Hi,
I'd like to ask did you also considered the occurrance of bryophytes? I think maybe the bryophyte layers may provide more water availability to those epiphytes if the epiphytes are grew on the bryophyte layers attached on the tree bark. Maybe comparing between the epiphytes that grew on the bryophyte layer or naked tree bark would provide more information to the distribution of your eight species. Thank you!
Yi-Nuo Lee.