QUESTION 134 (5 marks)
Two landscapes retain the same total area of forest. Landscape P has one large patch; Q has many small patches separated by cleared land. At forest edges, measurements show higher temperature and lower humidity than in the interior. A moisture-sensitive invertebrate is less abundant in Q.
a) Explain why equal forest area need not provide equal amounts of suitable interior habitat. [2 marks]
b) Use the measured edge conditions to explain a possible cause of the invertebrate pattern. [2 marks]
c) State one other factor that should be considered before treating that explanation as the only cause. [1 mark]
Practice marking scheme
Answer
More fragmented forest can have a greater proportion of edge habitat despite equal total area. Hotter, drier edges may reduce survival or distribution of the invertebrate; isolation may also reduce movement.
Working
Total forest area does not describe patch arrangement or microhabitat availability. Many small patches can have more edge relative to interior. The measured abiotic changes can increase water stress for a moisture-sensitive species. The abundance pattern is consistent with this mechanism but does not establish temperature and humidity as the only causes.
Marking criteria
- Identifies a greater edge-to-interior proportion in fragmented patches. [1 mark]
- Explains that arrangement changes suitable habitat without changing total area. [1 mark]
- Uses greater temperature/lower humidity at edges. [1 mark]
- Links the conditions to water stress or reduced survival/occupation. [1 mark]
- Names isolation, dispersal, predation, food, or another relevant confounder. [1 mark]
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
View the QCAA syllabusCompare your working with the guide above.