Conduct a Quantitative Survey of Plants, e.g., distribution of daisies

• Method: Line Transect (x3)
• Set a measuring tape straight across the habitat in the direction of change in an influential environmental factor e.g. soil water, pH, and nitrogen content.
• On a map of the habitat mark the trace of tape - this is a line transect.
• Walk beside the line and indicate, on the map, the position of each daisy plant touched by the line.
• Repeat the process twice more from other start positions.
• Combine the results to establish the daisy distribution.
• Relate the distribution to the variation of the environmental factors.
• A map is an appropriate mode for the display of the results.

Conduct a Quantitative Survey of Animals, e.g., fieldmouse population

Day 1

• Capture field mice using small mammal traps.
• Record the number of captured mice e.g. 20.
• Mark each with a dab of red paint on the belly surface.
• Release each at their capture site.
• Allow time for the mice to readjust to normal conditions.

Day 2

• Capture field mice as before.
• Record the number captured e.g. 18.
• Record the number of recaptures (marked mice) e.g. 6.
• Return the mice to the habitat at their capture site.

Calculation: Population = Day 1 Captures x Day 2 Captures
Number of Recaptures

= 20 x 18
6

= 60 mice

Change in population over a year is best displayed as a graph.

Determining the Frequency of a Plant Species

• Method: many random quadrats e.g. 100.
• Randomly pick quadrat sites within the habitat.
• At each quadrat record the plant species present.
• For each species record the number of quadrats is was found in.
• This number is its frequency if a hundred quadrats were used.

Frequency is the percentage occurrence of a species with a large sample of randomly chosen quadrats.

Suitable Quadrat Size: 1/4 m² (0.25 m²).

Frequency is displayed clearly as a bar chart.

Determining the Percentage Cover of Sedentary Species

Textbook Diagram: pin-frame

• Method: pin-frame.
• Set out a straight transect line across the habitat.
• Place the pin-frame beside the line at the start.
• Push down each pin, to the ground, and record the species touched.
• Move the frame to the next half-metre and repeat.
• Record the total number of pins used.
• For each species record the number of ‘hits’.
• Calculation: Percentage Cover = Number of ‘Hits’ x 100

Total Number of Pins

Percentage cover is the proportion of ground screened or occupied by a species.

Percentage cover is distinctly presented as a pie chart or histogram.

Investigation of Abiotic Factors (Three Mandatory Activities)

Soil pH

• Air-dry the soil - leave exposed to air until constant mass.
• Sprinkle a small pinch of soil onto a white plate.
• Add universal indicator solution until soil is quite wet.
• Thoroughly mix the soil and the universal indicator.
• Press the mixture so some indicator oozes out.
• Match the indicator colour to a colour on the pH chart.
• The number on the matching colour is the soil pH.

Cowslip and rock rose prefer basic soils.
Heather and bilberry prefer acidic soils.

Дата добавления: 2015-11-14