FUNCTIONAL DIVERSITY IN FUNGI

Diversity has various meanings but generally they reflect the variation in species assemblages within a community. Species establish interpopulation relationships that lead to stable community structure, and stable and resilient communities by definition contain a certain level of diversity. Communities with too great or too little diversity predictably undergo rapid change. Studies of fungal diversity have been limited by taxonomic and logistical difficulties in collecting and defining fungal individuals and species. Succession of fungi on substrates, seasonal fluctuations, inconsistent isolation techniques, and other considerations have also led to problems in assessing fungal species diversity. Although the problem has now been identified it is not likely that significant additions to our taxonomic knowledge will soon be useful in saving rapidly disappearing ecosystems. However, calculations of fungal diversity are not limited to taxonomic information. Several approaches provide measurements of functional diversity in situations where taxonomic information is poorly defined. These include using binary biochemical and physiological descriptors to characterize isolates, evaluating enzymatic capabilities for utilizing particular substrates and extracting DNA or RNA from the soil or other substrate and probing for genes that code for functional enzymes. Such functional approaches can provide timely information on the contribution of fungi to community diversity and toward the establishment of predictors of community stability. This paper reviews the problems in assessing fungal diversity and evaluates potential techniques for determining fungal diversity from a functional perspective.