A microtiter plate procedure for evaluating fungal functional diversity on nitrogen substrates

Ascertaining the effects of anthropogenic disturbance on belowground diversity is of paramount importance because pollution from agricultural practices and industrialization are increasing worldwide. Although we have methods for evaluating soil microbial function with respect to carbon use our ability to evaluate use of other compounds is limited. Because N cycling is of paramount importance in ecosystem stability, evaluation of the ability of saprophytic soil fungi to use a variety of N sources would provide important information on possible alterations in ecosystem stability with disturbance. Herein is described a procedure (soil Nitrolog) for evaluating fungal functional diversity on a suite of 95 different N substrates. The soil Nitrolog procedure was evaluated by testing fungal functional diversity at two sites in Big Bend National Park (Chihuahuan Desert), differing in elevation and plant community composition. The soil Nitrolog procedure distinguished between the two sites based on overall use of the 95 N substrates. In addition the procedure detected differences in individual substrate use based on site specific plant compounds in response to changes in the amount of N entering these ecosystems from anthropogenic inputs.