Dear Colleagues, Im using PCord to do Indicator Species Analysis. I have read the McCune and Grace book, but I still have two questions that I think I know the answers to, but want more opinions. (Perhaps I missed the answers in the book).
1) Do I need to have equal number of sample units within each group? For example, if I compared three habitats, and had 54 sample units from HabitatA, 35 from HabitatB, and 6 from HabitatC. Then, even if a species has only one individual total represented, and it was collected from HabitatC, it can return a significant p-value from the Monte Carlo test. 2) What is the Monte Carlo test saying? a) The Indicator Value given is correct (or at least higher... no lower) b) This species is a good indicator species (at least statistically speaking). It seems like it must not be (b), because I get significant Indicator Values that are very low (8.5 is the lowest, but many ranged from there to 25). [IVs can range from 0 to 100; 100 being no error: species is faithful and exclusive to particular habitat]. I see papers that have significant but low Indicator Values; some say these spp are good indicator species, others just let us look at the list w the IV and dont really comment all that much on how faithful/exclusive those species are to a particular habitat. I would appreciate your insights! Thank you, Shelly
