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§ The concept of biotope | 63 The vegetation, however, both in water and on land, will draw the bioptope into its sphere of influence and, with the advance of succession, more and more so. The stagnant water will gradually be silted up, the rupideserta becomes a closed grassland, then fruticeta, then lignosa. Hence, the biotope is exposed not only to cosmic and meteorological effects, but to a third one: the sum of impacts from the biocoenosis. Indeed, interrelationships and interactions start to become entwined, and it is very tempting to define the biotope by its biocoenosis. For simplicity, this may be acceptable when the biocoenosis reaches “maximum complexity”: the biotope is still there, and has impacts. This is indicated, amongst other factors, by the conclusion of the process: the climax of the plant association. The climax, when fully developed, will be the one permitted by the cosmic, meteorological, and the edaphic factors, which are under the influence of the former abiotic inputs, plus the energy sources available - in other words, the features of the biotope. The alpine region above the tree line is not classified as such because of the absence of trees; the forest is absent because the biotope is unsuitable to support such a formation. A calcareous mountain, stripped of its oak forests may become karst, characterised by saxi- and rupideserta formations, but this will be different were the mountain originally covered by spruce forest, because these two formations are climax stages of different succession series, and are determined by what the biotope controls. The above thoughts hopefully explain why we do think that the concept of the biotope is necessary, and why we do not want, by its abandonment, to “pull the rug” from under the biocoenosis. This would not be correct, because there is an inseparable interaction between living organisms and their environment, and the environmental requirements of the species have been formed during evolution, and are heritable (Bej-Bienko, see Tschegolev, 1951; Bej-Bienko and Mishtschenko, 1951). For this reason, the composition of an animal association can only be correctly perceived in the light of its environment, of its biotope. This is not to separate it but, to better grasp the conditions of life, the importance of the biotope needs to be better identified. If the biotope is exposed to cosmic and meteorological forces, we can imagine that changes in these factors provide a way to separate different biotopes. However, the effect of the same microclimatic conditions differs according to the quality of soil, bedrock, slope, aspect, etc. We have also seen that, with the formation of the biocoenosis, there are also biotic effects, and it is also obvious that anthropogenic factors exert an increasingly important effect on the biotope. The biocoenosis that occupies the biotope, as an imprint of the conditions existing there, provides a good characterisation of these conditions (Cajander, 1916; Rabeler, 1952). Thus, if we now consider phytosociology, and use its concepts for a synthesis of the biotope of the zoocoenoses, we cannot be accused to defining the biotope using a living community. It cannot be disputed that, for plants, a biotope is an area that is, as yet, without life, but provides the conditions necessary for plant cover;
