Experimental Design for TREC - TREC-Agroecology/plant-diversity GitHub Wiki

Plot and nested subplot dimensions

  • Plot size = 20m2 = 65.6ft 65.6ft.

    • Nested subplot sizes = 100m2, 10m2, 1m2

  • Perimeter measurements and flag placements.

    • Fifty-seven (57) total pin flags needed per plot.
    • Nine (09) blue perimeter flags.
    • Forty eight (48) orange nested subplot flags.

  • Put a pin flag at each point (31, 32, 33, 49, 50, 51, West center, True center, East center) and the following measurements:

  • Start from SW corner point 31 to SE corner point 33.

    • 0 m = point 31
    • 1 m
    • 3.2 m
    • 10 m
    • 16.8 m
    • 19 m
    • 20 m = point 33.

  • Then from SE corner point 33 to NE corner point 51.

    • 1 m
    • 3.2 m
    • 6.8 m
    • 9 m
    • 10 m = East center.
    • 16.8 m
    • 19 m
    • 20 m = point 51.

  • Then from NE corner point 51 to NW corner point 49.

    • 1 m
    • 3.2 m
    • 10 m
    • 16.8 m
    • 19 m
    • 20 m = point 49.

  • Then from NW corner point 49 to SW corner point 31.

    • 1 m
    • 3.2 m
    • 6.8 m
    • 9 m
    • 10 m = West center.
    • 16.8 m
    • 19 m
    • 20 m = point 31.

  • Then from South center point 32 to North center point 50.

    • 0 m = point 32.
    • 6.8 m
    • 9 m
    • 10 m = True center.
    • 11 m
    • 13.2 m
    • 20 m = point 50.

  • Then from West center at 10 m to East center at 10 m.

    • 1 m
    • 3.2 m
    • 6.8 m
    • 9 m
    • 11 m
    • 13.2 m
    • 16.8 m
    • 19 m

  • Eight (08) interior corners of 10m2 nested subplots are marked with a pin flag at 3.2 m from the perimeter.

Timing of observations

  • A general guideline: if new species are being found, keep searching, covering the entire area in a systematic manner such as walking the perimeter lines or a grid. If after ten minutes of gently moving dominant species to look for small and locally rare individuals – even crawling if necessary – while searching the entire subplot and no new species are found, then spend another ten to fifteen minutes and move on.

  • A plot should take 2-6 hours for a team of two to complete. The time required will vary depending on a number of factors: species richness at the site, density of vegetation, taxonomic expertise, and environmental conditions.