Native and invasive ectomycorrhizal fungi
Fungi are everywhere, in plain sight but often unseen, under every tree, in every log and patch of leaf litter. If you take a walk in the bush you will step on more fungi than you actually see. Tree roots are almost invariably ectomycorrhizal (ECM) with an array of fungi. Most ECM fungi are macrofungi that form readily visible fruit-bodies such as mushrooms or truffles. Many hundreds of species of ECM macrofungi are already known from nativeNothofagus and Eucalyptus forests in Australia, with numeous species awaiting formal description. ECM diversity appears greatly reduced in urban or plantation systems.
Estimates of ECM diversity are based mostly upon observations of fruit-bodies, as little work on root-tips has been done in Australia. However, fruit-body production is highly seasonal and patchy, some fungi may not fruit for years, and others are cryptic. The presence of fruit-bodies is indicative of the presence of the species in the soil, but absence of fruit-bodies means little. Examination of root-tips provides an alternative way to determine ECM diversity of a particular plant community or ecological site.
What do the Slippery Jack, Pine Mushroom, Deathcap, and Fly Agaric have in common? They are all fruit-bodies of fungal hitch-hikers, exotic ECM fungi, that have either deliberately or accidentally been introduced to Australia in association with exotic trees. Currently, more than a dozen species of exotic macrofungi are known to occur with Pinus in Australia. One of these, Amanita muscaria (Fly Agaric), is confirmed to have switched its host to Nothofagus (Myrtle Beech) in New Zealand, Tasmania and Victoria.
Such host switches have the potential to displace native ECM species, resulting in loss of diversity and reducing the health of the system. In order to assess potential impacts, we need to gain a greater understanding of the diversity and distribution of exotic ECM fungi in urban and plantation systems.
Ongoing research includes investigations of the rate of spread of the mycelium of Amanita muscaria in Nothofagus forests in south-eastern Australia, the associated diversity of native ECM species, and managment tools to reduce the dispersal of A. muscaria.
- Teresa Lebel (Royal Botanic Gardens Melbourne)
- Chris Dunk (La Trobe University)
- Mark Newbound (The University of Melbourne)
- Holsworth Wildlife Research Endowment
- Norman Wettenhall Foundation
Tedersoo, L., Gates, G., Dunk, C.W., Lebel, T., May, T.W., Kõljalg, U. and Jairus, T. (2009). Establishment of ectomycorrhizal fungal community on Nothofagus cunninghamii seedlings regenerating on dead wood in Australian wet temperate forests: does fruit-body type matter? Mycorrhiza 19, 403–416.
May, T., Dunk, C.W. and Lebel, T. (2006). Austral ectomycorrhizas overlooked. Mycological Research 110, 499–500.