Environment Agency England and Wales (2007) freshwater invertebrate species (single species families)

Quality Control

Routine and ad-hoc freshwater invertebrate samples taken by the Environment Agency are always sorted to family level. Since 1990, quality control procedures for family level identification have been in place which allows a high confidence to be placed on taxa which are from families containing a single species. Records earlier than 1990 were not subject to standardised quality control at the time of collection, but are included within this data set.

Validation on this data set is restricted to the correction of obvious spatial errors. The identification of these species has been subject to formal quality control since 1990 and should therefore be of a high standard. Due to the nature of the species in this data set (single species families), it is likely that most records, including those earlier than 1990 are of a good quality.

Method steps

1. This data was collected by ecologists working for the Environment Agency and its predecessor organisations. Most of the data originate from kick samples taken in main rivers and have been collected and analysed using standard sampling methodologies. The data was extracted from the Environment Agency's national ecology database (BIOSYS) and does not include older records held in paper copy only. Records for families, genera and species from chosen single species families have been extracted and are reported at the species level.

The records cover the Environment Agency regions across England and Wales. Sites are recorded at a minimum precision of 100m. The distribution of records is biased towards main rivers and areas with historical water quality issues. This is especially true of older records. The sampling methodologies and taxa identified are the same at all sites.