UK AWMN Invertebrate Sampling Methodology
Macroinvertebrates are sampled and analysed by the freshwater laboratory of Queen Mary, University of London. Sampling is undertaken in April/May each year.
At stream sites five separate one minute kick samples are made with a standard hand net. Only riffle sections are sampled. Each sample is separated into 3 size fractions with sieves. The finest sieve is 300um mesh. Each fraction is diluted to achieve maximum sample separation. Using a white tray, halogen lamp and fine forceps, all invertebrates are picked out and placed in a vial containing 70% IMS. With the exception of Diptera, Oligochaeta and Bivalva, taxa are identified to species level. Taxonomic grouping of certain species is carried out to reduce sample variability. Exact counts are made of each taxa.
At lake sites, samples are collected from littoral habitats with a standard hand net. At each lake, five one minute kick/sweep samples are collected from the dominant habitat. Samples are preserved and counted as at the stream sites.
All data are transferred to the central biological database and a list of dominant taxa, summary statistics and a graphic description of community structure are presented in the UK AWMN annual data reports.
Taxonomic quality control is ensured by the full participation of UK AWMN invertebrate analysts in regular ICP Waters Biological intercalibration exercises. Intercalibration reports can be downloaded from the ICP Waters website.
Page last modified: 1st December, 2011
Page published: 12 March 2010