high number of species in algal flora, Chlorophyta occupies sixth place.Apparently, it is explained by the presence of the large number of genera with little species number, e.g.84 genera represented only by one or two species out of 116 total genera in Iran's algal flora.
For the algal flora of Iran as a whole, rather high values of general genera quotient (4.9) (Table 1) testifies the richness of investigated flora.Such conclusion is proved to be true by the comparison of values of the genera quotient for some other floras.For example, genera quotient was 2.8 for system of lake Chany (Safonova, 1973), and 3.8 for water bodies of Yakutia (Vasilieva, 1989).

Comparison of algal flora of Iran with those of other countries
Table 2 shows a comparison of taxonomic spectrum of algal flora of different countries with that of Iran.The choice of the countries was arbitrary.The only generalized data brought in the literature (Muzafarov, 1965;Kogan, 1973;Tien, 1982;Chkhaidze, 1987;Wasser and Tsarenko, 2000;Tsarenko and Petlevanniy, 2001) were used in the paper.The compared countries and regions rather differ on the terrain, natural settings, remoteness from Iran, a degree of a level of algal flora knowledge and many other attributes.However, ostensibly such comparison is useful to reveal general regularity and characteristic features in the algal structures of these regions.
Absolute values of all comparable floras differ markedly and indeed depend on degree of algal study in the country.Therefore, proportion (in %) a division occupies in the total algal flora was preferred than its absolute value.
In all the compared floras as presented in Table 2, the basic role is played by two divisions, namely Chlorophyta and Bacillariophyta, occupying top two positions in taxonomic spectra.Contribution of these two divisions in the algal flora of Iran looks very close to the algal flora of Turkmenistan.This can be explained by the geographical location and presence of the general orographical and climatic attributes of the two countries.In other floras, the 1 st place is occupied by the green algae considerably leaving behind diatoms as it is evident in the flora of Ukraine range.In all the compared floras, the 3 rd place in taxonomic spectra is occupied by blue-green algae.It is evident that the diversity of Cyanophyta in some neighboring geographical regions (Turkmenistan, Central Asia) is very high compared with Iran.But contrary to it, in Iran, luxuriant growth of Cyanophyta is common in the rice fields and obviously a study on these habitats could add a few more taxa to the list of Iran.Parameters of the relative contribution on other divisions of algae when compared, the data obtained for Iran shows a concurrence with the data of other floras in most cases.