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Axel G. Rossberg | 5 Feb 19:01

NEXT SIZEMIC WORKSHOP: Sweden, June 1-6, 2009. Information on How to Apply

Julia Blanchard asked me to post the following.

Axel 
****************************************************************************

        Dear Colleagues, 

        The 2nd International SIZEMIC workshop:"Body size and
        ecosystem dynamics: Implications for conservation and
        management of natural resources" lead by Andrea Belgrano
        (Swedish Board of Fisheries) will take place on June 1-6,
        2009, at the Sven Lovén Centre for Marine Sciences, Strömstad,
        Sweden (http://www.tmbl.gu.se/).

        Please see the attached documents for information about this
        exciting workshop and instructions on how to apply. This
        information can also be downloaded from www.sizemic.org.

        All applications should be sent to
        andrea.belgrano@... before the close of Sunday,
        March 15th.

        Could you please forward this announcement to anyone who may be
        interested in attending.

        Thank you very much...and hope to see you in Sweden!

        Best wishes, 
        Julia
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Axel G. Rossberg | 17 Feb 13:59

Phylogenetic Correlations (II)

Dear Foodwebs List Members

this is the second part of a tutorial on phylogenetic correlations in
food-webs.  The first part discussed the question what phylogenetic
correlations are, and can be found here:

 http://www.mail-archive.com/foodwebs-meEmJjl1h1Ek+I/owrrOrA <at> public.gmane.org/msg00024.html

Here, I discuss the question how strong these correlations are.

Enjoy,

Axel

** Part II: HOW STRONG ARE PHYLOGENETIC CORRELATIONS IN FOOD-WEB TOPOLOGIES? 

PHYLOGENETIC CORRELATIONS IN HISTORICAL FOOD-WEB DATA

It is well known, and easily understood, that phylogenetic
correlations in data sets become the clearer the finer the taxonomic
resolution of the data sets is:  If there are more pairs of closely
related species, the similarities of these species become more
obvious.  For food webs, a theoretical analysis of this effect can be
found here http://axel.rossberg.net/paper/Rossberg2007a.pdf.

Historical food-web data sets, such as that compiled in Joel Cohen's
book "Community Food Webs" from 1990, are rather small and often have
comparatively low taxonomic resolution. This may explain why
phylogenetic correlations historically received little attention in
the field.
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Axel G. Rossberg | 24 Feb 13:51

Re: Phylogenetic Correlations (II)

From: Christian Mulder <Christian.Mulder@...>
Subject: Re: [Foodwebs] Phylogenetic Correlations (II)
Date: Mon, 23 Feb 2009 12:29:26 +0100
Message-ID: <OFD89213ED.78545398-ONC1257566.00393E58-C1257566.003F1ED2@...>

> 
> Hi Axel, interesting discussion. I am only wondering on the kind of taxonomic
> resolution of some cited references, like "Sand Beach, California"
> (J.W.Nybakken 1982 as Cohen's web #50).
> It is biologically hard to model, or even to imagine, trophic links between
> (1) debris, (2) plankton, (3) amphipods, (4) Blepharipoda, (5) Emerita
> analoga, (6) Tivela stultorum, (7) Donax, (8) Olivella, (9) Thoracophelia,
> (10) Nepthys, (11) Policines, (12) sea otter, (13) birds, and (14) fishes.
>  Member species of each of these taxa have not trophic roles sufficiently
> similar to warrant grouping them together, but crucial nodes of such a food
> web are missing (echinoderms, for instance). 

Hi Christian,

thank you for the comments.  

You are right that, if you look at each of the taxa more closely, we
will find differences between member species.  But this would not
preclude that species are trophically more similar within taxa such as
those listed above (i.e. mostly genera) than across them.  The
results of Cattin et al. (2004) and Bersier & Kerli (2007) would
suggest this is so.  However, since the question here is slightly
different from theirs, the answer might be different.  If one could
show that it was, this could be an interesting result.
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