Weed cover along a transect from a walking track into bushland

The idea

Disturbance at a track edge lets weeds invade bushland, and point-intercept quadrats along a transect measure how weed cover changes with distance from the disturbance.

Safety card

What you need

• 30 m tape, 12 pegs, a compass
• A 1 m × 1 m quadrat of four 1 m lengths of dowel or PVC with string strung at 5, 15, 25 … 95 cm both ways (10 strings each way, 100 intersections)
• The local council's weed identification sheet for the area; a native plant guide
• A 10 × 10 grid drawn on clear acetate for canopy cover, held overhead at arm's length
• Clipboard, record sheet, camera; permission from the land manager (council or National Parks)

How to do it

1. At a straight section of track, peg the tape at right angles to the track edge and run it 20 m into the bushland; record the bearing.
2. Place the quadrat at 0, 2, 4 … 20 m (11 positions) on the same side of the tape.
3. At each quadrat, look straight down at each of the 100 string intersections and record what is directly beneath: weed, native plant, leaf litter, bare soil or rock. Each intersection is 1 % cover.
4. Hold the acetate grid overhead at each quadrat and count the squares more than half filled by leaves: canopy cover %.
5. Note signs of disturbance at each quadrat (cut stems, dumped garden waste, drainage lines, trampling).
6. Run a second transect 10 m along the track and repeat. Plot weed cover and native cover against distance for both transects.
7. Propose one management action for the weediest section (for example track edging, removing dumped garden waste or a weeding program run with the land manager) and say which reading it would change.

What you should see

Two tables of 11 quadrats with percentage cover summing to 100 in each, and two graphs. Where the track edge is the main disturbance, weed cover is highest in the first few metres and falls with distance while native cover and leaf litter rise; where it does not, the disturbance notes show another source on the transect (a drainage line or dumped garden waste) and the learner records it as a finding. The Field of Mars Environmental Education Centre runs this analysis of disturbance against weed distribution as a Stage 5 program. It worked if the two transects were measured the same way on the same day.

What changes

What you change

distance from the track edge (m)

What you measure

weed cover %, native cover %, canopy cover %

What you keep the same

• quadrat size and intersection count
• same observer per transect
• same day and track section

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

• Weeds are only a problem on farms.
• A green bush is a healthy native bush.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

• Geography K–10 Syllabus (2015), NESA; current and taught in 2026, replaced from 2027. The outcome codes are not printed on the NESA landing page for this syllabus, which only links the document, so the url given is the syllabus document itself (geography-k-10-syllabus-2015.docx); the code and its outcome text were read in that document on 23 September 2026.GE5-2GE5-3GE5-7
• Geography 7–10 Syllabus (2024), NESA; implementation from 2027, not yet taught; code read on this page on 22 September 2026GE5-PRI-01GE5-MAN-01GE5-TAP-01
• Australian Curriculum v9AC9HG10K01AC9HG10K04AC9HG10S02

Sources

The pages the author read to write this activity.

1. fieldofmar-e.schools.nsw.gov.au/learning-programs/secondary-excursions-and-incursions/secondary-geography-excursions/environmental-change-and-management-excursion
2. education.nsw.gov.au/teaching-and-learning/curriculum/hsie/hsie-curriculum-resources-k-12/hsie-7-10-curriculum-resources/environmental-change-and-management-learning-sequence
3. curriculum.nsw.edu.au/learning-areas/hsie/geography-7-10-2024/outcomes
4. www.nsw.gov.au/education-and-training/nesa/curriculum/hsie/geography-k-10-2015