calculating biodiversity

Question 1

intro

Answer 1

Ecologists, such as those working for the Environment Agency, often perform calculations using specific formulae to determine the biodiversity of an area. One such calculation is a measure of the species diversity. The diversity of the organisms present in an area is normally proportional to the stability of the ecosystem, so the greater the species diversity the greater the stability. The most stable communities have large numbers of fairly evenly distributed species, in good-sized populations.

Pollution often reduces biodiversity. As a result of harsh conditions, a few species tend to dominate. If corrective steps are taken to improve environmental conditions, biodiversity levels usually increase.
Monitoring biodiversity is therefore a useful tool in successful conservation and environmental management.

Question 2

how to calculate biodiversity

Answer 2

The simplest way to measure biodiversity is to count up the number of species present - the species richness. However, this measure does not take into account the number of individuals present. Therefore in a meadow containing two daisies and 1000 buttercups, the daisies have as much influence on the richness of the area as 1000 buttercups. A community dominated by one or two species is considered to be less diverse than one in which several different species have a similar abundance.
Simpson’s Index of Diversity (D) is a better measure of biodiversity as it takes into account both species richness, and species evenness.
It is calculated using the formula:
D=1-[(n/N)*2
where:
[= sum of (total)
N = the total number of organisms of all species and
n = the total number of organisms of a particular species.
When using a technique such as Simpson’s Index of Diversity, scientists normally have to estimate population size using a variety of sampling techniques, such as using a quadrat to estimate the population of a plant species in an area.
Simpson’s Index of Diversity always results in a value between 0 and 1, where 0 represents no diversity and a value of 1 represents infinite diversity. The higher the value of Simpson’s Index of Diversity, the more diverse the habitat.

Question 3

biodiversity values

Answer 3

Although some habitats of low biodiversity are unable to support a large species diversity, those organisms that are present in the habitat can be highly adapted to the extreme environment of the habitat.
These organisms may not survive elsewhere. It is therefore important to conserve some habitats with low biodiversity, as well as those with high biodiversity, in order to conserve rare species that may be too specialised to survive elsewhere.