Ma. Castellano et Nl. Bougher, CONSIDERATION OF THE TAXONOMY AND BIODIVERSITY OF AUSTRALIAN ECTOMYCORRHIZAL FUNGI, Plant and soil, 159(1), 1994, pp. 37-46
Mycorrhiza management in forestry must be predicated on an understandi
ng of fungal biology and ecology. A fundamental building block of the
biology and ecology of any organism is accurate identification and an
understanding of its relationship to other organisms. The taxonomy of
the larger fungi has been largely based on morphological classificatio
n of sexual structures but now Taxonomy routinely incorporates mating
studies, and biochemical and molecular data. Taxonomy may not revoluti
onize theories on mycorrhiza but can clarify some of the inconsistenci
es due to misrepresentation or over-generalizations and inappropriate
conclusions drawn from studies with inaccurately identified fungi. To
illustrate this, we discuss an example where incorrect fungal names we
re repeatedly erroneously applied in morphological and physiological r
esearch reports on this fungus, e.g. Laccaria laccata. In this case su
bsequent taxonomic study revealed the reason for the conflicting resea
rch results reported for this fungus. We discuss the status of identif
ying the ectomycorrhizal fungi in various forest communities in Austra
lia and the relationships of this process to assessing their use in fo
restry. Recent intensive efforts to collect, isolate and identify Aust
ralian ectomycorrhizal fungi have revealed an enormous and unique spec
ies diversity, e.g., for truffle-like fungi, over 2000 collections fro
m the last five years alone have yielded 2 new families, 24 new genera
, and about 184 new species. Nearly 95% of the described and undescrib
ed fungi from Australia are novel, with some 22 genera and 3 families
endemic. In most cases the current systematic knowledge of mycorrhizal
fungi is inadequate to support clear framework for Australian taxa. T
his reflects the traditional Northern Hemisphere view of the world, th
e uniqueness of the Australian fungal flora, and how poorly it is know
n. For example, the genus Hymenogaster had been widely acknowledged as
the most reduced member of the Cortinariaceae. However recent work on
Hymenogaster species from the Southern Hemisphere has offered a numbe
r of alternative affinities to various species. We also discuss the ro
le proper identification of the organisms involved plays in understand
ing the ecosystem. Emphasis should be placed on how species diversity
equates with physiological and genetic diversity and how a sound taxon
omic understanding of species and their systematic position is essenti
al to properly manage them. Accurate taxonomic information will contin
ue to be required as the basis for assessing the role of ectomycorrhiz
al fungi in sustained ecological development. Of particular significan
ce is the role of ectomycorrhizal fungi in maintenance of plant divers
ity in natural ecosystems and those disturbed by management. In conclu
sion, we present some key research areas involving the use of taxonomy
that need priority attention.