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§ The structural elements of a zoocoenosis | 49 to animal size. It is sufficient to point to what wild boar or deer can do in an arvideserta; the corrumpent role of domesticated animals can be noticed immediately on any grazed area. A flock of sheep does not sustain certain characteristic desert formations, but can prevent the formation of a biocoenosis characteristic of that biotope. Carnivorous mammals, on the other hand, are obstant elements. The role of birds is very interesting: their obstant activity is the reason for the development of bird protection for economic reasons, albeit their populations often belong to more coeti; being not only corrumpents but, importantly, sustinents in the life of a forest, as convincingly illustrated by Turcek’s (1951) fascinating observations. Finally, not to ignore humans, let us conclude that we belong to populations that are fully active in all directions: corrumpent when building a city, obstant when protecting plants and nature, intercalary in hygiene, sustinent with crop cultivation, hospitants, or protempore, in the depth of primeval forests, and peregrinant all over the uninhabited areas of the Earth. § THE QUESTION OF BALANCE IN THE BIOCOENOSIS There is no doubt that multi-faceted human activities, wherever they meet nature, will profoundly influence the life and composition of biocoenoses. The longer this connection lasts, the more decisive human influence will be, and several authors (e.g. Tansley, 1935; Bejbienko and Mistchenko, 1951; Scsegolev, 1951) distinguish anthropogenic factors from abiotic and biotic ones. In this respect, let us only state that anthropogenic influence, from transient disturbance to sustained and long-lasting impact, is manifest to all degrees. This fact, when we link it to the concept of biocoenosis, takes on theoretical importance, because since Resvoy (1924), most authors designate balance as one of the criteria of a biocoenosis, and only associations able to self-regulate - and thus be “in equilibrium” - qualify as biocoenoses. The first appearance of this consideration, in almost identical phrasing, occurs in Bronn’s (1843, cit. Schwenke, 1953) long-forgotten discourses. Following this principle will logically lead to a conclusion that, in associations with sustained human influence, self-regulation will cease to operate, the equilibrium is lost, and what remains in the area in question can no longer be a biocoenosis, but an inferior replacement. This is where Schwenke (1953) concurred, excluding the areas under human agriculture from a biocoenosis, and calling it a merocoenosis. Rammer’s (1953) standpoint is even more extreme. We cannot agree with this position, because it does not separate the concepts of biotope and biocoenosis, and because it forces such an undefinable criterion as the equilibrium into the concept of biocoenosis and, excluding the developmental potential of an association, it forces - without proof some kind of stability onto a biocoenosis.
