Species Population Viability Rechner
Project species population growth or decline over time. Schätzen Sie viability unter Verwendung von birth und death rates mit exponential modeling.
Projected Population
1,359
Projected Population vs Projection Period
Formel
## 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.
Lösungsbeispiel
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
Häufig Gestellte Fragen
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.