Biodiversity analysis of mammals in the upper Indigirka River valley

limited number of scientific publications are devoted to the analysis of small mammal communities in North-East Yakutia, which does not allow us to estimate their previous abundance and distribution across biotopes in the upper reaches of the Indigirka River. Research on this topic in 2023 made it possible to obtain new, unique data on the state and abundance of game species and small mammals in the Oymyakon ulus (district) of the Republic of Sakha (Yakutia) in valley biotopes. The purpose of the work was to determine the biodiversity of mammals in the floodplain lands of the upper reaches of the Indigirka River. Research in the Oymyakon ulus (district) of the Republic of Sakha (Yakutia) was carried out in March-July 2023 in lands adjacent to one of the depleted gold deposits on the Bolshoy Taryn River, which is a right tributary of the Indigirka River. According to literary sources, 17 game species of mammals live in the study area. In 2023, three routes with a total length of 19.4 km were completed, on which traces of eight species were recorded. In the process of analyzing the trace activity of wild animals registered during the winter route surveys, it was found that traces of small animals (squirrel, ermine, Arctic hare, fox) were found in the immediate vicinity of the infrastructure facilities of the developed deposits. Traces of large, more anthropomorphic animals (elk, wild reindeer) and sable were recorded at some distance from industrial facilities. It was shown that the current population density of game species living in the floodplain of the Bolshoy Taryn River is within the limits of the official data of the Hunting Department of the Ministry of Ecology of the Republic of Sakha (Yakutia) for the Oymyakon ulus (district). This indicates the absence of a significant impact of industrial facilities on game species. To assess the biodiversity of small mammals using standard methods, 40 specimens were captured. During the capture period, 600 trap-days and 72 cone-days were processed. The Shannon diversity index for the small mammal community was 1.262. This shows the low biodiversity of small mammal species from the Insectivora and Rodents orders, which is explained by the peculiarities of the natural conditions of the area. The second reason for the small number of captured species, compared with those caught earlier in the middle reaches of the Indigirka River, is the fact that the capture of small mammals was carried out almost only in the valley of the Bolshoy Taryn River

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