Pitfall traps were set in ten model habitats: six zonal, characteristic of this particular biogeographic area and four azonal, present in a variety of biogeographic areas.

Line 1 (49°06'44.40"N, 46°52'38.40"E) – Sagebrush desert steppe on kastanozems (= mollisols) on the left bank of Bol’shaya Smorogda River in the “Otgonnyi” natural landmark, with predominance of Artemisia lerchiana (Fig. 2).

Figure 2.  

Sagebrush desert steppe (line 1) in spring, summer and in autumn.

Line 2 (49°06'42.67"N, 46°52'37.25"E) – Sagebrush-grassland desert steppe on kastanozems (= mollisols) on the left bank of Bol’shaya Smorogda River in the “Otgonnyi” natural landmark, with predominance of Artemisia lerchiana and Poa bulbosa (Fig. 3).

Figure 3.  

Sagebrush-grassland desert steppe (line 2) in spring, summer and in autumn.

Line 3 (49°12'42.60"N, 46°39'49.80"E) – Reedbeds in a floodplain on the right bank of Khara River (3 km upstream of the mouth), with predominance of Phragmites communis, Salsola collina and S. tragus (Fig. 4).

Figure 4.  

Reedbeds (line 3) in spring, summer and in autumn.

Line 4 (49°13'19.80"N, 46°39'45.00"E) – Salina on a floodplain terrace 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 (Fig. 5).

Figure 5.  

Salina on floodplain terrace (line 4) in spring, summer and in autumn.

Line 5 (49°13'22.28"N, 46°39'38.77"E) – Grass-forb steppe on kastanozems (= mollisols) on slopes of floodplain terraces on the right bank of Khara River (4 km upstream of mouth), with predominance of Agropyron desertorum (Fig. 6).

Figure 6.  

Grass-forb steppe (line 5) in spring, summer and in autumn.

Line 6 (49°13'24.60"N, 46°39'29.41"E) – Sagebrush-grassland desert steppe on kastanozems (= mollisols) on the watershed of 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 Fig. 7.

Figure 7.  

Sagebrush-grassland desert steppe (line 6) in spring, summer and in autumn.

Line 7 (49°13'41.40"N, 46°39'10.80"E) – Riverine wood on kastanozems (= mollisols) on the right bank of Khara River in the “Biologicheskaya” ravine, with predominance of Prunus spinosa, Rhamnus cathrtica, Spiraea hypericifolia, Rosa canina and Amygdalus nana Fig. 8.

Figure 8.  

Ravine wood (line 7) in spring, summer and in autumn.

Line 8 (49°12'52.20"N, 46°39'43.20"E) – Grass-forb steppe on kastanozems (= mollisols) in a depression at the bottom of a Khara River floodplain terrace (3 km upstream of the mouth), with predominance of Stipa sareptana and Amygdalus nana Fig. 9.

Figure 9.  

Grass-forb steppe (line 8) in spring, summer and in autumn.

Line 9 (49°12'23.40"N, 46°39'46.80"E) – Periodically-flooded salt-marsh with mineral hydrogen-sulphide clays on the bank of Lake Elton near the mouth of the Khara River, with predominance of Anabasis salsa Fig. 10.

Figure 10.  

Periodically-flooded lakeside salt-marsh (line 9) in spring, summer and in autumn.

Line 10 (49°10'3.00"N, 46°51'39.00"E) – Sagebrush-grassland desert steppe on kastanozems (= mollisols) on the northern slope of Ulagan Mountain, with predominance of Artemisia lerchiana and Agropyron desertorum (Fig. 11, Kalyuzhnaya et al. 2000).

Figure 11.  

Sagebrush-grassland desert steppe (line 10) in spring, summer and in autumn.

The demographic structure of the local populations of particular ground beetle species was studied in ten model habitats described above. 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. Due to 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 10^th, 20^th and 30^th(31^st) day of each month with the exception of the period with negative temperatures, from 1 November 2006 until 31 March 2007 (Makarov and Matalin 2009).

Based on gonad condition, as well as on the degree of wear-and-tear of the mandibles, claws and cuticle, six physiological states were distinguished in the adults of both sexes: teneral, immature, mature of the parental and ancestral generations and spent of the parental and ancestral generations (Matalin and Makarov 2011).

The life cycle of particular species was reconstructed according to the chorological series in each local population. In ‘spring breeders’, such chronological series are represented by: immature of parental generation after hibernation → mature of parental generation → spent of the parental generation → teneral of a new generation → immature of the new generation prior to hibernation (Figure 1 in Matalin and Makarov 2011). In ‘autumn breeders’, the chronological series is as follows: teneral of the parental generation → immature of the parental generation prior to aestivation → immature of the parental generation after aestivation → mature of the parental generation → spent of the parental generation prior to hibernation (Figure 1 in Matalin and Makarov 2011). In other ‘autumn breeders’, the same order of physiological conditions of the adults was observed, but without an aestivation parapause. The dispersal capacities of individual species were estimated according to the condition of hind wings and wing muscles. We recognised macropterous, brachypterous and apterous species (Fig. 12), as well as dimorphic species when in the local population both macro- and brachy-/apterous specimens were found. Moreover, in all species, three states of wing muscles were observed: functional (100% muscle-fibres are developed), non-functional (less than 75% muscle-fibres are developed) and absent (less than 15% muscle-fibres are developed).

Figure 12.  

Development of hind wings in carabid beetles (macropterous, brachypterous, apterous).

Lake Elton is situated inside the blind drainage Botkul-Bulukhta Desert Depression, which belongs to the Caspian Lowland (Fig. 1). The banks of Lake Elton are located 4.2-9.5 m below sea-level. A strongly-pronounced salt-dome structure is characteristic of this region. The largest salt-domes are located on the eastern (Ulagan Mountain, altitude 68.0 m) and western (Presnyi Liman Hills, altitude 43.6 m) lakesides. Seven rivers discharge 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 characterised by high levels of water mineralisation which range from 0.3 to 35.6 g/l (Gorelov et al. 2006). The study area is located at the borders between several natural-climatic zones. Thus, its landscape-zonal typology is still debated. According to some authors (Safronova 2006), this general area belongs to the steppe zone but, according to others (Sapanov and Gabdullin 2006), to the semi-desert belt. Despite this, desert steppes are typical plant associations in most of the habitats; on salinas in floodplain terraces and in lakeside salt-marshes, hyper-halophilic communities are formed; dense reed-beds occur in the river valleys; in gullies on lakesides, there are trees and shrubs (Safronova 2006). Near the village of Elton, all desert steppes have been destroyed or transformed into pastures and some of these have been developed into fallow lands of different ages.

49.111853 and 49.228167 Latitude; 46.653000 and 46.877333 Longitude.

Ground beetles (Carabidae, include Cicindelinae) were studied during the survey. The taxonomic coverage includes representatives of 22 tribes: Harpalini – 12 genera, Cicindelini and Sphodrini – four genera each, Pogonini and Platynini – three genera each, Carabini, Pterostichini, Zuphiini and Brachinini – two genera each, Bembidini, Broscini, Callistini, Clivinini, Dyschiriini, Elaphrini, Lebiini, Notiophilini, Oodini, Scaritini, Tachyini, Trechini, Zabrini – one genus each. In general, we recorded one-third of the ground beetle fauna of the Lower Volga Region (Kalyuzhnaya et al. 2000).