The HRS summary information on this site was last updated on 12/01/2024.
At that time, the HRS database held 1,787,683 records (including duplicates, records of taxa above the level of species - e.g. lots of generic level records, and records that have been flagged as "questionable" or "invalid"). There were 1,545,128 unique, species level records on which the summary data presented on this site is based. In this contect, a unique record is defined as a unique combination of hoverfly species name, grid reference and date.
The update process involves running a data analysis script which generates four CSV files from the unique records. These are:
- The latest year at which each species was recorded from each hectad (10x10km square of the OSGB grid),
- Unique combinations of species, year and day of the year - which are used to produce the phenology plots,
- Frescal trends for easch species, 1980-2022,
- Frescalo rescaled frequency for each species and hectad.
These (large!) files are then uploaded to a MySQL database on the web site from which the maps, phenology plots, etc are generated, This is quite a time consuming process, which is why it is not done after each new dataset has been submitted, but occasionally when substantially more data are available.