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5A | II. Biocoenosis and zoocoenosis
equilibrium situation is only conceivable if the corrumpent population is
appropriate for the existing food bases, and there is an obstant population
that is proportional to the existing corrumpent population. In the situation
used as an example, the interaction was stronger from the direction of the
obstants. Why would we call the relationship between these two populations
equilibrium, when it was obviously the outcome of an interaction, and it was
not the deer population that kept the associated obstant populations “in
balance’, but the latter that limited the former to the degree that they could
not utilise the otherwise available food biomass? It is also possible that the
plant cover has changed, and now can support more deer. This is again a
matter of interaction, and we cannot see why we should use the word
equilibrium instead, when the relative abundances are formed by the existing
interactions.
It is a generally accepted fact that the plant-based energy resources are,
always, in abundance in relation to the animals consuming them (Heikertinger
1951), and the animals, in most cases, do not utilise the food available.
An interesting case of the relationship within the interaction system is
observed between grassland-grazing cattle and insects (grasshoppers and
cicadas) (Wolcott, 1937). Where few cattle were grazing, most of the plant
production was consumed by insects but, where the number of cattle was so
high that they grazed the meadow low, the major part of plant production
was consumed by them, because the defenceless insects were, in part, excluded
and, in part, the open habitat attracted crows that decimated them. In this
situation, it is impossible to see an equilibrium; this is the outcome of
interactions.
There are more obvious signs of a disturbed interaction. Such as, for
example, when a corrumpent grazes the forest canopy bare; does this
phenomenon indicate a loss of an equilibrium?
When the oak forest is defoliated by Erannis (Hibernia) defoliaria or Tortrix
viridana, the only event was that one of the interacting partners became too
strong. If the energy source could limit its user, how could the equilibrium
be upset? The equilibrium is, therefore, a fiction that we impose on the
biocoenosis; there only exist interactions, that can take place so that the food
base far exceeds the needs of the consumers, but can also occur in the opposite
direction. Even if equilibrium were the essence of the biocoenosis, we could
only speak of a disequlibrium if all oak trees perished due to this trauma
and, consequently, also the herb layer in the semi-shaded understory. We do
not know of such a case; on the contrary, the trees sprout again, and the usual
state is restored. What had really happened? Nothing more than a temporary
disturbance to the usual order. However, there are no rigorous studies support
this image of “usual order”; how, then, could we claim that what we are
accustomed to seeing is the equilibrium of the biocoenosis, and the essence
of all biocoenoses? Only one thing is certain; that the producent level (and
only a part of it) was, temporarily, during the period of a vegetative cycle,