Quadrat

A quadrat is a frame used in ecology, geography, and biology to isolate a standard unit of area for study of the distribution of an item over a large area. Quadrats typically occupy an area of 0.25 m² and are traditionally square, but modern quadrats can be rectangular, circular, or irregular.^[1]^[2] A quadrat is suitable for sampling or observing plants, slow-moving animals, and some aquatic organisms.

A photo-quadrat is a photographic record of the area framed by a quadrat. It may use a physical frame to indicate the area, or may rely on fixed camera distance and lens field of view to automatically cover the specified area of substrate.^[3] Parallel laser pointers mounted on the camera can also be used as scale indicators. The photo is taken perpendicular to the surface, or as close as possible to perpendicular for uneven surfaces.

^ Krebs, C.J. (1999). Ecological Methodology. Addison-Wesley.
^ Wheater, C. Philip; et al. (2011). Practical Field Ecology: Project Guide. John Wiley and Sons.
^ Littler, M. M.; Littler, D. S. (1985). "Nondestructive sampling". Handbook of Phycological Methods. Vol. 4. Ecological Field Methods: Macroalgae. Cambridge, UK: Cambridge University Press. pp. 161–175. ISBN 9780521249157.

[1] Krebs, C.J. (1999). Ecological Methodology. Addison-Wesley.

[2] Wheater, C. Philip; et al. (2011). Practical Field Ecology: Project Guide. John Wiley and Sons.

[3] Littler, M. M.; Littler, D. S. (1985). "Nondestructive sampling". Handbook of Phycological Methods. Vol. 4. Ecological Field Methods: Macroalgae. Cambridge, UK: Cambridge University Press. pp. 161–175. ISBN 9780521249157.

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