A microtiter plate procedure for evaluating fungal functional diversity

A method (FungiLog) was developed that allows a quantitative approach to ex amining aspects of fungal functional diversity The BIOLOG microtiter plate method for measuring bacterial functional diversity was modified for use wi th fungal assemblages. Each BIOLOG plate contains 95 different carbon subst rates. Eight different tetrazolium dyes were evaluated and dimethylthiazoly l-diphenyltetrazolium bromide (MTT) was chosen as the most suitable indicat or of fungal growth. Procedures for inoculum preparation from a variety of substrates and inoculation into modified BIOLOG SF-N microplates were devis ed. By also plating out inoculum used to inoculate the FungiLog plates, tax onomic data can be obtained in conjunction with functional diversity. The F ungiLog method was subsequently evaluated for detecting landscape patterns of fungal functional diversity using decaying lechuguilla (Agave lechuguill a) leaves placed along an elevational gradient in Big Bend National Park, T exas. in 5 vegetation zones. Sites ranged from a high elevation (2098 m) zo ne dominated by live oak (Quercus emoryi) and pinyon pine (Pinus cembroides ) to a low land Chihuahuan Desert scrub (973 m). Ten, preweighed, 10-cm pie ces of lechuguilla leaves were collected from each vegetation zone. 5 per t ransect, after 6 mo decomposition. FungiLog data were used to calculate two measures of fungal functional diversity substrate richness and total activ ity. FungiLog patterns distinguished differences in total activity and subs trate richness among the low elevational and the high elevational sites at this stage in the decomposition of lechuguilla leaves. Furthermore, litter decomposition was greater for sites with high fungal functional diversity.