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Use of statistical process control for coastal marine biological
impact analysis
Don Maurera, George Robertsonb,
Mike Mengelb, Tom Gerlingerb,
Andrew Lissnerc
aCalifornia State University, Long Beach,
Biology Department 1250 Bellflower, Long Beach, California 90840,
USA.
bOrange County Sanitation District P.O. Box 8127, Fountain Valley,
California 92728-8127, USA.
cScience AppIications International Corporation, Environmental
Group, 10260 Campus Point Drive, San Diego, California 92121,
USA |
Abstract
Statistical process control, a procedure long practiced
in industry, was assessed to determine its applicability as an ecological
analysis technique. The procedure is easy to calculate, emphasizes
visual display of data, facilitates analysis and comparison, and
uses well tested zone rules to objectively identify out-of-control
conditions. Statistical process control was applied to a marine
database involving number of species, abundance and biomass of benthic
invertebrates sampled over 13 years (July 1985 to April 1998). Two
stations were evaluated representing reference and impact (i.e.,
test) conditions.
Statistical process control revealed that some out-of-control
conditions were naturally induced whereas others were probably related
to anthropogenic activities. The procedure also effectively depicted
seasonal fluctuations and long-term trends. Patterns and major trends
identified using the technique corroborated those previously documented
by analyses using more conventional approaches. While the procedure
is well established as an industrial quality control protocol, it
has the flexibility and latitude to be considered as a useful tool
in evaluating biological impacts. Comments on management applications
are included.
Keywords: Species; Abundance; Biomass; Zone rules
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