[R-sig-eco] Independence of vegetation samples

[Michael Marsh]

Reading David Warton's reply to Rajendra made me realize that my 
question (below) is related to his, and that I should specify the 
objectives of my investigation. I'm interested to see if there are 
separate, distinguishable plant communities/associations related to 
environmental variables, and if these relationships differ among the 
different vegetation life forms (e.g., shrubs, graminoids, herbaceous 
annuals or perennials). I've used mrpp() to test for closeness of 
relationships among clusters distinguished by hclust() and mvpart() 
clustering, and used manova() as a further test of the responses of life 
forms to different environmental variables. ,

Original question:
Is there a method in R for testing for independence of vegetation 
samples, for example because of relative proximity of different samples? 
I would like to treat the 3 radially arranged transects of Jornada Line 
Point Index plots as different sample units.
Mike Marsh
Washington Native Plant Society