[R] Comparing spatial point patterns - Syrjala test

[jiho]

Dear Lists,

At several stations distributed regularly in space[1], we sampled  
repeatedly (4 times) the abundance of organisms and measured  
environmental parameters. I now want to compare the spatial  
distribution of various species (and test wether they differ or not),  
or to compare the distribution of a particular organism with the  
distribution of some environmental variable.
Syrjala's test[2] seems to be appropriate for such comparisons. The  
hamming distance is also used (but it is not associated with a test).  
However, as far as I understand it, Syrjala's test only compares the  
distribution gathered during one sampling event, while I have four  
successive repeats and:
- I am interested in comparing if, on average, the distributions are  
the same
- I would prefer to keep the information regarding the variability of  
the abundances in time, rather than just comparing the means, since  
the abundances are quite variable.

Therefore I have two questions for all the knowledgeable R users on  
these lists:
- Is there a package in which Syrjala's test is implemented for R?
- Is there another way (a better way) to test for such differences?

Thank you very much in advance for your help.

[1] http://jo.irisson.free.fr/work/research_tetiaroa.html
[2] http://findarticles.com/p/articles/mi_m2120/is_n1_v77/ai_18066337/pg_7

Jean-Olivier Irisson
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+336 21 05 19 90
http://jo.irisson.free.fr/work/