Two New Associations from the Herbaceous Riparian Vegetation in the Central Danubian Plain, Bulgaria

PHYTOLOGIA BALCANICA 23 (2): 271 – 280, Sofia, 2017 271

Two new associations from the herbaceous riparian vegetation in the Central Danubian Plain, Bulgaria

Rossen T. Tzonev

Department of Ecology and Environmental Protection, Sofia University “St. Kliment Ohridski”, Faculty of Biology, Sofia 1164, Bulgaria, e-mail: [email protected] Received: January 02, 2017 ▷ Accepted: January 13, 2017

Abstract. The paper presents results of the phytocoenological analysis of some riparian herbaceous communities in the Central Danubian Plain, Bulgaria, in the vicinities of Pleven town. One of the associations is new to Bulgaria, while the other one is described for the first time. It also presents a not investigated yet vegetation type according to the Braun-Blanquet’s methodology: the tall-herb riverside vegetation of the lowlands.

Key words: aquatic communities, syntaxa, tall herbs.

Introduction ervoirs, with their qualitative indicators: turbidity, flow, mineralization, etc. The Central Danubian Plain lies between the Yantra The pronounced continental climate in the re- and Vit rivers on the east and west, and between the gion determines the overall relatively low runoff of Danube River and the Forebalkan in the north and the area. Due to the high runoff of the Maastricht south. The average altitude of the terrain is 138 m. The limestone in the Pleven syncline and the alluvial de- relief is formed by a thick loess cover (50 m) in the posits of river Vit, the Pleven Heighs have great- northern part and calcareous plateaus in the southern er humidity: 40–50 mm per year. Near the town of parts. According to Velev (1990), the climate is tem- Pleven and the Tuchenitsa and Gortalovo villages perate-continental, with western and northwestern there are also large unconfined karst springs (Mi- winds and average precipitation between 500 mm and hayilov & al. 1989, Zyapkov & Yordanova 2002), but 600 mm per year. According to Ninov (2002), cher- they have a little impact on the riparian vegetation. nozems and phaeozems are the widest spread soils in Much more important are the shallow groundwaters this part of the country, while luvisols occur seldom which are most frequent in the flooded riverside ter- in the southern parts. The centre of this geographical races. Their stocks are very large: on the terrace of region is occupied by the Pleven Heights. They have river Vit near Sadovets village, the mouth amounted a calcareous base with loess cover. Several rivers cut to 38 million m³. Groundwaters are very important them up, the largest of which is river Vit, with its main for maintenance of the river flows. During the peri- tributaries Chernelka and Tuchenitsa. Their canyon- ods of high water, they take in some of the surplus like valleys have rich biodiversity and some protect- moisture in the terrace, but during low flow the riv- ed areas like Kayluka Protected Area and Chernelka er drains them down into itself. The construction of and Studenets Natural Highlights also fall in there. dykes, rectification and corrections of river streams The water resources of the region are directly related in the 1950–1960 s had affected this vital connection. with the here studied vegetation type. These are sur- The increasingly eroded fundament (from rectifica- face running waters, groundwaters and standing res- tion of meanders) has led to a chiselled river level 272 Tzonev, R. • New associations from the herbaceous riparian vegetation and deep drainage of the groundwater from the riv- 1962; Kochev & Yordanov 1981; Kochev & al. 1986; erside terrace, especially to river Vit. Water quanti- Kochev & Tsolova, 1984, 1987; Bondev 1991, etc). The ty has decreased mostly due to the transit river flow. main study of the vegetation of this area according the On the other hand, this has inflicted rapid destruc- newly applied in Bulgaria Braun-Blanquet’s methodol- tive changes of the soils and vegetation cover in the ogy is subject of the PhD thesis of Tzonev (2002), with affected areas (Mihov & Hristov, 2010). subsequent contributions again by Tzonev (2009a, b, River Vit (3225 km2) is