Mongolia is a vast Central Asian country with the world's most extreme continental climate and notable aridity. Nevertheless, it has a great abundance and variety of lakes, some of which are large enough to be classified among the largest in Eurasia. It also has a considerable network of fast-flowing rivers that ramble undisturbed through spacious alluvial plains. Human intervention is barely detectable, both due to the scant population and its traditional occupations, consisting basically of livestock grazing; this has preserved Mongolian lakes and rivers in a pristine condition up to our times.

Since 2005 a team belonging to the Department of Ecology of Barcelona University (Spain) is prospecting Mongolia attracted by the existence of lakes with great similarities to those in the most arid Iberian territories, lakes which have either disappeared entirely in Iberia or are seriously damaged today. The Water Research Center of the National University of Mongolia, is actively involved in the project. This center is an inter schools unit allowing scientists from different disciplines at national and international institutions work together helping government and communities to manage, protect and restore water ecosystems through holistic research approach.

The objectives of the Mongolian Lakes Project are:

• Catalog the lakes of Mongolia with information about their characteristics and ecological health.
• Contribute to the knowledge of the biodiversity of entomostracans by expanding the existing information about Mongolian fauna and establishing taxonomic relationships between this and the existing fauna of the Iberian Peninsula, both representative of the longitudinal extremes of the Palearctic.
• Establish correspondences between the composition of the biota of the Mongolian and Iberian lakes for the purpose of identifying common species and/or isocies or vicariants that permit the establishment of reference conditions for types of lakes in industrialized Europe that currently lack reference sites.

Presently (year 2013) direct limnological information of a group of 728 lakes, including the most representative is available.

Ten expeditions have been conducted covering all the Mongol country and its different natural zones:

• September 2005, 87 lakes distributed throughout the Gobi desert, western mountain ranges of Altai and the Great Lakes Depression, the latter basically situated in the provinces of Khovd and Uvs.
• September 2006, 66 lakes in the eastern steppes and taigas of Sukhbaatar, Dornod and Khentii.
• January 2007, Ogii and Terkhiin Tsagaan lakes were visited to observe their state under winter conditions.
• September 2007, 102 lakes in the northern taiga, including Khuvsgul Lake, and the lakes of the steppes of central Mongolia in the Khuvsgul, Zavkhan and Arkhangai provinces.
• June 2008, the expedition focused Naiman nuur (Eight lakes) in Uvurkhangai province and some small steppe lakes in Dundgobi and Tuv provinces.
• September 2008, 84 lakes in the Gobi desert and in the western provinces (Khovd, Bayan-Ulgii and Uvs) including all of the most representative lakes located in the Great Lakes Depression.
• September 2009, 95 lakes in Khentii, Tuv, Dundgobi, Zavkhan, Khovd and Bayan-Ulgii including new surveys in some of the lakes of the Great Lakes Depression.
• September 2010, 74 lakes in Uvurkhangai, Arkhangai, Khuvsgol, Zavkhan, Govi-Altai, Bayankhongor, Umnugovi, Dundgovi, Tuv and Khentii provinces. Particular attention was paid to glacial lakes in Hangay mountains. Also Tayshir hidroelectric reservoir was included in the survey.
• September 2011, 84 lakes distributed mainly in the eastern steppes and desert steppes of Darkhan-Uul, Selenge, Khentii, Dornod, Sukhbaatar, Dornogovi, Dundgovi and Tuv.
• In August and September 2012 the limnological survey was devoted to lakes not visited previously in Tuv, Bulgan, Khuvsgul, Arkhangai, Zavhan, Uvs, Bayan Ulgii and Khovd provinces.

Exploration consisted of collecting basic parameters such as the lake substrate type, estimates of water permanence, water mineralization (through electrical conductivity, salinity and pH), the appearance of the water (turbidity, trophic characteristics), and analysis of the macrophyte and invertebrate communities. Logistical support was provided by Mongolian Ways (www.mongolian-ways.com), a Mongolian company whose contributions to the project were incalculable given the great difficulties implied in the locations of the lakes and travel within the country.

After the first general investigation of the Mongolian lakes over these eight years, it is anticipated that the study will continue in coming years for the purpose of expanding information about specific aspects in more restricted groups of lakes. All suggestions are welcome.

The Limnological Catalogue of Mongolian Lakes is part of the Project: “Biodiversity of Crustacea Entomostraca in the Palaearctic. Aplication for the assessment of the ecological status of Iberian Lakes” within the Program for the Conservation of Biodiversity promoted by ENDESA. The team would like to express its appreciation for their help to all those who have contributed in any way to the success of the project, especially to Dr. Dorjgotov, Director of the Geographic Institute of the Mongolian Academy of Sciences, for his support in the first campaign; to Dr. Enkhtaivan Sanaa, researcher of the Khuvsgul GEF/WB Project; and to Dr. Francesc Sabater, professor in the Ecology Department at the University of Barcelona. The limnological catalog is displayed with the help of Google Maps in a user-friendly application created by the Spanish company Geodata Sistemas S.L (www.geodata.es).