PAG 03 - Sampling Techniques Flashcards
List 3 abiotic factors.
Light intensity Temperature Water supply Nutrient supply
Humidity Wind speed Day length Rainfall
List 3 biotic factors.
Competition for resources Predation
Disease
How is percentage cover calculated?
Use a quadrat with squares. Count how many squares the required species is present in. Only count a square is more than half of the square is covered.
Outline the procedure to this practical.
- Choose an area to take samples from. Use a random number generator to generate 10 sets of random coordinates.
- Use two tape measures to create a set of axes off which coordinates can be read.
- Place the quadrat at each of the coordinates, placing the bottom left corner on the coordinate every time.
- Record the percentage cover for the chosen species.
- At each coordinate, a measure of the independent variable should be taken.
Eg. record light intensity using a photometer at each location
How can the results be used to determine the relationship between the chosen factor and the percentage cover?
Use a statistical test eg. Pearson’s linear correlation, Spearman’s rank
State Simpson’s Index of Biodiversity.
D = 1 - [sum(n / N)2]
What is species diversity?
Number of different species in a community and the relative abundance of each population.
What is the advantage of random sampling?
Prevents selective sampling from causing bias.
Outline the procedure of using a transect for systematic sampling.
- Use a measuring tape to make a transect over the area you wish to sample.
- Place quadrats at given intervals along the tape measure (e.g. every 5 metres). The bottom left-hand corner of each quadrat should be touching the relevant metre mark, and the left-hand edge runs along the tape measure
- Identify the different species in each quadrat using a key and count the number of each present. Calculate the percentage cover.
Which type of graph is used to represent the distribution of a species along a transect?
A kite diagram
