Oldal 110 [110]
OCR
108 ÍV. The dynamics of the animal communities infrequently, get above the detection threshold; let us see an example from my own studies. Neoglocianus maculaalba followed by Dasynerua papaveris and Aylax papaveris are usually members of the catenarium on poppies. Stenocarus ruficornis is not a member everywhere and in every year. We know of cases when Ceutorrhynchitena maculae-albae and Dasyneuraetena papaveris have occupied 95% of the poppy heads, but there have been cases when, through the 80% presence of Ceutorrhynchitena maculae-albae, hardly any Dasyneuraetena papaveris were observed. Finally, there was a case when the Ceutorrhynchitena maculae-albae, only occupied 7% of the available poppy heads, and only traces of the Dasyneuraetena papaveris were found. Stenocarus ruficornis was present at high densities last time in 1934 and, since then, has been sporadically present, including cases when it was under the detection threshold. The above example proves two things: the proportions of constituent populations of zoocoenoses - in the given case a catenarium - can show large shifts, but a certain constant species combination can still be detected. If we only consider the most common species, we can, indeed, talk of species combination stability but, if we consider all the species that find their energy sources in the oecus, the species combinations will fluctuate in time. In our opinion, the latter is the correct approach, because the reality is that all populations are active members ofthe community (dominant or not) ifthey are present, irrespective of our views. § SUCCESSION IN ANIMAL COMMUNITIES There is a question left to consider: is there succession in animal communities, or not? Succession is the phenomenon that manifests itself, at the same location, in the formation of sequential communities. Thus presented, the question will have an affirmative answer even on theoretical grounds. The changes in the composition of plant communities, progressing towards a climax, will obviously generate profound transformations, with the result in animal communities of a complete change in composition. The zoocoenological succession is, therefore, the consequence of the changes in the energy sources. These, however, can be of two kinds: either they accompany plant succession, or the energy source changes, due to the activity of some animal community, so much so, that the original zoocoenosis becomes extinct, and its place is occupied by another one. In plant succession, there is often a constructive element, while zoological succession is often triggered by destructive factors (Tischler, 1950: 184). During succession, a plant cover will become ever richer in energy sources, and the environmental conditions, due to the development of several levels,
