Floristic Research on the Karelian Isthmus

The Karelian Isthmus is located in the north-west of the Leningrad region, bordered by the Neva River in the south, the Gulf of Finland in the west and Lake Ladoga in the east. In the north-west, the Karelian Isthmus extends to the border between Russia and Finland, while in the north-east it stretches to the border between the Leningrad region and Karelia.

From north to south it spans 150-180 km (1 1/2°), while from west to east its width is 55-110 km. The area of the isthmus amounts to about 15,000 square kilometers, which is equivalent to half of Belgium, or a third of Denmark (not counting the island of Greenland). The isthmus accounts for 17% of the entire territory of the Leningrad region.

The Karelian Isthmus, which is distinguished by its unique nature (rocks, a sea coast, a plethora of lakes of various sizes), has long attracted the attention of both Russian and foreign botanists (for a long time, a significant part of the isthmus belonged to Finland). Nevertheless, until now the species composition of local flora has not been entirely accounted for, largely due to historical factors which effectively isolated Russia from Western Europe for a long period of time (until the early 1990s). For this reason, extensive herbarium collections, as well as numerous articles about rare plant species, until recently have not been available to Russian researchers. Of special significance was a monograph published in 1946, Karjalan kannas kasvien vaellustienä by I. Hiitonen, which covered the Finnish section of the isthmus. This work summarized the results of research into the flora of the Karelian Isthmus carried out by the mid-20th century. With respect to both the theoretical and practical significance of this work, it should be noted that I. Hiitonen for the most part limited himself to an in-depth study of species living in natural habitats and the possible routes of their migration to the Karelian Isthmus. In subsequent years, a number of species that are new both to the Karelian Isthmus and Northwest Russia as a whole were discovered, along with numerous new habitats of rare species.

Since 1994, the flora of the Karelian Isthmus has been studied in depth by A. Yu. Doronina. As a result of this research, and with the aid of herbarium collections in Russia (LE, LECB, WIR, MSK) and abroad (H, TUR, TURA, KUO, OULU, HSI, HEL, S), an Overview of vascular plants of the Karelian Isthmus was compiled. It comprised 1,184 species of wild vascular plants belonging to 472 geni and 114 families, as well as 186 cultivated species, species falling out of cultivation and hybrid species. An analysis of the systematic structure and life-forms of the aboriginal part of the flora has shown that the Karelian Isthmus flora belongs to the temperate-boreal type.

An ecological and phytocenotic analysis of the Karelian Isthmus flora has demonstrated that in terms of number, the isthmus is dominated by forest-related species. They include Diplazium sibiricum, Cinna latifolia, Carex sylvatica, Listera cordata, Neottia nidus-avis, Asarum europaeum, Aconitum lycoctonum, Ranunculus subborealis, Corydalis intermedia, Dentaria bulbifera, Astragalus subpolaris, Oxytropis sordida, Lathyrus linifolius, Chaerophyllum aromaticum, Geranium robertianum, Mercurialis perennis, Galeobdolon luteum, Lathraea squamaria and others. Of rare mire species the following are worthy of special mention: Trichophorum cespitosum, Rhynchospora fusca, Carex disticha, C. livida, C. paniculata, Juncus stygius, Dactylorhiza traunsteineri, Saxifraga hirculus, Pedicularis sceptrum-carolinum. The sandy beaches of the Gulf of Finland and Lake Ladoga are populated by Calamagrostis meinschausenii, Festuca arenaria, F. sabulosa, Leymus arenarius, Carex arenaria, Juncus balticus, Salix acutifolia, Lathyrus maritimus and others.

