Rao entropy with presence-absence data

Hello,
Is it possible, and meaningful, to calculate  Rao`s quadratic entropy 
index (function dbFD from package FD) with presence-absence data? I 
don't get a error message but when I use the function with 
(...,scale.Rao=TRUE) the calculations never end.

Thank you for your answer.

/Thomas

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Thomas M?ckel, PhD student

Department of Earth and Ecosystem Science
Lund University
S?lvegatan 12
SE-223 62 Lund
Sweden

Tel:+46 (0)46 - 222 4887
E-mail: Thomas.Mockel at nateko.lu.se