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OCR
§ 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
