Sunday, 25 June 2017

A big thanks to Thames Valley Environmental Records Centre

... and of course to all the botanists who submitted records to TVERC! All 340,000+ of TVERC's plant records for vice county 23 (Oxfordshire) now reside in the BSBI's Distribution Database (DDB), and my word what a difference it makes! The records go as far back as 1794 but most local recorders will want to know how it affects coverage for Atlas 2020 — see below!

The arrival of so many records is a result of a data sharing agreement struck between the records centre and BSBI. In return TVERC receive regular updates of records that come through me as county recorder. BSBI members often wield a more critical eye, recording esoteric taxa such as hybrids, taxonomically critical groups of plants and unusual garden escapees, so perhaps this will improve the coverage of their database. TVERC also get an extra pair of eyes validating their plant records, and this is what I will be doing over the winter, checking all of their hundreds of thousands of records! That's a lot of work but worth it for the great improvement it makes to the BSBI's data holding for Oxfordshire.

The improvement to progress with Atlas 2020 can be seen from the map showing how many taxa have been recorded in each tetrad (2km square) since 2000, with and without the contribution of TVERC's dataset. The improvement in coverage is immediately striking (502 of the 597 tetrads in the county with records versus 386), but more important is the greater concentration of redder areas. The broad pattern of recording effort is quite similar but has been consolidated, with Oxford and Otmoor well-recorded, the south-east and north-west doing well but with less well-recorded intervening areas. The Chilterns is looking much better but some boundary hectads still have few or no records. The average number of taxa per tetrad has shot up from around 90 to 174. SP50H (Oxford) scores highest with 546 taxa.

At the hectad (10km square) level all this adds up to a considerable improvement, putting us in a good position for the 2020 Atlas which will be published as hectad distribution maps. Most of the hectads in the county have records from every tetrad, 85% have a fifth or more of their tetrads with over 100 taxa recorded, and nearly 60% have a fifth or more with over 200. A good sample of a hectad should rerecord around 70% of previously recorded taxa, and nearly 70% of hectads have attained this if we compare 2000-2017 with the period 1987-1999.

All this good stuff leaves me having to rethink how we might spend the next two seasons recording for Atlas 2020! At the end of the season I will update my Atlas 2020 page with thoughts for 2018 and 2019. By then we will I hope also have access to the getting on 10,000 records submitted to iRecord.

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