Teresa Lebel

Sequestrate (truffle-like) fungi of Australia and New Zealand

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 species of Macowanites are sequestrate species of Russula (Russulaceae, Basidiomycota)

Australian taxa of the sequestrate genus Macowanites were examined by using LSU and ITS regions of nuclear ribosomal DNA and found to be paraphyletic within the agaricoid genus Russula. The type of the genus Macowanites, M. agaricinus, is described here as a generic synonym of Russula and an emended description of the genus Russula is provided. Descriptions and illustrations of nine new species, Russula albidoflava T.Lebel, R. albobrunnea T.Lebel, R. brunneonigra T.Lebel, R. galbana T.Lebel, R. pumicoidea T.Lebel, R. reddellii T.Lebel, R. rostraticystidia T.Lebel, R. sinuata T.Lebel and R. variispora T.Lebel, from Australia, are presented. Nomenclatural changes for five previously published Australasian species are also proposed.

Establishment of ectomycorrhizal fungal community on isolated Nothofagus cunninghamii seedlings regenerating on dead wood in Australian wet temperate forests: does fruit-body type matter?

Decaying wood provides an important habitat for animals and forms a seed bed for many shade-intolerant, small-seeded plants, particularly Nothofagus. Using morphotyping and rDNA sequence analysis, we compared the ectomycorrhizal fungal community of isolated N. cunninghamii seedlings regenerating in decayed wood against that of mature tree roots in the forest floor soil. The /cortinarius, /russula-lactarius, and /laccaria were the most species-rich and abundant lineages in forest floor soil in Australian sites at Yarra, Victoria and Warra, Tasmania. On root tips of seedlings in dead wood, a subset of the forest floor taxa were prevalent among them species of /laccaria, /tomentella-thelephora, and /descolea, but other forest floor dominants were rare. Statistical analyses suggested that the fungal community differs between forest floor soil and dead wood at the level of both species and phylogenetic lineage. The fungal species colonizing isolated seedlings on decayed wood in austral forests were taxonomically dissimilar to the species dominating in similar habitats in Europe. We conclude that formation of a resupinate fruit body type on the underside of decayed wood is not necessarily related to preferential root colonization in decayed wood. Rather, biogeographic factors as well as differential dispersal and competitive abilities of fungal taxa are likely to play a key role in structuring the ectomycorrhizal fungal community on isolated seedlings in decaying wood.

Fungi and fire in Australian ecosystems: a review of current knowledge, management implications and future directions

Fungi are essential components of all ecosystems in roles including symbiotic partners, decomposers and nutrient cyclers and as a source of food for vertebrates and invertebrates. Fire changes the environment in which fungi live by affecting soil structure, nutrient availability, organic and inorganic substrates and other biotic components with which fungi interact, particularly mycophagous animals. We review the literature on fire and fungi in Australia, collating studies that include sites with different time since fire or different fire regimes. The studies used a variety of methods for survey and identification of fungi and focussed on different groups of fungi, with an emphasis on fruit-bodies of epigeal macrofungi and a lack of studies on microfungi in soil or plant tissues. There was a lack of replication of fire treatment effects in some studies. Nevertheless, most studies reported some consequence of fire on the fungal community. Studies on fire and fungi were concentrated in eucalypt forest in south-west and south-eastern Australia, and were lacking for ecosystems such as grasslands and tropical savannahs. The effects of fire on fungi are highly variable and depend on factors such as soil and vegetation type and variation in fire intensity and history, including the length of time between fires. There is a post-fire flush of fruit-bodies of pyrophilous macrofungi, but there are also fungi that prefer long unburnt vegetation. The few studies that tested the effect of fire regimes in relation to the intervals between burns did not yield consistent results. The functional roles of fungi in ecosystems and the interactions of fire with these functions are explained and discussed. Responses of fungi to fire are reviewed for each fungal trophic group, and also in relation to interactions between fungi and vertebrates and invertebrates. Recommendations are made to include monitoring of fungi in large-scale fire management research programs and to integrate the use of morphological and molecular methods of identification. Preliminary results suggest that fire mosaics promote heterogeneity in the fungal community. Management of substrates could assist in preserving fungal diversity in the absence of specific information on fungi.

