Hygrotope And Trophotope Of The Steppe Pridniprovie Biogeoceonosis As Determinants Of The Earthworms (lumbricidae) Communities ?-diversity

Abstract

A. V. Zhukov, D. B. Shatalin

The role of the hygrotope and trophotope of the steppe Pridniprovie biogeoceonosis has been discussed in present article as being determinants of the β-diversity of earthworms (Lumbricidae) communities. Material has been colected to the period 1997-2015. 180 sample polygons have been studied which located in various types of biogeoceonosis. Biogeoceonotic characteristic of the sample polygons have been made on the basis of professor A.L. Belgard forest typology of a steppe zone of Ukraine. Earthworm communities of the steppe Pridniprovie have been established to be presented by 16 species. Hygrotopes, trophotopes and bitope ceonosis features have been shown to be able to explain 72.4 % of a communities’ abundance variation and 73.7 of their % α-diversity by means of second order model. Earthworm communities’ abundance reache their maximum values at a combination of conditions of humidity from hygromesophilous to hygrophilous and conditions of edaphotope trophicity from Dc (linden oakwood) to Dn (elm-ashen oakwood and alder forests). The maximum diversity of earthworm communities has been stated to be characteristic for a combination of mesohygrophilous conditions and a trophicity mode Dc, that there corresponds to forest type a linden oakwood with aegopodium. The coenomorphic structure of the biogeocoenosis is statistically significant predictors of both abundance and α-diversity of earthworm communities. Earthworm communities of marsh monocoenosis, meadow-steppe amphicoenosis and steppe monocoenosis have been found as being characterised by minimum abundance and diversity. Moderate level abundance and diversity are characteristic for meadow-forest amphicoenosis, forest pseudomonocoenosis with elements of transformation to steppe and forest-steppe amphicoenosis. High levels of these indexes are typical for forest monocoenosis. Given other conditions of humidity and edaphotope trophicity being equal in forest monocoenosis abundance and diversity of earthworm communities will be higher than in other biogeocoenosis types. The MDM-analysis (Multinomial Diversity Model) reveals that habitats coenotic features define 12.61 % of all entropy of earthworm communities, hygrotopes – 24.12 %, trophotopes – 12.3 %. The square-law hygrotope member defines 10.93 %, and trophotope – 2.05 %. Hygrotope and trophotope interaction defines 1.53 % of entropy of earthworm communities. Sites (α -diversity) define 36.45 % of entropy. There are other factors which influence a diversity of earthworm communities besides a humidity, trophicity and habitat coenotic features. Steppe Pridniprovie earthworm complexes have been divided into ecological groups on the basis of relation to humidity (hygromorphes) and to edaphotope trophicity (trophocenomorphes). Earthworms hygromorphes are presented by xerophylous (2 species), mesophylous (9 species), hygrophylous (4 species), ultrahygrophylous (1 species). Trophocoenomorphes are presented by oligotrophocoenomorphes (1 species), oligomesotrophocoenomorphes (4 species), mesotrophocoenomorphes (9 species), megatrophocoenomorphes (2 species).

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