PARENT SESSION
Poster Session 18: Statistics
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Nested circular transect sampling for low-effort assessment of spatial structure over multiple contiguous spatial scales.

Rose, Armin¹, ¹ Senckenberg Research Institute, Wilhelmshaven, Germany

ABSTRACT- A class of nested circular transect sampling designs (NECTS) is presented that allows detection of the spatial structure of a variable over multiple contiguous spatial scales, with a minimum of sampling effort and similar accuracy over the whole range of sampling distance lags (SDL). Ordinary circular transect sampling, already allowing equal-frequency discrete sets of sampling distances, is extended by a nested component. The proposed sampling design class is defined by the following conditions: (1) sampling sites are located equispaced along nested circular transects; (2) all circles have the same origin; (3) all circles contain equal numbers of sampling sites; (4) the number of sites per circle is preferably odd; (5) the largest SDL within a circle equals the shortest SDL within the next larger circle; (6) corresponding sampling sites of different circles are ordered to the same direction from the origin. Formulas are given that enable researchers to calculate all available SDLs, as well as all radii of nested circles that fit the conditions of the design class. A littoral data set examplifies the usefulness of the design for some kind of investigations, e.g. in pilot studies when the appropriate spatial scale(s) of a main studies sampling design have to be worked out.

Key words: Spatial autocorrelation, Spatial dependence, Circular transect sampling, Sampling distance