Geography of Ukraine, physical

Geography of Ukraine, physical. From a geographical viewpoint Ukraine consists not only of the current state of Ukraine but also of the adjacent lands inhabited predominantly by Ukrainians (see Territory, national and ethnic). It lies between 44°30' and 52°50' north latitude and between 20°30' and 42°00' east longitude, and extends from the Tysa River, the mouth of the Danube River, the Black Sea, and the Caucasus Mountains in the south to Narev River, the swamps of Polisia, and the upper reaches of the Desna River in the north; and from the Poprad River, Sian River, and Vepr River and the Bilovezha Forest in the west to the semideserts between the Don River and the Caspian Sea in the east.

Ukraine is one of the natural regions of Eastern Europe. It differs from neighboring regions by a series of gradations without any sharp breaks. From the standpoint of geology (see Geology of Ukraine), the core of the natural region consists of the Ukrainian Crystalline Shield. Occupying the southwestern part of the East European Platform, Ukraine serves as a transition to the Mediterranean Geosyncline in the south. The Ukrainian part underwent greater and more recent tectonic disturbance than the rest of the East European Platform. The southern frame of Ukraine consists of the Carpathian-Crimean-Caucasian Folded Zone; its northern and northeastern frame, of the Don-Dnipro Aulacogen; its western frame, of the Lviv Trough and the Lviv–Lublin Depression; and its eastern frame, which merges with the Voronezh Massif in the north and the Black Sea–Caspian Sea Divide in the south, of the Azov-Kuban Depression (see also Kuban Lowland).

The relief is superimposed on this geological framework. It consists mostly of flat to gently rolling lowland, a legacy of the long period of stability of the East European Platform. Since mountains rising above 1,000 m occupy only 1.5 percent of Ukrainian territory, the mean elevation for Ukraine is 207 m.

Ukraine’s relief is characterized by parallel, non-continuous belts of mountains, depressions, uplands, and lowlands that extend from west to east. Five belts may be distinguished: (1) the belt of folded mountains in the south consisting of the Carpathian Mountains, Crimean Mountains, and Caucasus Mountains, which is bounded in the south by the Tysa Lowland and the Black Sea Depression, while the mountain ranges are separated from each other by the Moldavian Plain, the Black Sea, and the narrow Kerch Strait; (2) the belt of submontane and southern depressions lying north of the mountains and consisting of the Sian Lowland, Dnister Lowland, Black Sea Lowland, Azov Lowland, Lower-Don Lowland, and Kuban Lowland; (3) the compact belt of uplands north of the depressions, extending from the upper Vistula River in the west to the Donets River in the east, and consisting of the Roztochia Upland, Opilia Upland, Volhynia-Kholm Upland, Podilia Upland, the Pokutian-Bessarabian Upland, and the Dnipro Upland, the Zaporozhian Ridge and Donets Ridge, and the Azov Upland; (4) the belt of northern lowlands, which includes Podlachia and the Polisia Lowland, Chernihiv Lowland, Dnipro Lowland, and Donets Lowland; and (5) the separate system in the northeast consisting of the southern spurs of the Central Upland and of the Lower-Don Lowland, both of which have a meridional orientation.

The drainage system, which cuts across the relief belts, unifies Ukraine in the north-south direction. Most of the rivers flow into the Black Sea and Sea of Azov. The drainage basins of the Dnister River, Boh River, and Kuban River lie entirely within Ukrainian territory, as does most of the Dnipro River and some of the Don River basin. Only the upper reaches of the Buh River, Sian River, and other tributaries of the Vistula River, which flows into the Baltic Sea, lie within Ukraine.

Fluvial processes (erosion, transportation, and deposition of materials by water) were the chief agents that shaped Ukraine’s landforms. As is evident from the substantial deposits of loess throughout Ukraine, except for Polisia and mountain slopes, Ukraine remained beyond the reach of the continental ice sheet during the Pleistocene glaciation. It was only in the Riss (or Dnipro) stage, when glaciation was at its height, that the ice cap covered Polisia and sent lobes down the Dnipro Lowland and Don Lowland. The continental ice sheet was a formidable source of meltwater that left huge ravines and valleys as it flowed south.

Glaciation left a distinct imprint on the landforms only in northwestern Ukraine. On territory that was covered by or adjacent to the ice sheet three types of landforms emerged: (1) ground moraine, which formed under the ice; (2) terminal moraine, which formed at the edge of the ice; and (3) outwash plain, formed by braided streams of meltwater extending well beyond the ice sheet. Ground moraine landforms are most common in Polisia and less so in the Desna River basin. In the Dnipro Lowland southeast of Kyiv they are covered by a veneer of loess. Terminal moraine deposits are limited to northwestern Ukraine: to the region near Svytiaz Lake north of Kovel, and to a gentle arc from Verkhy through Volodymyrets and Vysotske. Outwash plains are found in the northern part of the Chernihiv Lowland, the southern part of Polisia, interspersed among the moraines of Polisia and Podlachia, and in the western part of Subcarpathia. They were formed by meltwaters from the continental ice sheet northwest of them and from mountain glaciers in the Carpathian Mountains. Drying winds caused erosion of the light-textured surface and formed sand dunes, many of which are anchored by vegetation.

