Count the Kinds: Measuring Schoolyard Biodiversity with Quadrats

Investigation question: Does a regularly mowed lawn or a less-managed patch of the schoolyard hold more plant biodiversity, and how many quadrats does it take to find out?

Your role today

• Site setter: Rolls the dice, measures out each quadrat position from the baseline, lays the frame, and rerolls if the spot lands on a path, a hazard or an earlier quadrat.
• Point reader: Lowers the pointer, blunt end down, through each of the 25 string intersections and calls the code of the first plant touched, or 'bare'.
• Recorder: Tallies each call in the hits table, keeps the presence list for each quadrat, and checks that every quadrat totals 25 points.
• Kind keeper: Sketches and describes each new plant kind with a hand lens, assigns it the next class code, and checks the group's key against the class chart.

Safety

• Work only in the teacher-checked patches. Poison oak grows at the edges of many California school grounds and causes a severe rash; nettles, thistles and some weeds sting or prick. Do not touch plants you have not been told are safe, and never put plants or fingers in your mouth.
• Bees and wasps visit flowers in less-managed patches, and yellowjackets nest in the ground. Move slowly, do not swat, and step away from any nest. Students allergic to stings carry their prescribed epinephrine auto-injector outdoors, and the teacher knows who they are.
• Skewers have a sharp point: lower them blunt end down, never point them at anyone, and carry them point down. Unsharpened pencils are a safer substitute.
• Do not touch animal droppings, broken glass, needles or other litter; tell the teacher. Do not survey any area that has been sprayed recently.
• On sunny days wear a hat and sunscreen, bring water and take breaks from kneeling in the sun. Watch for sprinkler heads and holes when walking.
• Stay inside the marked patches and within sight of the teacher. Do not pull up or pick plants, and wash hands after the field session.

Procedure

1. Session 1, in class (5 minutes): write your prediction in q1 and answer q2. Look at the starter kind key and agree how your group will tell kinds apart (leaf shape, edges, hairs, how the leaves attach, flowers).
2. At the first patch, the Site setter rolls one die for the position along the baseline (the roll times 50 cm) and the second die for the distance into the patch (the roll times 50 cm, measured with the meter stick), then lays the frame with its corner on that spot. If the frame lands on a path, a flagged hazard or an earlier quadrat, roll again; never move the frame to a spot that looks more interesting.
3. Kind keeper and Recorder list every plant kind rooted inside the frame (the presence list). Each new kind gets the next class code, a sketch and a description in the kind key. Use the hand lens and do not pick the plant.
4. Point reader lowers the pointer, blunt end down, straight through each of the 25 string intersections and calls the code of the first plant it touches; if it reaches soil, mulch or dead leaves without touching a living plant, call 'bare'. Recorder tallies every call. A partner watches that the pointer stays vertical.
5. Repeat steps 2 to 4 for quadrats 2 and 3 in the same patch, then sample three quadrats in the second patch. Note the time, the weather and whether the lawn looks freshly mowed.
6. Session 2: total each patch's hits by kind and leave 'bare' out of the plant total. For each kind compute p = hits ÷ plant total, square it, add the squares, and compute Simpson's index D = 1 − (sum of p²).
7. Count each patch's richness: all kinds on your presence lists, whether or not the pointer hit them. Fill the accumulation table by counting how many kinds each quadrat added that earlier quadrats of the same patch had not.
8. Copy your group's totals to the class chart. Using the class data in the order groups sampled, plot total kinds found against number of quadrats sampled for each patch on one graph, one color per patch. Compute the class Simpson's index for each patch from the pooled hits.
9. Answer q3 and q4 on the recording sheet as a group, then the analysis questions individually.

Record your observations

Lab 1 recording sheet: Count the Kinds

You will sample three quadrats in Patch A (mowed lawn) and three in Patch B (less-managed patch). In each quadrat, list every plant kind you see (the presence list), then record the first plant touched at each of the 25 grid points. A point that touches only soil, mulch or dead leaves is bare. Use the class codes (K1, K2, ...) so every group means the same plant by the same code.

Analysis questions