the main river artery of 2013). Some of the above-mentioned papers were fo- the area. Basically, a rain-snow regime forms its flow, cused especially on the aquatic communities (Kochev but the karst sustentation also has its say. During & Yordanov 1981; Kochev & Tsolova 1987; Kochev & high-water periods, the waters account for about 60– al. 1986; Tzonev 2009a). However, herbaceous ripari- 65 % of the annual water amounts. The influence of an vegetation in the lowlands has not been investigat- the karst feeding shifts this maximum to April and ed not only in this region but also across the country May. During the low waters in late summer-autumn, (see Tzonev & al. 2009). the water masses shrink to 10–12 %. In summer, the effect of precipitation is offset by the enhanced Material and methods evaporation. The minimum flow is in October. The smaller tributaries like Tuchenitsa and Chernelka are shallow, with a short spring freshet and a long sum- The investigation of the vegetation was carried out in mer-autumn low-water flow. In the rivers crossing 2016, according to the methods of the sigmatic school the Pleven syncline, the karst feeding plays a signifi- (Braun-Blanquet 1964, van der Maarel 2005). Dur- cant role in the forming of their flow. The numerous ing statistical processing, an expanded scale of Braun- small dry valleys and steep slopes occasionally cause Blanquet for abundance/dominance (Braun-Blan- torrential floods (Mihaylov & al. 1989). The average quet 1932) was used, transformed according to van annual flow of river Vit during 1948/49 – 1967/68 der Maarel (1979). Cluster analysis of the relevés was was 14.0 m³/s. Water temperature in the summer made with SYNTAXA software (Podani 2001). The months (July and August) varies between 13–23 °C. average linkage method (UPGMA) was applied and Some ice (ice-forming takes on the average 36 days) floristic similarity among relevés was evaluated ac- is occasionally observed in the second half of Janu- cording to Horn’s Index (Krebs 1999). Taxonomic no- ary, but practically the rivers do not freeze out be- menclature followed Kozhuharov (1992) and Deli- cause of their small depth and fast streams. The aver- pavlov & Cheshmedzhiev (2003). New syntaxa were age turbidity of 400 g/m³ of river Vit near the village published and validated according to the rules of the of Sadovets is relatively high due to the drought, ero- International Code of Phytosociological Nomencla- sion, deflation and particularly to the unstable structure (Weber & al. 2000) and according to the cited ref- ture of the soils and loess. However, the smaller and erences (Horvat & al. 1974; Doniţá & al. 1992; Kojić shallower tributaries like Chernelka, Kamenitsa and & al. 1998; Sanda & al. 1999; Rodwell & al. 2002). The Tuchenitsa are relatively limpid especially in sum- work of Mucina & al. (2016) was leading in determi- mer. Mineralization of the water of all rivers in the nation of the synoptic scheme. In regard to the inves- region is relatively low. According to the prevailing tigated communities, most topical information from dissolved ions in the water, the area belongs mainly the neighbouring countries (Slovakia, Hungary, Czech to the hydrogen-carbonate-calcium-sulfate hydrofa- Republic, and Romania) was found in the works of cies and less to the hydrogen-carbonate-calcium-so- Valachovic 2001; Jarolimek & al. (1997); Jarolimek & dium hydrofacies (Yordanova & al. 2002; Mihaylov Šibik. (2008); Chytry (2009, 2011); Borhidi (2003), & al. 1989). Coldea (1997, 2012), etc. The vegetation of the Central Danubian Plain is rich: steppes, broadleaved forests, wetlands, etc. How- Results ever, data on the vegetation of this region are scattered and have been collected mostly according to the for- merly dominant method of the Russian Phytocoeno- The following syntaxonomic scheme is presented in logical School (Stoyanov 1948; Ganchev & Kochev the paper as a result from the analysis (Fig. 1): Phytol. Balcan. 23(2) • Sofia • 2017 273

Class Phragmito-Magnocaricetea Klika in Klika & Novak 1941 Order Nasturtio-Glyceiretalia Pignatti 1953 Alliance Glycerio-Sparganion Br.-Bl. et Sissingh in Boer 1942 Association Leersietum oryzoidis Eggler 1933

