Calculate the index of diversity for this site using the formula: d = \frac{N(N-1)}{\Sigma(n(n-1))} Where: - N = Total number of individuals - n = Number of individuals of each species - AQA - A-Level Biology - Question 4 - 2017 - Paper 3

Now calculate \Sigma(n(n-1)) for each species:

• For Hydrocotyle vulgaris: $3(3-1) = 3 \times 2 = 6$
• For Plantago maritima: $19(19-1) = 19 \times 18 = 342$
• For Ranunculus acris: $3(3-1) = 6$
• For Hieracium pilosellum: $3(3-1) = 6$
• For Calligonum cuspidatum: $10(10-1) = 90$
• For Prunella vulgaris: $16(16-1) = 240$
• For Pseudoscleropodium purum: $6(6-1) = 30$

Adding these together: $\Sigma(n(n-1)) = 6 + 342 + 6 + 6 + 90 + 240 + 30 = 720$

Plugging the values into the formula gives: $d = \frac{59(59-1)}{720} = \frac{59 \times 58}{720} = \frac{3422}{720} \approx 4.92$ Therefore, the index of diversity for this site is approximately 4.92.