First looks to see that the row names of the community data frame and the
site or environment data frame are identical. If not, it prints an error
message and exits. If which is NULL, it then looks at the site or environment data frame for
plots or samples that have missing values, and deletes those plots from both the
community and site data frames. Alternatively, if which is a numeric scalar or vector
it deletes the specified plots from both the community and site data.frames.
data(bryceveg) # returns a data frame called brycevegdata(brycesite) # returns a data frame called brycesitedemo <- dropplt(bryceveg,brycesite)
newcomm <- demo$comm
newsite <- demo$site