On the critical abundance of the taimyr population of wild reindeer
Authors: Shapkin А. , Ivanova R. 
Published: January 2024

The critical population for the existence of the Taimyr population of wild reindeer has been established. The processing of the initial information about the population size was performed using the apparatus of mathematical biology. The main practical task is to identify the lower limits of abundance and the critical load for the population, after which the collapse of this commercial population will occur. Also, regression equations were calculated for the total livestock of the population, the reproductive core (mature females) and juveniles (calves of the year) at different time intervals of the economic use of the resources of this population - Soviet and post-Soviet. For the Soviet period of using the resources of the population in 1969-1990 the parameters of the equation look like: y = 21.867x + 316.77 thousand (R2 = 0.886, Ᾱ = 6, rxy= - 0.41, p<0.05). For adult females, the trend equation for this segment of the reproductive cycles: y = 5.157x + 73.879 thousand, (R2 = 0.836). The total number of the population did not decrease: the average realized reproduction in this segment of the biological cycles is 61 calves per 100 mature females. In the post-Soviet period 1990–2021 equation of the linear trend of the Taimyr population: y = - 36.96х + 624.51 thousand (R2 = 0.75, Ᾱ = 5.18, rxy = 0.46, р<0.05). Evaluation by the straight-line trend equation of the juvenile group (calves of the year) gives a negative calculated value of the linear regression equation within y = - 21.4x + 175.51 thousand. (R2 = 0.944, Ᾱ = 2.9, rxy = 0.98, p<0.01). Such facts unequivocally signal the excess of the optimal intensity of fishing, because there is a gradual decrease in recruitment. The estimated critical number of the Taimyr population is 88.77 thousand wild deer, the critical limit of the fishery with a similar number is the removal of 71.9 thousand individuals. From here, hypothetically, only 16.87 thousand heads remain from the Taimyr population, which will lead to the collapse of this biological population.

The critical population for the existence of the Taimyr population of wild reindeer has been established. The processing of the initial information about the population size was performed using the apparatus of mathematical biology. The main practical task is to identify the lower limits of abundance and the critical load for the population, after which the collapse of this commercial population will occur. Also, regression equations were calculated for the total livestock of the population, the reproductive core (mature females) and juveniles (calves of the year) at different time intervals of the economic use of the resources of this population - Soviet and post-Soviet. For the Soviet period of using the resources of the population in 1969-1990 the parameters of the equation look like: y = 21.867x + 316.77 thousand (R2 = 0.886, Ᾱ = 6, rxy= - 0.41, p<0.05). For adult females, the trend equation for this segment of the reproductive cycles: y = 5.157x + 73.879 thousand, (R2 = 0.836). The total number of the population did not decrease: the average realized reproduction in this segment of the biological cycles is 61 calves per 100 mature females. In the post-Soviet period 1990–2021 equation of the linear trend of the Taimyr population: y = - 36.96х + 624.51 thousand (R2 = 0.75, Ᾱ = 5.18, rxy = 0.46, р<0.05). Evaluation by the straight-line trend equation of the juvenile group (calves of the year) gives a negative calculated value of the linear regression equation within y = - 21.4x + 175.51 thousand. (R2 = 0.944, Ᾱ = 2.9, rxy = 0.98, p<0.01). Such facts unequivocally signal the excess of the optimal intensity of fishing, because there is a gradual decrease in recruitment. The estimated critical number of the Taimyr population is 88.77 thousand wild deer, the critical limit of the fishery with a similar number is the removal of 71.9 thousand individuals. From here, hypothetically, only 16.87 thousand heads remain from the Taimyr population, which will lead to the collapse of this biological population.