Sequestrate fungi are a polyphyletic, diverse group of macrofungi with
truffle-like, underground (hypogeous) or emergent fruit bodies, which are well
represented in Australia and New Zealand. The first species in the region were
described in 1844, but sequestrate fungi have been poorly documented until
recent times. Regional diversity of sequestrate fungi is high in comparison to
other parts of the world: for ascomycetes and basidiomycetes 83 genera and 294
species are currently known in Australia and 32 genera and 58 species in New
Zealand. Only an estimated 12–23% of species are known for
Australia and 25–30% for New Zealand. On that basis, between
1278–2450 species may occur in Australia and 193–232 in New
Zealand. Centres of diversity for some groups of sequestrate fungi occur in
the region, e.g. Russulaceae (five known genera, 68 species) and
Cortinariaceae (eight genera, 33 species). Some other groups are less diverse
than in the northern hemisphere, e.g. sequestrate Boletaceae (seven genera, 25
species). More than 35% of Australian sequestrate genera and 95%
of species are endemic; for New Zealand about 45% of sequestrate genera
and 80% of species are endemic. Australia and New Zealand share
similarities in sequestrate fungi at generic level (11% of total) but
do not share many of the same species (4% of total). Knowledge of
biogeographical distributions is limited by incomplete taxonomic knowledge and
insufficient collections. Some Gondwanan, Australasian and
widespread/cosmopolitan patterns are evident. Some exotic sequestrate
fungi have been recently introduced and some fungi indigenous to the region
occur world-wide as exotics with eucalypt plantings. Within Australia and New
Zealand, there is evidence that characteristic suites of fungi co-occur in
different climatic and vegetation types. Mycorrhizas of Australian and New
Zealand taxa have a range of morphological and physiological attributes
relating to their effect on plants and broader roles in ecosystem nutrient
cycling and health. Spores of sequestrate fungi are dispersed by a range of
fauna. There are tripartite inter-dependent interactions between mycorrhizal
plants, sequestrate fungi and native mammals and birds that use the fungi as
food. Major environmental influences affecting the distribution, diversity and
abundance of sequestrate fungi include climate, topography, soil, vegetation
and animals. Imposed upon such influences are a range of natural and
human-induced disturbance factors which alter habitat heterogeneity, e.g.
fire, fragmentation and replacement of native vegetation and exotic organisms.
Rare and endangered sequestrate fungi are likely to occur in Australia and New
Zealand, but for most taxa there is insufficient data to determine rarity or
commonality. In the face of poor knowledge, assemblage-based and habitat-based
approaches are the most appropriate for conservation and management of
sequestrate fungi. Habitat heterogeneity may be important for the fungi at
scales ranging from different climatic and vegetation types to local
topographic-related variations.
Australasian sequestrate Fungi 20: Russula scarlatina (Agaricomycetes: Russulales: Russulaceae), a new species from dry grassy woodlands of southeastern Australia