The growth rate of a moose (Alces alces L.) population in early winter

Abstract

In practice of moose production planning estimates of the population size and the data on the magnitude of the increase are used (the number of embryos in pregnant females and number of females with calves), which are not accurate enough due to the large range of estimate of barrenness females (lim.: 5.2-72.1%), and unknown proportion of females in some populations. A large range of values of the proportion of calves in samples from 43 regions: 8.3-35.7% due to differences in habitat conditions and errors of observation. In our material the proportion of calves in the autumn herd was 16.8-24.3% and estimate juvenile mortality by November was 38.6-47.6% of that it less than published data (55-81%). The identity of estimates of the growth rate calculated from data of field observations and the parameters of survival and mortality has led to creation of method of calculation of average growth of livestock by the beginning of winter l using the number of calves (cj) in total sample (n) consisting of detected animals in the nature in October-November: λо = n / (n - cj). For example, a sample of 973 elk with calves c₁ = 163 gives the value of the exponent of the growth rate of the population at the beginning of winter: λo = 973 / (973 - 163) = 1,2012; and the growth rate of r₀ = ln 1.2012 = 0.183. The value r₀ = 0.183 in the form of the lagged growth rate: h = 1 - e^{- 0.183} = 0.168 (16.8%) serves as a measure of the limit value for total mortality of this species during the winter period providing zero growth rate of population. Second equation makes it easy to obtain values of parameter 1: regression of growth value on the date of the observations: y = 1.6212 • X^-0.1271; (R² = 0.8754) improving availability of the indicator "growth rate at the beginning of winter" for the practice of calculation of quotas of moose extraction.