Truffles
are close relatives to mushrooms. They differ from mushrooms because they
form their fruiting bodies underground and often do not have a cap and
a stem typical of most mushrooms. Australia has rich and diverse
communities of truffles; we have collected over 200 species 75 % of which
have not been previously detected or described in scientific literature.
It has been estimated that there may be as many as 1,500 truffle species
in Australia, but only 10 % may be known (picture
gallery).
The
truffles and Eucalyptus trees form close mutually beneficial associations
called mycorrhizas (view mycorrhiza
here). In the mycorrhizal association, the truffles receive food
(photosynthesized carbon) from the tree. The truffle filaments (the
mycelium), in turn, gather nutrients and water from the soil for use by
the trees.
The
truffles are also important for the nutrition and well-being of small mammals.
Many endemic marsupials depend on truffles as the primary source of food
either seasonally or throughout the year (picture
gallery). Such marsupials include endagered potoroos, bettongs and
bandicoots. The truffles benefit from being eaten by the small mammals
because the fungus spores pass through the mammal gut unharmed; the small
mammals are important vectors for dispersing the fungal spores. The
animals detect the truffles by their aromas, dig them up, eat them, and
later defecate the spores, which weather into the soil for later contact
with plant roots.
Taken
together, the marsupials, truffles and forest trees form an interconnected
net of associations which greatly improve the function of the whole ecosystem.
The truffles improve the forest growth and health and serve as a source
of nutrition for small mammals. The truffles, in turn receive their
nutrition from the trees and are dispersed by the small mammals.
Our previous studies have focused on two aspects of the
diversity of truffles. (i) What the factors determine where certain
species of truffles occur (view an abstract
here). (ii) What tree species are frequently associated with certain
species of truffles (view an abstract here).
Many of the habitat types of the endangered marsupials as well as the rare truffles we have found have been reduced by logging and development to remnants of their original broad extent. To help prevent extirpation of these habitats and their rare inhabitants, we plan to continue our research with a focus on more detailed description of the factors that determine presence of the truffle species. Thus far we have collected data in four occasions and detected more than 250 species of truffles. The species accumulation curve is still increasing and number of new species climbs.