EFFECT OF QUADRAT SIZE ON MEASUREMENTS OF SPECIES DENSITY

Maps for species of Australian Mammalia are used to examine the effect of the size of sample area on measurements of species density. Larger sample areas generally yield larger measurements. For example, the measurement of species density changes from 68 to 99, an increase of 38% in an area of high density, as the sample area changes from a small local area to a square 400 km per side. No single area size is intrinsically better than others. This effect needs to be taken into consideration in order for meaningful comparisons of studies to be made when different sizes of sample areas have been used. Examples to illustrate the great variety of sample areas that have been used are briefly discussed.