Class Epilobietea angustifolii Tx. et Preising ex von Rochow 1951 Order Convolvuletalia sepium Tx. ex Moor 1958 Alliance Archangelicion litoralis Scamoni et Fig. 1. Numerical analysis of the releves with the SYNTAXA program. Passarge 1963 Association Brachypodio sylvatici-Angelicetum sylvestris ass. nova. Association Leersietum oryzoidis Eggler 1933 Leersia oryzoidis is (L.) Sw. is a widespread species nelka and Tuchenitza (Pleven region). The species in Bulgaria, mostly along the rivers and in rice fields is strongly dominant and occupies the wetlands pe- in the lowlands (Kozhuharov 1992; Delipavlov & ripheries at a water depth up to 1 m. It forms small Cheshmedzhiev 2003). The species forms monodom- monodominant communities (Fig. 2), from several inant communities, occasionally floating in the shal- to several scores of square meters in size. The accom- low water bodies. Only one community was described panying species are mostly from the class Phragmito- from the wetlands along the Danube River according Magnocaricetea, such as Lythrum salicaria, Lycopus to the dominant methodology by Kochev & Yordanov europaeus, Typha angustifolia, Schoenoplectus lacus- (1981) . No relevés from Bulgaria have been published tris, as well as some other aquatic species (including according to the Braun-Blanquet’s school. However, it neophytes) like Bidens frondosa, Persicaria mitis, etc. was assumed that the association Leersietum oryzoidis Some nitrophilous species – Rumex obtusifolius, Ur- was distributed in Bulgaria on the basis of unpublished tica dioica, Rubus caesius, etc. – could also participate data by Šumberova & Tzonev (Šumberova & al. 2011). in the floristic structure. Due to the ecology of Leersia Šumberova & al. (2011) pointed out that this associa- oryzoides, distribution of the species in Bulgaria pre- tion is widespread in most countries from the temper- sumably matches the distribution of the association ate parts of Europe (Serbia, Ukraine, Czech Republic, Leersietum oryzoidis. This means that this syntaxon Austria, Hungary, Germany, France, Romania, etc.). is widespread in many river valleys in North Bulgar- The communities of this association (Table 1) are ia (Iskar, Ogosta, Osam, Yantra, etc.), but also south- established in shallow standing or slowly running wa- wards from the Stara Planina Mts – Maritsa, Tundzha, ters in the valleys of river Vit and its tributaries Cher- Struma, etc. The communities could be also found in various types of standing water, namely small dams, flooded areas, etc.

