The region of Strandja Mountain is situated in the south-eastern part of Balkan Peninsula; it covers a significant part of South-eastern Thrace and belongs to European deciduous woodland region. Specific geological, climatic and bio-geographical characteristics determine the presence of natural ecosystems with high biological diversity.In „Strandja nature park“ organized on the Bulgarian territory (1 161 sq. km) from the group of small mammals (Insectivora, Rodentia and lagomorpha) multiply the 27 species. Recently, so of development of agriculture and cattle breeding in this region, many seminatural habitats and agricultural areas have been formed. landscape fragmentation in South-eastern Thrace offers an opportunity to examine the effect of landscape structure on distribution of Dormouse (Gliridae) in typical and the often widespread in the region of Strandja Mountain plant associations, which have been traditionally studied in the evaluation of bio-diversity of small mammals there: (I) woodlands: (i) Riparian dense woodlands with grass cover of irregular composition, dependant on cyclic floods along the river valley of Fakiiska River and outfall of Veleka river; (ii) Deciduous woodlands of Colchisian-Mediterranean type – with evergreen colchisian sub-forest; (iii) Artificial mixed woodlands afforested mainly with maritime pine (pinus pinaster) with unevenly developed grassy subforest: less developed in the dense parts of the forest and with richer biodiversity in the lighted parts. (II) Open landscapes: (i) Meadows and pasture grass communities with semi-shrub and shrub vegetation, and agricultural areas under alfalfa, autumn cereals or vines, or desolated arable lands; (ii) Open wet zones along rivers covered with hydrophilic and hygrophilic vegetation with presence of small groups of trees and intermediate shrub floor in particular places). The set of the investigated habitats covering typical and most common plant associations in this region included much of habitats traditionally studied in biodiversity estimation of small mammals in northern Strandzha region. During the time period of investigation 2004-2014, the established distribution of Dormouse (Gliridae) in the studied biotopes revealed presence only of dryomis nitedua and glis glis in deciduous woodlands of colchisian-mediterranean type and artificial mixed woodlands. These results corresponds to the established biotopic adherence of Dormouse in other part of its range in Bulgaria where the species inhabits mainly forest habitats, but often meet in uncultivated lands with the shrubby vegetation. Although in previous studies in the research area has been reported about the presence of bone remains from the common dormouse (muscardinus avellanarius) in pellet of birds, under the current study its presence in research area was not confirmed. Habitat fragmentation in investigated region caused human activities such as agriculture, rural development and urbanization can lead to reduction in the amount of available habitat and lowering the total number of inhabiting in them Dormouse species. It is necessary to pay special attention to preserve their integrity and providing continuous monitoring numbers of Dormouse species in them. The set of for standard exterior characters (length of: head and body (lHB), tail (lC), hind foot (lP) and ear (lA), expressed through and their minimum (min), mean (X) and maximum (max) value, measured in [mm], was applied to obtain population somatometrical characteristics and to evaluate species morphometric variation of the studied dormouse. The established exterior characteristics of the adult specimen of glis glis (female, n = 6, lHB = 102,0 - 141,7 - 167,0; lC= 109,0 - 128,7 - 137,0, lP= 24,0 - 26,0 - 28,0, lA = 14,0 - 16,2 -19,0; male, n=6, lHB = 140,0 - 143,3 - 145,0; lC= 114,0 - 116,3 -120,0 , lP = 26,0 - 28,3 - 30,0 , lA = 15,0 - 16,3- 8,0 ; ) and dryomis nitedua (female, n =7, lHB=87,0 - 99,1 - 107,0; lC = 84,0 - 89,2 - 97,0 , lP =18,5 - 20,3 - 21,0 , lA =15,0 - 12,8 - 11,0 male, n=5, lHB = 98,0 - 109,2 - 116,0; lC = 45,0 - 63,9 - 90,0, lP = 21,0 - 22,4 - 26,7 , lA = 15,0 - 17,1 - 23,3 ) from investigated region, which can be considered  a zoogeographical crossroads, with a late Pleistocene connection between the Balkan Peninsula and the mammalian fauna of Anatolian peninsula, enriched the knowledge about its somatometrical variation in europe. The evaluation of local somatometric  characteristics and its variation of  under the specific ecological conditions of the south-eastern part of Thrace, particularly in Strandzha Mountain region, affords an opportunity for comparative analysis and revealing of somatometric  population diversity of this species in main natural and agricultural ecosystems situated on the territory of the Bulgaria and Turkey. Moreover, such characteristics could be useful when the species is observing as bio-indicator as an integral part of bio-monitoring system of rating environment quality in south-eastern part of Thrace, and in other specific parts of the species range.