ABSTRACT
Sampling methods have been developed for studying different properties (e.g., density, spatial pattern) of sets of points or items (e.g., trees, nests, etc.) distributed within an area of space. In many instances, sampling is the only solution as it is not possible to map or census all the points in the area; consequently, the field ecologist is constrained to select points from subregions within the total area. Diggle (2003) calls the sampling methods involved in this last case sparse sampling methods to distinguish them from those concerning mapped populations within an area. In general, sparse sampling methods can be divided into two different classes, depending on the way points within a subregion are selected. One method is quadrat or plot sampling, and the other method is plotless sampling. Although quadrat sampling has always been a popular field technique in forestry and plant ecology, plotless sampling techniques have also been applied by foresters and plant ecologists when rapid estimates of the density of plants in a large region are needed. In fact, plotless sampling is often considerably more efficient than quadrat sampling because searching for all the items in a quadrat might be time consuming.
