Pīkao (or Pīngao)

Pīkao (or Pīngao)

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This task is about interpreting information from a text.

pikao

Pīkao (Pīngao)

Pīkao is a native plant that grows on sand dunes. Once it was common on sandy beaches all over New Zealand but now it is becoming rare. It is special because it is only found in New Zealand and it plays an important role in stabilising the sandy coast and creating an environment where other species can live. Its brightly coloured leaves are highly valued for weaving.

The Sustainable Harvest of Pīkao
Traditionally pīkao was harvested in autumn. The head was removed from the leaves and at the same time a side shoot was removed from the plant and transplanted deep in the sand, next to the parent plant. This was a way of making sure that the pīkao survived and of thanking Tāne Mahuta. In the 1980s there was an increased demand for pīkao for weaving. This occurred at a time when pīkao was already becoming scarce due to fire, grazing by stock and rabbits, vehicles on beaches, coastal developments and competition from introduced plants. This prompted the Forest Research Institute to conduct an investigation examining what method of harvest was the most sustainable.

The effect of three harvesting methods was investigated. The methods were:

  • Clipping of leaves (high quality leaves are selected and cut individually from plants);
  • Cutting (whole leaf clusters are cut from the plant);
  • Wrenching (the centre bit of a leaf cluster is removed by bending and pulling).

Scientists measured such things as the number of plants that died, the number of shoots and flower heads produced by surviving plants and how much fibre was collected for each method of harvesting. They also looked at whether or not the time of year when harvesting happened made a difference. They found that clipping was the least harmful method of harvesting for the plants and that also there was less wastage as only high quality leaves were taken. Both the other methods resulted in damage to the growth shoot causing many plants to die and would inevitably result in some wastage. The time of harvesting made no significant difference to plant survival.

 
a) Why did the Forest Research Institute carry out an investigation about pīkao?

 
 
 
 
 
 
b) What specific question about sustainability did they decide to investigate?

 
 
 
 
c)
What did they measure and how might have they measured each thing?
 
 
 What the scientists measured  A possible method for measuring
     
     
     
     
     
d) What "control" do you think the scientists used?

 
 
 
 
 
e) Based on these findings, if you were a Department of Conservation scientist what course of action would you recommend? Why?

 
 
 
 
 
 
 
f) Investigations like this take a lot of time and resources and so they are expensive. Was this a good investigation for the Forest Research Institute to carry out? Why or why not?

 
 
 
 
 
 
Task administration: 
This task can be completed with pencil and paper.
Copyright: 
Image: Department of Conservation 
Text: Derived from Pikao, Department of Conservation (CC-BY-4.0)
Level:
5
Curriculum info: 
Science, Understanding about science, Living World
Keywords: 
Earth systems, sustainability, conservation, kaitiakitanga, investigation, pikao, pingao
Description of task: 
Students read an article about an investigation into the sustainable harvest of pīkao and identify key features of the investigation. Assessment focus: interpreting information about how scientists work.
Curriculum Links: 
Capability: Engage with science
This resource provides opportunities to discuss using science information/investigations to make wise decisions about the environment.
 
 

 
Science capabilities: 
Engage with science
Answers/responses: 
 

Y10 (04/2005)
a) Pīkao is becoming increasingly scarce plus a second reason (e.g., increased demand, importance of pīkao to the coastal environment etc). difficult
b) Identifies specific question e.g., What was the most sustainable harvesting method? moderate
c) Plant survival
Plus counting plants before and after harvest
Number of shoots
Plus counting (and averaging) shoots on plants that were harvested in different
ways and in the control group
Flower heads
Plus counting (and averaging) flowers on plants that were harvested in
different ways and in the control group
Harvest season
Plus comparing plants where harvesting has been done in spring with those
where harvesting was in autumn
Fibre yield
Plus weighing fibre or counting suitable leaves
moderate

moderate

moderate

difficult

difficult
d) Leave some plants unharvested very difficult
e) Recommend clipping of leaves plus explanation of less damage to the plant difficult
f) Any justified opinion.
A response that includes a commercial, cultural, or ecological reason.		 moderate
very difficult
 
Trial size: 188 Year 10 students. NOTE: In many areas pīkao is known as pīngao. Teachers will need to choose the appropriate word to use for their area.
Diagnostic and formative information: 

In Question a) 31% of students in the trial were able to give a full explanation as to why the Forest Research Institute carried out an investigation about pīkao and another 31% were able to give a partial explanation e.g., they were able to identify that pīkao was becoming rare.

In question b) 56% of students in the trial were able to give a specific question for investigation and another 29% were able to indicate a general area for investigation. Responses from the trials for question c) are unpacked in the chart on the following page.

What was measured

Percentage of students able to only name what was measured

Percentage of students able to name what was measured and give way of measuring

Plant survival

19%

56%

Number of shoots

20%

51%

Number of flowers

23%

46%

Time of harvest

22%

29%

Fibre yield

29%

39%

Question d) indicated that students were unclear of the meaning of the word "control" in this context. Examples of responses to the question "What control do you think scientists used?" that illustrate this confusion are:

  • "They issued licenses to get it so it would not be taken by every Joe Blogg and his dog" (Controlling access)
  • "Fencing" (Controlling access)
  • "My best guess is laws" (Controlling access)
  • "Stopped people from going on the beach with vehicles" (Controlling access)
  • "They controlled the rival plants and stock and rabbits" (Pest control?)
  • "May be traps and poisons" (Pest control?)
  • "Weed sprayer" (Pest control?)
  • "Making sure that the pīkao survived and of thanking Tāne Mahuta" (Cultural controls)
In question e) 24% of trial students recommended clipping of leaves as the best form of harvest and explained this caused least damage. A further 15% recommended this method of harvest but gave no explanation as to why. A further 25% recommended some other future action, e.g., more research needed.

In question f) only 13% of trial students gave an opinion as to the value of the research that indicated an understanding of commercial, cultural or ecological reasons. 56% of students gave an opinion of the value of the research that showed surface level understanding, e.g.,"The research was important because pīkao was rare", but with no explanation as to why it mattered if pīkao was endangered.

Next steps: 

Students in the trial seemed unable to relate the idea of a controlled experiment to something that can happen out-of-doors, not just in the "fair testing" activities of the school laboratory. They may need opportunities to explore other examples of real investigations that have taken place in field settings. Discussing the nature of "controls" in these settings could help students to develop their "nature of science ideas" (NOS) about how scientists seek to eliminate alternative explanations to make their investigations as robust as possible. Several of the NOS themes from the ScienceIS web-site could be a focus of next learning - check these out at http://www.tki.org.nz/r/science/science_is/nos/

Similarly the students appeared to have little confidence in stating and justifying a values position with respect to scientific research. The overarching value of ecological sustainability in the NZ Curriculum provides a useful starting point for developing activities to improve this skill.