Hello everyone,
I used a Braun-Blanquet modified classes to collect habitat variable data, assigning % classes to my shrubs cover.
How can I transform these classes into proportional abundance, in order to calculate diversity, evenness and so on? Is it possible?
Thank you in advance. Ilaria
You need to know species number in order to calculate species abundance, which might be proportional to the number of species you calculated cover for if you calculated it individually for all species :)
I am not sure that this is possible. Presumably your percentage cover data was based on estimates (you use the word 'assigning') and not on quantitative measurements. If this is correct, you are hoping to use a quantitative measure (one of the many diversity indices, which then lead on to evenness measures) on qualitative data. This is unlikely to give you the kind of results which you desire. Perhaps it is better to talk about the number of B-B classes which you have determined, and then to see how many of them have a much larger % occurrence than you might expect (and alternatively how many of them have a smaller % occurrence than you expect).
If you have the information of how many species you have recorded, you can use it to calcute species diversity :)
You have just a list of present shrub syntaxonomic classes. It is too crude distribution; vegetation diversity need lower (ordo, alliance, association) and more fine units to be presented enough correctly. But, Braun-Blanquet method assign an attribute to each plant species, which is specific for this vegetation school: characteristic species. If you have complete plant list, you can use a TURBOVEG software to express a vegetation diversity.
https://www.cell.com/heliyon/fulltext/S2405-8440(18)38688-2
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