Page 101 [101]
OCR
V. THE DYNAMICS OF THE ANIMAL COMMUNITIES § DYNAMIC PLANT COVER - DYNAMIC ANIMAL ASSEMBLAGES The profound differences between plant and animal communities can be most clearly seen in phenomena triggered by dynamic changes in the biocoenoses. Changes in plant cover are of two types: the appearance of the plant cover changes by season, relatively quickly and visibly (aspects), or undergoes a slowly progressing, relatively gradual change, which can only be recognised through long-term, continuous studies, and is independent of the seasons (succession). The aspects do not influence the composition of the association; they show a characteristic sequence, visible by the changing seasons, and represented by different species groups. The succession, on the other hand, influences the composition of the association, causing the dropping out of certain species and the appearance of new ones; so this is the process of the formation of a new association. It is obvious that the composition of animal associations must, in some form, follow both kinds of changes, because both directly impact the corrumpent elements. Apart from these, other changes, which have no parallel in the plant kingdom, can also occur in the zoocoenosis. These are due to the previously mentioned profound differences between plants and animals, and is the precise cause of the kaleidoscope-like variability that we attempt to conceptualise below. § THE ASPECTS Changes in the seasons influence the animal communities, too, either by influencing their ontogeny (in poikilotherms) or behaviour (migrating birds, hibernation in mammals). Consequently, animal communities also have aspects. The aspect is a periodically returning, season-dependent change in the same animal community, reflecting the concurrent seasonal changes in plant cover. All animal communities appear as a series of aspects, following each other in a regular manner and, generally, show the same species combinations
