Species Population Viability Calculator
Estimate a species population trajectory using exponential growth or decline based on birth rate, death rate, and current population.
Projected Population
1,359
Projected Population vs Projection Period
सूत्र
## Population Viability Analysis Population viability analysis (PVA) projects whether a species can sustain itself over time. The simplest model uses exponential growth. ### Formula **N(t) = N0 x e^(r x t)** Where N0 is the current population, r is the net growth rate (birth rate minus death rate), and t is time in years. A positive r indicates growth; negative r indicates decline. The minimum viable population for most mammals is estimated at 500-5,000 individuals.
हल किया गया उदाहरण
500 individuals with a 12% birth rate and 10% death rate, projected 50 years.
- 01Net growth rate = 0.12 - 0.10 = 0.02 (2%/year)
- 02Projected = 500 x e^(0.02 x 50) = 500 x e^1.0 = 500 x 2.718 = 1,359
- 03Doubling time = ln(2) / 0.02 = 34.7 years
अक्सर पूछे जाने वाले प्रश्न
What is the minimum viable population?
The minimum viable population (MVP) is the smallest number of individuals needed for a 95% chance of survival over a set period. For most vertebrates, estimates range from 500 to 5,000.
Does this model account for inbreeding?
No. This simple exponential model ignores genetic factors. Small populations face inbreeding depression, which reduces fitness and can accelerate decline.
What is an extinction vortex?
An extinction vortex occurs when declining populations suffer compounding problems: reduced genetic diversity, inability to find mates, and loss of social structure, each accelerating the decline.