Dragonfly records from the British Dragonfly Society Recording Scheme

British Dragonfly Society Recording Scheme

Description

Dragonfly and damselfly records collected and collated by the BDS Recording Scheme (formerly the Dragonfly Recording Network), a part of the British Dragonfly Society, for the period 1800-2022.

This dataset incorporates the whole of the historical Dragonfly Recording Network (DRN) dataset and the more recent records maintained in iRecord. Data for recent years may be incomplete, as recorders add batches of records that may include earlier sightings. It is the Society's intention that the dataset will be updated at least annually.

Geographic Description

Great Britain. All records are provided to NBN Atlas with an OSGB36 grid reference. For records from Ireland please refer to the appropriate CEDaR dataset. Records from the Channel Islands are not included.

Purpose

This dataset represents the curated, accepted records of the BDS. It aims to provide full coverage across Great Britain and welcomes additional contributions via iRecord or otherwise by arrangement.

Data quality

Records are only included after verification and acceptance by a BDS County Dragonfly Recorder (CDR).

The date of the most recent verification is included in the dynamicProperties sub-term 'verifiedDate'.

Where a record at genus rank can only be of one species, the reassignment to species has been made and the original identification is included in the term 'occurrenceRemarks'. An example is Brachytron to Brachytron pratense. Records of vague taxa above the rank of genus have been excluded.

In general, those records awarded 'Accepted - correct' status have photographic (see 'MediaCount' sub-term, below) or specimen evidence seen by the verifier whereas those awarded 'Accepted - considered correct' do not pass this strict test. Some CDRs, however, award 'Accepted - correct' status to records without further evidence. Some older records and some from sources outside iRecord have an unqualified 'Accepted' status.

Some source systems do not distinguish the Life Stage ('stage' term) of the individual(s) recorded. An attempt has been made (using algorithms) to assign the most likely stage to each, defaulting to 'adult'.

Since the dataset update of Feb 2023 an indication is included where the original record had media (typically photographs) available to the verifier. Where this is known, the number of media items is present in dynamicProperties sub-term 'MediaCount'. e.g. {"MediaCount":3}

Methods

Each record is a field observation with an individual count of a single Life Stage, though many are set to 'present' when uncounted. Where a single iRecord record has been 'flattened' to multiple NBN Atlas records, one for each life stage recorded, these are held together by and can be aggregated on the 'recordNumber' term. Where several species are recorded at the same time, these have the same key value in the 'eventID' term.

The value in the 'lifeStage' term is also coded into the 'occurrenceID' term as a suffix. For example, value iBRC18178171.Ad indicates an adult and 'lifeStage' contains the value 'adult'.

Some records are from site monitoring. If and only if the 'fieldNotes' term includes a 'Recorded all species' component, the recorder asserts having recorded all species seen on that date at that site, not just the interesting ones.

Records from BTO (BirdTrack), Butterfly Conservation (BBS, WCBS, etc.) are pumped directly into iRecord and reviewed by BDS verifiers. However, there are currently some issues with BirdTrack records having vague map references due to conversion from point-and-radius co-ordinates to OS grid squares and the large size of many BTO sites. We hope to refine the map references of many of these records in time for the next update.

The life stage 'Oviposition scars' is specific to Chalcolestes viridis (Willow Emerald Damselfly) and is used to record 'tracks' on plant stems where eggs have been laid. These are typically seen in the winter and care is advised not to allow these records to confuse the adult flight period phenology of the species. Some records of 'Oviposition scars' may be included with an observation date beyond the nominal end-year of the dataset, i.e. in the January following.

Citation

British Dragonfly Society Recording Scheme 2023. Dragonfly records from the British Dragonfly Society Recording Scheme. Occurrence dataset on the NBN Atlas.

Rights

BDS follows NBN's Open Data recommendations and has a policy that only records with a licence of CC BY or more open are included. Data from other organisations are included with permission and remain the copyright of the provider. Where available the provider's initials and UNIDs are included per-record in the otherCatalogNumbers term for traceability.

Data generalisations

Recorders working in different source systems may record abundances in different ways. These are standardised here into ranges within the term 'individualCount':

present, 1, 2–5, 6–20, 21–100, 101–500, 501+

A zero '0' abundance value is generally accompanied by the 'occurrenceStatus' term being set to 'absent'. This is a Record of Absence, meaning "I looked for this species but did not find it", and is usually from a single-species survey.

Caution: Since the dataset update of Feb 2023 the hyphen separator in these ranges has been changed to '–' / Unicode: U2013 / 'En Dash' / keystroke: Alt0150. Reliable fonts supporting this character are Arial, Times New Roman (Excel), Liberation Sans (LibreOffice), Helvetica (MacOS). The reason for this change is that CSV format downloads from NBN Atlas are often loaded into Microsoft Excel but even when Excel is explicitly told that the column contains Text it interprets range '2-5' or '6-20' as a date if it contains a minus sign (U+002D) as the hyphen.

Attempts have been made to correct typographical errors, free text entries and miskeyings into the most likely intended value or range. Examples: "O" to '0'; " 1" to '1' (removing the leading space); "approx 4" to '2-5'. Where this has been done, the original value is perserved in the term 'occurrenceRemarks'.

Attempts have also been made to include records from sources that have no abundance and/or life stage data, by presuming abundance value 'present' and life stage value 'adult'. Where this has been done, a note to that effect is added to term 'occurrenceRemarks'.

Some records from BTO (BirdTrack) contain multiple Life Stage Abundances but these are not currently unpacked correctly by iRecord and only the first stage of the list currently reaches NBN Atlas.

Information withheld

- A small number of Sensitive records.

- Vague records (see above).

- Records with a status of Unreviewed, Queried but not replied to, Not accepted.

- Records awaiting technical improvement before acceptance.

Digitised records