Mironov A.N. 2013. Biotic complexes of the Arctic Ocean // Invertebrate Zoology. Vol.10. No.1: 3–48 [in English].

P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Nakhimovsky Prospekt, 36, 117997, Moscow, Russia; e-mail: miron@ocean.ru

KEY WORDS: Arctic, fauna, flora, biotic complex, biogeographic regionalization, crowding zone, ecosystem.

ABSTRACT: There are three main approaches to biogeographical regionalization: the species (or faunistic, floristic, biotic), community (biocenotic) and landscape (bionomic) approaches. They differ over seven criteria. Areographic analysis is used in the biotic approach. The biocenotic approach is often based on the cluster analysis. The biotic approach adopts the assumption of continuity in a species range, whereas in the biocenotic approach a species range is considered as interrupted. Environmental data are not used in these two approaches. The use of environmental data at the initial stage of regionalization is the main distinguishing character of landscape biogeography. More than 70 schemes of biogeographical regionalization of the Arctic seas or the whole Arctic Ocean have been compared. Most biogeographic schemes were constructed based on methods using elements of biotic, biocenotic and landscape approaches. The number of biogeographic regions recognized on the Arctic shelf increases from schemes based purely on the biotic approach to those based on mixed elements of the biotic and biocenotic approaches, and increases further in schemes based on the biocenotic, landscape and mixed biocenotic-landscape approaches. The pure biotic approach revealed only three biogeographic regions on the Arctic shelf plus one region in the deep-sea. The biocenotic-landscape approach gave more than 50 biogeographic regions (the sum of suggested subdivisions) in the Arctic Ocean. A group of small biocenotic-landscape regions falls into one large biotic province. The biotic boundaries (zones of crowding of species ranges) in the Arctic Ocean overlap by up to several hundred km, whereas the biocenotic and landscape boundaries are linear. Some biocenotic-landscape provinces completely fall into zones of crowding of species ranges. A biotic complex is defined as a totality of living organisms or a totality of communities occurring in a region outlined by a crowding zone. A biotic complex together with a biogeographic (biotic) region is considered as a large ecosystem or biogeocomplex. The results of the biogeographic regionalization of the Arctic Ocean support the hypothesis that a biotic complex is a large universal structural-functional unit of the living realm. In theory any biotic boundary can be revealed by different approaches to biogeographical regionalization at the large scale - biotic, biocenotic or landscape. On the other hand most biogeographic boundaries, revealed by biocenotic and landscape approaches, are not biotic boundaries. It is suggested that initially broad biotic boundaries evolved into narrow ones. The gradual convergence of species range limits as a result of common species adaptations was termed “the crowding effect of adaptations”. Based on this approach, the great width of crowding zones in the Arctic Ocean reflects a young age of the Arctic biotic complexes. The latter in turn is explained by young geological age of the present-day Arctic environments.

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