Freshwater Ostracoda (Crustacea) of Inari Lapland in northern Finland

Abstract

-Collections of ostracods from various habitats in and around Lake Inari, Finnish Lapland, provide the first record of these crustaceans from Finland north of the Arctic Circle. From a total of 35 sites visited, 14 species were collected, out of which four appeared to be new to Finland: Fabaeformiscandona lapponica, Pseudocandona pratensis, Eucypris pigra and Paralimnocythere relicta. Two major assemblage groups were recognised by clustering classification and multi-dimensional scaling ordination, one dominated by Cyclocypris ovum, the second by Candona candida. Taxonomic diversity of the most assemblages was of expected range based on the inventory of 53 freshwater species of Finland.

The non-marine Ostracoda of Lapland: changes over the past century

“…Although we noted three assemblage types we found that the average mutual Bray-Curtis similarity between the site assemblages was relatively low. our previous research on the ostracod fauna of Inari Lapland (Iglikowska and Namiotko, 2010) and our comparison with the ostracod fauna of Poland (Iglikowska and Namiotko, in press), revealed that all Lapponian assemblages are drawn from a single coherent assemblage type, regardless of habitat type. Dominance of any one of the three mentioned species may simply reflect factors such as the timing of colonization of the habitat.…”

“…2). Iglikowska and Namiotko (2010) found no significant correlation between habitat type and ostracod species composition in Lapland. In the current study the most noticeable change from the beginning of the 20 th century seems to be a retreat of the Arctic species C. laciniata and T. glacialis in Lapland.…”

“…A remarkable difference between the surveys conducted at the beginning of the 20 th century and the present survey is the absence of the boreal and Arctic species Candona laciniata, Fabaeformiscandona lapponica and Tonnacypris glacialis, from the current survey. In recent decades the absence of Arctic species generally has been reported in Russian Lapland (Akatova and Järvekülg, 1965;Vekhov, 2001) and Finnish Lapland (Iglikowska and Namiotko, 2010;2011).…”

“…of these five species only the eurytopic widely tolerant Cyclocypris ovum and Cypridopsis vidua were collected during the current study and our recent contribution (Iglikowska and Namiotko, in press) from the Norwegian part of Lapland. Tolonen (1997) and Iglikowska and Namiotko (2010;2011) recorded a total of 17 species from Finnish Lapland, only one of which, F. lapponica, is boreal. There are no historic records from this area available for comparison.…”

“…To obtain a more comprehensive assessment of freshwater ostracod diversity in Lapland, existing data on the deep lake ostracod fauna (Iglikowska and Namiotko, 2010) and on the fauna of shallow lakes, peat bogs and temporary pools (Iglikowska and Namiotko, in press) are supplemented here with records from water bodies fed by spring water, including records from Swedish Lapland where no studies have been carried out since Ekman (1908).…”