title

Large carnivorans in fragmented landscapes: road mortality of bears and a new case from Ukraine

author(s)

Igor Merzlikin (orcid: 0000-0002-8337-327X)

affiliation

Mykhailivska Tsilyna Nature Reserve (Sumy, Ukraine);
A. S. Makarenko Sumy State Pedagogical University (Sumy, Ukraine)

bibliography

Theriologia Ukrainica. 2025. Vol. 30: 119–126.

DOI

language

Ukrainian, with English summary, titles of tables, captures to figs

abstract

Habitat fragmentation of animals, especially large mammals, leads to increased contact with roads, which, in turn, often results in incidents on motorways and railways. Road mortality is currently recognised as one of the important anthropogenic factors affecting populations of large carnivorans, and records of wildlife–vehicle collisions are increasingly used as an indicator of changes in species distribution and spatial activity. Analyses of factors influencing bear mortality on roads in other countries showed that deaths of bears on motorways and railways depend on a range of factors, the most important of which include traffic intensity and speed, road characteristics and surrounding landscapes, season and time of day, as well as behavioural features determined by the age and sex of the animals. In Ukraine, researchers have paid little attention to the causes of bear mortality (except for hunting-related cases), largely due to the low population size of the species and the rarity of confirmed records. However, the growth of the bear population in Ukraine and the increase in its migratory activity will undoubtedly raise the risk of mortality caused by road traffic. Therefore, it is important to develop and implement measures aimed at preventing and/or minimising collisions between animals and vehicles, particularly in regions where the species is expanding its range. This paper presents a description of a finding of a dead bear cub killed by a vehicle west of Horodets (Sarny Raion, Rivne Oblast), in early August 2025, nearby to the Horyn River in the Tryshcheva tract. At this site, the road passes through a forest habitat, with an old oak forest on one side and a mixed plantation established in the 1990s on the other. The importance of this record lies in the following aspects: it represents a new record of the species in Sarny Raion; the occurrence of a bear cub indicates local reproduction of the species (it is unlikely that a female bear would undertake long-distance movements with a very young cub); and this is the first documented case of death of a brown bear cub on roads in Ukraine. This new record demonstrates the southward and eastward expansion of the species within Rivne Oblast, indicating an expansion of the Polissia segment of the species’ range, which can be regarded, to some extent, as population recovery.

keywords

large carnivorans, brown bear, wildlife–vehicle collisions, habitat fragmentation

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