JOURNAL OF BOTANY VOL. IX, NR. 1 (14), 2017 39 RICHNESS OF RARE PLANT SPECIES IN DIFFERENT HABITAT TYPES IN THE SOUTHERN OPILLYA, WESTERN UKRAINE Dmytrash-Vatseba Iryna, Shumska Nadiya Vasyl Stefanyk Precarpathian National University, Ukraine Abstract. Rare plant species richness in different habitat types of the Southern Opillya are studied. Meadow steppes appeared to have the highest species richness. Occurrence and population size of rare species in habitats are analyzed. Species of rare occurrence and small populations predominate in almost all habitat types. However, wetland species are most threatened due to melioration. Keywords: habitat type, rare plant species, species richness, frequency of occurrence, population size, the Southern Opillya, Western Ukraine INTRODUCTION Anthropogenic transformation of natural landscapes causes a decrease in population size and even extinction of populations of many plant species. This process of habitat degradation starts of rare species extinction. The rare species compose 20-25% or more of local species diversity in many regions. There are several important steps to be done for successful conservation of biological diversity: to find rare species in flora of a region that need conservation; to determine number and state of populations of rare species; to create management-plans for their conservation and restoration. Populations of rare species that grow in one habitat all face the same future in the case of its degradation. Thus, creation of management-plans of their conservation needs integral assessment of populations of rare species in each habitat type. Natural and semi-natural landscapes of the Southern Opillya are highly fragmented and isolated due to transformation of 60-70% of the territory into agricultural lands. Forests (mainly oak and beech ones) cover from 16% to 30% of the territory, whereas other habitat types have very small areas (meadows – 4.5%; wetlands – 0.4%; ponds – 0.4%; meadow steppes – 0.2%) [35, 36]. Additionally many habitats have experienced transformation due to continuous anthropogenic pressure. Conservation strategy of populations of rare plants varies depending on habitat type. Thus, the present study aimed to investigate rare plant species richness in different habitat types of the Southern Opillya, trends in the species occurrences and patterns in population size in each habitat type. MATERIAL AND METHODS According to Meusel et al. [20], the Southern Opillya is situated within Central European Province of Deciduous Forest region. According to the Geomorphological zoning of Western Ukraine [43], the territory belongs to the Southern Opillya Undulating Eminence of Wolyn-Podillya region. The Southern Opillya occupies the area of 3500 km2 on North of Ivano-Frankivsk Region, Southwest of L’viv Region and West of Ternopil Region (Western Ukraine). Relief of the region is undulating accept for valleys of Dniester, Bystrytsya, Gnyla Lypa etc. rivers. Main criteria of the rare species determination were as follows: 1) conservation status of species at international, national or regional scales; 2) limited distribution of species within the Southern Opillya; 3) the small size of most populations. We studied distribution of rare plant species in the years 2009-2016 [7-9, 11, 13, 28, 31-34, 38] using route methods. We also examined herbarium materials of M. G. Kholodny Institute of Botany, NAS of Ukraine (KW), Taras Shevchenko National University of Kyiv (KWU), Institute of Ecology of the Carpathians NAS of Ukraine (LWKS), Ivan Franko National University of L’viv (LW) and Vasyl Stefanyk Precarpathian National University and considered literature data [1, 3-4, 5-6, 15-19, 22-24, 26-27, 30, 37, 39-45]. 40 JOURNAL OF BOTANY VOL. IX, NR. 1 (14), 2017 Rare species were classified by their habitat types on the following groups: forest, forest margin, wet meadow, dry meadow, meadow steppe, gypsum outcrops, wetland and aquatic species [16]. We studied rare species number, also number and size of populations in each habitat type. Small populations were counted entirely. Large populations were estimated using sampling counts. Populations of rare species were divided into ten classes depending on their size: A – from one to ten individuals; B – from eleven to fifty; C – from 51 to a hundred; D – from 101 to 500; E – from 501 to a thousand; F – from 1001 to 5000; G – from 5001 to ten thousand; H – to 100000; I – to a million; J – more than a million. The nomenclature follows Red Data Book of Ukraine [29] and the Nomenclatural Checklist of S. L. Mosyakin and M. M. Fedoronchuk [21]. RESULTS AND DISCUSSIONS Flora of the Southern Opillya comprises 259 rare species. Out of them 91 species are listed in the Red Data Book of Ukraine [29], thirteen in the Annex I of