Calculate one year of steady-state population dynamics

Calculates one year of population dynamics under steady-state assumptions using demographic parameters and returns population size statistics and offtake results. The steady state is defined as a constant sex–age cohort structure over time, with population size potentially growing or declining at a constant rate.

Usage

calc_projected_population_size(
  herd_size_total,
  fecundity_female,
  fecundity_male,
  probability_death,
  probability_offtake,
  probability_growth,
  growth_rate_herd,
  herd_structure,
  cohort_share
)

Arguments

herd_size_total: Numeric. Total population size at the start of the year, including all cohorts (# heads)
fecundity_female: Numeric. Daily number of female offspring per adult female (# offspring/day)
fecundity_male: Numeric. Daily number of male offspring per adult female (# offspring/day)
probability_death: Named numeric vector of length 10. Probability of animal dying within the model time interval for 10 cohorts (fraction) (cohorts= FB: Female Birth, FJ: Female Juvenile, FS: Female Sub-adult, FA: Female Adult, FC: Female Culling, MB: Male Birth, MJ: Male Juvenile, MS: Male Sub-adult, MA: Male Adult, MC: Male Culling).
probability_offtake: Named numeric vector of length 10. Probability that an animal will be removed from the herd within the model time interval for 10 cohorts (fraction). (cohorts= FB: Female Birth, FJ: Female Juvenile, FS: Female Sub-adult, FA: Female Adult, FC: Female Culling, MB: Male Birth, MJ: Male Juvenile, MS: Male Sub-adult, MA: Male Adult, MC: Male Culling).
probability_growth: Named numeric vector of length 10. Probability of growing into the next age class for 10 cohorts (fraction) (cohorts= FB: Female Birth, FJ: Female Juvenile, FS: Female Sub-adult, FA: Female Adult, FC: Female Culling, MB: Male Birth, MJ: Male Juvenile, MS: Male Sub-adult, MA: Male Adult, MC: Male Culling).
growth_rate_herd: Numeric. Annualized growth rate at which the herd reaches steady state (fraction)
herd_structure: Named numeric vector of length 8. Final steady-state share of each of 8 sex-age cohorts (FB, FJ, FS, FA, MB, MJ, MS, MA) (fraction). Shares should sum to 1.
cohort_share: Named numeric vector of length 6. Final steady-state share of 6 grouped sex-age cohorts (FJ, FS, FA, MJ, MS, MA, where FJ = FB + FJ and MJ = MB + MJ) (fraction). Shares should sum to 1.

Value

A named list with:

cohort_stock_start: Numeric vector of length 6. Population size in each of the 6 sex–age cohorts at the start of the year (# heads). (cohorts= FJ, FS, FA, MJ, MS, MA)
cohort_stock_end_projected: Numeric vector of length 6. Population size in each of the 6 sex–age cohorts at the end of the year, projected using the steady-state growth rate (# heads). (cohorts= FJ, FS, FA, MJ, MS, MA)
cohort_stock_end_exact_simulated: Numeric vector of length 10. Population size in each of 10 sex–age cohort at the end of the year, based on a demographic daily simulation over 365 days (# heads) (cohorts= FB: Female Birth, FJ: Female Juvenile, FS: Female Sub-adult, FA: Female Adult, FC: Female Culling, MB: Male Birth, MJ: Male Juvenile, MS: Male Sub-adult, MA: Male Adult, MC: Male Culling)
cohort_stock_average: Numeric vector of length 6. Average population size in each of the 6 sex–age cohorts over the year (# heads). Estimated from cohort_stock_start and cohort_stock_end_projected (cohorts= FJ, FS, FA, MJ, MS, MA)
cohort_offtake_heads: Numeric vector of length 10. Total number of animals removed from the herd over the year, by 10 sex–age cohorts (heads/year) (cohorts= FB: Female Birth, FJ: Female Juvenile, FS: Female Sub-adult, FA: Female Adult, FC: Female Culling, MB: Male Birth, MJ: Male Juvenile, MS: Male Sub-adult, MA: Male Adult, MC: Male Culling)

This function is part of the run_demographic_herd_module().

Usage

Arguments

Value

See also