1 Topic by lesbentley

  • lesbentley
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Topic: Newbie Questions

I have been given the post of records officer for a recently formed bat group in North East England. Unfortunately I have no experience with biological/ecological records, so I hope you people will be able to give me some help and advice, or tell me where I can go to get help.

We are trying to design a spreadsheet(s) for our bat records, such that it would be suitable for submitting to our local records office (ERIC), and NBN.

I have many questions, but the most pressing one is that I need to have a clear and precise understanding of the meaning of the term "Abundance" as it applies to biological records.

I am worried that the term "Abundance" may have been used wrongly in some of our spreadsheets, and that we do not fully understand its meaning, or how to use the term appropriately in relation to various types of data pertaining to bats. I hope some of you can shed some light on this. [If there is a more appropriate place to post this, please let me know.]

2 Reply by MikeWeideli

  • MikeWeideli
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Re: Newbie Questions

Hi

Abundance is just the number seen. It can be an exact count or something more general. I think on most Bat databases I have seen it is an approximate count as a number.

Mike Weideli

MikeWeideli's Website

3 Reply by lesbentley (edited by lesbentley 27-09-2018 21:29:58)

  • lesbentley
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Re: Newbie Questions

I don't "see" many bats, but the other night I had 2,028 detections of bats. "Bats seen" are often a very small proportion of "bats detected".

Whether a bat is "seen" or "detected", it is usually seen or detected as a "bat pass" (flyby). So does every bat pass count as an abundance of "1"? And are abundances additive? Do 90 bat passes (perhaps made by 2 or 3 individuals) count as an abundance of 90? Or is it only distinct individual bats that count towards abundance?

I guess another way of putting the question would be: Is abundance (in the context of biological records) the same as "absolute quantity of individuals", or is it "quantity of individuals pre unit area/per unit time", or can it be used for events, e.g. "bat passes seen per unit time" where no mention is made of the quantity of individual organisms?

"Presence", "occurrence", and "quantity" are easy concepts to grasp, as they apply to many different aspects of daily life, and are objective terms. "Abundance" is different. In every day life I have an abundance of bills to pay. This is a vague and subjective term meaning only that I have a "lot" of bills to pay. In the context of biological records "abundance" seems to be a jargon word, having a different meaning to its every day use. I'm still struggling to understand this jargon meaning.

4 Reply by Matt Smith

  • Matt Smith
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Re: Newbie Questions

If you are unsure about numbers I would generate 1 record per species per site for a given date, but record the number of passes in a separate numeric field.  "Abundance" as used in biological records can mean an exact count, or it can be use to record categories / ranges - eg 1-10, 11-50, 51-100.  It is up to you how you use this.

Best advice, speak to the Bat Conservation Trust, they may have a "standard" spreadsheet or recording layout already in place.

5 Reply by lesbentley

  • lesbentley
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Re: Newbie Questions

Thanks Matt, what you say seems to make a lot of sense.

6 Reply by mbeard

  • mbeard
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Re: Newbie Questions

Great question.

Please let us know what BCT tell you.

Mike Beard
Natural Course Project Officer
Greater Manchester Local Records Centre

mbeard's Website