Oldal 125 [125]
OCR
§ Synphysiological characteristics | 123 3. Community relationships Given that populations co-existing in the same area are not necessarily connected by coenological links, but mere co-occurrence, an indispensable characteristic of a zoocoenosis is a community relationship. We have already presented the essence of direct and indirect, unilateral or mutual coenological links (p. 127). These links create the coenological relationships that force certain populations into a coenosis, or create important links between given associations. Populations belonging to the same association must, at least, be linked by a unilateral, coenological association (catenarium, presocium, supersocion) and, whilst these can be held together by mutual coenotic links, catenae can only be held together by direct coenotic links. Only the existence of these links enables us to declare that certain groups of populations belong to one coenosis. The special quality of the coenotic relationships is justified by a further factor. The symmetric, indirect coenological association refers to cases when there is one, or more, obstant populations of the same species in two or more zoocoenoses. Such links reveal a “kinship” between zoocoenoses that develop independently of each other, which we can call species overlap (after Balogh, 1953, although with a slightly different interpretation). The species overlap means that populations of the same species appear in two, or more, different zoocoenoses. The importance of species overlap is considerable, because the dominance relationships of a community can be influenced by the fate of another one, and can even change its species spectrum. The effect of this kinship due to species overlap can be manifested between individuals of the same zoocoenosis, as well as between different zoocoenoses; in the former case, by the identity of the foundation member of the zoocoenosis while, in the latter, due to the identity of a structural element. This is all because a population should be considered as a structural element of a species (Gilyrov, 1954). All species are divided into populations, and their relationship with other species materialises through these populations. In respect of the survival and fate ofa spatially isolated Aporiaetena crataegi catenarium, these are no different to the fate of the Aporiaetena catenae on the other islands of Aporiaetena crataegi. Between such catenae there can be a direct kinship; a direct kinship exists among zoocoenoses that rely on taxonomically identical herbivorous elements. There can also be species overlap via an obstant element: the indirect kinship. In this case, we are faced with different zoocoenoses, that have kinship because they are identical energy sources for one or more obstant populations. Consequently, zoocoenoses that share one, or more, obstant elements (populations) that belong to the same species are in indirect kinship. Direct kinship is intuitive, and this is also expressed in the zoocoenological terminology. A species overlap relating to indirect kinship is a characteristic
