Conservation of habitatsAQA A-Level Biology: Subtopic test

1. 1
   A lowland heathland nature reserve is dominated by heather. If left unmanaged, birch and pine seedlings colonise the heath and it develops into woodland. The reserve is home to heathland specialists such as the nightjar and the sand lizard, which need open ground.

   (a)

   Why does the heathland need to be managed to conserve it?

   [1 mark]

   • ATo stop succession so that it is not replaced by woodland
   • BTo speed up succession to the climax community
   • CTo increase the nutrient content of the soil
   • DTo prevent any animals from grazing on it

   (b)

   Which management technique would prevent succession on the heathland?

   [1 mark]

   • APlanting birch seedlings
   • BGrazing by ponies that eat young tree seedlings
   • CAdding fertiliser to the soil
   • DPlanting pine trees on the edge

   (c)

   Explain why the number of nightjars and sand lizards would fall if the heathland were left unmanaged.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A coastal wetland in a developing country is a breeding ground for migratory wading birds and a nursery for fish. Local people want to convert part of it into shrimp ponds to provide food and income, while conservation groups want it protected.

   (a)

   Which statement best describes sustainable use of the wetland?

   [1 mark]

   • AUsing as much of it as possible while it lasts
   • BMeeting present needs without reducing the ability of future generations to meet theirs
   • CNot allowing any human use of it
   • DReplacing it with a human-made habitat

   (b)

   Which would be a suitable compromise between local needs and conservation?

   [1 mark]

   • ADraining the whole wetland for shrimp ponds
   • BFencing the whole wetland and excluding local people
   • CAllowing shrimp ponds in a limited zone while protecting the bird breeding areas
   • DIntroducing a non-native fish to increase the catch

   (c)

   Suggest how the conflict between the local people and the conservation groups could be managed so that both are satisfied.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A nature reserve manager compared three plots of chalk grassland after 5 years. Plot A was grazed by sheep. Plot B was cut once a year and the cuttings were removed. Plot C was left unmanaged. Plot A had 38 plant species and 4 scrub seedlings per 100 m². Plot B had 31 species and 2 scrub seedlings. Plot C had 14 species and 46 scrub seedlings.

   (a)

   Describe the effect of the management on the number of plant species and the number of scrub seedlings.

   [3 marks]

   (b)

   Explain why management increases the number of plant species on chalk grassland.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A peat bog in northern England supports rare plants such as sphagnum moss and sundew, and nesting birds. A company wants to extract peat from part of the bog to sell as garden compost, which would provide local jobs. Peat accumulates at about 1 mm per year.

   (a)

   Discuss how the needs of people and the conservation of the peat bog can conflict, and how the bog could be managed sustainably.

   [6 marks]

   (b)

   The company's report states that extraction would affect only 4% of the bog and that rare birds still nest on the rest. An independent survey found that two rare plant species fell by 60% within 500 m of the site and the water table fell by 30 cm at 300 m, but it was carried out in one summer. A university study found that bogs restored by blocking ditches began to accumulate peat again within 10 years, but species diversity took 30 years to recover. Evaluate this evidence to advise whether the extraction should go ahead.

   [6 marks]

   Total for question 4: 12 marks

End of questions