Performance of sampling strategies in the presence of known spatial patterns

A - Papers appearing in refereed journals

Alexander, C. J., Holland, J. M., Winder, L., Woolley, C. and Perry, J. N. 2005. Performance of sampling strategies in the presence of known spatial patterns. Annals of Applied Biology. 146 (3), pp. 361-370.

AuthorsAlexander, C. J., Holland, J. M., Winder, L., Woolley, C. and Perry, J. N.
Abstract

In crop protection and ecology accurate and precise estimates of insect populations are required for many purposes. The spatial pattern of the organism sampled, in relation to the sampling scheme adopted, affects the difference between the actual and estimated population density, the bias, and the variability of that estimate, the precision. Field monitoring schemes usually adopt time-efficient sampling regimes involving contiguous units rather than the most efficient for estimation, the completely random sample. This paper uses spatially-explicit ecological field data on aphids and beetles to compare common sampling regimes. The random sample was the most accurate method and often the most precise; of the contiguous schemes the line transect was superior to more compact arrangements such as a square block. Bias depended on the relationship between the size and shape of the group of units comprising the sample and the dominant cluster size underlying the spatial pattern. Existing knowledge of spatial pattern to inform the choice of sampling scheme may provide considerable improvements in accuracy. It is recommended to use line transects longer than the grain of the spatial pattern, where grain is defined as the average dimension of clusters over both patches and gaps, and with length at least twice the dominant cluster size.

KeywordsAgriculture, Multidisciplinary
Year of Publication2005
JournalAnnals of Applied Biology
Journal citation146 (3), pp. 361-370
Digital Object Identifier (DOI)doi:10.1111/j.1744-7348.2005.040129.x
Open accessPublished as non-open access
Funder project or code510
ISSN00034746
PublisherWiley

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