quadrat sampling Alejandra Gonzalez-Beltran Philippe Rocca-Serra 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. http://www.coml.org/investigating/observing/quadrat_sampling.html systematic sampling ready for release