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§ The question of balance in the biocoenosis | 59
or new elements become dominant in the biocoenosis. Catastrophic factors
can sweep away a whole community from the space it occupied before, but
a community can also be restricted leading to the transformation of its
composition, or to depress the abundance of its members.
The seeming stability of a biocoenosis is caused by the rarity of any
catastrophic effect on its main interaction system. The components of the
biocoenosis are in permanent flux according to the working of their correlative
links, and here, in the “depth” of the biocoenosis, interaction disturbances
can occur but these are essentially like those along the “main” paths, thus
there is no need to group them as “equilibrium”. The flux in the biocoenosis
is incessant, but without any two identical states (Kuehnelt, 1951:57). The
changes are not only from season to season, but from year to year, and,
following the laws of succession, may undergo long-wave transformation,
too. This pendulum-like movement is not equilibrium, but the manifestation
of an order that remains in effect during changes caused by interacting forces
(Glen, 1954). This order means that a meadow remains a meadow, a forest
a forest, and a reedbed transforms into a hygrophilous meadow, then a
mesophilic grassland, then a forest. Just because our own lifespan is too short
to see these changes as movement, there is no reason to declare a state of
equilibrium that, itself, remains unaltered. The forces active in this situation
are identical with the interactions, and operate in the most primitive
biocoenoses, too. Their number and effect may increase but their essence
remains the same. One triggers the other, and the system gradually becomes
more complex. it is disputable that the climax is an end state because it is not
only subject to wider effects such a climate, but can also degenerate and can
undergo retrogression (Tansley, 1935; Sod, 1953).
The arguments above try to justify why do we not want to use the term
equilibrium in the definition of the biocoenosis. The boundaries of a
biocoenosis are the limits of the interaction network; there are differences
between a forest, a meadow, a rock face or arvideserta, irrespective of whether
they are in equilibrium or not. Disturbances within the interactions do not
upset the foundation of a biocoenosis, only create obstacles in the path of
succession. The autogenous succession is a process under the influence of
plant cover, while the allogeneic succession is under the influence of outside
factors (Tansley, 1929, 1935).
The disturbance in the interactions, in many cases, are of the second type,
and it is unimportant whether this is caused by a herd of grazing bisons,
termite mounds or human activity.