Just try it and you will see. You may get a lot of criticism from people who
either never used or would never use these indices, but I am sure that it
will help you to analyze your data. You don't have to publish it, but you
will get a better insight into your data.

The size is another hot potato in your project. You touched the question of
minimal area that is another sensitive problem in vegetation sampling. Are
your patches large enough to get the majority of species in them? You will
get some random noise, if your areas are too large, but skewed results, if
they are too small. It depends on the vegetation types you are working with.

Adolf Ceska
P.S. I prefer Sorensen's similarity index. 



-----Original Message-----
From: Ecological Society of America: grants, jobs, news
[mailto:[email protected]] On Behalf Of Rajasri Ray
Sent: June-13-11 10:23 PM
To: [email protected]
Subject: [ECOLOG-L] Similarity index

Hello,
       I am trying to compare species composition among different patches
which vary in their sizes to a great extent.I am planning to compute
Jaccard's similarity index for this. For species enumeration, in some
patches I have documented presence of all members (due to very small size of
the patch ~ 80 - 500 sq. m).There is problem to apply uniform area concept
for species composition. I would like to know whether Jaccard's is suitable
for that kind of comparison.
Thanks
Rajasri  

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