[R-sig-eco] Morisita horn similarity index

[Jari Oksanen]

Vegan::vegdist has actually two related indices: Morisita index (“morisita”) that assumes that input data are integers (individuals, not percentages), and its Horn-Morisita (“horn”) variant that does not have this restriction. However, you should always check the formulae of indices, because the names may be used loosely. There is also Horn index that is not implemented in vegan::vegdist. For these indices, vegan follows Krebs’s “Ecological Methodology”.

cheers, Jari Oksanen
> On 27 Nov 2015, at 15:41 pm, Zoltan Botta-Dukat <botta-dukat.zoltan at okologia.mta.hu> wrote:
> 
> Dear Moses,
> 
> Vegdist supposes that input data are numbers of individuals not percentages. So, I'm afraid it cannot help to Moses.
> 
> 
> 
> 
> 2015.11.27. 13:17 keltezéssel, Roman Luštrik írta:
>> Hi,
>> 
>> `vegdist` function of vegan package
>> <http://cc.oulu.fi/~jarioksa/softhelp/vegan/html/vegdist.html> implements
>> the morisita index. Is this what you're looking for?
>> 
>> Cheers,
>> Roman
>> 
>> 
>> On Fri, Nov 27, 2015 at 4:55 AM, moses selebatso <selebatsom at yahoo.co.uk>
>> wrote:
>> 
>>>  Hello
>>> I am trying to analyse diet overlap (level of similarity) between two
>>> species. I have diet composition in %. I have tried to find the best tool,
>>> and thought Morisita horn will do, but I cant find the right package for.
>>> Is this the best tool?
>>> Thank you,
>>> Moses
>>>         [[alternative HTML version deleted]]
>>> 
>>> _______________________________________________
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>>> R-sig-ecology at r-project.org
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>> 
>> 
>> 
> 
> 
> -- 
> Botta-Dukát Zoltán
> --------------------------------
> Ökológiai és Botanikai Intézet
> Magyar Tudományos Akadémia
> Ökológiai Kutatóközpont
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> www.okologia.mta.hu
> 
> 
> Zoltán BOTTA-Dukát
> --------------------------------
> Institute of Ecology and Botany
> Hungarian Academy of Sciences
> Centre for Ecological Research
> --------------------------------
> H-2163 Vácrátót, Alkomány u. 2-4.
> HUNGARY
> Phone: +36 28 360122/157
> Fax..: +36 28 360110
> botta-dukat.zoltan at okologia.mta.hu
> www.okologia.mta.hu
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