The rapid rate of decline in the Earth’s biodiversity under the influence of direct and indirect anthropogenic pressure makes it necessary to develop the scientific foundations for its conservation at all levels of life. Ecologists have come to understand that the best way to ensure the conservation of populations of organisms and their communities is to preserve the environment in which they live. The countries of the European Community, where special programs have been developed since mid 1980s, have shown the greatest activity in preserving environmental conditions. Currently, the «European Union Nature Information System» (EUNIS) has become the most popular among such programs. Habitat is a central concept in EUNIS. For the purposes of EUNIS, habitat is defined asa place where plants or animals normally live, characterized primarily by its physical features (topography, plant or animal physiognomy, soil characteristics, climate, water quality etc.) and secondarily by the species of plants and animals that live there (Davies et al., 2004). Most often, habitat is considered to be synonym of the term biotope. The EUNIS biotope classification would correspond to the ecosystem classification if heterotrophic components were largely present in it. However, at present, these organisms, are not used for classification of terrestrial ecosystems. The latter (especially benthos) are important in the characterization of marine habitat types.
The author does not deny the extreme importance of the EUNIS habitat classification for ecological science and solving problems of nature conservation. He is only sure that the concept of habitat classification began to be developed in the Soviet Union as early as 1920–1930th in the papers by L. G. Ramenskiy who in 1927 published the definition of habitat type: The type of habitat or natural area is determined by a combination of climate conditions, relief, irrigation, and the nature of the soil and subsoil. The same type can be covered by a meadow, or a forest, or plowed up, etc.: these are its transitional states (in virgin untouched nature, each type is inhabited by a completely definite combination of plants - steppe, forest, meadow, etc.). Afterwards L. G. Ramenskiy began to use the term land type instead of habitat type.
In the 1930s, by the land type he meant an ecosystem unit in which plant community would exist without human influence. The land type in nature is represented by a set of various modifications that arise, as a rule, under man pressure. Modifications can transform into each other and revert to the original state of the type. Later, such plant community was called potential vegetation (Tüxen, 1956). In 1932–1935, L. G. Ramenskiy supervised the inventory of natural forage lands in the USSR, which used this concept of land type (Golub, 2015). The inventory of natural forage lands in the USSR resulted in their hierarchical classification: 19 classes and 43 subclasses were established. The exact number of distinguished types was not calculated, according to L. G. Ramenskiy rough assessment, there were more than thousand. In most cases, the potential vegetation of the types could not be identified. Proceedings of this inventory were not published. However, the L. G. Ramenskiy former post-graduate student N. V. Kuksin, who took part in the inventory in Ukraine, wrote the book about the forage type lands in this republic of the USSR (Kuksin, 1935). The typology of hayfields and pastures presented in that book is very similar to the habitat classification developed on the principles of the EUNIS system (Kuzemko et al., 2018).
By the late 1940s, L. G. Ramenskiy had concluded that modern science was unable to establish potential vegetation for many habitat types. Therefore, he recommended calling the land type what he previously attributed to modifications. For practical reasons and for the sake of brevity, it is advisable to also call types the main groups of modifications of land types (forest, meadow, arable) (Ramenskiy, 1950, p. 489). As a result, his understanding of land type became the same as later habitat was interpreted in the EUNIS system. The typology by L. G. Ramenskiy lands and the classification of EUNIS habitats have the same essence and basis, but different groups of human society proposed them: the first exploits land resources, the second tries to protect them. Based on L. G. Ramenskiy typology, recommendations are made on the use of biotopes with the purpose to obtain sustainable maximum economic production. Based on the classification of the EUNIS system, recommendations are drawn up for the protection of plant and animal populations, as well as their community’s characteristic of a given biotope. The land typology by L. G. Ramenskiy could well be deployed towards the protection of biotopes, if there was a demand from society for such use. So keen interest in nature conservation, as now, did not exist in the course of the L. G. Ramenskiy lifetime.
At present, the EUNIS biotope classification has begun to be used on the territory of the former USSR, while the land typology by L. G. Ramenskiy has been forgotten. There are two reasons for this phenomenon: 1) isolationism of Soviet science, which separated domestic scientists from their colleagues in the West; 2) L. G. Ramenskiy ideas were too ahead of time, their depth, essence and importance became understandable to biologists only few decades later.
The paper shows that the formation of L. G. Ramenskiy views concerning the typology of habitats could been influenced by the ideas of the Russian forest scientist A. A. Krudener.
The Habitat Classification of mammals in Korea based on the National Ecosystem Survey