Variability in the identification and enumeration of marine benthic invertebrate samples and its effect on benthic assessment measures.
Studies designed to measure anthropogenic impacts on marine benthic communities depend on the ability of taxonomists to consistently discriminate, identify, and count benthic organisms. To quantify errors and discrepancies in identification and enumeration, 20 samples were completely reprocessed by another one of four participating laboratories. Errors were detected in 13.0% of the data records, affecting total abundance by 2.1%, numbers of taxa by 3.4%, and identification accuracy by 4.7%. Paired t-tests were used to test for differences in the Benthic Response Index (BRI), total abundance, numbers of taxa, and the Shannon-Wiener index between the original and the reanalysis data. Differences in the BRI were statistically insignificant. Although statistically significant differences were observed for numbers of taxa, total abundance, and the Shannon-Wiener index, the differences were small in comparison to the magnitude of differences typically observed between anthropogenically affected and reference sites.
Ranasinghe
J Ananda
JA
Southern California Coastal Water Research Project, 7171 Fenwick Lane, Westminster, CA 92683-5218, USA. anandar@sccwrp.org
Montagne
David E
DE
Weisber
Stephen B
SB
Bergen
Mary
M
Velarde
Ronald G
RG
D000818:Animals; D002965:Classification; D004784:Environmental Monitoring / Q000592:standards*; D007448:Invertebrates; D015588:Observer Variation; D011157:Population Dynamics; D011786:Quality Control; D015203:Reproducibility of Results; D013048:Specimen Handling; D014873:Water Pollutants / Q000009:adverse effects
D014873:Water Pollutants