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Frequency of taxa in a vc & RPR taxa (analysis spreadsheet)

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Frequency of taxa in a vc & RPR taxa (analysis spreadsheet)

by AndyAmphlett » Fri Jan 16, 2015 1:26 pm

Vice-county Checklist: frequency of species and hybrids and listing of candidate Rare Plant Register taxa

As a generalisation (there are exceptions), County Floras tend to describe frequency and abundance of plant taxa in each county in somewhat inconsistent and non-standardised terms. Terms such as local or common, can refer to overall whole vice-county frequency, or to the actual abundance of a plant where it occurs. It is not always clear what is meant. Frequency is a spatial measure, while abundance is a population measure. Anyone who makes use of the National Vegetation Classification (NVC) will be familiar with the way in which that classification clearly separates these two parameters.

BSBI Rare Plant Registers (RPR) include taxa which are 'Rare' or Scarce' within a vice-county. These are frequency measures; 1 - 3 and 4 - 10 'sites' respectively. These categories do not reflect the actual abundance of the listed taxa, just their spatial frequency. The Excel spreadsheet (link below) applies the same spatial frequency approach as employed to delimit vice-county 'Rare' and 'Scarce', but using seven frequency categories, (Rare, Scarce, Near Scarce, Local, Frequent, Common, and Very Common), it categorises all species and hybrids recorded in a vice-county. The spreadsheet uses tetrad frequency data to categorise taxa, but for 'Rare' and 'Scarce' taxa it also makes use of monad and hectad frequency, while for 'Near Scarce' taxa it also uses monad frequency.

The frequency categories 'Rare' and 'Scarce' used here, are consistent with their use in BSBI Rare Plant Registers. The spreadsheet identifies native and archaeophyte species and hybrids which are Rare or Scarce in a vice-county, and hence should be considered for inclusion in a RPR. The outputs also clearly show the number of taxa with no recent records in a vice-county.

EDIT ADDED 20/01/2015

Following further testing of the spreadsheet, a revised version (dated 19th January 2015) is now available. Updated links to the Excel file and Explanatory notes are given in a post below, dated 16/2/2018.

The Explanatory Notes must be read carefully. Please do not be put off by their length and detail, as the Excel analysis file is much easier for you to use, than the notes were for me to write! :) However, if new to running DDb queries, and copying, pasting and sorting data in Excel, it may be a little daunting. I think the results are worth it though. Tom H. is going to see if this type of analysis, or something similar, can be made more easily available within the DDb. In the meantime please make use of the version provided at the link above.

NB there are some limitations on how the spreadsheet works for vice-counties in Ireland. These are explained in the Explanatory notes.

EDIT ADDED 21/01/2015

The capacity of the spreadsheet has been increased from 2000 to 3250 taxa. This should provide enough capacity for even the most diverse vc, with the most assiduous recording of aliens, critical taxa etc..

Andy.
Last edited by AndyAmphlett on Fri Feb 16, 2018 2:37 pm, edited 3 times in total.
AndyAmphlett
 
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Re: Frequency of taxa in a vc & RPR taxa (analysis spreadshe

by AndyAmphlett » Tue Jan 20, 2015 12:28 pm

Please note, the Excel file and Explanatory notes have both been revised. The links in the original posting (16th January) have been updated; they now download the revised versions. If you have previously downloaded these files, please download the new versions.

The revised Excel file has a number of improvements. In particular, it uses both the VCCC and Atlas 2000 to assign 'Native' status to taxa, and the most recent year recorded query is improved. The Summary worksheet now has a number of additional features, eg. it provides summaries and graphs of native and alien taxon frequencies.

Andy.
AndyAmphlett
 
Posts: 307
Joined: Fri Nov 23, 2012 9:32 am
name: Andy Amphlett

Re: Frequency of taxa in a vc & RPR taxa (analysis spreadshe

by AndyAmphlett » Thu Jan 12, 2017 1:01 pm

If you recently tried to use the Excel file linked above, you will have found that it was not working. This was due to a change in the way some of the DDb queries returned results. There is a workaround, and I have added some new text to the Explanatory notes. Please download the notes again (new text is in red).

Andy.
AndyAmphlett
 
Posts: 307
Joined: Fri Nov 23, 2012 9:32 am
name: Andy Amphlett

Re: Frequency of taxa in a vc & RPR taxa (analysis spreadshe

by AndyAmphlett » Fri Feb 16, 2018 2:35 pm

Hi,

The free version of Dropbox no longer allows access to a 'Public Folder'. I have therefore put the Excel file and Explanatory Notes (Word) into a folder on Google Drive.

https://drive.google.com/drive/folders/ ... sp=sharing

Andy.
AndyAmphlett
 
Posts: 307
Joined: Fri Nov 23, 2012 9:32 am
name: Andy Amphlett


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