Association Brachypodio sylvatici-Angelicetum sylvestris ass. nova hoc loco, holotypus relevé №13, Table 1 This association (Table1) presents a vegetation type which has never been investigated before in Bulgaria – riverine tall-herb vegetation in the plains and lowlands (see Tzonev & al. 2009). It could be compared with the high-mountain tall herbs which were described al- ready in the first study, according to the Braun-Blan- Fig. 2. Association Leersietum oryzoidis in the Kaylaka Protected quet’s school in Bulgaria (Horvat & al. 1937) and sub- Area (photo Rossen Tzonev). sequently continued by Roussakova (2000). 274 Tzonev, R. • New associations from the herbaceous riparian vegetation s 0 0 0 0 0 0 0 0 0 0 0 0 o n t. C 13 25 63 13 13 13 25 13 13 (%) 9 1 + 95 16 River Yasen, Vit Vit Yasen, E24.52793 N43.41659 9/12/2016 6 1 85 15 River E24.52336 N43.41001 9/12/2016 Disevica, Vit Vit Disevica, 1 1 + + 10 95 18 River E24.48747 N43.37647 9/15/2016 Turnene, Vit Vit Turnene, 4 1 1 1 1 6 90 Area Kayluka Kayluka Protected Protected E24.63049 N43.38132 8/26/2016 9 1 2 90 2b Area Kayluka Kayluka Protected Protected E24.63683 N43.35699 8/26/2016 1 1 4 24 95 2a 2b Area Kayluka Kayluka Protected Protected E24.62172 N43.37800 8/26/2016 Tx. et Preising ex von Rochow 1951 Rochow von ex Tx. et Preising 1 3 + + 15 90 Area Kayluka Kayluka Protected Protected E24.62143 N43.37715 8/26/2016 1 1 + 20 80 2a Area Kayluka Kayluka Protected Protected E24.63787 N43.73683 8/26/2016 o s 0 C n t. 80 50 90 40 70 50 50 30 20 10 20 10 20 10 10 10 10 10 10 (%) 100 8 0 1 1 9 3 80 2a Epilobietea angustifolii Natural Chernelka 9/5/2016 E24.54911 N43.33396 Monument 0 1 8 3 + + 10 90 2a Natural Chernelka 9/5/2016 E24.54836 N43.33307 Monument 0 1 4 + 12 90 2a 2a 2a 10 Natural Chernelka 9/5/2016 E24.54870 N43.33813 Monument 0 3 1 1 7 3 + 20 70 2a Natural Chernelka 9/5/2016 E24.54776 N43.32730 Monument 8 1 4 + + 75 2a 2b 17 River River E24.47347 N43.36959 9/15/2016 Turnene, Vit Vit Turnene, Scamoni et Passarge 1963 and class class 1963 and Scamoni et Passarge ass. nov. nova holotypus nom. rel. 13 hoc loco rel. nom. holotypus nova nov. ass. 0 1 1 3 + + + 20 90 2b 2b 13 Natural Chernelka 9/5/2016 E24.53895 N43.34140 Monument 0 1 1 1 4 + + + 10 95 2a 12 Natural Chernelka 9/5/2016 E24.54829 N43.34194 Monument 0 1 1 1 1 4 + + + 20 70 2b 2b 11 Natural Chernelka 9/5/2016 E24.54936 N43.33971 Monument Archangelicion litoralis litoralis Archangelicion 0 1 1 3 + + + 15 90 2a 2a 2a 2b 14 Natural Chernelka 9/5/2016 E24.53251 N43.35286 Monument (M. Bieb.) Nyman Bieb.) (M. 0 1 1 5 + + + + 10 70 2a 2b 2b Area Kayluka Kayluka Protected Protected E24.62440 N43.38086 8/26/2016

