NEW FIND OF THE RARE AND ENDANGERED SPECIES BANGIA ATROPURPUREA (ROTH) C. AGARDH (RHODOPHYTA) IN SERBIA

Data about distribution of Bangia atropurpurea (Roth) C. Agardh indicate that this species was found on relatively small number of localities in freshwaters in Europe and world. In Red List of Algae, in some countries, this species is defined as a extinct (Ex) (Poland) or as endangered (En) (Slovakia). In this study, morphological and ecological characteristics of rare and endangered species B. atropurpurea that was found on three localities in Serbia: in Trgoviški Timok River (East Serbia), Gvozdačka Reka River (West Serbia) and Raška River (South-western Serbia). The Raška River is new find of the species B. atropurpurea.


INTRODUCTION
Freshwater red algae (Rhodophyta) appear to be an endangered algal group in many countries.These algae can characterize their environments in many ways owing to their different preferences for physical, chemical, and biological variables (Eloranta and Kwadrans, 2004).Data on the distribution of Bangia atropurpurea (Roth) C. Agardh indicate that this species has been found at a relatively small number of localities in freshwaters in Europe and elsewhere (Kumano, 2002).Requiring specific ecological conditions, the species B. atropurpurea is included in red lists of algae in some countries, where it is defined as extinct (Ex) (Poland) (Sieminska, 1992) or endangered (En) (Slovakia) (�arhold and �indak, 199�).�arhold and �indak, 199�).

�ATERIAL AND �ET�ODES
The species B. atropurpurea was recorded on 9 September 2006 in the Raška River (Southwest Serbia), in the immediate vicinity of Sopoćani immediate vicinity of Sopoćani vicinity of Sopoćani �onastery (N-43° 06 ' 92� " , E 020° 22 ' 473 " ) (Fig 1).Algological samples were taken by standard methods and immediately fixed in 4% formalin.The fixed algological material is stored in the collection of the Institute of Biology in Kragujevac, Serbia.The following water parameters were measured at the sampling the sampling sites: (°C), velocity (m/s), p�, BOD 5 (mg/l) and conductivity at a temperature of 25°C (measured with a digital conductometer of the �ANA EP-3 type and expressed in µS/cm).Chemical analyses were performed by standard methods (AP�A,19�5).

RESULTS AND DISCUSSION
A new find of the species species Bangia atropurpurea was recorded in the Raška River at an altitude of 695 m in fast cold waterthat was aerated and had a temperature of 12.4°C.Electroconductivity of the water was 3�0µS /cm, while its p� value was 7.9�.The thalli µS /cm, while its p� value was 7.9�.The thalli B. 4*.

2.
3. atropurpurea were visible to the naked eye.Coverage the naked eye.Coverage was less than 5% .In the community of macroalgae at the same locality, thalli of the species Vaucheria sp. and Cladophora sp. were also recorded on the locality's limestone substrate (Table 1).

1.
In regard to its morphological traits, the thallus of the alga was close to traits of the given species described in the literature (Kumano, 2002).The plant of B. atropurpurea recorded in the Raška River was erect, filamentous, unbranched, caespitose, dark-purple tinged with brown, 2-5 cm high, and 30-63 (100) µm in diametre.Its cells were �-20 µm long and 30-50 µm in diameter in sterile plants; 10-16 µm long and 35-63 µm in diametar in mature plants; and 70-100 µm in diameter in monosporangial plants.It was fastened to the substrate by means of rhizoids growing downwards from the lower cell through the common outer wall.Filaments initially consist of a single row of cylindrical cells that are 6 µm in diameter, and � µm long when young.Later, the cells are disk-shaped, 6 µm in diameter, and 20 µm long (Table 1).
Bangia atropurpurea is a freshwater alga (Kumano, 2002) that can be found in brackish water (Eloranta and Kwandrans, 2004).It has also been found in streams and rivers, mostly as an epilithic alga.It lives on limestone substrates, travertine barriers, and large rocks, but avoids easily movable substrate (Č a d o, 195�, 1977; � a t o n i č k i n ; � a t o n i č k i n and P a v l e t i ć, 1960; S t a r m a c h, 1977; S a b a t e r et al., 19�9;Simić and R anković, 199�;Simić, 2002).In the past, thalli of this species were found mostly in places exposed to lapping of water: in the exposed to lapping of water: in the littoral part of lakes, (Č a d o, 195�, 1977;Obušković and O b u š k o v i ć , 199�), on waterfalls, and on mill-wheels (Vo u k, 1953).Thalli can also be found among threads of the species Cladophora glomerata as an epiphytic (metaphytic) alga (� a t o n i č k i n and P a v l e t i ć, 1960; P e t r o v s k a 1966; S i m i ć and R a n k o v i ć, 199�).
The species prefers water with low temperature (below 14°С) (Č a d o, 195�, 1977;Petković, 19�0;Sabater et al., 19�9; S i m i ć and R a n k o v i ć, 199�).For the most part, it is alkalophilic, dwelling in water where measured p� is up to �.  , et al., et al., al., al., ., 1999), respectively.S l a d e č e k (1973) defines this defines this species as an indicator of oligosaprobic water, while S a b a t e r et al. (19�9) classify it as euryvalent in (19�9) classify it as euryvalent in classify it as euryvalent in relation to the concentration of organic matter.Finds in rivers of Serbia confirm that this species inhabits clear oligosaprobic and oligo-beta-mesosaprobic waters (Simić, 2002).Simić, 2002Simić, ). ć, 2002)).
The stenovalence in relation to substrate, water temperature, current velocity, and water quality is quality is the reason for the small number of habitats housing this species in Serbia, other parts of Europe, and elsewhere.Owing to this, any human influences, direct or indirect, that lead to changes in physical or chemical parameters or to deterioration of water quality in the habitat and its immediate vicinity are potentially unfavorable.
3 (S a b a t e r (S a b a t e r et al., 19�9).It is characteristic of water with low characteristic of water with low conductivity: from 19� to 2�� µS/cm (S a b a t e r , 19� to 2�� µS/cm (S a b a t e r , et al. 19�9) and from 220-500 µS/cm (R o t t et al., R o t t et al.

Table 2 .
Values of morphometric, abiotic, and biotic parameters at investigated sites.