Introduction

Outdoor activity | Levels: 2-4: This activity is designed to introduce and re-enforce ideas about the impact of animal pests. It could also be used for plant pests, and to show the relationships between living things in a community.

Possum. Photo: R Morris.
Possum

This activity is designed to introduce and re-enforce ideas about the impact of introduced animal species, but could also be used for introduced plant species and to show the relationships between living things in a community.

Learning outcomes

  • Students will gain knowledge of the impact of introduced animal species on our native bush.
  • Students will investigate plant species and their relationships between living things in a community.

Curriculum links

Science: Living world

Level 1 and 2

Life processes: Recognise that all living things have certain requirements so they can stay alive.

Ecology: Recognise that living things are suited to their particular habitat.

Level 3 and 4

Ecology: Explain how living things are suited to their particular habitat and how they respond to environmental changes, both natural and human induced.

Learning levels

  • Primary
  • Secondary 

Topics

  • Forests and green spaces
  • Pests and threats

Curriculum learning areas

  • Science
  • Health and PE

Activity instructions

Equipment

  • Playing field/tennis court/gym
  • 4 cones (boundary markers)
  • 10+ ice cream container lids
  • 2+ sponge balls
  • 2 Processing cards

Activity Part 1:

Brainstorm introduced species in New Zealand with students – what are they, characteristics, different impacts they have, major problems etc. Explain that you will be running an activity that looks at these issues.

Define the playing area using the cones (1/2 a netball court for approx 20 students).

All students are trees (they can choose a native if they want to, a good way to test their knowledge of native trees). Trees are slow growing so can only walk.

Choose one student to be a possum. Possums chase and tag the trees. If they tag a tree the tree also becomes a possum. Possums must link arms/hold hands and chase other trees together.

Run the activity for 5-10mins until all the trees have become possums.

At the end of the game find out how many trees and possums are left.

Processing:

What happened to possum numbers during the activity?

What happened to tree numbers? Why?

What things could we do reduce the numbers of trees being caught?

  • Introduce hunters

Activity Part 2:

Everyone in the class is a tree, except for one who is a possum and now also one who is a hunter.

The hunter uses the sponge balls to ‘shoot’ the possums.

If a possum is hit, it breaks from the chain and becomes a tree again.

The hunter then retrieves the ball and does one more lap before ‘shooting’ again.

Run the activity for 5-10 minutes. Find out how many trees and possums are left.

Processing:

What happened to possum numbers during the activity?

What happened to tree numbers? Why?

How did the hunter feel?

Why did the hunter have to do a lap before shooting?

  • Tracking down prey again.

What other things should we consider?

  • Possum numbers, hunter numbers, tree numbers, area size, hunter technique

Activity Part 3:

Depending on student feedback, the activity could be run by varying different factors. For example:

  1. Using a larger area:
    What happened to possum numbers?
    How hard was it for possums to get food?
    Why was it harder?
    - Resource distribution.
    How was it different for the hunter? Why?
  2. Introduce more hunters:
    What happened to possum numbers?
    How hard was it for hunters?
    What did the hunters have to do to kill possums effectively?
    - Co-operative strategies.
  3. What other possum control techniques are there?
    - Poisoning, trapping.
  4. Introduce poison:
    Introduce ice cream container lids as the poison bait stations. Hunters can drop this in the playing area. If a possum steps over it they die and become a tree. The hunter can collect poison and redistribute it but only by dropping.
  5. Introduce two possum populations:
    What happened to possum numbers?
    How hard was it for the hunters?
    Did possums or hunters have to alter their strategies? Why/why not?
Processing:

What strategies did possums and hunters develop for success?

  • Co operative and individual.
  • Identifying and avoiding threats (poison, hunter)
  • Catching trees
  • Ball retrieval
  • Herding possums to kill

Why are possums so successful at this activity in real life?

  • Possums are well adapted for browsing on a range of plants; have no natural predators; and are good breeders.

Why are possums so harmful to native New Zealand species?

  • Because they eat the best new plant growth (shoots, tips); seriously damage native forests – in some areas they have eaten whole canopies of rata, tötara, tïtoki, köwhai and kohekohe; they compete with native birds for habitat and for food such as insects and berries; they also disturb nesting birds, eat their eggs and chicks and may impact on native land snails; possums spread bovine tuberculosis to cattle and deer – a problem for farmers; they are a nuisance in home suburban gardens.

Are there any other introduced pests that pose a similar problem?

  • Many – plant (broom, wilding pines, old man’s beard) and animal (cat, rat, ferret, weasel, stoat)

Are there any ways that you and I contribute to this problem?

  • Yes – planting problem exotic species in our gardens, not controlling our pets etc.

Is there anything we can do to reduce this problem?

  • Yes – find out about problem exotic plants, don’t buy them in the future and remove them from our gardens; plant local native plants in our gardens;, help re-plant other neighbourhood areas with natives; put a bell on our cats, keep them indoors at night; take our dogs only to public areas where they are allowed; keep our dogs on a leash when required; minimise resource use in general to reduce habitat destruction etc.

Possum Picnic

Processing Questions:

  1. What did you learn about the environment from this activity?
  2. What other introduced species do you know of in New Zealand?
  3. Where did these species come from and why?
  4. What can we do to prevent these things happening again?

Credit

This activity was created by Barry Law and Bert McConnell of the Christchurch College of Education.

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