Carabid beetles of the environs of the Elton Lake: fauna, population dynamics, demography

Study Extent

Lake Elton is situated inside the blind drainage Botkul-Bulukhta Desert Depression, which belongs to the Caspian Lowland. The shores of lake Elton are located 4.2-9.5 m below sea level. A strongly pronounced salt-dome structure is characteristic of this region (Nikolaev et al., 1998). The largest salt-domes are placed on the eastern (Ulagan Mountain, altitude 68.0 m) and western (Presnyi Liman Hills, altitude 43.6 m) lakesides. Seven rivers are disembogued into lake Elton: Khara, Solyanka, Chernavka and Lantsug from the Northwest, and Karantinka, Bol’shaya and Malaya Smorogda from the Southeast (Nekrutkina, 2006). All these rivers are characterized by the high level of the water mineralization which ranged from 0.3 to 35.6 g/l (Gorelov et al., 2006). Desert steppes are typical plant associations in most of the habitats there, on salinas in floodplain terraces and in lakeside salt-marshes, hyper-halophilic communities are formed, dense reedbeds occur in the river valleys, while in gullies on lakesides there are trees and shrubs (Safronova, 2006). Near the village of Elton, all desert steppes are broke or transformed into pastures. At present some of these are developed into fallow lands of different ages.

Sampling

The demographic structure of the local populations of the ground beetles were studied in ten model habitats. Plastic pitfall traps of 0.5 l capacity and 95 mm upper diameter containing 4% formalin as a fixative were used. In each habitat ten traps were arranged along a transect at 10 m intervals. Because of the high daily air temperature and low air humidity, the fixative content was increased to 3/4 of the trap’s volume. The traps were set from 10 May 2006 until 10 May 2007 and were checked at 10-day intervals on the 10th, 20th and 30th(31st) of each month with the exception of the period with the negative temperatures from November 1st, 2006 until March 31st, 2007 (Makarov, Matalin, 2009; Matalin, Makarov, 2011). Line 1 – Sagebrush desert steppe on the kastanozems (= mollisols) on the left bank of Bol’shaya Smorogda River in “Otgonnyi” natural landmark with predominance of Artemisia lerchiana. Line 2 – Sagebrush-grassland desert steppe on the kastanozems (= mollisols) on the left bank of Bol’shaya Smorogda River in “Otgonnyi” natural landmark with predominance of Artemisia lerchiana and Poa bulbosa. Line 3 – Reedbeds in floodplain section on the right bank of Khara River (3 km upstream of the mouth) with predominance of Phragmites communis, Salsola collina and S. tragus. Line 4 – Salina on floodplain terrace in floodplain section on the right bank of Khara River (3.5 km upstream of the mouth) with predominance of Halocnemum strobilaceum, Salicornia prostrata, Salsola collina, S. tragus and Limonium gmelinii. Line 5 – Grass-forb steppe on the kastanozems (= mollisols) in the slope of floodplain terraces on the right bank of Khara River (4 km upstream of mouth) with predominance of Agropyron desertorum. Line 6 – Sagebrush-grassland desert steppe on the kastanozems (= mollisols) on the kastanozems (= mollisols) in the watershed of the Khara and Lantsug rivers (4.5 km upstream of the mouth of Khara River) with predominance of Artemisia lerchiana, Agropyron desertorum, Anisantha tectorum and Anabasis salsa. Line 7 – Riverine wood on the kastanozems (= mollisols) on right bank of the Khara River in “Biologicheskaya” Ravine with predominance of Prunus spinosa, Rhamnus cathrtica, Spiraea hypericifolia, Rosa canina and Amygdalus nana. Line 8 – Grass-forb steppe on the kastanozems (= mollisols) in depression at the bottom of Khara River floodplain terrace (3 km upstream of the mouth) with predominance of Stipa sareptana and Amygdalus nana. Line 9 – Periodically flooded salt-marsh with the mineral hydrogen-sulfide clays on the lakeside of Elton Lake near the mouth of Khara River with predominance of Anabasis salsa. Line 10 – Sagebrush-grassland desert steppe on the kastanozems (= mollisols) on the northern slope of Ulagan Mountain with predominance of Artemisia lerchiana and Agropyron desertorum.

Method steps

1. Plastic pitfall traps of 0.5 l capacity and 95 mm upper diameter containing 4% formalin as a fixative were used. In each habitat ten traps were arranged along a transect at 10 m intervals.

Coleoptera: Carabidae

1. Carabidae
   common name: Ground beetles rank: family

Extreme east of Volgograd Region. Blind drainage Botkul-Bulukhta Desert Depression, Caspian Lowland.