Macroinvertebrates of two abstracted streams: taxon data

Method description:

The waterbodies studied are both tributaries of the Lowther, a sub-catchment of the Eden (Cumbria) catchment. The Heltondale Beck has a total length of 25.1 km and a catchment area of 11.8 square kilometres. The Howes Beck (also known as the Cawdale Beck) has a total length of 17.5 km and a catchment area of 9.1 square kilometres.

Sampling took place on the 23rd and 24th September 2010. Sampling reaches were selected approximately 100 metres upstream and downstream of water abstraction points in two streams, the Howes Beck and the Heltondale Beck. Location was recorded on Global Positioning System and a 100 metres sampling reach established around these locations within which the survey was carried out (50 meters upstream and 50 meters downstream). Water depth (centimetres) and wetted width (meters) were recorded at the centre of the 100m reaches as a mean of three readings. Map variables and geology were derived for those point locations using the Intelligent River Network (Version 17), which was first described in: Dawson, F.H., Hornby, D.D. and Hilton, J. (2002), A method for the automated extraction of environmental variables to help the classification of rivers in Britain. Aquatic Conserv: Mar. Freshwater Ecosyst., 12: 391*403. doi: 10.1002/aqc.534

The habitats in the100 metre reaches were assessed using the River Habitat Survey (RHS) method, for which the standard protocol is described in: Environment Agency. (2003) River Habitat Survey in Britain and Ireland. Field Survey Guidance Manual: 2003 version Environment Agency, Bristol , UK.

For macroinvertebrate sampling, five riffles were chosen at random within the 100 metre sampling reaches. Macroinvertebrate samples were collected from each of the five riffles using a Surber sample with a mesh size of 250 micrometer and sampling area of 0.0625 square meteres, disturbing the substrate by hand in the sample area to a depth of approximately 5 cm. Samples were then washed into plastic sample bags, labelled and were preserved with a 4 percent formaldehyde solution in the field. In the laboratory, samples were washed through a 250 micormenter sieve and all macroinvertebrates were picked from the samples and identified to the lowest taxonomic level possible, usually species. Valid taxonomic names and unique taxon identification codes were provided in: Davies, C. and Edwards, F.K. (2011) Code list for recording the macroinvertebrates in freshwater in the British Isles. Centre for Ecology & Hydrology, Wallingford.

Data entry was validated by crosschecking data print outs with laboratory sheets.