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Sep. 29, 2011

The Kazakh Steppe

by Kara Rogers

Click to enlarge images

Altyn Emeil National Park
Photo credit: Walton Lloyd Burns

The Kazakh Steppe, covering more than 804,500 square kilometers from the southern edge of the Ural Mountains to the northern shores of the Caspian and Aral seas, is the largest dry steppe region in the world. Its climate, marked by hot, dry summers and cold winters, is influenced by wind -- the constant presence of which brings drought in summer and snowstorms in winter. In fact, wind is a defining force on the dry steppe. At times, it can cause evaporation to exceed precipitation.

The Kazakh Steppe is classified broadly as a temperate grassland and is very much like the remaining prairie of North America. And while the landscape is flat in many areas (as one might expect in a prairie) the plains are interspersed with low mountains and hills and are etched by rivers and lakes that are associated with wetlands and are often are enclosed by small forests. The steppe's southern end consists primarily of desert.

Despite the formidable climate, the diversity of land types supports a wide range of mammals, birds, and plants. In fact, although the Kazakh Steppe's biodiversity is not as well characterized as in other ecoregions, scientists estimate that 800 species of plants can be found there. Some of its most unique species include xerophytes, plants adapted for survival in water-deprived environments, and halophytes, plants adapted for survival in salty environments, such as in saline soils and saltwater lakes. Examples of plants inhabiting the Kazakh Steppe include grasses such as Stipa zalesskii and furrowed fescue (Festuca rupicola) and sagebrushes such as Artemisia marschalliana.

The Kazakh, together with the Pontic-Caspian Steppe in the east and the Emin Valley Steppe in the west, makes up a major portion of the Eurasian Steppe, which consists of a patchwork of grasslands, savannas, and shrublands. The Eurasian Steppe has long been inhabited by nomadic peoples, who move between pastures, never settling permanently in any one place. In recent decades, however, human activity -- especially the intensification of agriculture -- has made an already challenging environment for plants and animals even more formidable.

Saiga tatarica

Beginning in the 1950s, plowing, overgrazing, the construction of roads, and mining caused significant modifications in some areas of the Kazakh Steppe's natural habitat. In the 1990s, many agricultural lands were abandoned, and the use of chemicals such as pesticides decreased significantly. At the same time, however, there occurred increases in activity associated with mining and oil drilling and with illegal hunting of species such as the saiga antelope (Saiga tatarica), which is now critically endangered as a result of poaching.

Today an estimated 17 to 36 percent of the Kazakh Steppe remains relatively undisturbed. But while some of this land is preserved within protected areas, these safe havens encompass only a portion of the region's natural diversity and are not contiguous across the region. (Habitat fragmentation has been a major concern for Kazakh Steppe species that have large ranges.) Fortunately, increased awareness of the threat facing the steppe and ongoing study of its biodiversity may help ensure that the last grasslands of this important ecoregion remain undisturbed.
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Kara Rogers is a freelance science writer and senior editor of biomedical sciences at Encyclopaedia Britannica, Inc. She is a member of the National Association of Science Writers and author of Science Up Front on the Britannica Blog. She holds a Ph.D. in Pharmacology/Toxicology, but enjoys reading and writing about all things science. You can follow her on Twitter at @karaerogers.

This post also appears on the Britannica Blog.

About Kara Rogers

Kara is a freelance science writer and senior editor of biomedical sciences at Encyclopaedia Britannica, Inc. She is the author of Out of Nature: Why Drugs From Plants Matter to the Future of Humanity (University of Arizona Press, 2012).

The views expressed are those of the author and are not necessarily those of Science Friday.

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