The table below gives the populations (in thousands) of ten species (A-J) in four areas (a-d) consisting of the number of habitats given within brackets against each. Study the table and answer the question which follows: [figure] Which area out of a to d shows maximum species diversity?
- b
- d
- c
- a
Answer
(2) d
Solution
Species richness (number of species present, '–' = absent):
area a: 8 species (E and I absent); area b: 7 species (B, D and G absent); area c: 10 species; area d: 10 species.
Areas c and d have equal richness, so we compare evenness. In c, most individuals belong to A (11.3) and H (8.4), and five species have small populations (below 1.5 thousand), whereas in d the populations of A to J are more evenly distributed (four species have large populations, 7.3–11.3 thousand).
The Shannon diversity index H = - pi pi confirms this: area c ≈ 1.91, area d ≈ 2.01.
∴ Area d, with the maximum number of species and the most even distribution of their populations, shows the maximum species diversity.
Answer: (2)