1. Nc decline VS habitat area decline 2. Extrapolating Nc from mortality rate

[gaell...@gmail.com]

Hi all, 

First, comment about Nc decline VS habitat area decline. There are scenarios where there is a known recent population decline, without necessarily losing habitat area. It is the case of Pinna nobilis, Mediterranean endemic, undergoing mass mortality (MM) due to a parasite, without a proportional habitat decline.

In Section 3: indicator 2: IF AVAILABLE, PLEASE RECORD THE OVERALL DECLINE IN SPECIES' HABITAT AREA. In this case, the % of decline in the species habitat area is less relevant than the % of decline in the species population size over the past 5 years. 

In the case of P. nobilis however, research relative to mortality and current population status is ongoing, but nos census data or mortality rate following the MM are known to this day. 

Second comment, relating to section 5: HOW WAS NC CALCULATED IN THIS POPULATION? Considering mortality rate post MM had been available, I was thinking on extrapolating Nc based on Nc prior MM and % mortality due to MM. However, it doesn’t fall under any of the possible answers to the question (options are: Count; Extrapolated based on habitat area and known density; Unknown)

Any reflexion, advice, comment on either of these points are welcome :)

Gaëlle

[shoban]

Great questions!  Myriam and Alicia can also reply, being plant people, but:

1. I think that typically this question should refer to decline in habitat area, BUT if you know of a strong census decline, I would put that number.  For example in the USA, some forest species declined by 99% due to insect pest.  I think it would be ok to put that decline even though habitat is still available.  What do others think?  Has anyone had this type of situation already and what did you do?

2. An extrpolation based on mortality sounds also good to me.  Maybe Unknown should be Unknown/ Other?  What do other people think?

[Myriam Heuertz]

Hello,

I agree with the suggestions, the cause of the decline can be other than habitat loss, and we should capture this decline (it could be pest outbreaks, or due competition because of an invasive for example). We perhaps just need a little rephrasing in the Koboform questions to ask for this Nc decline in a more general way (or just make an addition to the guidance document):

- IF AVAILABLE, PLEASE RECORD THE OVERALL DECLINE IN SPECIES' HABITAT AREA (OR, IF RELEVANT, IN CENSUS SIZE NC)

- HOW WAS NC CALCULATED IN THIS POPULATION? (Count, extrapolation, unknown/other)

We can discuss this on Monday, too!

Best wishes,

Myriam

--
You received this message because you are subscribed to the Google Groups "Genetic indicators project" group.
To unsubscribe from this group and stop receiving emails from it, send an email to genetic-indicators-...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/genetic-indicators-project/3cfc9012-443e-47af-bb59-6ba1b1f54ca7n%40googlegroups.com.

--

Myriam Heuertz (DR2)

Biogeco, INRAE, Univ. Bordeaux

Mailing address:

INRAE UMR BIOGECO 1202
Domaine de l'Hermitage
69 route d'Arcachon, CS 80227
33612 Cestas Cedex, France

Email: myriam....@inrae.fr  

Phone: +33 5 35 38 5329 (office), +33 780 41 33 85 (mobile)

[shoban]

Related to this, in the USA team we asked about the question " - IF AVAILABLE, PLEASE RECORD THE OVERALL DECLINE IN SPECIES' HABITAT AREA (OR, IF RELEVANT, IN CENSUS SIZE NC) "

How to record whether it is a decline in area, Nc, or unknown?  We suggest to explain this in the next box, which asks for a reference.  So include a sentence in the box such as "The 67% decline reported above is based on a known or inferred 67% decline in number of individuals, from 10,000 to currently 3,300.  REFERENCE INFO"