Field investigation

• The aim of part A is to use random sampling to estimate the population size of a plant species.
• The method for part A involves using a random number generator to obtain 2 numbers, which are used as coordinates to find a location on the 2 tape measures set up.
• In part A, the quadrat is set down at the coordinates and the number of the required plant species is counted and recorded.
• The process in part A is repeated 9 times to take 9 more samples.
• The population size is estimated using the formula: area sampled / total area x number of plant species counted.
• The aim of part B is to use continuous sampling with a transect line to investigate the effect of variation in a factor on the distribution of a plant species.
• The equipment for part B includes a frame quadrat (25 cm by 25 cm), tape measures, clipboard, pen, and paper.
• In part B, a hypothesis of the effect of a change in an abiotic factor (eg light intensity) on the distribution of the plant species is written down.
• A tape measure is laid down from the base of a tree to an open area of ground/ along a location with an ecological gradient.
• The quadrat is placed along the ‘0’ end of the tape measure, with one corner touching the ‘0’ mark.
• The number of plants is counted and recorded in a table.
• The process in part B is repeated at 5 m intervals until the end of the transect line is reached.
• Data from the class is gathered to find the mean number of plants at each point along the transect.
• A graph of ‘number of plants’ against the ecological gradient that is observed as the distance along the transect line increases is plotted.
• The results are compared to the hypothesis.
• Without repetitions, the results from only one belt transect may be anomalous and not reliable.
• Wash hands thoroughly after the experiment.