Identification of valuable biotopes was carried out on the example of a small territory —the “Gagarka” forest park, located on the Northern coast of the Gulf of Finland within the borders of St. Petersburg (Fig. 1). Field data on landscapes, vegetation, flora and fauna were collected in 2018 to proof the need to create a specially protected natural territory of regional significance.
The study area of 58.7 ha is an accumulative sea terrace with absolute elevations not exceeding 2.5 m above sea level. Despite of small area size, the vegetation is quite diverse and it is represented by the coniferous (spruce and pine) forests, several types of black alder forests, tree and shrub fens, littoral meadows, coastal and aquatic vegetation. Rare species of herbaceous plants and shrubs listed in the Red books of the Russian Federation (Krasnaya…, 2008) and St. Petersburg (Krasnaya…, 2018) are recorded and they often dominate in the plant communities.
The preservation of biological diversity may be successful only if the landscapes and the biotopes hosting plant and animal species, including rare ones, are protected. Objects of protection can be both rare and typical ones for the regional biotopes. The environmental value of biotopes of the “Gagarka” forest park was assessed according to the following criteria: ecotopic (areas with rare and specific landforms, soils, hydrochemical regime), geobotanical (the presence of primary plant communities, rare plant communities; widespread, but with a tendency to reduce the area as a result of natural or anthropogenic impacts), floristic (the presence of rare species and species located on the border of their ranges), faunistic (the presence of rare animal species, the species richness of fauna, the presence of permanent habitats of animals and birds, as well as biotopes used in certain seasons: during breeding, nesting, molting and migration). In addition, the compliance of biotopes with the European habitat classification EUNIS (European Nature Information System) was taken into account (Davies et al., 2004, EUNIS, 2018).
Plant communities are the main indicator of habitats, and their borders mark the boundaries of habitats. In this regard, the geobotanical map (Fig. 2) is the basis for creating a map of biotopes. In addition to the geobotanical map, the map of actual landscapes, the map of the locations of rare plant species, and faunistic materials were used to create a map of valuable biotopes (Materialy…, 2018). It shows 6 types of habitats, that are particularly important for the conservation of biological and biotopic diversity (Fig. 3).
All valuable habitats of the “Gagarka” forest park are located in the littoral zone of the Gulf of Finland and near its coast. They are grouped into 4 categories: black alder forests as a model of natural tree communities of the Littorina terrace and habitats of rare plant and animal species, coastal fens as rare plant communities on the territory of St. Petersburg and habitats of rare plant species, littoral meadows as rare plant communities on the territory of St. Petersburg and habitats of rare plant and animal species, shallow waters of the Gulf of Finland as habitats with highly productive communities of macrophytes, rare plant species, with a large species diversity and a high number of birds, including rare ones. The creation of new protected area “Gagarka” is necessary to preserve the habitats and rare species that grow and live here.
The effects of hybridization on the small-scale variation in seed-bank composition of a rare plant species, Erica ciliaris L.
