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§ The concept of animal association | 37
associations, cannot be satisfactory (Smith 1928; Kuehnelt 1951) because the
factor that binds the population in question to the association may be
something totally different, and unrelated to dominance. The role of a
population may be the same at low vs. high dominance situations. From the
perspective of the end result of an association, events during the low-density
state of a given population are the really important ones for the eventual fate
of the association (Thalenhorst, 1951; Schwerdtfeger, 1953).
It is obvious that two factors can force animals to form associations: a)
trophic links, that organises populations in a hierarchical order, i.e. vertically,
and b) the exploitation of a common resource, that orders them horizontally,
sometimes even along an extended chain.
The animal association is, therefore, the frequency of coexisting animals
that co-occur to utilise a common energy resource, while they are in mutual
dependency via a food chain (BejBienko, in Shegloev 1951, p. 101; Kuehnelet,
1951; Park in Allee et al., 1949. p. 437: “.. organisms would tend to form
natural groups of foods and feeders - in other words, would form
communities”).
In a vertical orientation, the animal association is reliant on the producent
elements of the biocoenosis, generally meaning the plants, and the closer a
population is to this producent level, the closer its relationship is to the
immediate environment, together with the associated parasitic and episitic
elements relying on the same plant energy source.
We can, therefore, define animal association any animal assemblage that
fulfils the above criteria. Subsequently, we will use the term in this sense,
while we shall consider other terms of association within this category at a
later stage (see p. 70).
It follows from this, however, that not all animal assemblages can be
considered animal associations, and we need to distinguish between animals
living in a certain area (the faunal representation) and the existing animal
associations in the same area (Szelényi, 1955). The substantial difference
between plant and animal associations is most clearly manifested here.
It is an intrinsic feature of any plant association that it strives to cover most
of the area available. Under a closed plant cover, however, weaker species
cannot survive; the plant cover necessarily becomes a plant association, in
which only species that have a similar set of vital optimum conditions can
survive (Cajander, 1909). Such a plant association is relatively stable, bound
to an area, and occurs where the influence of the dominant species on the
others is obvious.
In a plant association, therefore, competition has a determining role. The
plant associations, apart from providing an energy resource, create other
environmental conditions, depending on the associations’ own structural
complexity, and this represents a set of life conditions, second only in
importance to the energy source (food). In the animal association, however,
the effect of competition for space is of less importance; an animal association