Diversity and habitat relationships of hypogeous fungi. II. Factors influencing the occurrence and number of taxa

Fruit-bodies of hypogeous fungi were sampled over two seasons across 136 fo rested study sites representing a stratified sample of the climatic, geolog ical and topographic features of far south-eastern mainland Australia. Two hundred and nine species, over three-quarters being undescribed, were recor ded. Statistical models based on various environmental attributes measured for each site were developed for the occurrence of several common taxa. At a landscape scale, climatic factors such as mean minimum temperature of the coldest month and annual mean moisture index were important explanatory va riables for most taxa examined, but the type of response varied. More local ly, topographic position, soil fertility, time since last fire and micro-ha bitat structures such as the leaf litter layer and number of large fallen t rees also influenced the distribution of taxa in different ways. A model wa s then developed for the number of fungal species occurring at each site. I mportant explanatory variables were type of substrate, topography and diver sity of potential host eucalypt species. The utility of each model construc ted needs evaluation by further sampling of hypogeous fungi. Possible impli cations of our findings for forest management are discussed. Further analys es of our existing data are also identified.