Aeolian processes were particularly intensive during the glacial stages of the Pleistocene, when strong, dry winds removed fine particles from the bare periglacial surfaces and deposited them further south in sheltered valleys or in areas with more substantial vegetation. Thus loess accumulated throughout most of Ukraine. The deepest deposits (25–50 m) were left on the oldest uplands and on high river terraces that were least prone to erosion. Wind and water continued to modify the loess layer. In the Black Sea Lowland and Kuban Lowland, where the climate is drier and hot, dry winds are common, some of the shallow depressions or pody were formed probably by the wind.

Fluvial processes are still the dominant relief-shaping force. In the mountains swift streams cut deep valleys, undermine slopes causing slides, and in flood carry coarse sediment downstream. Traces of ice erosion such as U-shaped valleys, cirques, and horns can be found only at the higher elevations of the Carpathian Mountains and Crimean Mountains, and in the Caucasus Mountains (where glaciers still exist). Little remains of the terminal moraines, many of which were removed or modified by the fluvial processes. The highest uplands are deeply incised by rivers and streams. Even lower uplands, which are covered with loess, are susceptible to erosion that forms gullies and ravines. In the lowlands, water erosion is negligible and deposition prevails. Slow-flowing rivers form braided streams with many islands.

Climate, which includes the forces of erosion and affects the development of soils, flora, and fauna, is a major landscape-forming factor. The climate of Ukraine is temperate, cool, and semicontinental. It differs considerably from that of adjacent regions (the Central European climate of Poland, the East European continental climate of the Moscow region, and the subarid climate of the Caspian Lowland), and constitutes a transitional stage to the Mediterranean climate.

Precipitation and temperature vary inversely in Ukraine. A moisture surplus (compared to the amount necessary for secure crop cultivation) is encountered only in the Carpathian Mountains and at the higher elevations of the Caucasus Mountains and Crimean Mountains. In low-lying areas moisture decreases from north to south: northwestern and northern Ukraine receive an adequate amount; central Ukraine, a varying amount; and south-central Ukraine, the Donets Ridge, and the Kuban Lowland, an inadequate amount. Dry conditions prevail in the northern Crimea, the Black Sea Lowland, the Donets Lowland, and the Lower-Don Lowland.

The zonation of moisture balance is reflected in the zonation of soils, natural vegetation (before it was cleared for farming), and wildlife. In northern and northwestern Ukraine gray, acid podzol soils developed on sandy fluvio-glacial deposits under a canopy of coniferous and mixed forests that provide a habitat for a fauna common to the Central European forests. The zone of unstable moisture conditions was conducive to the development, on a loess base, of gray forest soils under broadleaf groves (usually at higher elevations), typical chernozems under meadow steppe, and degraded chernozems under forests that had replaced meadows. Forest and grassland fauna intermingled in this transitional zone of forest-steppe. In the zone of moisture deficiency to the south of the forest-steppe a complex of common chernozems developed on a loess base and under a grassy meadow steppe. The dry Black Sea Lowland was covered with a narrow-leaved grassy steppe, which is associated with southern chernozems and chestnut soils. The fauna of both steppe zones was the typical fauna of the temperate grassland biome.

While moisture balance serves as the major controlling factor in the latitudinal zonation of soils, flora, and fauna, the increasing severity of winters from west to east limits the longitudinal distribution of plants, particularly of broadleaf tree species. Thus the English yew is limited to the westernmost extreme of Ukraine, the hornbeam does not grow beyond the Poltava–Homel line in the east, and Ukraine’s border region in the Lower-Don Lowland, with its severe winter and shallow snow cover, marks the eastern limit of winter wheat. The increasing continentality of the climate towards the east, including the depth of ground freezing, results in corresponding modifications of the soil.

Mountains are characterized by a vertical zonation of climate, soils, vegetation, and fauna. Most species of the fauna inhabiting the Carpathian Mountains are common to the middle-European forests; those in the Crimean Mountains, a mixture of Mediterranean and endemic species; and those in the Caucasus Mountains, a mixture of species from Asia and Europe.

From the standpoint of climate, flora, and fauna, Ukraine is unique. It is the only country in Europe with a predominantly meadow natural vegetation (associated with the forest-steppe, and the adjacent meadow steppe) that merges gradually with the forest vegetation in the northwest, the steppe vegetation in the south and east, and the Mediterranean vegetation on the Black Sea shore. (See also Forest belt, Forest-steppe, Regions of Ukraine, Rivers, Steppe, and Water resources.)

BIBLIOGRAPHY
Rudnyts'kyi, Stepan. Osnovy zemleznannia Ukraïny, 1 (Lviv 1924)
Kubiiovych, Volodymyr (ed). Heohrafiia ukraïns'kykh i sumezhnykh zemel', 2nd edn (Cracow-–Lviv 1943)
Lan'ko, Andrii; Marynych, Oleksander; Shcherban', Mykhailo. Fizychna heohrafiia Ukraïns'koï RSR (Kyiv 1969)
Marynych, Oleksander; Lan'ko, Andrii; Shcherban', Mykhailo; Shyshchenko, Petro. Fizychna heohrafiia Ukraïns'koï RSR (Kyiv 1982)

Ihor Stebelsky

[This article originally appeared in the Encyclopedia of Ukraine, vol. 2 (1988).]