The Natural Potential of Mountains in Bulgaria and Its Sustainable Use - Sustainable Development in Mountain Regions: Southeastern Europe - page 45

morphographic features via characteristics of the Earth's surface, composed of het-
erogeneous rock substrate (mountains, plains, plateaus, valleys, etc.). On the other
hand it determines the features of the whole natural complex by the specificities
of interaction between other components - both more strongly or weakly dynamic
natural as well as anthropogenic ones. They depend on its morphometric character-
istics (altitude, vertical and horizontal dismemberment, exposition, slopes) (Alexiev
et al., 2005 ). It follows therefore that its leading role as a natural component and as a
natural factor is expressed mainly with respect to the conditions of the environment
for existence and economic activity of man, with a lesser impact on the resource
aspect. Evaluated from this viewpoint, the mountains occupy a very important part
of Bulgarian territory in relation to the “height change of the climatic conditions,
the landscape diversity and the lower anthropogenic impact on nature, compared to
that in the plains” (Danilova, 1980 ).
In Bulgaria there is an almost zonal pattern to territories differing with respect
to height of mountain relief in the central and southern parts of the country.
Hypsometric analysis distinguishes six altitude belts as shown in Fig. 5.1 and
Table 5.1 .
The extension in the middle of the country (and along the parallel) of the
Stara Planina Mt. chain plays the role of a natural barrier to the invasion of
cold continental air masses from the North in winter and is accepted as a cli-
matic boundary between the moderate-continental climate to the north and the
transitional-continental climate to the south, whilst the high mountains of the
Fig. 5.1 Altitude belts (by Mihailov, in: The natural and economic potential of the mountains
in Bulgaria, 1989 ). 1 - lowlands (< 200 m); 2 - hilly lands (200-600 m); 3 - low-mountains
(600-1,000 m); 4 - mid-mountains (1,000-1,600 m); 5 -high-mountains (1,600-2,200); 6 - alpine
(> 2,200 m)