[Interconnectedness between ecological successions and catenary arrangement of space].

Abstract

e-mail: mu4@eco.nsc.ru Four aspects related to succession theory are highly disputed. The first aspect concerns broad usage of the term "succession" for any level of life organization. The second aspect concerns the compatibility of chronological and chorological community successions. The third aspect deals with the semantics of the "succession" notion. And the fourth aspect relates to the compatibility of the concepts "succession" and "ecosystem evolution". Indiscriminant use of the term "succession" has been eroding its original meaning. Succession pertains only to the coenotic level of life organization, rather than any level. Succession is not a mere substitution of living forms at different ontogenetic stages, nor merely a change in population structure or biological species composition: succession is an optimization process of a coenotic relations system. Biotic changes at other levels take place independently of coenotic processes. Succession gives an impression of a stochastic chorological sequence only when considered within the frameworks of one subjectively or arbitrary chosen habitat. The latter is regarded as a reference one, while ignoring other neighbouring habitats where biota also undergoes complementary successional changes in different degrees. Recently an importunate postulate urging to believe succession to embrace only chronological community sequences, occurring in one and the same habitat during long time, is being increasingly discussed. This claim is not justified as any succession inevitably embraces several habitats, either successively or simultaneously. The stock of biota in one habitat is evidently not enough for the constant stochastic process. All habitats undergoing successional changes, rather than being isolated and functionally self-sufficient, are arranged in catenas, i.e. standardized chorological sequences determined by geomorphology, drainage, hydrology, microclimatic trends and biotic interchange within the corresponding biome. Therefore succession represents not just a chronological, but rather chrono-chorological phenomenon. Such notion perfectly complies with the gnoseological principle of indivisibility of time and space, which can transform accordingly from one into another. The term "succession", both literally and semantically, denotes inheritance and stereotyping of the environmental experience in an ecosystem, conventional and optimal for the given biome, rather than ecosystem transition into a critically different state. Deviation from a stereotype is possible only in the eluvial ecosystems of catenas, where matter turnover is highly imbalanced, thus providing biota a chance to implement its evolutionary potential. The other ecosystems of a catena exclude this possibility due to predetermination of their ecological regimes. In those ecosystems successions are often interrupted and then resumed at different starting points, thus ensuring persistent mitigation to ecosystem evolution, which is a revolutionary and irreversible process that cannot be reproduced by definition.