New data on species diversity of Annelida (Oligochaeta, Hirudinea) in the Kharbey lakes system, Bolshezemelskaya tundra (Russia)

Study Extent

Tundra covers an area of approximately 15% of the entire territory of Russia – along the entire coast of the Arctic Ocean, from the Finland border in the west to the Bering Strait in the East. Bolshezemelskaya tundra is a vast plain with an area of 1,660 km2 located between the Pechora and Usa Rivers (in the west and south) and the Ural Mountains in the east, adjacent to the Barents Sea in the north. Hills with prevailing heights of 100–150 m and moraine ridges of up to 250 m high characterizes its relief. The main part of the Bolshezemelskaya tundra is occupied by permafrost. Here, peat bog and silt-marsh soil types prevail; in the south, there are weakly podzol-gley soils. The climate is subarctic, with long cold winters and short cool summers. Many rivers which are mainly tributaries of the Pechora and Usa flow through the plain. The main watershed is located in its central part, with the largest lakes systems in the east of the Bolshezemelskaya tundra: the Vashutkiny, Padimeyskiye, Kharbey Lakes and the other lakes of the Korotaikha River basin. In this study, we focused on the waters of the Kharbey system, the main element of which is Bolshoy Kharbey Lake, located in the headwaters of the River Kharbeytyvis, the right tributary of the Seyda River. In addition, this system includes the lakes Golovka and Maliy Kharbey. The larger lakes are interconnected by natural channels, and are surrounded by numerous shallow adjacent lakes and have a glacial origin. The Bolshoy Kharbey is the largest lake of the system (Vinberg and Vlasova 1976); its area is 21 km2, and depth is up to 18 m (70% of the lake has a depth of 1-6 m). The shoreline of the lake is indented, forming bays and gulfs. The lakeshore habitats are dry, mostly low, and peaty in some places. Bottom sediments in littoral habitats are pebble-boulder or sandy, in deeper water, the sandy bottom is covered with silt. There are many temporary water bodies in the catchment area of the Kharbey lakes. To the west of the Kharbey lakes, there is Lake Syattey-ty, which consists of two connected reservoirs. The area of the larger lake, Bolshoy Syattey-ty, is 7.4 km2; the catchment area is 66.2 km2. Gradually-sloping shores located near numerous small lakes are overgrown with sedge and willow; depth of these smaller lakes is 3.2-7.4 m; bottom sediments are mostly sandy and sometimes silty. Previously published information and an extensive collection of new specimens from fresh water bodies of the Kharbey Lake area collected by M. Baturina and O. Loskutova in 1998-99, 2009, 2010 and 2012 were used in this study. Within this study, the following water bodies of the Kharbey lakes system (Bolshezemelskaya tundra) were investigated: Lake Bolshoy Kharbey, Lake Golovka and unnamed smaller lakes adjacent to Lake Bolshoy Kharbey, arbitrarily identified as К1, K2, L, D1, D2 (Fig. 1B). Additionally, 41 small temporary habitats (including swamps, depressions and ponds), located within the catchment area of B. Kharbey, were investigated. In 2014, hydrobiological material was collected in Lake Syattey-ty (Bolshezemelskaya tundra) and small water bodies in its watershed.

Sampling

Oligochaete samples were taken with a Petersen grab (sampling area 400 cm2) on soft bottoms and with a handle blade trawl (Zinchenko et al. 2014) on gravel bottoms. Since the common hydrobiological equipment (sweep net, dredge, scraper, bottom grab, etc.) is often ineffective in collecting parasitic and predatory leeches, we inspected various aquatic plants and animals, as well as submerged objects (rotten wood, driftwood, snags, stones, etc.) for attached hirudinids. Some leeches were picked out from zoobenthic samples. In most cases, piscivorous leeches were collected directly from captured living hosts. Newly collected specimens were fixed and kept in 80% ethanol solution.

Method steps

1. Morphological analysis was performed using a stereomicroscope MSP-2 var. 2 (LOMO) and compound microscope Leica DM 4000. The worm species determinations were based on existing taxonomic keys (Chekanovskaya 1962; Lukin 1976; Nesemann and Neubert 1999; Timm 1999) in accordance with the present-day classification of each group. As to names of higher oligochaete taxa, there is still no unanimous opinion; therefore, we left them as in Timm (1999). Voucher specimens were deposited at the Institute of Biology, Syktyvkar (Oligochaeta) and Limnological Institute, Irkutsk (Acanthobdellida and Hirudinea).

This article provides current data on annelid fauna from Kharbey Lakes and adjacent water bodies. The annelid fauna includes 68 species, including 51 oligochaete species and 17 species of leeches.

1. Annelida
   rank: phylum
2. Clitellata
   rank: class

Tundra covers an area of approximately 15% of the entire territory of Russia – along the entire coast of the Arctic Ocean, from the Finland border in the west to the Bering Strait in the East. Bolshezemelskaya tundra is a vast plain with an area of 1,660 km2 located between the Pechora and Usa Rivers (in the west and south) and the Ural Mountains in the east, adjacent to the Barents Sea in the north. Hills with prevailing heights of 100–150 m and moraine ridges of up to 250 m high characterizes its relief. The main part of the Bolshezemelskaya tundra is occupied by permafrost. Here, peat bog and silt-marsh soil types prevail; in the south, there are weakly podzol-gley soils. The climate is subarctic, with long cold winters and short cool summers. Many rivers which are mainly tributaries of the Pechora and Usa flow through the plain. The main watershed is located in its central part, with the largest lakes systems in the east of the Bolshezemelskaya tundra: the Vashutkiny, Padimeyskiye, Kharbey Lakes and the other lakes of the Korotaikha River basin.