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Date November 2018 Marks available 2 Reference code 18N.3.SL.TZ0.14
Level Standard level Paper Paper 3 Time zone TZ0 / no time zone
Command term Outline Question number 14 Adapted from N/A

Question

Wisconsin Department of Natural Resources has issued guidelines to control invasive plants within the state. One mechanical method is to cut the plants down where they occur. However the time of year the plants are cut down is important in their control. The chart shows the months when it is recommended to cut down the plants and the months when they should not be cut down.

State which plant can be cut in August. 

[1]
a.

Suggest a reason for not cutting invasive plants at certain times of year.

[1]
b.

Outline reasons for controlling invasive plants.

[2]
c.

Discuss what precautions should be taken before considering biological control of the invasive plants.

[2]
d.

Markscheme

Japanese stiltgrass ✔

a.

produce seeds which spread when cutting
OR
avoid vegetative proliferation/cloning
OR
may provide habitats for other species ✔

Accept any other reasonable answer

b.

a. «biotic» competition with native plants
OR
disrupt the food chain/ecosystem ✔

b. competition for abiotic factors ✔
Accept competition for light/space/water/etc for b

c. reduce competitive exclusion / avoid overlapping niches ✔

d. can cause changes to soil ✔
eg: Rhododendrons/conifers acidify the soil, making it difficult for other species to grow

e. break/damage/cause death/extinction of native plants ✔

c.

a. «control» introduced species should only target alien plants
OR
«control» introduced species should not outcompete endemic species ✔

b. should not upset food chains/habitats ✔

c. should have some natural control/predator ✔

d. should not spread outside required area/not become invasive themselves
OR
field testing for effectiveness ✔

d.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.
[N/A]
d.

Syllabus sections

Option C: Ecology and conservation » Option C: Ecology and conservation (Core topics) » C.3 Impacts of humans on ecosystems
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Option C: Ecology and conservation » Option C: Ecology and conservation (Core topics)
Option C: Ecology and conservation

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