Report of a Working Group, published in the bookDevelopmentsinnumericalecology1987Bölter, M., P. Legendre, J. DeLeeuw, R. Park,P.Schwinghamer, S.E. Stevens & M. Troussellier. 1987.Numerical ecology: Developments for microbial ecology.Pp.469-484 in: P. Legendre & L. Legendre [eds.]Developmentsinnumericalecology.NATOASIseries,Vol.G-14.Springer-Verlag,Berlin.