The site is located within the Naurzum district of Kostanai Region. The wetland lies in the eastern part of the Sypsynagash Depression 45 km to the south-west of Karamendy (Dokuchayevka) village, 25 km east-south-east of Razdolnoye and 200 km to the south of the regional centre, Kostanai. 8 km to the north of the lake there is a section of the Kostanai-Karamendy-Razdolnoye-Bestau motorway.
The only water supply for the lake are springs, but they are susceptible to changes in climatic conditions depending on fluctuating amounts of precipitation and there appears to be no regular hydrological pattern. Apart from the largest lake, Sankebai, the group includes four medium-sized (c90 ha) salt and brackish waterbodies. At its south-western extremity a short seasonal rivulet enters Sankebai lake. The surrounding landscape consists of a rolling plain covered with Stipa-dominated grass steppe on sandy soils. The site is remarkable for the large number of Spring inundated depressions and a variety of more or less permanent fresh or salty puddles and small lakes. The freshwater lakes have fringes of Phragmites australis, Typha angustifolia and Scirpus lacustris, while the majority of saltwater lakes lack emergent vegetation and often dry out in the height of summer.
Sankebai, or Bolshoi (Big) Sankebai, lake stretches 2.5 km from west-east. In years of maximum water levels it can be 1.7 km in width and covers an area of 3.8 km2. The lake occupies a depression with stable banks built of compressed sand. During warm periods, the gradually receding waters reveal a considerable number of shoals, and the newly emerged fringes are quickly covered with an exuberant growth of Salsola communities. Typical species in these areas are Salicornia europaea, Ofaiston monandrum, Suaeda prostrata and S. corniculata. Further from the water they are replaced by other halophytic communities (Halocnemum strobilaceum, Ofaiston monandrum, Suaeda prostrata and S. corniculata) with perennials. The meadows contain a rich variety of herb-grass associations with the majority of the vegetation constituted by a few common species including Puccinellia tenuiflora, Artemisia nitrosa, Calamagrostis epigeios, Elytrigia repens, Carex melanostachya, Sonchus arvensis, Juncus gerardii, Leymus racemosus, Pseudosophora alopecuroides and Thermopsis lanceolata. The only woody species is a sparse growth of Tamarix ramosissima. The outer undulating dry land are covered with typical steppe vegetation growing on sandy soils, with a predominance of Stipa pennata, Artemisia marschaliana, Scorzonera ensifolia and Gypsophila paniculata.
Malyi (Small) Sankebai lake is a subsidiary waterbody (0.9km2) that relies on the occasional overspilling of water from Bolshoi Sankebai. In periods of drought this lake becomes isolated of the main waterbody and severely contracts in size and becomes heavily mineralized. Also nearby, just to the south-west of Bolshoi Sankebai lake, is a small freshwater lake covering 23 ha and with a profuse growth of fringing vegetation. Around this core group of lakes there is a dispersed collection of salt lakes varying in size from 5 to 20 ha. Their average depth seldom exceeds 0.4 m in spring and by early autumn those which have not dried up completely are only 15-20 cm deep. The lakes lie in rather distinct hollows with either gently sloping shores or low cliffs 0.5 to 1.5m in height. The banks are sandy and the bottoms are covered by an impressive layer of viscous silt up to 20 cm thick. These wetlands are favoured in spring by swans, Common Shelducks and northern waders. The wetland system as a whole is very important for breeding and intra-migratory resting. The area is also reputed to be a regular stop-over site for migrating Grus leuogeranus from the West-Siberian population of this species. Extensive spring flooding makes the area important for migrating populations of waders and dabbling ducks.
up to 2007, 102 species had been recorded including 60 waterbirds representing the following groups: Podicipediformes – 4 species, Pelecaniformes – 1, Ciconiformes – 4, Anseriformes – 24, Rallidae – 2, Charadriformes – 10, Laridae – 12 and Gruidae – 3. In years when the area is well flooded Sankebai lake holds breeding Anser anser, Fulica atra, dabbling and diving ducks, grebes, Larus ridibundus, Chlidonias leucoptera and Ch.niger. The most numerous species are Fulica atra, Aythya ferina, Anas strepera, A. querquedula, A. platyrhynchos, A. clypeata, A. acuta and Aythya fuligula. Of breeding waders the common are Numenius arquata (10-15 pairs), Limosa limosa, Tringa stagnatilis, Tringa totanus, Charadrius dubius, Vanellus vanellus, Himantopus himantopus and Recurvirostra avocetta. When water levels are low, breeding birds are largely absent. During the wet years 1991-1995, the lakes were regularly used by tens of thousands of migrating Anser albifrons and Anser anser with accompanying flocks of Branta ruficollis, Anser erythropus and, occasionally, Anser fabalis. However, more recently when water levels have been low, goose numbers have only been a few thousand. Despite this, even during phases of low water levels the site appears to be attractive to migrating flocks of swans, Coots and ducks. Thus, in 1998-1999, single counts recorded the following numbers of waterfowl: swans – 500 and 600 individuals (Cygnus cygnus - 90.6 to 97.5%, C. columbianus - 0 to 6.7% and C. olor - 2.5 to 2.7%), 2,500 geese, 1,500-2,000 ducks and 1,500 Coots. In spring the numerous flocks of ducks are distributed widely amid the numerous flooded depressions. In 2005-2007 the number of waterbirds recorded was in the region of 15,000 birds. It was also found that the lakes lie on a route for migrating groups of Grus grus. Typical terrestrial birds breeding at the site include Perdix perdix, Coturnix coturnix, and, to a lesser extent, Grus virgo and Tetrax tetrax. Nesting predators include Circus aeroginosus, C. macourus, C.pygargus and Asio flammeus. Twelve species included in the Red Data Book of Kazakhstan occur. In 1997-2000 on Sankebai and adjoining lakes there were small numbers Grus leucogeanus. In September 2002 a pair remained for a fortnight. The steppe areas are also inhabited by a good population of Tetrax tetrax. Grus grus, Anser erythropus, Branta ruficollis, Aythya nyroca and Oxyura leucocephala occur on passage. A regular visitor to the site is Larus ichthyaetus. Two rare raptors (Haliaeetus albicilla and Aquila heliaca) that nest in the nearby Sypsynf forest common hunt around the lakes. Circus macrourus and, probably, Glareola nordmannii nest around the lakes’ hollows. Aquila clanga occurs occasionally.
