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Front Page > Technology > Observing and Counting > Quadrat Sampling - Passive:

Quadrat Sampling- Passive

Quadrat sampling is a classic tool for the study of ecology, especially biodiversity. In general, a series of squares (quadrats) of a set size are placed in a habitat of interest and the species within those quadrats are identified and recorded. Passive quadrat sampling (done without removing the organisms found within the quadrat) can be either done by hand, with researchers carefully sorting through each individual quadrat or, more efficiently, can be done by taking a photograph of the quadrat for future analysis. Abundances of organisms found at the study site can be calculated using the number found per quadrat and the size of the quadrat area. This is a time-tested sampling technique that is best suited for coastal areas where access to a habitat is relatively easy.

Research assistants record the organisms found in quadrats along a transect line in Kasitsna Bay, Alaska. (Natural Geography in Shore Areas - NaGISA. Katrin Iken)

A research scientist uses a quadrat to study the biodiversity in Prince William Sound, Alaska. (Natural Geography in Shore Areas - NaGISA. Brenda Konar)

A photograph of a quadrat sample that can be used to document the organisms present without having to remove them. (Natural Geography in Shore Areas - NaGISA; see full-size image -- 83K)

Click on the link below to see what Census projects use this technology:

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