PARENT SESSION
Contributed Oral Session 26: Soil Fungi
Monday, August 8, 1:30 PM - 5:00 PM, Meeting Room 518 C, Level 5, Palais des congrès de Montréal
Effects of grazing Collembola on morphology and nitrogen flux in mycelia of saprotrophic basidiomycete fungi.
Tordoff, George*,1, Boddy, Lynne1, Jones, Thomas1, Chamberlain, Paul2, Black, Helaina2, 1 Cardiff University, Cardiff, UK2 Centre for Ecology and Hydrology, Lancaster, Lancaster, UK
ABSTRACT- Saprotrophic cord-forming basidiomycete fungi are important decomposition agents in forests, where they often attain a large biomass and interconnect discrete units of dead organic material. However, interactions between these fungi and soil invertebrates are little understood, particularly regarding the possible effects of invertebrate grazing on the spatial organisation of mycelia and on the redistribution of nutrients within mycelial systems. Collembola (springtails) are an abundant group of soil and litter dwelling invertebrates, and many species are known to be mycophagous. Here we present results of microcosm studies investigating the effects of grazing Collembola on morphology and nutrient partitioning in mycelia of several common cord-forming fungi. In one study, fungus-Collembola interactions were investigated by combining three Collembola species (Folsomia candida, Protaphorura armata and Proisotoma minuta) and four cord-forming species (Phanerochaete velutina, Hypholoma fasciculare, Phallus impudicus and Resinicium bicolor) in soil microcosms each containing two species (one fungus, one Collembola). The three Collembola species had different effects on mycelial growth pattern, and the region of mycelium grazed differed across fungal species. These different effects on fungal morphology may affect the ability of these fungi to locate heterogeneously-distributed woody resources on the forest floor. In a further study, stable isotope techniques were used to investigate the effects of Collembola (P. armata) grazing on patterns of nitrogen (added as 15N) translocation and storage within the mycelium of P. velutina. It appears from this work that invertebrate grazing can modify patterns of nitrogen flux within basidiomycete mycelia, which may have consequent effects on nutrient dynamics in forest soils.
Key words: Collembola, Fungi, Nutrients, Interactions