Brown bear (Ursus arctos) conservation and genetics in northern Greece

Callisto Hauser bears

A PhD study by Charilaos Pilides in collaboration with the Greek NGO Callisto and supported by Hauser Bears and the European Nature Heritage Fund, Euronatur. Supervised by Prof. Stephen Harris.


The largest carnivore of Europe the brown bear (Ursus arctos) remains threatened in Greece with an estimated population size of only 190-260 individuals split into two distinct nuclei over a range of 16,500km2. In the west of the country, the larger bear subpopulation in the country, extends over Pindos mountain range all the way to the Alps and forms the southernmost range of the species in Europe. Approximately 220 km to the east, the Rodopi mountain complex hosts a smaller contiguous bear population with neighbouring Bulgaria.

Over the past two decades intensive conservation actions at a range scale have taken place by NGOs for the conservation of the species and recently and bears have been observed outside their current distribution indicating a possible re-colonisation of their historical range. While this is encouraging, at the same time a rapid development of the transportation infrastructure can be observed throughout the country, leaving a permanent effect on the landscape. An example of such development is Via Egnatia, a 680 km closed highway part of the trans-European highway network (TENT), which connects the eastern with the western part of the country.


Transportation corridors and other large scale infrastructure such as dams and reservoirs may hinder the gene flow of the population. Roads particularly act as a considerable barrier to dispersal of wildlife, have a significant effect in fragmenting habitats and lead local populations to extinction. In Greece this development has lead to a direct increase on bear mortality since over the past two years 10 bears have been killed in road traffic accidents.

As the construction of such infrastructure continues, the need to investigate the unseen effects of this development in terms of fragmentation and viability of bear sub-populations is high. The magnitude of the impact of highways on brown bears can be better evaluated once accurate information on the genetic status of the species, its structure, effective population size, the sources, sinks and connectivity of the population throughout its distribution has been obtained.


To evaluate the conservation status of the brown bear in Greece using genetic methods and to assess the effect of large scale infrastructure on its viability. The whole of the brown bear distribution in the country will be sampled using non-invasive techniques and the effect of human disturbance and landscape characteristics on the gene flow of brown bears will be modelled with the use of Geographic Information Systems. Specifically the main aims are to:

  • Sample representatively the brown bear distribution in Greece with the use of non-invasive genetic methods and investigate its structure, diversity and identify the sources and the sinks of the population.
  • Determine whether the two main distribution nuclei of Pindos and Rodopi are genetically distant or whether there is gene flow between them.
  • Provide a basic level on bear numbers and relative densities in each of the major sample units.
  • Assess the barrier effect of the closed Egnatia highway on the movements and gene flow of bears
  • Evaluate the effect of large scale human disturbances as natural landscape characteristics on gene flow, identify the major recolonisation routes that need to be preserved and proceed in guidelines to ensure habitat connectivity.
  • Create a pedigree for the species in the country.

Relevance to conservation

The project falls under a larger framework of activities targeting bear conservation in the area. The project aims contribute significantly in our knowledge on the conservation status of the brown bears in Greece and on the effect of highways on its fitness. The results will be used to preserve habitat corridors important for bears and other wildlife in the area minimise the ecological impact of large infrastructure in the country. Furthermore the intention is to utilise the results of the project towards the compilation of an evidence based National Action Plan through a human dimension facilitated approach.


Contact details

Charilaos Pilides
Mammal Research Unit
School of Biological Sciences
University of Bristol
Woodland Road
Bristol BS8 1UG, U.K.

Telephone: 0117 9287593
Email: Charilaos Pilidis