The sequestrate genus Rosbeeva T.Lebel & Orihara gen. nov. (Boletaceae) from Australasia and Japan: new species and new combinations

The sequestrate genus Chamonixia has been shown to have affinities to the Boletales, in particular the genus Leccinum. Australasian and Japanese species of Chamonixia were examined using morphological and molecular (ITS and nLSU rDNA) data and found to also have affinities with Leccinum and Leccinellum, however they form a distinct clade separate from the European type species C. caespitosa Rolland and North American species. A new genus, Rosbeeva T.Lebel & Orihara gen. nov., is proposed for the Australasian, Japanese and Chinese taxa. The species R. mucosa (Petri) T.Lebel comb. nov. is restricted in distribution to Singapore and Borneo, and R. pachyderma (Zeller & C.W. Dodge) T.Lebel comb. nov. to New Zealand, with Australian collections considered to belong to a revised R. vittatispora (G.W.Beaton, Pegler & T.W.K.Young) T.Lebel comb. nov. or a new species R. westraliensis T. Lebel sp. nov. The Chinese species R. bispora (B.C.Zhang & Y.N.Yu) T.Lebel & Orihara comb. nov is transferred to the new genus based upon morphological data. Two new species from Japan, Rosbeeva eucyanea Orihara and R. griseovelutina Orihara, are also described and illustrated. A key to all species of Rosbeeva is provided. Due to the highly modified gastroid sporocarp forms of both Chamonixia and Rosbeeva, many macroscopic characters of use in agaricoid taxonomy are difficult to interpret. However, color change and texture of sporocarps are of some use to distinguish genera and species. Microscopic characters such as spore shape, dimensions, and ornamentation, and pileipellis and hymenophoral trama structure, are essential for determining genera and species.

Two new species of sequestrate Agaricus (section Minores) from Australia

The novel species Agaricus lamelliperditus and A. colpeteii are described and illustrated, and affinities to other taxa determined by analysis of ITS sequence data. Both taxa resemble several other recently described Australian sequestrate Agaricus species, in particular A. pachydermus, A. wariatodes and A. chartaceus, which all have a powdery hymenophore from very early stages of basidiome formation. Both novel species have affinities to section Minores.

Characterisation of ectomycorrhizal formation by the exotic fungus Amanita muscaria with Nothofagus cunninghamii in Victoria, Australia

The occurrence of the exotic ectomycorrhizal fungus Amanita muscaria in a mixed Nothofagus–Eucalyptus native forest was investigated to determine if A. muscaria has switched hosts to form a successful association with a native tree species in a natural environment. A mycorrhizal morphotype consistently found beneath A. muscaria sporocarps was examined, and a range of morphological and anatomical characteristics in common with those described for ectomycorrhizae formed by A. muscaria on a broad range of hosts were observed. A full description is provided. The likely plant associate was determined to be Nothofagus cunninghamii based upon anatomy of the roots. Analysis of ITS-1 and ITS-2 regions of nuclear ribosomal DNA sequences confirmed the identities of both fungal and plant associates. These findings represent conclusive evidence of the invasion of a non-indigenous ectomycorrhizal fungus into native forest and highlight the ecological implications of this discovery.

Towards management of invasive ectomycorrhizal fungi

Ectomycorrhizal fungi are increasingly recognized as invasive species. Invasive ectomycorrhizal fungi can be toxic to humans, may compete with native, edible or otherwise valuable fungi, facilitate the co-invasion of trees, and cause major changes in soil ecosystems, but also have positive effects, enabling plantation forestry and, in some cases, becoming a valuable food source. Land-managers are interested in controlling and removing invasive fungi, but there are few available strategies for management and none are based on robust scientific evidence. Nonetheless, despite the absence of relevant experiments, we suggest that knowledge of the fundamental ecology of fungi can help guide strategies. We review the literature and suggest potential strategies for prevention, for slowing the spread of invasive fungi, for eradication, and for long-term management. In many cases the most appropriate strategy will be species and context (including country) specific. In order to effectively address the problems posed by invasive ectomycorrhizal fungi, land managers and scientists need to work together to develop and robustly test control and management strategies.

The truffle genus Cribbea (Physalacriaceae, Agaricales) in Australia

Australian taxa of the sequestrate genus Cribbea were examined by the use of ITS and nLSU sequences of nuclear rDNA and found to belong to the Physalacriaceae with affinities to Xerula and Oudemansiella. A new species, Cribbea turbinispora P.Catcheside & T.Lebel, from South Australia is described, and the previously described species C. lamellata (J.W.Cribb) A.H.Sm. & D.A.Reid is synonymised under C. gloriosa (D.A.Reid) A.H.Sm. & D.A.Reid. Descriptions and illustrations of the Australian species of Cribbea, including C. gloriosa, C. reticulata (J.W.Cribb) A.H.Sm. & D.A.Reid, C. turbinispora, and descriptions of the ex-Australian taxon C. andina (Speg.) J.E.Wright & E.Horak are presented. A key to all presently described Cribbea species is provided.

Description and affinities of a new sequestrate fungus, Barcheria willisiana gen. et sp. nov. (Agaricales) from Australia.

A new sequestrate fungus, Barcheria willisiana gen. et sp. nov., is described and its affinities evaluated using nLSU rDNA sequence data. This unusual fungus has several characters that are reminiscent of species of Agaricus and Lepiota, but with a very reduced basidiome form. The nLSU rDNA of four Australian taxa, Barcheria willisiana, Agaricus xanthodermus, Leucoagaricus naucinus, and Lepiota discolorata, was sequenced for this study. Parsimony analysis of the sequences placed Barcheria within an Agaricus clade.