The impact of the railway on the movement of wild ungulates in Central Yakutia

The construction of linear structures significantly impacts the livelihoods of wild ungulates in Yakutia, disrupting the integrity of the natural environment by fragmenting forest areas and reducing the extent of forest biocenoses and wildlife habitats. Between 2015 and 2022, studies were conducted to assess the impact of the Berkakit–Tommot–Nizhny Bestyakh railway on the movements of wild ungulates in Central Yakutia. During the winter months (November to January), seven trails, totaling 280 km, were surveyed along a 40 km section of the railway. A total of 115 tracks from four species of wild ungulates—Siberian roe deer, wild reindeer, red deer, and elk—were recorded over various years. We observed that the negative impact of the engineering structure on the movements of wild ungulates was primarily evident during the initial phase of its construction. During the early stages of railway construction, the high level of disturbance and the introduction of an unfamiliar artificial structure disrupted the natural movement patterns of wild ungulates. However, these patterns were restored following the completion of the railway. Wild ungulates exhibited varying responses to the unfamiliar artificial structure: wild reindeer began to cross the railway in the first year after its construction, while roe deer and red deer did so within one year, and elk took six years to adapt. The natural movement routes of wild ungulates were reestablished four to five years after the railway was completed. The succession of vegetation in the altered forest landscapes along the railway enhanced the forage base for roe deer, red deer, and elk, as abundant grass and shrub cover emerged, leading to the development of new alternative habitats in the previously disturbed areas. Therefore, the Berkakit-Tommot-Nizhny Bestyakh railway, at its current level of operational intensity, does not pose a significant threat to the movement paths of wild ungulates.