Comparing ecosystems using Simpson’s Diversity Index
| Species | Rockhampton | Cairns | Toowoomba | |||
| n | n(n-1) | n | n(n-1) | n | n(n-1) | |
| A | 10 | 90 | 72 | 5512 | 35 | 1190 |
| B | 9 | 72 | 6 | 30 | 34 | 1122 |
| C | 11 | 110 | 3 | 6 | 31 | 930 |
| D | 10 | 90 | 3 | 6 | 0 | 0 |
| E | 8 | 56 | 1 | 0 | 0 | 0 |
| F | 12 | 132 | 3 | 6 | 0 | 0 |
| G | 10 | 90 | 4 | 12 | 0 | 0 |
| H | 11 | 110 | 3 | 6 | 0 | 0 |
| I | 10 | 90 | 2 | 2 | 0 | 0 |
| J | 9 | 72 | 3 | 6 | 0 | 0 |
| Total (N) | 100 | 912 | 100 | 5186 | 100 | 3242 |
Calculate Simpsons Diversity Index for the three ecosystems in the table (Rockhampton, Cairns and Toowoomba).
Low species diversity (numbers close to 0) suggests:
- relatively few successful species in the habitat
- the environment is quite stressful with relatively few ecological niches and only a few organisms are really well adapted to that environment
- food webs which are relatively simple
- change in the environment would probably have quite serious effects
High species diversity (numbers close to 1) suggests:
- a greater number of successful species and a more stable ecosystem
- more ecological niches are available and the environment is less likely to be hostile
- complex food webs
- environmental change is less likely to be damaging to the ecosystem as a whole