Oldal 92 [92]
OCR
90 | IV. Categories of animal associations certain biotopes, because every zoocoenosis is anchored somewhere in space, attached to the population that constitutes the first level of the food chain. This uncertainty of the borders of animal associations should not be understood by viewing the populations of a zoocoenosis as dispersed, irrespective of the biocoenosis and oecus. There is not a dispersion - there is a mixing. Individual catenae can be zoocoenoses totally independent of each other, in the sense that their species spectrum will not overlap at all; the catenae will not be separate in space but mixed, as in the elements of a “mosaic”. A little like a mixture of glass beads of different colour, where the ones of the same colour belong to the same population. The animal association is held together, not by spatial limitation but, by their tropic connections. This is, however, a totally different kind of connection than the ones that exist in plant associations, and this needs to be considered when analysing a zoocoenosis. Structurally, every zoocoenosis is linked to plants, through the herbivorous population that provides the base of its existence. This population is, necessarily, spatially anchored either to one oecus (the case of Neoglocianus [Ceutorrhynchus] macula-alba), a sub-biotope (Agrotis segetum [segetis]), or a whole biotope (Lymantria dispar). Being linked to plants by a trophic connection, the population must also follow these plants in space; the caterpillars of the winter moth to the canopy, the pupae to the soil. In the canopy, however, the obstant elements of the tortricid moths are also active; scale insects live on the twigs with their ecto- and endoparasites; the soil is also the site for pupation for weevils, and; the trunk is the site where obstant elements hunt for codling moth. From this example, perhaps, it becomes clear what we mean in relation to the impossibility of identifying the borders of animal associations, if we aim to do this spatially. From this, two things follow: 1.) the trophic chains are the zoocoenological categories that can be most sharply identified (see Jermy, 1955, Park in Allee et al., 1949, p. 495: “These natural groups are relatively self-sufficient... ”); 2.) the single ontopopulations are linked, more or less, to a spatial level (Park, in Allee et al., 1949: “... and the component species populations are spatially integrated and stratified”). From these two statements, a decisive question arises: should we view associational categories in the spatial levels, or in trophic chains, and the communities formed by them? As we established earlier, we can only agree with the latter option. If, however, only the populations coexisting in levels, oecuses and biotopes form assemblages, then it is, indeed, impossible toseparate the zoocoenoses spatially; because what we see together in space is, from the point of view of the best described categories - the catena and the catenarium - is merely co-occurrence. How should we view the presocium, whose populations are related to whole biotopes, whereby viewing the animal association from this perspective,
