Surrey Botanical Society

Monad Records by Date Class

The number of records of Vascular Plants and Charophytes recorded by the SBS in MapMate as at 5th October, 2015 stood at 573,026. although 11,221 of these records had been deleted (but their unique IDs retained by MapMate) and 11,163 records had a less precise OS Grid Ref than a 1Km Square (see Table 1).

Surrey covers 2,105 monads, including 1,822 complete monads, 145 with 50% to 99.9% coverage and 138 with 0.1% to 49.9% coverage.

A list of monads and the percentage of each 1km square in Surrey was copied from the Biological Records Centre and imported into a MS Access table. The analyses of records and taxa for each Date Class and all years were carried out in MS Access using queries developed for the purpose (see Appendix 2 for records & Appendix 3 for taxa) using the list of Surrey monads and SBS MapMate data.

Length of OS GridRefOS GridRef TypeNumber of OS GridRefsPercentage of OS GridRefs
4Hectads - 10km Square2,6030.463
5Tetrads - 2km Square8,6051.53
Subtotal (not mapped)11,1631.995
6Monads - 1km Square117,41020.898
8100m Square423,80575.436
1010m Square9,2611.141
121m Square1080.019
Subtotal (mapped)550,58494.494
Total records 561,805100
Deleted records11,221
Table 1. Summary of Mapmate records by OS Grid Reference

Ten records where the OSGridRef was null; 2,603 hectad records and 8,605 tetrad records; and 11,221 deleted records were not included in the analyses by monad.

In addition 815 records where the Taxon was recorded as 'Not present' were not included in the analyses by monad.

The majority of the records (550,584 or c. 94.494%) are at a sufficient precision to enable analyses at the monad (1km Square) level (Table 2). (Table 2).

Date ClassYear RangeRecordsDistinct TaxaCumulative no. of distinct taxa
DC 01666-1929919205205
DC 11930-19699,7541,2631,301
DC 21970-198616,8121,5771,771
DC 31987-199975,8832,0042,306
DC 42000-2009153,6031,9862,542
DC 52010-2019303,8232,1152,799
Table 2. Summary of MapMate records and taxa by Date Class (Year Range). N.B. The Date Classes are historical and not intended to allow comparison between the number of records for each class. 12,268 records were duplicates with respect to Taxon, Monad and Date Class, hence the diifference in total number of records from Table 1.

The analyses also revealed 54 monads without any records or taxa and an additional 110 monads with fewer than 20 records (1666-2019).

The data were also used to populate Interactive Google maps developed by Robin Day expressly for the purpose. These maps enable users to search for a grid reference or place name and select whether to display the number of records or taxa in every Surrey monad by date classes.


I am extremely grateful to David Williams, Robin Day and Peter Wakeham for invaluable assistance and Bill Chadwick who provided the code for SBS use which Robin adapted.

The analyses would not have been possible without the massive input of the original records from SBS members, recorders and MapMate users.

Download Records Analysis Spread Sheet | Download Taxa Analysis Spread Sheet

Brian Pitkin, Surrey Botanical Society