[R-sig-eco] Distinctiveness and contribdiv( )

[Pekin, Burak K]

Yes Peter, I am looking for something that really conveys irreplaceability, in other words, the relative 'endemism' of species within a site. So, a site that contains species which are found only in a few other sites within a region is considered more 'irreplaceable' or 'distinct' than a site that contains more 'generalized' species which are found in many sites within the region, irrespective of the total number of species found within them. Does the beta component of contribdiv ( ) do this, or does it also take into account the total number of species within the sites?
-Burak

-----Original Message-----
From: psolymos at gmail.com [mailto:psolymos at gmail.com] On Behalf Of Peter Solymos
Sent: Wednesday, December 01, 2010 1:36 PM
To: Pekin, Burak K
Cc: r-sig-ecology at r-project.org
Subject: Re: [R-sig-eco] Distinctiveness and contribdiv( )

Burak,
Not exactly clear what you want, but Lu et al. 2007 describes the differentiation coefficient D that is the sum(beta)/sum(gamma) and can be obtained as attributes(contribdiv(x))$diff.coef . Note also that there is a link between diversity partitions and distance indices so you might as well use the components from the contribution diversity approach. Or is it something like irreplaceability in the reserve selection literature you need?
Cheers,
Peter

Péter Sólymos
Alberta Biodiversity Monitoring Institute and Boreal Avian Modelling project Department of Biological Sciences CW 405, Biological Sciences Bldg University of Alberta Edmonton, Alberta, T6G 2E9, Canada
Phone: 780.492.8534
Fax: 780.492.7635
email <- paste("solymos", "ualberta.ca", sep = "@")



On Wed, Dec 1, 2010 at 11:17 AM, Pekin, Burak K <bpekin at purdue.edu> wrote:
> Hello, Is there a diversity index similar to the 'contribution diversity approach' contribdiv()in vegan that reflects only  the compositional 'distinctiveness' of a site within a region. contribdiv()combines 'distinctiveness' with a within-site diversity measure such as richness, I on the other hand am looking for an index that measures only the relative number of species within a site that are 'distinct' or 'unique' within a region.
>
> Cheers,
> Burak
>
>
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