Ibragimova A.G.1*, Seleznev D.G.2, Frolova L.A.3, Subetto D.A.4, Potakhin M.S.4,5,6, Belkina N.A.4,5, Kotov A.A.1 2025. Cladoceran remains as a tool for reconstruction of past environmental conditions during the Late Pleistocene-Holocene in Central Karelia (NW Russia). Part II. Qualitative approach including species co-occurrence analysis // Arthropoda Selecta. Vol.34. No.3: 339–346 [in English].
1 A.N. Severtsov Institute of Ecology and Evolution of Russian Academy of Sciences, Leninsky Prosp. 33, Moscow 119071 Russia.
2 Papanin Institute for Biology of Inland Waters Russian Academy of Sciences, Borok, Yaroslavl Area 152742 Russia.
3 Institute of Archaeology and Ethnography SB RAS, Kutateladze Str. 7/3, Novosibirsk 630090 Russia.
4 Нerzen State Pedagogical University of Russia, Moika Embankment 48, St. Petersburg 191186 Russia.
5 Northern Water Problems Institute of the Karelian Research Centre of the Russian Academy of Sciences, A. Nevskogo Prosp. 50, Petrozavodsk 185030 Russia.
6 Petrozavodsk State University, Lenin Ave. 33, Petrozavodsk 185910 Russia.
* Corresponding author
Aisylu Ibragimova: ais5_ibragimova@mail.ru; https://orcid.org/0000-0002-3667-0466
Dmitry Seleznev: dmitriy@seleznev.name; http://orcid.org/0000-0003-2782-1696
Larisa Frolova: larissa.frolova@mail.ru; http://orcid.org/0000-0001-8505-0151
Dmitry Subetto: subetto@mail.ru; https://orcid.org/0000-0002-3585-8598
Maxim Potakhin: mpotakhin@mail.ru; https://orcid.org/0000-0002-2630-2176
Natalia Belkina: bel110863@mail.ru; https://orcid.org/0002-0002-9928-022X
Alexey Kotov: alexey-a-kotov@yandex.ru; https://orcid.org/0000-0002-8863-6438
doi:10.15298/arthsel.34.3.05
ABSTRACT. This paper is the second in a series devoted to the study of cladoceran taphocenoses in the bottom sediment core from Lake Torosjarvi (Central Karelia, NW Russia). The quantitative data on species abundances in each layer of the core were analysed using CONISS cluster analysis (see Part I). Here, a cladoceran species association analysis based on binary data (presence/absence) was performed, which has not previously been applied to analyse palaeodata. Two major and three small (each represented by a couple of species) clusters of mutually associated species were identified via the species association analysis. The major clusters correspond to cold-water and warm-water conditions respectively, as well as to two major periods in the lake history: an early period characterised by cold water and oligotrophic conditions, and a second period characterised by a relative warming and stronger development of higher aquatic vegetation. The conditional boundary between the periods was estimated using qualitative data clustering as ca. 10.6 ka cal. yr BP, which roughly corresponds to the separation of Lake Torosjarvi from a larger water body — Lake Segozero, which belonged to the palaeobasin of the Onega Glacial Lake. The pairs of associated species are corresponded to the zones obtained by dividing the core into smaller periods based on CONISS clustering, as outlined previously (see Part I). Division of the sediment core by the species abundances may yield a more detailed result in the revealing of a community change, and the change in environmental conditions by zones may be more gradually reconstructed. Simultaneously, the division of the core by species occurrence reflects more general changes in the lake environment.
KEY WORDS: Holocene, paleolimnology, taphocenosis, subfossil, Cladocera, Karelia, Lake Torosjarvi, bottom sediments.