The uniqueness of the Karelian Isthmus flora is largely attributable to coastal and rock species. The composition of coastal species is determined by the Gulf of Finland and its specific characteristics (Blysmus rufus, Cakile baltica, Lotus ruprechtii, Archangelica litoralis, Myosotis ramosissima, Scutellaria hastifolia, Valeriana salina, Tripleurospermum maritimum, Atriplex calotheca, A. littoralis, Salsola kali, Isatis tinctoria). Some of these species (coastal halophylous species) can be found on the shores of the Gulf of Finland where there are sufficiently high levels of salinity - to the north of the town of Zelenogorsk: Triglochin maritimum, Puccinellia pulvinata, Scirpus tabernaemontani, Bolboschoenus maritimus, Blysmus rufus, Eleocharis parvula, Carex glareosa, C. mackenziei, Spergularia salina, Glaux maritima, Centaurium littorale, C. pulchellum, Cuscuta halophyta, Plantago maritima, Tripolium vulgare. Rock species are to be found on the Baltic crystalline shield (Woodsia ilvensis, Asplenium septentrionale, A. trichomanes, Hierochloл australis, Steris alpina, Silene rupestris, Draba incana, Saxifraga cespitosa, Crepis czerepanovii, Polypodium vulgare, Cystopteris fragilis). The latter two species can also be found in the southern part of the Karelian Isthmus, though their frequency of occurrence is far lower in this area.

On the basis of detailed maps of species distribution, a geographic analysis of the aboriginal part of the flora and comparative data on twelve local floras, the territory of the Karelian Isthmus can be divided into three floristic sectors - western, northern and southern. The western sector is the richest in terms of flora composition. It includes the shores of the Gulf of Finland and adjacent territories and islands that are influenced by the sea. In the north-west, the western floral sector extends into neighboring Finland. Baltic species are only to be found in this sector, and they are entirely absent to the east of this region: Alisma juzepczukii, A. wahlenbergii, Eleocharis fennica, Hierochloл baltica, Polygonum oxyspermum, Batrachium marinum, Cakile baltica, Lotus callunetorum, L. ruprechtii, Cuscuta halophyta, Hieracium prolatatum, Tripleurospermum maritimum. The northern floristic sector is bordered by the western sector in the west, the southern sector in the south and east, and by Lake Ladoga in the north-east. In the north, the northern sector protrudes into neighboring Finland and Karelia. The northern floristic sector, which has no outlet to the Gulf of Finland, is characterized by the following species: Asplenium trichomanes, Equisetum variegatum, Hierochloл australis, Luzula campestris, Coeloglossum viride, Nymphaea tetragona, Alchemilla cymatophylla, A. samuelsonii, Melampyrum cristatum, Eupatorium cannabinum. The southern floristic sector also has no outlet onto the Gulf of Finland and comprises the highest section of the Karelian Isthmus. In the east, its climate is influenced by Lake Ladoga. The following species are only to be found in the southern sector: Diplazium sibiricum, Botrychium simplex, B. virginianum, Selaginella selagineloides, Carex atherodes, C. otrubae, C. paniculata, C. sylvatica, Juncus capitatus, Calypso bulbosa, Cypripedium calceolus, Aconitum lycoctonum, Batrachium mongolicum, B. penicillatum, Pulsatilla patens, Ranunculus subborealis, Gypsophila fastigiata, Corydalis intermedia, Agrimonia pilosa, Alchemilla glabricaulis, Oxytropis sordida, Chaerophyllum aromaticum, Peucedanum oreoselinum, Hottonia palustris, Centaurium erythraea, Mentha aquatica, Origanum vulgare, Utricularia ochroleuca, Ligularia lydiae. All these species belong to the very rare and rare types, while some have only been discovered in single locations.

A large number of rare species have been registered on the Karelian Isthmus. Nineteen of them have been included in the Red Data Book of the Russian Federation (Botrychium simplex, Isoëtes lacustris, I. setacea, Alisma wahlenbergii, Caulinia tenuissima, Rhynchospora fusca, Carex livida, Cypripedium calceolus, Dactylorhiza baltica, D. traunsteineri, Epipogium aphyllum, Calypso bulbosa, Myrica gale, Silene rupestris, Pulsatilla vernalis, P. pratensis, Armeria vulgaris, Lobelia dortmanna, Senecio aquaticus), 85 are listed in the Red Data Book of Nature of the Leningrad Region, 204 are in the Red Data Book of the East Fennoscandia, and 142 species are included in the Red Data Book of the Baltic Region. Unfortunately, as a result of poorly managed economic activities, many of these species are no longer to be found on the Karelian Isthmus, such as Selaginella selaginoides, Ligularia lydiae, Carex caryophyllea _ C. hartmanii, Calypso bulbosa, Cypripedium calceolus, Juncus capitatus, Pinguicula vulgaris.

Anna Doronina
The Botanical Institute of St. Petersburg State University
e-mail: baccador@mail.ru

Top | Back | Home