An investigation was carried out in a temperate woodland that contained a number of areas with two different types of ground cover vegetation. • On higher ground where the soil was drier, the dominant ground cover plant was bracken, Pteridium aquilinum. • On lower ground where the soil was wetter, the dominant ground cover plant was bramble, Rubus fruticosus.

1. (a)Describe how the abundance of the two plant species at higher and lower ground sites could be measured.[4]
2. (b)(i)Soil from under bracken and under brambles was collected and placed in two funnels. A bright light was placed over each funnel so that small invertebrate animals moved down the funnels and were collected in two collecting vessels. The main groups of invertebrates present were identified and counted. Some of the results are shown in Table 8.1. Table 8.1 invertebrate group | number present in soil under bracken | number present in soil under brambles --- | --- | --- pseudoscorpion | 49 | 21 wireworm | 22 | 12 gamasid mite | 18 | 7 springtail | 10 | 1 total | 99 | 41 It was not possible to identify the invertebrates as far as genus or species level, and only the wireworm group could be classified as far as the taxonomic level above genus. Name the taxonomic level represented by the wireworm group.[1]
3. (b)(ii)State the null hypothesis for a statistical test comparing the data from the two types of site.[1]
4. (b)(iii)Simpson’s Index of Diversity for invertebrates from the soil under bracken was calculated as 0.663 using the formula: D = 1- (Σ(n/N)²) n = number of individuals of each species present in the sample N = the total number of all individuals of all species. Calculate Simpson’s Index of Diversity for the invertebrates from the soil under brambles. Complete Table 8.2 and use the space provided to show your working. Show all working to three decimal places. Write your final answer on the dotted line. Table 8.2 animal taxon | number present in soil under brambles | n/N | (n/N)² --- | --- | --- | --- pseudoscorpion | 21 | | wireworm | 12 | | gamasid mite | 7 | | springtail | 1 | | total | 41 | | Simpson’s Index of Diversity =[3]
5. (b)(iv)Describe what Table 8.1 and the calculated figures for Simpson’s Index of Diversity show about the effect of bracken and bramble vegetation cover on the diversity and abundance of soil invertebrates in the woodland.[2]

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