L. L. uliginosus L. L. aquaticus (L.) L. L. L. ssp. L. ssp.

L. L. Huds. (L.) R. Br. (L.) R. L. L. L. Brachypodio sylvatici-Angelicetum sylvestris sylvatici-Angelicetum Brachypodio (Houtt.) DC (Houtt.) Sm. var. L. Diagnostic table of the syntaxa. Diagnostic of table Table 1. Table releve of Number Locality Latitude Longitude (sq. m) plot Sample (m) depth Water cover Vegetation Data Association sylvestris Angelica sylvestris Brachypodium sylvaticum Beauv. P. (Huds.) Bromus ramosus the allinace species Diagnostic for Rubus caesius Urtica dioica Eupatorium cannabinum hederacea Glechoma aquaticumMyosoton Moench Scrophularia umbrosa Dumort. Epilobium hirsutum arvensis Sonchus lupulusHumulus Calystegia sepium Heracleum sibiricum Cucubalus baccifer Chaerophyllum bulbosum Geranium robertianum Geum urbanum Symphytum officinale japonica Torilis nigrumVerbascum Phytol. Balcan. 23(2) • Sofia • 2017 275 s 0 0 0 0 0 0 0 0 0 o n t. C 38 63 13 13 13 13 75 38 25 13 25 25 100 (%) 9 1 1 1 4 + + 95 2a 2a 16 River Yasen, Vit Vit Yasen, E24.52793 N43.41659 9/12/2016 6 1 1 1 1 4 + + 85 2a 2b 2b 15 River E24.52336 N43.41001 9/12/2016 Disevica, Vit Vit Disevica, 1 4 + + + + 10 95 18 River E24.48747 N43.37647 9/15/2016 Turnene, Vit Vit Turnene, 4 1 1 6 5 + 90 2a Area Kayluka Kayluka Protected Protected E24.63049 N43.38132 8/26/2016 9 1 1 1 2 4 + 90 2a Area Kayluka Kayluka Protected Protected E24.63683 N43.35699 8/26/2016 Klika in Klika 1941 et Novak 1 4 4 24 95 Area Kayluka Kayluka Protected Protected E24.62172 N43.37800 8/26/2016 1 3 5 + + 15 90 Area Kayluka Kayluka Protected Protected E24.62143 N43.37715 8/26/2016 1 1 1 4 + 20 80 2a 2a Area Kayluka Kayluka Protected Protected E24.63787 N43.73683 8/26/2016 o s 0 0 C n t. 80 60 10 10 30 40 50 40 30 40 20 10 60 50 20 40 20 30 10 30 (%) Phragmito-Magnocaricetea 8 0 1 1 9 80 Natural Chernelka 9/5/2016 E24.54911 N43.33396 Monument 0 1 1 1 1 1 1 1 8 + + 10 90 Natural Chernelka 9/5/2016 E24.54836 N43.33307 Monument 0 1 1 1 + + + 12 90 2a 2b 10 Natural Chernelka 9/5/2016 E24.54870 N43.33813 Monument 0 1 1 1 1 7 + + + 20 70 2a 2a Natural Chernelka 9/5/2016 E24.54776 N43.32730 Monument 8 1 1 1 + + + 75 2b 17 River River E24.47347 N43.36959 9/15/2016 Turnene, Vit Vit Turnene, 0 1 3 + + + + + + Br.-Bl. et Sissingh in Boer et class Sissingh 1942 and Br.-Bl. 20 90 2a 13 Natural Chernelka 9/5/2016 E24.53895 N43.34140 Monument 0 1 + + + + + 10 95 2b 2b 12 Natural Chernelka 9/5/2016 E24.54829 N43.34194 0 Monument 0 1 + + 20 70 2b 11 Natural Chernelka 9/5/2016 E24.54936 N43.33971 Monument Glycerio-Sparganion Glycerio-Sparganion Eggler 1933 0 1 + + + 15 90 2a 2b 2b 14 Natural Chernelka 9/5/2016 E24.53251 N43.35286 Monument (DC.) Arcang. (DC.) Arcang. 