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Human Environmental Impact Challenges

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Human Environmental Impact Challenges

Read the case study and use its evidence to investigate how human choices affect ecosystems in Aotearoa New Zealand. Answer in complete sentences where needed.

Case study: Te Awa Stream

Te Awa Stream flows past a town and a dairy farm before reaching a coastal wetland. Over several years, more houses and roads were built nearby. Rain washes soil, fertiliser and animal waste from bare ground into the stream. Stormwater from roads can carry oil and rubbish. In summer, some stream sections become warm and algae grow quickly. When algae die and decompose, microbes use oxygen in the water. Fish and aquatic insects need dissolved oxygen to survive. A group of residents planted native trees beside one stream section, organised rubbish clean-ups and asked the council to improve stormwater treatment. The stream is an invented example, but its pressures and possible responses are realistic.

Investigate the evidence

Use the case study to support your reasoning. More than one pressure can affect the same ecosystem.

1.Which explanation best describes how fertiliser entering the stream could affect fish?

It can encourage algae growth; decomposition may lower dissolved oxygen.
It immediately makes the water colder, so fish grow faster.
It removes all microbes from the water.
It changes stream water into seawater.

2.Complete the chain: Rain washes fertiliser into the stream → algae grow rapidly → use oxygen as dead algae decompose → less oxygen is available for fish.

3.Match each human pressure with its most direct environmental effect. Write the correct letter beside each number.

1. Building roads and houses
2. Fertiliser and animal waste washing off paddocks
3. Litter entering a stream

C. Excess nutrients can contribute to algal growth
A. Rubbish can injure or be eaten by wildlife
B. Natural habitat is removed or broken into smaller areas

4.The case study says algae grow quickly in some warm sections and that fertiliser washes into the stream. Give one reason the evidence does not prove fertiliser is the only cause of the algae growth.

Choose and justify a response

Consider both benefits and trade-offs. A useful environmental response should match the problem and be practical to maintain.

5.Which action most directly helps stop soil and nutrients from nearby paddocks entering the stream?

Plant a strip of native vegetation beside the stream.
Add more road drains that empty into the stream.
Remove plants from the stream bank.
Organise a clean-up only at the coastal wetland.

6.A clean-up removes rubbish already present, while better stormwater treatment aims to reduce rubbish and contaminants entering the stream. Which statement best compares these actions?

7.A proposed wetland restoration would improve habitat and filter some runoff, but would require land and ongoing care. Give one likely benefit and one practical challenge.

8.Which is the fairest conclusion about responsibility for improving Te Awa Stream?

Only residents should act because the stream passes the town.
Only farmers should act because all pollution comes from farms.
Different land users and the council can each reduce pressures within their control.
No one can help unless every source of pollution is removed at once.

9.A monitoring team finds fewer aquatic insects downstream than upstream. Give one possible link to the pressures described in the case study and explain why the observation alone does not prove the cause.

10.Plan a small investigation to test whether a native streamside planting strip is associated with clearer water after rain. State what you would compare, what you would measure and one factor to keep consistent.

11.Write a two-sentence recommendation to the town council. Name one action, identify the environmental pressure it targets, and include one way to check whether it is helping.