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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;