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58 | IL. Biocoenosis and zoocoenosis are, apparently, well-adapted. This effect can have an impact on homeothermic as well as poikilothermic animals, sufficient to remember the effects of hard winters on birds. How can we talk about equilibrium when a weather anomaly, in whatever direction, threatens the life of living things? Should we also classify this impact as disequilibrium? Why would we decide about the coenosis status of an association on this basis, when its essence is clearly not this unusual influence, but the interactions that bind it together? Even though a coenosis can be disturbed by irresistible forces, extreme temperature, storms, flood, fire and humans, it can be restored after every such disturbance. Restored, because the interactions are so much the essence of a biocoenosis that it has to appear wherever living beings are associated, as life itself is present. In this respect, we have to seek the correct explanation of self-regulation, too. What constitutes the ability to self-regulate? We agree with all authors who claim that this is the process that recreates the disturbed order. We see the same in agrobiocoenoses, where this tendency is the only explanation for the phenomenon that agriculture must compete continuously with the pioneer weeds that try to occupy space; that specially adapted corrumpents break into monocultures, and devour everything that is foreign to the biotope, and; in areas where cultivation has stopped, succession continues after a few years. This ability to self-regulate is not changed by constant human interference. Therefore, we have to distinguish these from coenoses in which human influence is negligible, and this is why we call them agrobiocoenoses. No one can doubt that agrobiocoenoses are different from “natural” ones, but this difference is sufficiently indicated by a different name, although the forces regulating the community are identical in both. The interactions can be disturbed by several factors, and our current knowledge indicates that such smaller or bigger disturbances are common in any biocoenosis, despite us noticing only the more obvious ones. The interaction is undisturbed if; the producent level does not suffer from a catastrophic factor, other structural elements do not exhaust their energy bases, and due to their activities, the conditions in the biocoenosis become richer, and allow the insertion of new elements. Disturbance in the interaction occurs when the producent level suffers a catastrophic factor, or other structural elements use their energy base to such an extent that conditions for life are restricted, and new elements can only insert themselves with difficulty, or not at all. The survival of a biocoenosis is only threatened by interaction disturbances that endanger the existence of the most important producent elements. In the interactions of a biocoenosis, or its smaller constituent communities, such disturbance can only be caused by sudden catastrophic factors (“catastrophic mortality factor”, Ullyett, 1947). Its cause can be extraordinary temperature, flood, fire, etc.; in zoocoenoses, it can also be the activity of obstant elements. The result is a new beginning; a new biocoenosis develops,
