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VORTEX example

Data Needed for a Population Viability Analysis (PVA) with Vortex

  1. Dynamic Life Table (Updated Annually):

    • Annual breakdown of the population’s age structure, survival rates, mortality rates, and fecundity for each age class.
    • This allows for real-time adjustments in the model based on observed population changes, enhancing the model’s responsiveness and predictive accuracy.

  2. Initial Population Size and Structure:

    • Number of males and females in each specific age class (e.g., 0-1 year, 1-5 years, etc.).
    • This detail is crucial to accurately modeling mortality and reproduction rates within each group.

  3. Probability of Reproduction by Female Age Class:

    • Proportion of females reproducing each year, broken down by age class.
    • It helps reflect changes in fecundity as females age.

  4. Litter Size:

    • Average number of offspring per reproductive event and annual variability in litter size.
    • Specify if litter size changes with age or environmental conditions.

  5. Age- and Sex-Specific Survival Rates:

    • Annual survival rates specific to each age and sex group (e.g., 75% annual survival for juveniles aged 1-3 years).
    • Include environmental variability (standard deviation) to simulate annual fluctuations.

  6. Age of Sexual Maturity:

    • Average age at which males and females reach sexual maturity.
    • This data defines when each individual can begin contributing to reproduction.

  7. Maximum Lifespan:

    • Documented maximum age for the species.
    • This sets a boundary for individual longevity in simulations.

  8. Immigration and Emigration Rates:

    • The average number of individuals entering and leaving the population each year.
    • Useful for simulating connectivity and evaluating the impact of individual movement.

  9. Inbreeding Coefficient:

    • Information on the initial inbreeding coefficient of the population.
    • Important for modeling inbreeding effects in small or isolated populations.

  10. Catastrophe Probability and Severity:

    • Frequency of specific catastrophic events (droughts, fires, diseases) and their impact percentage on mortality or fecundity.
    • Specify both the frequency (e.g., once every 10 years) and the reduction in survival or fecundity.

  11. Additional Genetic Data (Optional):

    • Initial level of genetic diversity, rate of diversity loss, and mutation rate.
    • These data help assess long-term genetic risks.

  12. Carrying Capacity (K):

    • Habitat carrying capacity, or the maximum number of individuals the environment can sustain.
    • Include any environmental variability affecting carrying capacity (e.g., fluctuations due to resource availability).

  13. Density-Dependent Mortality Rate:

    • How population density influences mortality or fecundity rates, especially when the population approaches carrying capacity.
    • This parameter is important to simulate the effects of resource competition.