New Zealand Bush Ecosystems
New Zealand Bush Ecosystems
Embedded Files
In this activity, you will build a food web that represents the New Zealand bush ecosystem. You will use images of organisms within the ecosystem to explore the relationships between them.
By the end of this activity, you should be able to:
- understand the difference between a food chain and a food web
- describe some of the relationships between organisms within the New Zealand bush ecosystem
- explain why birds have an important role in the New Zealand bush ecosystem
- explain possible outcomes of an imbalance of diversity within our ecosystems.
LOI 2: How living things respond to environmental changes, both natural and human-induced.
LOI 3: The balance between human interaction and the biodiversity in an ecosystem.
L4 Living World - Ecology: Explain how living things are suited to their particular habitat and how they respond to environmental changes, both natural and human-induced.
L5 Living World - Ecology: Investigate the interdependence of living things (including humans) in an ecosystem.
Key Concepts: Change, Connection
Related Concepts: Biodiversity, Sustainability
Background Information
Background Information
Feeding relationships are often shown as simple ‘food chains’, but in reality, these relationships are much more complex, and the term ‘food web’ more accurately shows the links between organisms within an ecosystem.
A food web diagram illustrates ‘what eats what’ in a particular habitat. Pictures represent the organisms that make up the food web, and their feeding relationships are typically shown with arrows. The arrows represent the transfer of energy and always point from the organism being eaten to the one that is doing the eating.
Activity
Activity
1. As a class, discuss prior knowledge of food webs. (The video clip Understanding food webs in the Life in the Sea context provides background information on food webs.)
2. Organise students into groups of 3–4. Give each group a copy of the Ecosystem Organisms – student worksheet and ask them to work co-operatively to gather information about the food (or prey) that each organism eats and the organisms that they are eaten by. You are encouraged to use web-based searches to research and collect this information.
3. Give each group a set of organism cards. We may start that activity by using our organism cards to build simple food chains before we move on to building a food web. For example:
Ensure that you are using the arrow direction correctly. The arrow represents the transfer of energy and always points from the organism being eaten to the one that is doing the eating.
4. Each group will now be given a large sheet of paper to build their food web on. You should begin by gluing the organism cards of native New Zealand organisms on to their sheets of paper, leaving room around the edges to later add the cards of introduced predators. An example of a layout is shown below:
5. Ask the students to assign each of the native birds (kiwi, kererū, tūī) a different coloured marker pen. The students can now show the feeding relationships within the web between the birds, the flora (plants) and invertebrates. Encourage students to think about the transfer of energy within the system and draw their arrows to reflect this.
5. Assign each of the native birds (kiwi, kererū, tūī) a different coloured marker pen. You can now show the feeding relationships within the web between the birds, the flora (plants) and invertebrates. Think about the transfer of energy within the system and draw arrows to reflect this.
6. Add the introduced predators to the outer edges of their food web (stoats, rats and possums). Assign each of these organisms a different coloured marker pen and add the feeding relationships represented by arrows.
7. Predict possible outcomes of an organism within the ecosystem, either being eliminated or increasing greatly in population size. Be encouraged to realise that either event would have a flow-on effect to the other organisms due to the connected nature of an ecosystem. The following scenarios are suggested to give a context to consider:
- Intensive planting efforts of nectar and fruiting trees have produced sufficient food for tūī. This has caused a boom in the population of tūī fledglings.
- An area of native bush is to be converted to farmland. This involves the clearing of the entire native bush in the area to allow the land to be farmed.
- A community group has decided to stop all predator control methods within their local bush area due to the costs involved (this includes the cessation of hunting, trapping, dropping of aerial baits and use of bait stations).
Discussion questions
Discussion questions
- What does a food web tell us about the relationships within an ecosystem?
- Why do New Zealand native birds (particularly the tūī and kererū) have such an important role in our ecosystem?
- What possible outcomes could occur if tūī were eliminated from the New Zealand bush ecosystem?
- What could occur if stoats, rats and possums were eradicated?
- What could possibly occur if the population of stoats increased greatly?
Page updated
Report abuse