PHYTOLOGIA BALCANICA 15 (2): 235 – 244, Sofia, 2009 235 Poo bulbosae-Achilleetum pseudopectinatae: a new plant association Desislava Sopotlieva Department of Phytocoenology and Ecology, Institute of Botany, Bulgarian Academy of Sciences, Acad. Georgi Bonchev St., bl. 23, 1113 Sofia, Bulgaria, e-mail: [email protected] Received: May 14, 2009 ▷ Accepted: July 17, 2009 Abstract. A new grassland association defined by the presence of the Balkan endemic Achillea pseudopectinata is described from South Bulgaria. The association is characterized ecologically and floristically. The analysis of floristic elements shows that the Submediterranean species are the most numerous. The analysis of life forms demonstrates that therophytes and hemicryptophytes prevail in these communities. The association is of a zooanthropogenic origin and belongs to the Trifolion cherleri alliance. The Festuco-Brometea species are also strongly present. Key words: Balkan endemic, dry grasslands, Trifolion cherleri Introduction dry grassland communities harbouring the Balkan en- demic Achillea pseudopectinata accompanied by Poa Dry grasslands are of interest to European research- bulbosa and Thymus striatus have been found. On the ers owing to their great species richness and high Besapar Hills, Achillea pseudopectinata falls into the as- conservation value because of the presence of rare sociations described by the dominance approach: Psilu- and endemic species. They are suitable as model rus aristatus + Brachypodium distachyon (Stanev 1977), systems for biodiversity analyses. Along with this, Andropogon ischaemum-Brachypodium distachyon they are considerably influenced across Europe by and Andropogon ischaemum-Thymus striatus (Stanev a number of factors, namely destruction, afforesta- 1980). In all three associations, similarly to the descrip- tion, abandonment of traditional uses, and invasion tion from the Straldzha-Aytos region, Achillea pseudo- of neophytes (cf. European Dry Grasslands Group – pectinata occurs jointly with Poa bulbosa and Thymus http://edgg.org/). Rather detailed information on dry striatus. This vegetation is described as a new associa- grasslands in the Western Mediterranean and North tion Poo bulbosae-Achilleetum pseudopectinatae. and Central Europe is available, whereas information about Southeast Europe is scarce. In Bulgaria, dry Materials and methods grasslands referred to various syntaxa have been stud- ied phytocoenologically by Tzonev (2002), Meshinev & al. (2005), Apostolova & Meshinev (2006), Tzonev The study region is situated, between 42–43° N and & al. (2006), Sopotlieva & Apostolova (2007) and Pe- 26–27°E, in Southeast Bulgaria. It is assigned to the dashenko & al. (2009). Straldzha-Aytos phytogeographic region (Bondev During the studies of grasslands diversity in the 2002). The region is characterized by mild climate Straldzha-Aytos geobotanical region (Sopotlieva 2008) with mean annual temperatures of 12.2 °C for Aytos 236 Sopotlieva, D. • Poo bulbosae-Achilleetum pseudopectinatae assoc. and Yambol, 12.4 °C for Sliven; mean annual precipi- ing countries (e.g. Sanda & al. 1997, 1999). Phytosoci- tation of 490.6 mm for Aytos, 567 mm for Sliven, and ological nomenclature is according to the Internation- 535.9 mm for Yambol (unpublished data provided by al Code of Phytosociological Nomenclature (Weber & Bulgarian National Institute of Meteorology and Hy- al. 2000). drology, Bulgarian Academy of Sciences). A soil sample was collected for chemical anal- A total of 349 relevés have been collected in the ysis in the plot of relevé No 6, in order to study the Straldzha-Aytos geobotanical region, following the chemical characteristics of the soil. The sample was Braun-Blanquet approach (Braun-Blanquet 1965; air-dried. Pre-treatment of the sample for the chemi- Westhoff & van der Maarel 1980). The plots were set cal analysis has followed ISO 11464:1994 (E). Electri- in places of visually assessed homogeneity of the top- cal conductivity (EC) and pH were measured in water ographic conditions and plant cover, each with an ar- solution with 1:5 soil/water ratio and pH-meter Jen- 2 ea of 16 m (Chytrý & Otýpková 2003). The abun- way3310 (ISO 10390:1994 (E)). CaCO3 concentration dance and cover of each species have been assessed was measured in 1:10 water solution with Photometer according to the nine-point combined scale of Braun- PC 22, the results are presented in mg/l. Humus was Blanquet, with subdivisions 2m, 2a and 2b proposed determined according to the modified Turin method by Barkman & al. (1964) (Westhoff & van der Maar- (Kononova 1966). All analyses were performed at the el 1980). The total cover of vegetation was recorded in Analytical Laboratory, Department of Phytocoenolo- percentage. gy and Ecology, Institute