Non-bird biodiversity: The fish population contains 3 native species - Carassius carassius, Carassius auratus and Phoxinus percnurus. In the 1980s Perca fluviatilis was found in Sankebai lake and Esox lucius in 2006-2007. Also in the 1980s a series of small-scale commercial fish-raising activities introduced a few alien species including Leuciscus leuciscus, Coreginus peled and Cyprinus carpio. The latter succeeded in becoming established but died out in 1998 when water levels were very low.
Amphibians and reptiles are represented by Bufo viridis, Rana arvalis, Vipera ursini and Lacerta agilis. Mammals include about 30 species of which murine rodents are the most numerous and diverse. In open steppe and semi-moist depressions Spermophilus major, Sicista subtili, Allocricetulus eversmanni, Microtus arvalis and Lagurus lagurus occur, often with Allactaga major and Spermophilus pygmeus. Around the lake hollows Meles meles, Cricetus cricetu, Arvicola terrestris, Microtus oeconomus, Microtus gregalis, Apodemus sylvaticus are frequent, and, close to the low bushes and scrub, Ochotona pusila. Common throughout the site are Ellobius talpinus, Erinaceus auritus, Lepus europaeus, Mustela nivalis, Mustela erminea, Mustela eversmanni, Vulpes corsac, Vulpes vulpes and Canis lupus. Occasionally the lakes are visited by groups of Sus scrofa.
Habitat and land use
The wetland complex in question is located in a relatively sparsely populated area. The permanent human population is practically absent; in the warm season of the year the territory happen to be inhabited by the temporary contingent of people which numerical composition seldom exceeds 10-15 individuals (herdsmen, truck farmers and fishermen). In the nearby villages (Ulendy, Sholakkopa, Akbulak and Razdolnoye) that are situated in 15-25 km away on permanent residence there are about 2,5 thousand people. The major rural economy of the region of sandy plains that the of area of the Lake happens belonging to is cattle-raising which, at the moment of speaking, has not yet undergone the full recovery after the recession it has been truck by in the middle 1990-s. The livestock numbers are being kept low so far, as they are not transcend the limit necessary for maintenance of individual rustic economies. In summer period, the cattle -owners of Ulendy settlement set their stock for pasturing by the shores of Sankebai lake; small portion of flooded plain is used for hay-making. Apart from it, a fraction of lowland plots is claimed by tillage: the watering of a variety of vegetable gardens cultivated at these grounds is fulfilled by means of deflection of small volume of Lake’s waters. At periods of favorable hydrological regime the principal water-body acquires appropriate state for resuming trade-fish catching activities. In 1980-s there has been conducted a series of fish-introductory operations; since 1997, after drastic drop of the water-level with ensuing large-scale fish-kill, the fishing has remained practically deactivated until 2006, when the populations of Carassius carassius, Carassius auratus and Esox lucius were discovered to have been sufficiently restored. However, dew to the absence of available market outlets for local fish reserves, the catching is performed in a rather insignificant level. As a fishery the Lake is assigned to the management of individual entrepreneur, as the hunting grounds - to the regional society of hunters and fishermen.
Pressure/threats to key biodiversity
The major factor influencing the numbers and species composition of the waterbird fauna is the unstable hydrological regime that is common to every steppic lake system dependent for its replenishment on spring-delivered water catchments. Frequent fires also presenting a significant threat to ecosystems on the whole and nesting populations of birds in particular. Fishing causes disturbance and there is the possibility of direct mortality of birds in fishing nets. Poaching may affect the tranquility of the site, as well as direct mortality of key species. There is also disturbance from farming operations in the vegetable garden plots and associated irrigation activities. In the future, the gradual increase in livestock numbers may have an impact.
Conservation responses/actions for key biodiversity
The first detailed examination of avifauna of the lakes occurred in October 1996. Within a programme investigating the fly-ways of Anser erythropus, the joint Finn-Kazakhstani ornithological expedition carried out regular autumn observations of geese migrating through the vast area incorporating many lake systems of the Region, including the Sankebai lakes. In 1999 and 2001 representatives of a WWF Project working group evaluated the state of the lakes' ecological conditions and cursorily investigated biological aspects of the waterbird populations present in early summer. Since 2005, the monitoring of migrating waterfowl in the region has been conducted within the UNEP/GEF Project “Development of Migratory Routes and Wetland Habitats with regard to Conservation of Grus leucogeranus and other Waterbirds in Asia”. No special conservation projects have been carried out. On the proposal of the GEF/UNEP/WWF Project “Econet – Central Asia” working group the Regional Agency of Forestry and Bio-resources Management issued an order (#12 of 14.3.2001) for inclusion of the area into the List of Especially Important Wetlands of the Region.