LIVERWORTS FROM THE MORAČA RIVER BASIN-TAXONOMIC AND ECOLOGICAL ANALYSIS

During the period of 1997-2007, we carried out detailed bryological research in the Morača River basin, Montenegro. Liverworts were collected at 45 locations. Thirty-five liverworts were recorded, including representatives of 24 genera and 19 families. The most frequent liverwort was Radula complanata, which was found at 17 localities. Seventeen taxa were registered at only one location in the investigated area. Scapania aequiloba is treated as endangered, and Athalamia hyalina as critically endangered, Leiocolea collaris, L. bantriensis and L. turbinata as vulnerable species. In addition, Fossombronia caespitiformis, Lophocolea bidentata var. bidentata, Riccia cavernosa, and Tritomaria quinquedentata are here registered for the first time in the bryoflora of Montenegro.


INTRODUCTION
Bryological research in Montenegro started in the middle of the 19 th century.Many foreign researchers, travel writers, and others have collected bryophytes on the coast (Boka Kotorska, Budva) and in some mountain areas (Rijeka Crnojevića, Komovi, Prokletije and Durmitor, and canyons of the Tara, Piva, and Komarnica Rivers).However, the largest part of Montenegro has still not been investigated from the bryological point of view.This statement applies especially to canyons, gorges, and high mountainous areas.
According to the check-list of liverworts and hornworts of Southeast Europe (S a b o v l j e v i ć and N a t c h e v a , 2006), most countries have more liverwort species than Montenegro .Bryological research has undergone intensification during the last ten years.D r a g i ć e v i ć and Ve l j i ć (2006) summarized bryological data for this area and mentioned 569 moss taxa, 101 of which are liverworts.E r z b e r g e r and P a p p (2007) found 28 new bryophytes in Montenegro, of which 10 species are liverworts (from the mountains Rumija and Lovćen and the environs of Kotor).Also, P a p p and E r z b e r g e r (2007) reported an additional eight liverworts for the bryoflora of Montenegro.
From what has been said above, it is evident that there is both terrain and time discontinuity in research on mosses in this area.As a result, we have insufficient knowledge about the bryoflora, its resources and taxonomic diversity, ecology, and vulnerability.Almost every new investigation yielded species new for the bryophyte flora of Montenegro.
The Morača is a mountainous-lowland river whose basin lies between high mountains in the north and Zeta Valley and the Lake Skadar basin in the south of Montenegro.Because of its areas, length (app.97 km), extremely high average fall of the river (the source is located at 1,650 m and estuary at app. 6 m above sea level), heterogeneous geological and pedological substratum, characteristic flora and fauna, and specific climate (lying between Adriatic-Mediterranean and temperate-continental zones), we expected that this would be a very attractive region from the bryological point of view.The Morača canyon is not unknown in bryological literature.To be specific, initial research was carried out by P a v l e t i ć and P u l e v i ć (1980).Since that time, we have not been able to collect a certain number of taxa recorded by the mentioned authors at different localities in the research area (some of them representing unique finding places for certain mosses).Also, M i l i k i ć et al. ( 2001) worked on several springs in the Morača basin (these data are included in the present paper).In neighboring countries (Serbia, Croatia, and Macedonia), a limited number of published data refer to watercourse areas (P a v l e t i ć , 1957,1959,1960 The main goals of this paper were to investigate taxonomic diversity, ecology, and threatened status of bryophytes from the Morača River basin, with special reference to liverworts, which are poorly known in the given region.The obtained results could be important for the near future, since the building of several new hydroelectric power stations is planned in the Morača basin, which will have a number of negative consequences for its flora and fauna.

MATERIAL AND METHODS
Bryological investigations of the Morača basin were performed in the period of 1997-2007.Liverworts were collected from 45 locations between the source of the Morača River and its estuary in Lake Skadar (Map 1).The bryophyte collection is housed in the Natural History Museum of Montenegro in Podgorica.
For identification of the collected material, the following bryological literature was used: P a v l e t i ć (1968)

Analysis of floristic elements
From phyto-geographical analysis of liverworts found in the investigated area, one can conclude that the majority of taxa are temporal floristic elements.Slightly fewer are boreal, Atlantic, and sub-Mediterranean species (Fig. 2).The two liverworts which do not belong to the mentioned types of floristic elements represented only 6.25% of the total number of taxa.

Types of distribution of liverworts
The types of distribution of liverworts from the Morača River basin are given according to D u e l l et al. (1999).In keeping with expectations, the greatest number of taxa are of the holarctic type, almost half as many are Euro-Asian-African-North American taxa, and the smallest number are cosmopolitan species (Fig. 3).

