Composition and ecology of macrofungal and myxomycete communities on oak woody debris in a mixed-oak forest of Ohio

Woody debris is recognized as an important structural component in forests, but little is known about the epixylic communities that it supports in many forest types. The goal of this study was to identify the macrofungal (ascomycetes and basidiomycetes) and myxomycete communities found on woody debris in the topographically dissected mixed-oak forests of southern Ohio and identify environmental parameters that influence species richness and species distributions. Fifty oak (Quercus spp. L.) logs were selected across slope aspects and slope positions throughout the landscape to maximize microsite variability. Over a 2-year period, 130 epixylic species were collected (28 ascomycetes, 72 basidiomycetes, and 30 myxomycetes). Log surface area explained a significant amount of variation in species richness (R(2) = 0.51, P < 0.001). Richness was significantly (P < 0.05) correlated with volume of woody debris in the plot (+) and with study log volume (+), lichen cover (-), and surface structural characteristics (amount of bark (+), solid wood (-), and fragmented wood (+)). Canonical correspondence analysis revealed that slope aspect, bark cover, percent slope, and woody stem density influenced individual epixylic species distributions. Because of their influence on epixylic communities, various environmental parameters must be accounted for in regional epixylic studies.