UK GCSE level age ~14-16, ~US grades 9-10 Biology revision notes re-edit 23/05/2023 [SEARCH]

Surveying ecology : 6. Kite diagrams to show abundance and distribution of organisms, graphical representations of biodiversity data e.g correlation between two variables

Doc Brown's Biology exam study revision notes

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There are various sections to work through, after 1 they can be read and studied in any order.

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(6A) Kite diagrams to show abundance and distribution of organisms

Kite diagrams are used to show abundance and distribution of organisms along a transect.

The transect can be measured out in a linear way across a habitat e.g. a field, a stretch of woodland, a rive bank - methods of surveying and using quadrats has already been described in previous sections.

You might counting the abundance of identified species in 1 m2 quadrats.

A kite diagram could also be produced based on the depth of an aquatic or marine environment, where the transect is simply a vertical sampling line - you sample the water a fixed depth intervals.

You might be counting the number of identified species in given volume of water e.g. 1 litre.

An example of a kite diagram is shown below involving counting three species at 1 m intervals.

The vertical y axis represents the abundance of the organism e.g.

the percentage cover in vegetation or lichen on a stone surface,

It might represent the number of crustaceans per volume of water,

or any other quantitative measure of the abundance of an organism.

The abundance is plotted above and below the zero base line to give a symmetrical shape (often 'kite looking').

The relative abundance of each organism at a given distance along the transect is given by the thickness of the 'kit shape'

The horizontal x axis is the distance along the line of the transect.

Examples of interpreting a kite diagram (based on the diagram above)

Species 1:

To the nearest m, it occurs twice between 1 and 24 m, and, 32 and 45 m along the transect.

The maximum abundance of 14% occurs at 5 m and 18.5 m along the transect.

Species 2:

To the nearest m, it occurs three times at 1-10 m, 11-36 and 38-55 m along the transect.

The maximum abundance of 14% occurs at 29 m and 43 m along the transect.

Species 3:

To the nearest m, it occurs once between 35 and 56 m along the transect.

The maximum abundance of 22% occurs at 51 m along the transect.

(6B) Graphical representations of biodiversity and ecology data

Examples (B = x axis, A = y axis)

Graph 1 Positive correlation

Variable B could be distance in km from a polluted urban area into farmland and woodlands.

Variable A could be a measure of biodiversity e.g. all species of animals or perhaps specific type of organism like butterflies.

A not unsurprising positive correlation as the environment becomes less polluted.

Graph 2 Negative correlation

Variable B could be the concentration of a pollutant in a lake.

Variable A could be the population density (concentration) of an organism affected by the pollution.

A not unsurprising negative correlation, increase in pollution levels, decreases the population of an organism.

Graph 3 No obvious correlation

Variable B could be the distance from the centre of deciduous woodland to the edge of the wood.

Variable A could be the population density of a particular organism e.g. a fungus growing on the ground.

If the woodland is fairly constant in composition, then you not expect any gradation in the density of the population of the fungus.

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