0 1 1 1 5 + + + 10 70 2a Area Kayluka Kayluka Protected Protected E24.62440 N43.38086 8/26/2016 Desf. (L.) Palla (L.) Sw. intermedia L. Murr. L. L. L. L. L. (L.) Pers. L. (L.) Huds. (L.) Huds. L. L. L. L. Leersietum oryzoidis L. ssp. (Schrank) Opiz. Curtis (Huds.) Coville (Huds.) L. Continuation. Table 1. Table releve of Number Locality Latitude Longitude (sq. m) plot Sample (m) depth Water cover Vegetation Data longifoliaMentha Association oryzoidesLeersia the alliance speciesDiagnostic for salicariaLythrum europaeus Lycopus Solanum dulcamara Berula erecta pseudocyperusCarex aquatica Mentha Sparganium erectum Iris pseudacorus angustifoliaTypha Carex riparia lacustris Schoenoplectus Other species frondosa Bidens repens Ranunculus mitis Periscaria Carex hirta vitalba Clematis Plantago major dactylon Cynodon Equisetum ramosissimum Rumex conglomeratus 276 Tzonev, R. • New associations from the herbaceous riparian vegetation s 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o n t. C 13 13 13 13 13 13 13 (%) 9 1 95 16 River Yasen, Vit Vit Yasen, E24.52793 N43.41659 9/12/2016 6 1 1 + 85 15 River E24.52336 N43.41001 9/12/2016 Disevica, Vit Vit Disevica, 1 1 10 95 2a 18 River E24.48747 N43.37647 9/15/2016 Turnene, Vit Vit Turnene, 4 1 1 1 6 90 Area Kayluka Kayluka Protected Protected E24.63049 N43.38132 8/26/2016 9 1 2 90 Area Kayluka Kayluka Protected Protected E24.63683 N43.35699 8/26/2016 1 4 + 24 95 Area Kayluka Kayluka Protected Protected E24.62172 N43.37800 8/26/2016 1 3 15 90 Area Kayluka Kayluka Protected Protected E24.62143 N43.37715 8/26/2016 1 1 20 80 Area Kayluka Kayluka Protected Protected E24.63787 N43.73683 8/26/2016 o s 0 0 0 0 C n t. 20 10 20 20 20 20 20 20 20 40 20 20 20 10 10 10 10 10 10 10 10 (%) 8 0 1 1 9 + 80 Natural Chernelka 9/5/2016 E24.54911 N43.33396 Monument 0 8 10 90 Natural Chernelka 9/5/2016 E24.54836 N43.33307 Monument 0 1 1 + + + + 12 90 10 Natural Chernelka 9/5/2016 E24.54870 N43.33813 Monument 0 1 7 + + + 20 70 2a Natural Chernelka 9/5/2016 E24.54776 N43.32730 Monument 8 1 + + + + 75 2a 17 River River E24.47347 N43.36959 9/15/2016 Turnene, Vit Vit Turnene, 0 1 + 20 90 13 Natural Chernelka 9/5/2016 E24.53895 N43.34140 Monument 0 + + + + + + 10 95 12 Natural Chernelka 9/5/2016 E24.54829 N43.34194 Monument 0 + + 20 70 11 Natural Chernelka 9/5/2016 E24.54936 N43.33971 Monument 0 + + + 15 90 14 Natural Chernelka 9/5/2016 E24.53251 N43.35286 Monument 0 1 5 + + 10 70 Area Kayluka Kayluka Protected Protected E24.62440 N43.38086 8/26/2016 (L.) Planch. (L.) Planch. L. (L.) P. Beauv. (L.) P. L. L. (L.) Mill. (L.) Mill. L. L. L. L. M. Bieb. ex Willd. ex Bieb. M. L. L. Erhr. Erhr. L. L. (L.) L. (L.) L. L. Mill. Mill. L. L. L. L. L. Continuation. L. Table 1. Table releve of Number Locality Latitude Longitude (sq. m) plot Sample (m) depth Water cover Vegetation Data strumariumXanthium negundoAcer Agrostis stolonifera officinalis Althaea laciniatus Dipsacus Erigeron acer latifoliusEvonymus helix Hedera inflexus Juncus Prunella vulgaris cerasifera Prunus Rumex obtusifolius Salix alba Amorpha fruticosa Artemisia absinthium vulgaris Artemisia cernuaBidens tripartita Bidens Cichorium inthybus mas Cornus crus-galli Echinochloa Elymus caninus oxycarpa Fraxinus Galium album Parthenocissus quinquefolia Phytol. Balcan. 23(2) • Sofia • 2017 277 s 0 0 0 0 0 0 0 0 o n t. C 13 (%) The habitat of the lowland type tall herbs is described for Bulgaria in the Red Data Book of Bul- 9 1 95 16 River Yasen, Vit Vit Yasen, E24.52793 N43.41659

