An ecological survey was conducted to assess the biodiversity of a woodland clearing. The table shows the number of individuals of different tree species sampled in a quadrat:
| Tree Species | Number of individuals (nnn) |
|---|---|
| English Oak (Quercus robur) | 15 |
| Silver Birch (Betula pendula) | 8 |
| Common Beech (Fagus sylvatica) | 5 |
| Rowan (Sorbus aucuparia) | 2 |
Using the formula:
d=N(N−1)∑n(n−1) d = \frac{N(N-1)}{\sum n(n-1)} d=∑n(n−1)N(N−1)where N N\,N is the total number of organisms of all species and n n\,n is the total number of organisms of each species, calculate the index of diversity (ddd) for this woodland clearing.
Which of the following options correctly states the value of ddd (to 2 decimal places) and provides the correct ecological interpretation of a high index of diversity?
d=3.02d = 3.02d=3.02; a high value of ddd indicates a more stable ecosystem with complex food webs, meaning a change in abiotic conditions is less likely to affect all species.
d=3.02d = 3.02d=3.02; a high value of ddd indicates a less stable ecosystem because intense interspecific competition makes the community highly vulnerable to abiotic changes.
d=0.33d = 0.33d=0.33; a low value of ddd indicates a more stable ecosystem because a few highly adapted dominant species can survive any environmental change.
d=2.83d = 2.83d=2.83; a high value of ddd indicates a highly stable ecosystem because there is a high level of genetic diversity within each of the species present.
