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OCR
120 |VIL Zoocoenological characteristics Concerning the life form categorisation, we agree with Remane (1943) who distinguished two groups. “Lebensformtyp” includes species that, due to adaptation to similar conditions and life history, have similar morphologies, and helps us deduce their life history; “Lebensweisetyp” includes species that display similar life history (i.e. sapro-, copro-, or necrophages) but this cannot be deduced from their morphology. We call the first a structural life form, and the second trophic life forms. The latter only approximates with Remane’s Lebensweisetyp, which stands between our concept of coetus and Balogh’s (1946) syntrophium, but is more like the latter. From a zoocoenological point of view, of course, only the trophic life form can serve as a structural characteristic. The studied semaphoront groups will be classified into appropriate coeti by their life forms, but only if the populations have real community relationships. From the first two structural characteristics, therefore, the trophic relationship is indispensable, because only this association will prove the true coherence of the structure. The semaphoront groups and coeti are only building blocks; the (trophic) relationship is the force keeping them together. 1. Life form We can distinguish two categories based on trophic relationships. One is the coetus, a necessary part of the framework for the zoocoenosis. We know four of these: corrumpent, sustinent, intercalary and obstant coeti. Within each, because of the endless variety of specialised life forms, we find populations with the most diverse life histories, autecology and behaviour. Therefore, it is necessary to establish a second category, that of the elementary life form, syntrophium. The populations that damage the producents of the biocoenosis belong in the individual coeti (corrumpent coetus), playing a role in its continued existence (sustinent coetus), removing the non-living debris and excreta (intercalary coetus), or living off the previous three categories (obstant coetus). Within the same coetus, the populations that have adapted to the common energy source in similar ways, belong to the same syntrophium. According to Thienemann’s first biocoenetic principle (1941), the richer the fauna of an area, the broader the syntrophium spectrum of the coeti of the resident zoocoenosis, while the less variable the life conditions in a biotope, the narrower the syntrophium spectrum, as argued by Thienemann’s 2™ and Franz’s (1951b) 3" biocoenotic principles. The life form groups are remarkable for two reasons: zoocoenoses can be grouped by: 1) their structural elements, and; 2) the coetus rank of the dominant population. Based on the identity of the structural elements, we can distinguish zoocoenoses with 2, 3 or 4 coeti, meaning initial, precedent or plenary zoocoenoses.
