Biodiversity & population indices

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Card 1 of 65.1.9

5.1.9

Question

State Simpson's reciprocal diversity index formula.

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All 6 Flashcards — Biodiversity & population indices

Card 1concept

Question

State Simpson's reciprocal diversity index formula.

Answer

$D = \dfrac{N(N-1)}{\sum n(n-1)}$ — where $N$ = total individuals (all species) and $n$ = individuals of each species. Higher $D$ = more diverse (minimum 1).

Card 2concept

Question

State the Lincoln (capture–mark–recapture) index formula.

Answer

$N = \dfrac{n_1 \times n_2}{n_3}$ — $n_1$ = marked & released, $n_2$ = second catch, $n_3$ = marked individuals in the second catch, $N$ = estimated total.

Card 3definition

Question

In Simpson's index, what are $N$ and $n$?

Answer

$N$ = the TOTAL number of individuals of ALL species added together; $n$ = the number of individuals of ONE particular species.

Card 4concept

Question

Two communities have the same number of species — why might their $D$ differ?

Answer

Because $D$ also depends on **evenness**. A community dominated by one species has a LOWER $D$ than one where individuals are spread evenly.

Card 5concept

Question

Name two assumptions of the Lincoln index.

Answer

Marks don't harm the animals or change catchability; marked animals mix back fully; no births, deaths or migration between samples; marks aren't lost.

Card 6concept

Question

How do you use Simpson's index to measure biodiversity CHANGE over time?

Answer

Sample the same site with the same method each year, calculate $D$ each time, and compare — a rising $D$ means biodiversity is increasing.

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Topic 5.1 hub

Experimental and data skills

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