Trakia Journal of Sciences, Vol. 8, Suppl. 2, pp 493-498, 2010 Copyright © 2009 Trakia University Available online at: http://www.uni-sz.bg ISSN 1313-7050 (print) ISSN 1313-3551 (online) CONSERVATION STATUS ANALYSIS OF TERRESTRIAL SNAILS IN THE REGION OF STARA ZAGORA, DEPENDING ON ALTITUDE M. Marinova, D. Georgiev* Department of Biology and Aquaculture, Faculty of Agriculture, Trakia University, Stara Zagora, ABSTRACT The species diversity and the conservation importance of terrestrial snails encountered in the region of Stara Zagora and the flanks of the Sarnena Sredna Gora mountain was analyzed. The terrestrial malacofauna of the Stara Zagora region was characterized for a 7-year period on the basis of both own studies and the fundamental research of (1) and (2). The region encompasses territories at a different altitude (Fig. 1) – plain (100 to 200 m altitude), premountainous (200−300 m altitude) and mountainous (400−600 m altitude) areas. Eighty terrestrial snail species were determined, 27 of them with a status of conservationally important taxons. Key words: Snails, Sarnena Sredna Gora, Upper Thracian plain, conservation status INTRODUCTION Investigations on the Stara Zagora urban Investigations of the terrestrial malacofauna malacofauna have been carried out by (1) and in the region of Stara Zagora Marinova and Georgiev only for the Ayazmoto The diversity of malacofauna on pastures in park in 2009 (unpublished). According to (2) the region of Stara Zagora and the flanks of the 54 snail species were encountered in the Stara Sarnena Sredna Gora mountain was Zagora city and region, representing 22.9% of investigated in two aspects: faunistic and the Bulgarian malacofauna. The high degree of parasitological. The latter aimed at similarity (83%) of urban fauna and that of the determination of the role of the different snail Stara Zagora surroundings should be species in life cycles of parasites. In this emphasized. The authors believe that this was connection, studies performed on the subject due to the urbanized environment – a powerful could be further divided into two directions: anthropogenic pressure that increases the first, to establish the species composition of species diversity though invasion of species snails involved in transmission of parasites from adjacent forest habitats, with a typical among livestock animal species (for which predominance of introduced and reduced snails are intermediate hosts) and second, to presence of endemic species (1, 8, 18). determine some population traits of molluscs that are beneficial for the relationship of the Terrestrial snails in Sarnena Sredna Gora parasite and its definitive host (3, 4, 5, 6, 7). mountain The diversity of molluscs in the Sarnena Performed studies exhibited 14 terrestrial Sredna Gora mountain was investigated by (2). snails belonging to 13 genera, 9 families, 2 Sixty three terrestrial snail species were found orders and 2 subclasses of the Gastropoda out or 26.6% of all molluscs encountered in the class. country. Six snail species are reported as new for the region. A considerable diversity (41 Terrestrial gastropods in the urban snail species) was observed in open grass environment habitats and areas with shrub vegetation ________________________ *Correspondence to: Dian Georgiev dominated by Jerusalem thorn (Paliurus spina- Department of Biology and Aquaculture, Faculty of christi) and European Hornbeam (Carpinus Agriculture, Trakia University, 6000 Stara Zagora, betulus). Then followed oak and pine forests e-mail:[email protected] with 37 and 22 registered species, respectively. In the investigated cave in Sarnena Sredna Trakia Journal of Sciences, Vol. 8, Suppl. 2, 2010 493 MARINOVA M. et al. Gora mountain, (2) has discovered a Starozagorski Mineralni Bani, Rosovets, flourishing population of Oxychilus glaber Stoyan Zaimovo, Ostra Mogila, Edrevo. From striarius. the viewpoint of the climatic zoning of Bulgaria, investigated territories are in climatic The purpose of this investigation was to areas characterized with a transition from analyze the conservation status of terrestrial moderate continental to continental snails in the region of Stara Zagora and the Mediterranean climate. According to the flanks of the Sarnena Sredna Gora mountain climatic zones of (9), they are situated in a through analysis of available literature and transitory continental climatic zone, with most own studies. of them being in the Upper Thracian subregion and the Sub Balkan kettle subregion. More MATERIAL AND METHODS recent data (10), place the studied area in the Characteristics of the investigated region. transitory climatic zone with territories situated Studied territories (Fig. 1) are within a region in the Upper Thracian plain climatic region that begins from the east part of the Upper and Sarnena Gora climatic region. According Thracian plain, with a typical plain relief and to (10), the climate of the transitory climatic continues to territories located on the flanks of zone is characterized with a mild winter and Sarnena Sredna Gora and the mountain itself. transient snow cover. From the point of view The territories could be classified as plains at of the soil geographic zoning of Bulgaria (11), altitudes of 100 to 200 m. Here are the pastures the studied region is referred to the Balkan- at the villages of Obruchishte, Zagortsi and Apennine soil subregion of the Mediterranean Rakitnitsa, pre-mountainous pastures at 200 to soil region. 