[R-sig-eco] questions about food web metrics

[Carsten Dormann]

Dear Jarrett,

most of the indices you're looking for are available in the package sna 
(social network analysis). If your data are not one-mode networks but 
rather bipartite, then you could look at the function as.one.mode in 
package bipartite to convert two-mode into sna-compatible one-mode networks.

HTH,

Carsten


Jarrett Byrnes wrote:
> Dear R-sig-eco group,
>
> I'm working on a food web analysis project in R, and rather than re- 
> invent the wheel, I was wondering if any of you had suggestions for  
> packages, or had written code yourselves for calculations of some of  
> the more involved algorithmic metrics, such as
>
> Number of Food Chains
> Average (and variance in) Food Chain Length
> Shortest Path Length between two species
> Longest Path Length between two species (all of which I guess feeds  
> back to the ave. food chain length...)
> Finding Loops (chains in which a taxa occurs twice)
> Trophic Similarity between species
> Clustering Coefficients
>
> and any other food web metrics of interest.  Also, any methods for  
> dealing with network stability and the analysis of weighted networks  
> not already in the sna or network package - particularly those dealing  
> with food webs - would be great.
>
> In addition to my own work, I'd like to compile all of these methods  
> into a foodweb package to post on CRAN for general usage, so, any  
> contributions would be most welcome!
>
> -Jarrett
>
>
>
>
> ----------------------------------------
> Jarrett Byrnes
> Postdoctoral Associate, Santa Barbara Coastal LTER
> Marine Science Institute
> University of California Santa Barbara
> Santa Barbara, CA 93106-6150
> http://www.lifesci.ucsb.edu/eemb/labs/cardinale/people/byrnes/index.html
>
>
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>
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>   

-- 
Dr. Carsten F. Dormann
Department of Computational Landscape Ecology
Helmholtz Centre for Environmental Research UFZ 
Permoserstr. 15
04318 Leipzig
Germany

Tel: ++49(0)341 2351946
Fax: ++49(0)341 2351939
Email: carsten.dormann at ufz.de
internet: http://www.ufz.de/index.php?de=4205