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Table 1 Parameters of the VORTEX model used to simulate Crested Ibis population growth

From: Can we reestablish a self-sustaining population? A case study on reintroduced Crested Ibis with population viability analysis

Variable Explanation or notes Default values
# of iterations # of times the simulation is run 500
# of years # of years the population is modeled 50 (2019‒2068)
Extinction definition How extinction is defined in the model Only one sex remains
# of populations # of populations to be modeled 1
Inbreeding depression The level and effect of inbreeding depression Yes
Lethal equivalents The severity of inbreeding depression 0
EV concordance of reproduction and survival The concordance between reproduction and survival in different populations Not applicable—only 1 population modeled
Dispersal rate The rate of dispersal between populations Not applicable—only 1 population modeled
Reproductive system The mating system Monogamy (Zhai et al. 1994)
Age at 1st reproduction in females Age at which females begin breeding 2 (Zhai et al. 1994)
Age at 1st reproduction in males Age at which males begin breeding 2 (Zhai et al. 1994)
Maximum age at reproduction Age of females/males when breeding ceases 15 (Yu et al. 2007)
Maximum # of progeny produced/year Maximum # of offspring produced by females each year 5 (Zhai et al. 2001)
Sex ratio at birth Sex ratio of offspring at hatching 1:1
Density dependence of reproduction The relationship between reproduction and population density Yes
P(0) % adult females breeding at low density 35.70% (Additional file 1: Table S1)
P(K) % adult females breeding at carrying capacity 50.00% (estimates)
A Allee parameter 0 (Chen 2018)
B Steepness parameter 2 (Ralls et al. 1988)
Proportion of adult females breeding The percentage of adult females that breed each year (35.7 − ((35.7 − 50) × ((N/K)2))) × (N/(0 + N))
EV in % breeding EV in % of adult females breeding each year 10% set as default
Distribution of # of offspring/female Statistical distribution characterizing the # of offspring produced Specify exact distribution
1. Offspring
2. Offspring
3. Offspring
4. Offspring
5. Offspring
Percentages of females with certain numbers of offspring 1.25%
2.50% (Additional file 1: Table S2)
Female mortality Mortality rates of females, specified for three age classes (0–1, 1–2, and 2+) by the mean and SD For baseline: 0–1, 45.1%; 1–2, 15.1%; 2+, 5.9% (Wang 2015); SD set at 10% of the mean as default
Male mortality Mortality rates of males, specified for three age classes (0–1, 1–2, and 2+) by the mean and SD Identical to female mortality
Number of catastrophes Each type of catastrophe is implemented separately and occurs independently 2
Catastrophe frequency Frequency of catastrophes affecting the population Catastrophe 1: 14%
Catastrophe 2: 15%
Catastrophe severity Reduction in survivorship/reproduction as a result of the catastrophe Catastrophe 1: reduction in survivorship/reproduction: 0.1/0.1
Catastrophe 2: reduction in survivorship/reproduction: 0.1/0.1
Mate monopolization % of adult males breeding/year 28.11% (Additional file 1: Table S1)
Initial population size The number of individuals at the beginning of the simulation 150 (population size in 2018)
Age distribution of initial population Distribution of individuals by age at the beginning of the simulation Stable age distribution
Carrying capacity The carrying capacity of the environment 420 (estimates)
Harvest Whether individuals were removed from the population No harvest
Supplementation Whether individuals were added to the population No supplementation
  1. #: number; EV: environmental variability