Nested quadrats are a special sample unit that includes a series of different sized quadrats all placed at the same location. They are usually positioned so that all have a common corner point, causing the area sampled by smaller quadrats to be included in the progressively larger ones.
Nested quadrats are a useful approach when no single sample unit size suits all species that need to be sampled for frequency and density. The nesting allows for the more abundant species to be efficiently assessed in the smaller quadrats while increasing the likelihood of encountering the less common species in the larger quadrats.
Nested quadrats may also be used when planning the sampling protocol to determine the optimum sample unit size for the specific area.
References and Further Reading
Bonham, C.D. 1989. Measurements for terrestrial vegetation. John Wiley Son, New York, NY. pp 19-40.
Mueller-Dombois and Ellenburg. 1974. Aims and methods of vegetation ecology. John Wiley Sons, New York, NY. pp 48-50.