Analysis of ecological parameters
Humidity, substratum type, substratum pH, and daylight are the most important ecological factors responsible for the character, structure, and composition of bryophyte vegetation.
Humidity -Of 35 taxa registered in the researched area, 33 have been processed.Most of the recorded liverworts were mesophilous.Bryophytes which prefer water, increased humidity, marshland, or habitats near or in contact with water create a group of hygrophilous species.As expected, the fewest species are xerophilous (Fig. 4).
Substratum type -This analysis encompassed 29 taxa.Bryophytes which grow only on soil, humus, or a similar substratum are classified as terricolous taxa (10).The corticoulous group consists of four taxa.These species could only be found on tree bark.Cliffs are the only substratum type inhabited by saxicolous taxa.In the present investigation, 14 species grow on this substratum type.Only one liverwort inhabits three substratum types and that is Plagiochila asplenioides (an indifferent terri-humisaxicolous species) (Fig. 5).
Substratum pH -Thirty taxa inhabiting substrata with different pH values were analyzed.Most of them are liverworts which prefer acidic substrata (Fig. 6).Liverworts which prefer basic habitats, especially limestone, from a group with seven taxa or 23.33%.A third group -indifferent taxa -consists of 10 representatives.
Liverworts are dominant in the mesophilous group because they require humid habitats.Since limestone is slightly drier, the more frequent presence of taxa which prefer acidic substrata was expected.
Daylight -This analysis encompassed 28 taxa.The number and percentage of types are shown in Fig. 7.
The majority of liverworts were sciophilous species (26-92.86%), and only two taxa belonged to the group of indifferent species.This analysis and ones performed earlier show how one ecological factor can influence another one.Some things are therefore predictable.To be specific, since most of the recorded liverworts were mesophilous (ecological factor -humidity) and acidophilous (ecological factor -substratum pH) forms, it was to be expected that the greatest number of them belong to the sciophilous category (avoiding daylight).
Investigation of the flora of bryophytes in the Morača River basin revealed the presence of a significant number of liverworts and mosses.Of the total of 101 liverworts cited in D r a g i ć e v i ć and Ve l j i ć (2006), 35 taxa were found in this basin.Four taxa are here recorded for the first time in Montenegro.The presence of several species from the red list makes this region interesting and indicate the need for further investigations.Phytogeographic analysis showed that many species have temporal types of distribution.The study area lies between zones with Mediterranean and continental climates.Even though the investigated area belongs to the Mediterranean region, the dominance of mesophilous and skiophilous taxa emphasizes the significant humidity of canyons and gorges at the investigated localities.It can be concluded that such diversity of liverworts is predominantly caused by specific microclimatic conditions in the Morača River basin.

Map 1 .
Examined area with localities 1-45 and its position in Montenegro (insert).
, G r o c h o v s k a (1971), P e t r o v (1975), L a n d w e h r et al. (1980), and S m i t h (1990).Nomenclature is given according to R o s s et al. (2007).Data on ecological parameters were taken from S o ó (1964) and B o r o s and j á r a i -K o m l ó d i (1975), while information about floristic elements and distribution is given according to D u e l l (1983) and D u e l l et al. (1999).
The registered taxa belong to 19 families and 24 genera.The majority of families are represented by just one genus.The genera with the most species are Lophocolea and Leiocolea with three, other genera being represented by one or two taxa.The families Geocalycucaceae and Lophoziaceae have the highest number of representatives, with six and four species, respectively.Other families are represented by one or two taxa.The most frequent liverwort (Radula complanata) was collected at 17 localities.Frullania dilatata was found at 16, Pellia epiphylla at 13, and Plagiochila asplenioides at 11 places in the researched area.Sixteen species were collected at only one locality (Athalamia hyalina, Cephalozia bicuspidata, Chiloscyphus pallescens, Fossombronia caespitiformis, Leiocolea bantriensis, L. collaris, L. turbinata, Lophocolea heterophylla, L. minor, Plagiochasma

Fig. 3 .
Fig. 3. Number and percentage of main distribution types represented.

Fig. 4 .
Fig. 4. Number and percentage of taxa in relation to humidity.

Fig. 5 .
Fig. 5. Number and percentage of taxa in relation to substratum type.

Fig. 6 .
Fig. 6.Number and percentage of taxa in relation to substratum pH..

Fig. 7 .
Fig. 7. Number and percentage of taxa in relation to light.

Table 1 .
List of recorded liverwort taxa with locality number (*species new for the bryophyte flora of Montenegro).