An ecologist assesses the ground-dwelling beetle biodiversity in two forest compartments, Compartment P and Compartment Q, which are managed under different forestry schemes. The abundance of three beetle species captured in pitfall traps is shown in the table below:
| Species | Compartment P (nnn) | Compartment Q (nnn) |
|---|---|---|
| Carabus violaceus | 15 | 85 |
| Pterostichus madidus | 18 | 10 |
| Nebria brevicollis | 17 | 5 |
| Total (NNN) | 50 | 100 |
Using the Simpson's Index of Diversity formula, d=1−∑(nN)2\displaystyle d = 1 - \sum \left(\frac{n}{N}\right)^2d=1−∑(Nn)2, which of the following statements is a correct interpretation of these ecological data?
Compartment Q has a higher index of diversity than Compartment P because its total population size (N=100N = 100N=100) is twice as large, leading to higher genetic variation.
Compartment P has a higher index of diversity (d≈0.66d \approx 0.66d≈0.66) than Compartment Q (d≈0.27d \approx 0.27d≈0.27) because both compartments have the same species richness, but Compartment P has greater species evenness.
Compartment Q has a higher index of diversity because its community is dominated by one highly abundant species (Carabus violaceus), which increases ecosystem stability.
Compartment P and Compartment Q have identical indexes of diversity because they both contain exactly three species, meaning they have the same species richness.
