BeeWalk bumblebee distributions for Great Britain 2008-2016

Quality Control

Data are collected by volunteers whose identification abilities will vary. Frequent bumblebee ID training courses are provided for volunteers, identification resources are provided on the project website, and the category ‘indeterminate bumblebee’ is provided as a catch-all for bees where the identification is uncertain. Trials carried out as part of the NPPMF project have found that volunteer’s error rate using the BeeWalk methodology is not significantly different to that of an expert. Photographs and/or specimens are not required for each sighting, but unusual sightings (rare or difficult-to-identify species) are checked by referral to the recorder unless they are known to be experts. The dataset has been validated and verified using the NBN Record Cleaner, and as a consequence some erroneous grid references have been corrected and records outside their range have been checked and confirmed by an expert after referral to the original recorder, or downgraded to ‘indeterminate bumblebee’ where no evidence could be provided. The cryptic Bombus lucorum complex are treated as B. lucorum sensu lato, and only queens and males of B. terrestris & B. lucorum (sl) are recorded to species (indistinguishable workers are treated as the aggregate species terrestris/lucorum and have been removed from this dataset.

Method steps

1. Volunteers walk a set transect on a monthly basis between March and October (inclusive), recording all bumblebees seen within a 4m x 4m 2m ‘recording box’ in front of the recorder (see www.beewalk.org.uk for full details). Photographs are not submitted in support of all records, but netting and photographing bumblebees to help ID is encouraged, and BBCT maintain an ID support service, BeeWatch. BBCT also run a series of ID training events aimed at BeeWalkers to upskill volunteers. Records submitted are validated and their distribution verified using the NBN Record Cleaner with verification rules from the Bees, Wasps and Ants Recording Society. Records which fail verification or validation checks are referred back to recorders for further evidence: if none are forthcoming the records are not included in this dataset

The BeeWalk survey covers Great Britain (but not Northern Ireland). Recording effort is biased towards Somerset, South Wales and the Scottish central belt as a result of publicity pushes, but East Anglia, Cornwall, north/mid Wales and north-west Scotland are under-represented in the dataset. Records within this dataset are collected at 100m resolution but are displayed at summary 1km resolution. Full access may be granted on application to the data manager.