9/12/2016 garia, vol. 3 (Valchev & al. 2015). The species composition of the prevailing communities and some 6 1 85 15 River suggestions about the existing, but still not de- E24.52336 N43.41001 9/12/2016 Disevica, Vit Vit Disevica, scribed higher syntaxa were made in that work. The 1 10 95 2b 18 order Convolvuletalia sepium was also mentioned in River E24.48747 N43.37647 9/15/2016 Turnene, Vit Vit Turnene, it. This order has being referred earlier to the class

4 1 Galio-Urticetea (see Chytry 2009, Coldea 2012), but 6 90 Area Kayluka Kayluka Protected Protected E24.63049 N43.38132 8/26/2016 in the latest revision of Mucina & al. (2016) it was referred to Epilobietea angustifolii. The latter was de- 9 1 2 90 Area Kayluka Kayluka

Protected Protected scribed for Bulgaria for the first time by Dimitrov E24.63683 N43.35699 8/26/2016 (2004) and the new association included in it was al- 1 4 24 95

Area so described. Kayluka Kayluka Protected Protected E24.62172 N43.37800 8/26/2016 The new association identified here (Fig. 3) is 1 3

15 90 referred to the alliance Angelicion litoralis Scamo- Area Kayluka Kayluka Protected Protected E24.62143 N43.37715 8/26/2016 ni et Passarge 1963. This alliance has not been reported so far for the Balkan vegetation. Lanikova & 1 1 20 80 Area Kayluka Kayluka Protected Protected E24.63787 N43.73683 al. (2009) accepted it as part of Senecionion fluvila- 8/26/2016 o s 0 C n t. tilis (with the synonym names Calystegion sepium 10 10 10 10 20 10 10 10 (%) and Epilobion hirsuti), which is well known from 8 0 9 + + + 80 the neighbouring countries to Bulgaria, such as Natural Chernelka 9/5/2016 E24.54911 N43.33396 Monument Romania (Coldea 2012). According to Lanikova & 0 8

10 90 al. (2009), the alliance includes natural vegetation Natural Chernelka 9/5/2016 E24.54836 N43.33307 Monument types of annual and perennial nutrient- and moisture-demanding herbaceous plants. The stands 0 + 12 90 10 Natural Chernelka 9/5/2016 E24.54870 N43.33813 Monument are dense, involving several herbaceous lianas and herbs producing a large amount of biomass. The 0 7 20 70 Natural Chernelka 9/5/2016

E24.54776 natural communities grow mostly on the fringes N43.32730 Monument and clearings of the floodplain forests of the inves- 8 1 75 17 River River tigated vegetation in this study. In the latest Euro- E24.47347 N43.36959 9/15/2016 Turnene, Vit Vit Turnene, pean revision of Mucina & al. (2016) though, Arch- 0 + 20 90 2a 2b 13 angelicion litoralis is described as “tall-herb fringe Natural Chernelka 9/5/2016 E24.53895 N43.34140 Monument vegetation on river banks of Central and Eastern

0 Europe”. According to Dengler & al. (2004), the 10 95 12 Natural Chernelka 9/5/2016 E24.54829 N43.34194 Monument differences between both alliances are as follows: Senecinion fluviatilis is more typical for large riv- 0 + 20 70 11 Natural Chernelka 9/5/2016 E24.54936 N43.33971 Monument ers, with great fluctuations in the water level, while Archangelicion litoralis is more typical of smaller 0 + 15 90 14

Natural rivers with less significant changes in the water lev- Chernelka 9/5/2016 E24.53251 N43.35286 Monument el across the year. This corresponds to the ecology 0 5 10 70

Area of communities from the study in this paper. Kayluka Kayluka Protected Protected E24.62440 N43.38086 8/26/2016 As the alliance Archangelicion litoralis has not (L.) Dum. (L.) Dum. L. L. (Michx) Schribner (Michx) (L.) Gray. been so far recognized for the Balkans, only the as- L. (L.) P. Beauv. Beauv. (L.) P.

L. sociations from Senecionion fluviatilis were com- L. pared here with the described communities. These Continuation. associations described from Romania (Cold- ea 2012), Hungary (Borhidi 2003), Czech Repub-

Table 1. Table releve of Number Locality Latitude Longitude (sq. m) plot Sample (m) depth Water cover Vegetation Data Paspalum paspaloides lapathifolia Persicaria Peucedanum alsaticum Prunus spinosa Robinia pseudacacia Scirpus sylvaticus Setaria verticillata maximum Tordyliium Conocephalum conicum lic (Lanikova & al. 2009), and Slovakia (Jarolimek 278 Tzonev, R. • New associations from the herbaceous riparian vegetation

