QUESTION 25 (4 marks)
Severe weather events have caused widespread loss of seagrass in meadows off Location A. Seagrasses have the capacity to recover from weather-associated disturbances and return to pre-impact levels within 4 to 60 months. Deep-water meadows have a higher rate of recovery than shallow-water
Describe how stratified sampling could be used to study how seagrass meadows off Location A recover after a severe weather event. Identify a surveying technique and purpose for the study in your response.
QCAA guide · typeset solution
QCAA sample response and mark allocation
25 | Stratified sampling could be used to investigate how the percentage cover of seagrass changes along a depth gradient over a 60-month period. Quadrats could be used to estimate the percentage cover of seagrass at 250 km intervals along a 7 km belt transect north of location A, covering both shallow-water and deep-water meadows. Multiple quadrats should be placed at each interval to ensure the reliability of data, and the depth at each sampling point must be recorded. Data could be collected each month for 60 months. | • indicates the study will take place over time [1 mark] • indicates that sampling will occur in both deep and shallow water [1 mark] • identifies an appropriate surveying technique [1 mark] • identifies an appropriate purpose for the study [1 mark] |
QCAA sample response and marking criteria reproduced from the official guide.
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