Competition Coefficient (α₁₂):
Competition Coefficient (α₂₁):
The Competition Coefficient Calculator is a tool used in ecological and biological studies to measure the competitive interactions between two species sharing the same resources. It determines how one species affects the growth or population of another species relative to its own competition. By quantifying interspecific and intraspecific competition, this calculator aids in understanding ecosystem dynamics and population sustainability.
Formula of Competition Coefficient Calculator
The competition coefficient is calculated using two primary methods:
1. Growth Rate Formula
Competition Coefficient (α₁₂): Effect of Species 2 on Species 1
α₁₂ = (Change in Growth Rate of Species 1 due to Species 2) / (Change in Growth Rate of Species 1 due to Species 1)
Competition Coefficient (α₂₁): Effect of Species 1 on Species 2
α₂₁ = (Change in Growth Rate of Species 2 due to Species 1) / (Change in Growth Rate of Species 2 due to Species 2)
2. Population and Carrying Capacity Formula
Competition Coefficient (α₁₂): Effect of Species 2 on Species 1
α₁₂ = (Population of Species 2 × Resource Usage of Species 2) / (Carrying Capacity of Species 1)
Competition Coefficient (α₂₁): Effect of Species 1 on Species 2
α₂₁ = (Population of Species 1 × Resource Usage of Species 1) / (Carrying Capacity of Species 2)
Key Variables:
- Population of Species 1 and 2: Number of individuals in each species.
- Resource Usage: Amount of shared resources consumed by one individual of a species.
- Carrying Capacity: Maximum population of a species that the environment can sustain, given the available resources.
Key Insights:
- If α₁₂ > 1, Species 2 has a stronger competitive effect on Species 1 than Species 1 has on itself.
- If α₁₂ < 1, Species 2 has a weaker effect on Species 1 compared to its own intraspecific competition.
Useful Conversion Table
| Term | Description | Example Values/Notes |
|---|---|---|
| Population of Species 1 | Number of individuals in Species 1 | E.g., 100 individuals |
| Population of Species 2 | Number of individuals in Species 2 | E.g., 150 individuals |
| Resource Usage | Resources consumed by one individual of a species | E.g., 1 unit of food per individual |
| Carrying Capacity | Maximum sustainable population for a species | E.g., 200 individuals for Species 1 |
| Competition Coefficient | Degree of interspecific competition | Calculated using formulas above |
Example of Competition Coefficient Calculator
Scenario:
Two species, A and B, share the same food resource in a forest. Their populations and resource data are:
- Species A: Population = 100, Resource Usage = 1.5 units/individual, Carrying Capacity = 300.
- Species B: Population = 80, Resource Usage = 1 unit/individual, Carrying Capacity = 250.
Step 1: Calculate α₁₂ (Effect of Species B on Species A)
α₁₂ = (Population of Species B × Resource Usage of Species B) / (Carrying Capacity of Species A)
α₁₂ = (80 × 1) / 300 = 80 / 300 = 0.267
Step 2: Calculate α₂₁ (Effect of Species A on Species B)
α₂₁ = (Population of Species A × Resource Usage of Species A) / (Carrying Capacity of Species B)
α₂₁ = (100 × 1.5) / 250 = 150 / 250 = 0.6
Interpretation:
- α₁₂ = 0.267: Species B has a weaker effect on Species A compared to Species A’s own competition.
- α₂₁ = 0.6: Species A has a moderate competitive effect on Species B.
Most Common FAQs
The competition coefficient quantifies the impact of one species on another in terms of shared resource use and population growth.
It helps ecologists understand species interactions, predict population dynamics, and evaluate ecosystem stability.
Yes, a coefficient greater than 1 indicates that the interspecific competition is stronger than intraspecific competition for the affected species.