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The use of water traps for cranefly monitoring: an assessment of operator efficiency
Author(s) -
BLACKSHAW R. P.
Publication year - 1987
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1987.tb03254.x
Subject(s) - statistics , operator (biology) , sorting , biology , trap (plumbing) , mathematics , environmental science , environmental engineering , algorithm , biochemistry , repressor , transcription factor , gene
SUMMARY Unskilled operators used water traps to monitor cranefly populations in 48 grassland sites in the summer of 1984. For each trap operated the numbers of males and females were recorded and these counts were checked in the laboratory to give estimates of operator error. Operators also recorded the amount of time they spent implementing the scheme. The probability of reporting a correct count for male craneflies was 0.796 and for females 0.846. There was a greater tendency for the male counts to be under‐rather than overestimated, and vice versa for females. Generally, the number of errors made was not related to either the number of craneflies taken or the rate at which they were sorted. Average times were calculated for different aspects of the monitoring system: 37 min for setting up four water traps; 40 min per field per week for servicing traps excluding handling craneflies; 18 flies/min sorting rate. Overall, the mean time spent implementing the scheme in one field was 209 min. It was concluded that operator error can be as important as predictive error in the implementation of a forecasting scheme and that it cannot be assumed that any monitoring system operates with complete accuracy.