400 m altitude (Stara Zagora, Ayazmoto, Zheleznik residency area, Malka Vereya, Kolena, Dalboki) and mountainous pastures at altitudes over 400 m. − Oryahovitsa, 494 Trakia Journal of Sciences, Vol. 8, Suppl. 2, 2010 MARINOVA M. et al. Studies territories belonged to the Thracian- macroelement content of soil. They could be Middle Tundzha soil province, and the Sredna classified as mesophiles-calciphiles (12 Gora soil province. In this study, the species) and zerophile-calciphile (1 species). biogeographical zonality pattern of Bulgaria as Two species: Zebrina detrita and Xerolenta per (12) was used. Territories were within the obvia were typical xerophiles. The number of Mid Bulgarian biogeographical region of the calciphilic species was 21 or 26.25% of all Upper Thracian plane and the subregion of the found out in the region. The members of the Tundzha hilly country. With respect to the Zonitidae family have more specific flora and fauna, the Mid Bulgarian environmental requirements but nevertheless, biogeographical region is characterized with a are represented with a considerable diversity. marked predominance of northern species but Some of them, apart being mesophiles, were also with a number of Mediterranean elements also troglophiles (O. glaber), whereas others that have found good conditions for (A. minor) are clear hygrophiles. A large part development here (12). of studied habitats in the region are suitable for the existence of these species. Apart the Methods for determination of snails reduced light intensity, deciduous forests are Terrestrial snails were collected manually and characterized by higher humidity and lower stored either in 70% ethanol or dry. temperature of the leaf cover. Small-sized species were collected by With regard to the conservation importance, separation from the soil or leaf cover using a terrestrial malacofauna in the investigated 0.5×0.5 cm sieve. region showed a high diversity (Тable 1). From the 80 terrestrial snail species, 27 The species identification of terrestrial snails (33.75%) were with a status of was done according to the manuals of (13), conservationally important taxons. Nine (14), (15) In this study, the nomenclature of species (11.25%) were of national importance– (16) was used. P. elegans, Agardhiella trunctella, Vallonia RESULTS AND DISCUSSION excentrica, Chondrula bicallosa, Vitrea Species composition of snails pygmaea, Oxychilus hydatinus, Limax flavulus, On studied territories in the Stara Zagora Krynickillus urbanskii, Helix figulina. Vallonia region, 80 terrestrial snail species were found excentrica, Chondrula bicallosa and Vitraea out (two species were determined on the genus vereae are species, rare for Bulgarian fauna level) belonging to 25 families, 3 orders and 2 whereas L. flavus and H. figulina (2.5% of subclasses of the Gastropoda class. regional malacofauna) were Tertiary relicts. According to (17) 8.8% of species inhabiting Their systematic position (16) was as followed: the Black Sea coast, plain and hilly areas are From observed terrestrial snail species, most preglacial relics. prevalent were the typical mesophiles – a total of 35 species or 14.8 % of Bulgarian terrestrial Fifteen species (18.75%) were of European malacofauna (Тable 1). Representatives of this importance − Argna macrodonta rumelica, group were found out in a considerable number Zebrina detrita, Macedonica marginata, of habitats. Then followed the group of Laciniaria plicata, Bulgarica frutillaria, B. mesophilic species that had a broader varnensis, B. bulgariensis itricata, Cecilioides ecological tolerance – mesophiles-hygrophiles, spelaeus, Vitrea neglecta, Tandonia kusceri, presented with 16 species (6.77%) and Limax macedonicus, Helix lucorum, H. mesophiles-xerophiles with 13 species (5.5%). pomatia, Lindholmiola girva and Xerolenta The high prevalence of mesophilic-xerophilic obvia. Of them, 3 (3.75%) were important for species is due to the vegetation diversity, the world’s natural heritage – Vallonia changing with altitude. The numerous roads in enniensis, Balea perversa and