Influence of the Introduction of Sika Deer on the Current State of the Number and Distribution of Ungulate Mammals in the Ussuriysky Nature Reserve (Russian Far East)

The results of long-term observations are summed up, making it possible to assess patterns and identify the reasons for changes in the numbers, current distribution, and interspecific relationships of ungulates in the Ussuriysky Nature Reserve. A comparison of archival materials and data from the last decade shows that changes in the abundance and distribution of most ungulate species in the reserve are inextricably linked with the increase in the number of sika deer. After the introduction of this species into the territory over 70 years, its number increased from 25 to 1180 individuals, and the population density reached an average of 30 individuals/1000 ha. Over the same period, the number of red deer in the Ussuriysky Nature Reserve decreased from 450 to 130 individuals, that is, more than three times. In the Suvorovsky forestry, there is currently a decrease in the number by about half (from 250–280 to 110 individuals); in the Komarovsky forestry, the number has decreased by about 10 times (from 180–200 to 15–20 individuals). The number and distribution of roe, musk deer, and wild boar in the territory has not changed as obviously. The current number of roe in the reserve is 170 individuals, with a population density of 4 individuals/1000 ha. The number of wild boars is about 200 individuals, with a population density of 4–5 individuals/1000 ha. The accounting methodology that was developed and applied has made it possible to obtain reliable data on the number and distribution of ungulates throughout the Ussuriysky Nature Reserve. There are concerns about a further increase in the number of sika deer in connection with the implementation of biotechnical measures in the reserve.