Calystegia sepium could also be found in the floristic structure of these communities. Grasses like Bromus ramosus and Brachypodium sylvaticum (the name-giv- ing taxon of the association) indicate the relationships and genesis of these communities – with the alluvial forest galleries dominated by Salix alba, S. fragilis, Populus alba, etc. Tall-herb communities grow natu- rally on the forest fringes of such forests, but could also exist independently from the forest succession in suitable for them places. The floristic structure in- dicates high presence of nitrophilous species, most- Fig. 3. Association Brachypodio sylvatici-Angelicetum sylvestris in ly because of the primary eutrophic and nitrophilous the Chernelka Natural Highlight (photo Rossen Tzonev). conditions in the deep river valleys. Species like Urti- ca dioica, Rubus caesius, etc. are well presented in this & Sibik 2008) are dominant or differentiated in a more vegetation and are indicators of nitrogen soil pollu- common species complex along the Danube River or tion. The naturalness of the newly described associa- at the foothills and low-mountain regions in Bulgar- tion is comparatively high, because only one invasive ia, namely Impatiens glanduligera, I. noli-tangere, Peta- (neophyte) species, Bidens frondosa, has registered a sites hybridus, P. kablikianus, Lunaria rediviva, Carex high presence (60 %) in the communities. pendula, Echinocystis lobata, Sicyos angulatus, Glycyr- Geographical distribution of the new association rhiza echinata, etc. Similar associations are Calystegio presumably is not restricted only to the middle stream sepium-Epilobietum hirsuti Hilbig & al. 1972 or Cusc- of river Vit and its tributaries Chernelka and Tuchenit- uto europaeae-Calystegtieum sepium Tuxen ex Lohmey- sa. Very similar species compositions were also observed er 1953. However, they have a more different floristic by the author in the basin of river Iskar and its tributar- and physiognomic structure. The first one has a poor- ies Panega and Ruchene rivers and many others. In sum- er species composition; the second is with more herba- mary, the newly described association has wider dis- ceous lianas. Both lack the typical tall herbs like Angel- tribution, especially along the rivers in the Forebalkan ica sylvestris. The shadow-tolerant grasses like Bromus region and the southern calcareous part of the Danubi- ramosus were also absent from the so far known syn- an Plain. It includes the middle streams of Danube’s trib- taxa from other geographical regions not very far from utaries Ogosta, Vit, Osam, Iskar, Yantra, Rusenski Lom, North Bulgaria. This was the reason for describing the and their smaller tributaries Chernelka, Tuchenitsa, Ka- new association and also the first report of the alliance menitsa, Rositsa, Burzia and many others. Archangelicion litoralis for the Balkans. The new association is distributed along the rivers Discussion in the transitional zone between the Danubian Plain and the Forebalkan. It occurs mostly on calcareous Two associations – one new to Bulgaria and one new to ground and its main peculiarities are described in the science – are presented in the paper. The alliance Arch- Introduction. More typical is the late-summer (Au- angelicion litoralis is also reported for the first time for gust-September) maximum development of tall-herb Bulgaria and probably for the Balkan Peninsula too. It vegetation because of the lowest water level and de- extends its distribution reported by Mucina & al. (2016) nuding gravel bars, or soils with high moisture. for Central and East Europe to the southeastern part of The community appearance is formed by the tall the continent. If researches of tall-herb communities in herbs, mostly Angelica sylvestris, but also Eupatori- Bulgaria will continue along the Danube and the rivers um cannabinum, Lythrum salicaria, Epilobium hirsu- in the southern lowland part of the country, such as Mar- tum, and Bidens frondosa. There is also a sublayer of itsa, Tundzha, Arda, etc., they will significantly enhance short and creeping herbs like Glechoma hederacea, Ra- the number of the newly described for the country and nunculus repens, Mysoton aquaticum, etc. Lianas are probably for Europe syntaxa from tall-herb vegetation. not so numerous but, species like Rubus caesius, Cucu- Existence of several associations of Senecionion fluviatil- balus baccifer, Clematis vitalba, Humulus lupulus, and is could certainly be expected, such as Cuscuto europae- Phytol. Balcan. 23(2) • Sofia • 2017 279

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