Bio-Geography of Georgia
Georgia is located in the south-eastern part of Europe. The utmost western
and eastern boundaries of the country lay between 40o44' and 46044' Eastern
longitudes, while northern and southern ones - between 41007' and 43035' Northern
latitudes. From the North Georgia is bounded by the Greater Caucasus Mountains,
from the South by the Minor Caucasus and from the West by the Black Sea. Total
surface area of the country is about 69,500 sq. km., total length of borders
- 1968 km., almost 16 % of which (512 km) is a coastline.
Topography of Georgia has a very complex character. Elevations under the Sea
Level vary from zero near the Black Sea coast to 5,068 meters at the top of
the Mt. Shkhara. Main orographic elements include Greater Caucasus Range, the
Inter-mountainous Depression, the Minor Caucasus Mountains and the South Georgian
Volcanic Upland.
Location of Georgia on the border between the moderate humid Mediterranean and
the dry continental Aral-Caspian areas is responsible for the climatic conditions.
The country is divided into two climatic zones - humid subtropical climate dominates
in the Western Georgia, while Eastern Georgia features a transition from subtropical
to moderate. The mean monthly temperatures vary from -20 C to +30 C in January
and from +230 C to +260 C in August. The mean annual precipitation vary from
1000 to 2800 mm in the West and from 300 to 600 mm in the East of the country.
There are 25,075 river bodies in Georgia with the total length of 54,768 km.
The biggest river of the eastern part is Mtkvari (that afterwards enters to
the Caspian Sea), with its numerous tributaries: the Potskhovi, the Didi Liakhvi,
the Aragvi, the Iori, the Alazani, the Paravani, the Algeti, and the Khrami.
The largest one in Western Georgia is Rioni with tributaries: the Tskhenitskali,
the Tekhura, and the Kvirila. Other important rivers include the Enguri, the
Kodori, the Acharistskali, the Chorokhi, and the Khobi. All the rivers in Western
Georgia belong to the Black Sea basin.
There are more than 850 lakes in Georgia, though their total area does not exceed
170 sq. km. The largest are Lake Paravani (37 sq. km.) and Lake Paliastomi (17.3
sq. km.) and the deepest Lake Ritsa (116 m) and Lake Amtkeli (72 m).
Soils' zoning in Georgia include the Western, the Eastern and the Southern soil
districts. For the Western district is characterised plain bog and podzolic
(Plintusols)soils, the red earth and yellow (Feralsols) soils of foothills,
mountain forest and meadow soil zones. In the Eastern district main soil types
include kashtanozem (chestnut )and chernozem soils (steppe zone) and hydromorphic
kashtanozems in the Eldari semi-desert and southern part of the Iori Highland.
Large area in the steppe zone of Eastern Georgia is occupied by humus-carbonate
(Mollisol) soils (the Samgori, Shiraki, Krtsanisi Valleys, Marneuli adm. district,
etc.). Salt soils (solonchaks and solonetzs) are widely spread in the Taribana-Natbeuri,
Marneuli and Gardabani Valleys and in Eldari. Mountain and plain chernozems,
as well as mountain-meadow soils mainly represent the Southern district. In
the western part of the district there we have alluvial carbonate, mountain
gley-sod soils, in a forest zone - brown forest soils.
Compared with the relatively small area there is big number of diverse ecosystems
in Georgia that is caused by complex topography, climatic conditions and geographic
location in general. There exist four Eurasian bio-geographical regions: the
Eastern Mediterranean, the Northern Boreal, Iran-Turanian and Kolkhetian.
Rugged topography and complex range configuration provoked geographic and ecological
isolation of the ecosystems in Georgia. Because of climatic difference between
eastern and western parts, the existing ecosystems vary in a vertical zoning
as well. In western Georgia there are only five vertical zones: forest (under
1900 m), sub-alpine (1900-2500 m), alpine (2500-3100 m), sub-nival (3100-3600
m) and nival (above 3500 m) zones; while in Eastern Georgia - seven: semi-desert,
arid valleys and light forest (150-600 m) zone, forest (600-1900 m), sub-alpine
(1900-2500 m), alpine (2500-3000 m), sub-nival (3000-3500 m) and nival (above
3000 m) zones.
From the point of view of biological diversity one can find here such unique
ecosystems as: peat bogs, Kolkhic polydominant forests with evergreen undergrowth,
sub-alpine elfin woodlands, flood-land forests, alpine meadows, cave and canyon
ecosystems, coniferous and deciduous forests, arid light forests, steppes, etc.
It is also significant that Kolkheti represents one of the refugium of the Tertiary
flora. There still exist rich dendroflora of the Tertiary period: 88 species
of tree and bush vegetation.
Recent human activities caused dramatic changes of natural ecosystems in Georgia:
areas of forest and semiarid vegetation have significantly decreased, correspondingly
areas of secondary meadows and agricultural land have in opposite increased.
More than three fourth of the Kolkheti Lowland and surrounding foothills have
completely changed mostly due to the drainage of wetlands.
© UNEP/GRID-Tbilisi, 2000
1, M. Alexidze St. Tbilisi, 380093, GEORGIA
Phone/Fax: (995-32) 942808
E-mail: grid@gridtb.caucasus.net
Last Updated: 24/02/2000