Hi Jari, I'm sorry I didn't get the reply from Ben Bolker, I'll take note of that in future. Do missing values include NAs and blanks? Thanks. Kang Min -- View this message in context: http://r-sig-ecology.471788.n2.nabble.com/Vegan-fisher-alpha-error-tp5125719p5126119.html Sent from the r-sig-ecology mailing list archive at Nabble.com.