Plan it, walk it, record it, test it: your transect data, on your phone, in the field.
01 · Before you go
Plan your question
The guide asks you to collect your own data from a natural or semi-natural habitat: one shaped by people but dominated by wild, not planted, species. A mown lawn or flower bed won't do; a field margin, hedgerow, woodland edge, rough grassland or shoreline will.
Species (1–3)
Sampling design
Question & hypotheses
Quick check. Your transect must run along the gradient, from one extreme of your abiotic variable to the other. Aim for at least 10 quadrats in total so your statistics have a fair chance.
02 · Pack the bag
Kit list
03 · In the field
How to run a belt transect
Find the gradient.Walk the site first. Identify where your abiotic variable is highest and lowest and choose a start point at one extreme.
Lay the tape.Run the tape measure in a straight line across the gradient, from one extreme to the other. Note the compass bearing or take a photo so it could be repeated.
Place the first quadrat at 0 m.Always put it on the same side of the tape, with the same corner touching the line, so every placement is standardised.
Measure the abiotic variable first.Take the sensor reading inside or beside the quadrat before you disturb it. Hold the probe at the same height or depth every time; let it settle before reading.
Record abundance.Count individuals (rooted inside the frame; include plants on two edges only) or estimate percentage cover. Enter it in section 4 straight away.
Move on by your interval.The notebook fills in the next distance for you. Repeat until you reach the end of the tape.
Repeat the transect.Lay repeat transects parallel to the first, a few metres away, across the same gradient. Bump the transect number in section 4.
Leave no trace.Don't pick or dig up organisms; identify from photos or a field key. Put back any stones you move and keep trampling to a minimum.
Control what you can. Sample all quadrats in one session, in similar weather, with the same person reading the sensor. Light readings in particular change as clouds pass; take three quick readings and record the mean if it's patchy.
04 · Data
Record a quadrat
Everything saves automatically on this device. Export it in section 6 before you close the tab for good.
05 · Back at base
Test for a correlation
Spearman's rank correlation coefficient (rs) tests whether abundance tends to rise or fall as the abiotic variable changes. It works on ranks, so it doesn't need a straight line, but it does need a trend in one direction.
Show the working (ranks, d, d²)
rs = 1 − 6Σd² ⁄ n(n² − 1)
Rank each column separately (tied values share the mean rank), find the difference d between the two ranks for each quadrat, square it and sum. With many ties, the formula is approximate; the notebook's rs above uses the tie-corrected method.
Look before you trust the number. If abundance peaks in the middle of your transect and falls at both ends, you may have found the species' optimum (a range of tolerance) and rs can be weak even though the variable matters a lot. Describe the shape in your conclusion.
Correlation ≠ causation. Other factors change along the same gradient (shade is also cooler and damper). Name at least one that could be responsible instead of, or as well as, your chosen variable.
06 · Keep it
Save your data
Download a CSV to open in Excel, Google Sheets or your graphing software, or copy it to paste into an email or document.