Bern Convention and Revised Annex I of Resolution 6, twelve in EU Habitats Directive (Annex II; Annex IV), 94 in Red Lists of Ivano-Frankivsk, L’viv and Ternopil Regions [25]. Forests are habitats for 50 rare plant species, 23 of which are listed in the Red Data Book of Ukraine [29]. High occurrence and large populations are typical only for three forest species (Allium ursinum L., Galanthus nivalis L. and Leucojum vernum L.). Lilium martagon L., Neottia nidus-avis (L.) Rich., Epipactis purpurata Smith, Listera ovata (L.) R. Br., Phyllitis scolopendrium (L.) Newman etc. also have high occurrences but their populations include from few to several hundred individuals. Other forest species are scarce and have small populations (e. g. Atropa belladonna L., Lycopodium annotinum L., Cephalanthera rubra (L.) Rich., Staphylaea pinnata L., Orthylia secunda (L.) House). Several species were found in one locality (Campanula latifolia L., Phyteuma spicatum L., Orchis purpurea Huds.). Aconitum besserianum Andrz. ex Trautv. is likely to become extinct in the Southern Opillya [6]. There are 24 species of forest margins, five of which are listed in the Red Data Book of Ukraine [29] and one (Cypripedium calceolus L.) in Annexes of Bern Convention and EU Habitats Directive. Several species have scattered distribution within the region (Festuca heterophylla Lam., Dactylorhiza maculata (L.) Soó s. l., Astrantia major L., Melittis sarmatica Klokov) but their populations do not comprise more than several hundreds of individuals. There are many species (Cypripedium calceolus, Aconitum moldavicum Hacq. ex Rchb., A. hosteanum Schur, Crepis sibirica L., Avenella flexuosa (L.) Drejer, Cimicifuga europaea Schipcz., Lathyrus latifolius L.) with limited distribution and population size. Several margin species are threatened due to their rare occurrences and extremely small populations (e. g. Rhamnus tinctoria Waldst. et Kit., Laserpitium prutenicum L., Festuca tenuifolia Sibth.). A single known population of Tephroseris papposa (Rchb.) Schur counts only eight individuals. Meadows are habitats for 38 rare plant species. Seventeen species are listed in the Red Data Book of Ukraine [29], three in Annex I and Resolution 6 of Bern Convention and two in Annexes of EU Habitat Directive. Species Dactylorhiza majalis (Rchb.) P. F. Hunt & Summerhayes and Trollius europaeus L. occur relatively often. Instead, other species are scarce due to degradation of suitable habitats (melioration, overgrazing). Wet meadows of the river valleys are habitats for Colchicum autumnale L., Fritillaria meleagris L., Carex hartmanii Cajand, that occur in several localities but have large populations. Other species are also very rare and have small populations (Allium angulosum L., Dianthus stenocalyx Juz., Gentiana pneumonanthe L., Iris sibirica L.). Crepis mollis (Jacq.) Asch. is known from a single locality. Population size of species growing in moderately humid and dry meadows usually do not exceed 500 individuals. Very few species are widely distributed among meadow habitats (Platanthera bifolia (L.) Rich., Potentilla alba L., Gladiolus imbricatus L.). The majority of meadow species have limited distribution (Traunsteinera globosa (L.) Rchb., Aconitum lasiocarpum (Rchb.) Gáyer, Adenophora lilifolia (L.) Ledeb. JOURNAL OF BOTANY VOL. IX, NR. 1 (14), 2017 41 ex A. DC Senecio schvetzovii Korsh., Scorzonera humilis L.). Several species were found in a single locality (Сoeloglossum viride (L.) C. Hartm., Thesium ebracteatum Hayne, Potentilla thyrsiflora Huels. ex Zimmeter). Meadow steppes have the highest plant species richness among different habitat types. There are 83 rare species, 29 of which are red-listed [29]. Seven else are conserved at international scale (all seven species are listed in Annexes II and IV of EU Habitat Directive; five species in Annex I and Resolution 6 of Bern Convention; Carlina onopordifolia Besser ex Szafer, Kucz. & Pawł. in European Red List [2] and the IUCN Red List as Vulnerable species). Populations of Stipa species (S. capillata L., S. pennata L., S. pulcherrima K. Koch and S. tirsa Steven), Sesleria heufleriana Schur and Poa versicolor Besser are large in number, hence these species often dominate in vegetation. Several species are present in almost all localities studied (Adonis vernalis L., Chamaecytisus blockianus (Pawł.) Klásk., Echium russicum J. F. Gmel., Iris aphylla L. subsp. hungarica (Waldst. & Kit.) Hegi, Pulsatilla grandis Wender., P. patens (L.) Mill. s. l., Trifolium rubens L., Cirsium pannonicum (L. f.) Link), however their populations are not big. Most species have rare occurrence and small populations. Many plants are known from a few locations (Euphorbia volhynica Besser ex Racib., Daphne cneorum L., Aconitum pseudanthora