New records and disappearance from old sites of narrow-clawed crayfish pontastacus leptodactylus in northwestern russia

Abstract

The narrow-clawed crayfish Pontastacus leptodactylus is known as a species expanding their range in northern areas of the Europe. This study aims to present new records, check the previously knows sites of P. leptodactylus records in the northwestern region of Russia (Karelia, Murmansk, and Arkhangelsk regions), and discuss possible reasons for its current range extension to the north and disappearance in southern locations of this region. Twenty years ago, the northern border of the P. leptodactylus range run from southern Finland to the east-north of Lake Ladoga, skirting to the north of Lake Onego, and further east to the Northern Dvina. To date, it disappeared widely from northern lakes and rivers being recorded only in 25% of previously known locations (mainly in southern Karelia), where this species was introduced and established in the 1920s–1970s. At the same time, during the last decade, P. leptodactylus was recorded more northern, in lakes at White Sea costs. Considering that some of the new sites of P. leptodactylus are located in uninhabited by humans areas, the reason due to which this crayfish extends its range close to the Arctic areas may be its natural dispersal. Local climate warming might also facilitate the successful adaptation and establishment of this species there.