of Botany, Bulgarian Acade- The relevés were analysed by numerical methods my of Sciences. (TWINSPAN, Cluster Analysis), and seven of them formed a separate group that could be interpreted Results and discussion on the association level. An additional relevé was re- corded in the summer of 2008 in Mt Mala Aytoska. Five other relevés from the Besapar Hills (Stanev An outline of the association 1977, 1980) were also used, selected by the presence The association Poo bulbosae-Achilleetum pseudopec- of Achillea pseudopectinata in the plots. Quantitative tinatae is described on the basis of 13 relevés (Table 1). estimates of the species cover of these five relevés Relevé 8 is designated here as a nomenclatural type have been adapted to the new Braun-Blanquet scale (Holotype). based on Meshinev & Apostolova (2002). Communities of this association have been identi- The taxonomy and nomenclature of the spe- fied in South Bulgaria (Fig. 1) and can be referred to cies follows Kozhuharov (1992) for vascular plants the thermophilous vegetation. Their horizontal struc- and Natcheva & Ganeva (2005) for mosses. Contra- ture is of semi-open to closed type, with total cover ry to the common use of Achillea depressa in Kozhu- between 50 % and 90 % (Fig. 2). Achillea pseudopecti- harov (1992) and different literature sources, in this nata or Dichanthium ischaemum are the main domi- paper the name Achillea pseudopectinata is accepted nant species (with scores 3–4), and occasionally Psil- by reason of priority (Saukel & al. 2003). The floristic urus incurvus and Scleranthus perennis also have high elements are given according to Assyov & al. (2002) abundance. The average number of species per relevé for vascular plants and according to Ganeva & Düll is 34, and the general species diversity of the associa- (1999) for mosses. The life forms have been assessed tion is 143 plant species. on the basis of data about the biological type of the Therophytes (Th) (67 species, 46.9 %) and hemi- species, according to Kozhuharov (1992). The diag- cryptophytes (H)(63 species, 44 %) claim approxi- nostic values of species were evaluated according Mu- mately equal shares. Chamaephytes (Ch) and cryp- cina (1997) and different available literature sources tophytes (K) are lesser in number, represented by from the West Mediterranean (Rivas-Martínez & al. seven species (4.9 %) and six species (4.2 %), re- 2001; Rivas-Martínez & al. 2002; Pérez Prieto & Font spectively. 2005), Central Europe (e.g. Korneck 1993; Valachovič Geographical distribution of the studied vegeta- 1995; Chytrý & Tichý 2003; Chytrý 2007; Jarolímek tion determines the presence of a great number of & Šibík 2008), the Balkans (e.g. Micevski 1970, 1977, Submediterranean species (30 species, 21 %). Gen- 1978; Micevski & Matevski 1984) and the neighbour- erally, a marked Mediterranean influence has been Phytol. Balcan. 15(2) • Sofia • 2009 237 registered: the Submediterranean, Mediterranean, Euro-Mediterrane- an, and Mediterranean-Asian spe- cies amounted to 40.6 %. Eurasian spe cies accounted for 11.2 % (16 species). The endemic elements are represented by seven Balkan, three Bal kan-Anatolian and one Balkan- Dacian species, and they togeth- er make up 7.7 % of the association’s composition. The communities of the associa- tion in the Straldzha-Aytos district are distributed on slanted slopes, main- ly with sunny exposition (facing west or south), at altitudes between 66 m and 334 m. On the Besapar Hills, they Fig. 1. Map of localities of the association Poo bulbosae-Achilleetum pseudopectinatae occupy ridges or south-facing slopes (with 10 × 10 km UTM grid). (slope 15–25°) (Stanev 1977, 1980). The base rock is exclusively silicate. The communities develop on shallow or medium deep, dry, eroded soils, with fine skeleton material and tram- pled surface. The stands are used as pasture, but the intensity of grazing is low or moderate. The soil sample anal- yses have shown moderately acid- ic soil (pH 5.91), low humus con- tent (1.45 %), total nitrogen content of 0.11 %, and highly enriched hu- mus with nitrogen (C/N 7.65). The -1 amount of CaCO3 was 31 mg.l , and conductivity 30 μS.cm-1. Assignment of the association to a higher syntaxonomical level Fig. 2. Th e association Poo bulbosae-Achilleetum pseudopectinatae in the locality near Laka village, Burgas district. In the Table 1 not only therophytes and hemicryptophytes but also different phytosoci- The communities of Poo bulbosae-Achilleetum ological contingencies show more or less equivalent pseudopectinatae include a great number of thero- presence. According to the above-mentioned litera- phyte species, and of species with a short vegetation ture, the Trifolion cherleri alliance is represented by 12 period, e.g. Poa bulbosa that