Peter K. Buchanan

Assembly history dictates ecosystem functioning: evidence from wood decomposer communities.

Community assembly history is increasingly recognized as a fundamental determinant of community structure. However, little is known as to how assembly history may affect ecosystem functioning via its effect on community structure. Using wood-decaying fungi as a model system, we provide experimental evidence that large differences in ecosystem functioning can be caused by small differences in species immigration history during community assembly. Direct manipulation of early immigration history resulted in three-fold differences in fungal species richness and composition and, as a consequence, differences of the same magnitude in the rate of decomposition and carbon release from wood. These effects - which were attributable to the history-dependent outcome of competitive and facilitative interactions - were significant across a range of nitrogen availabilities observed in natural forests. Our results highlight the importance of considering assembly history in explaining ecosystem functioning.

Do assembly history effects attenuate from species to ecosystem properties? A field test with wood-inhabiting fungi.

Assembly history, or the order of species arrival, can have wide-ranging effects on species, communities and ecosystems. However, it remains unclear whether assembly history primarily affects individual species, with effects attenuating at the level of communities and ecosystems or, alternatively, has consistent effect sizes across increasing levels of ecological organisation. We address this question using a field-based manipulation of assembly history of wood-inhabiting fungi. The largest effect sizes were observed for the frequency of some individual species, and mean effect sizes were lower for community metrics of fungi immigrating from the regional species pool. There was little evidence, however, of attenuation in effect sizes at the ecosystem level (carbon, nitrogen, decomposition) in comparison to the species or community level. These results indicate that assembly history can have strong effects on ecosystem properties even under natural levels of environmental variability.

Molecular evidence for long distance dispersal across the Southern Hemisphere in the Ganoderma applanatum-australe species complex (Basidiomycota)

We examined phylogeographic relationships in the cosmopolitan polypore fungus Ganoderma applanatum and allies, and conservatively infer a possible age of origin for these fungi. Results indicate that it is very unlikely that members of this species complex diversified before the break-up of Gondwana from Laurasia ca 120M years ago, and also before the final separation of the Gondwanan landmasses from each other that was achieved about 66M years ago. An earliest possible age of origin of 30M years was estimated from nucleotide substitution rates in the 18S rDNA gene. Phylogenetic reconstruction of a worldwide sampling of ITS rDNA sequences reveals at least eight distinct clades that are strongly correlated with the geographic origin of the strains, and also correspond to mating groups. These include one Southern Hemisphere clade, one Southern Hemisphere-Eastern Asia clade, two temperate Northern Hemisphere clades, three Asian clades, and one neotropical clade. Geographically distant collections from the Southern Hemisphere shared identical ITS haplotypes, and an ITS recombinant was noted. Nested clade analysis of a parsimony network among isolates of the Southern Hemisphere clade indicated restricted gene flow with isolation-by-distance among the New Zealand, Australia-Tasmania, Chile-Argentine, and South Africa populations, suggesting episodic events of long-distance dispersal within the Southern Hemisphere. This study indicates that dispersal bias plays a more important role than generally admitted to explain the Southern Hemisphere distribution of many taxa, at least for saprobic fungi.

Checklist of fungi on Nothofagus species in New Zealand

Abstract An annotated list is provided of 906 taxa of fungi (including oomycetes and myxomycetes) which have been recorded in New Zealand in close association with the five endemic taxa of Nothofagus (southern beech), as ectomycorrhizal mycobionts, pathogens, or saprobes causing decay of wood and leaves. The list has been compiled from data associated with specimens held in Herbarium PDD and in Herbarium NZFRI(M), and from the literature. Nothofagus forests are an important conservation resource, and a vast storehouse for New Zealand fungi; approximately 35% of the known New Zealand agaric mycota are associated with Nothofagus, and 50% of the known polypore species. Of the 226 named species of ectomycorrhizal fungi found in New Zealand beech forests (205 agarics, 19 Aphyllophorales — clavarioid, hydnoid, etc., 1 as‐comycete, 1 mitosporic fungus), about 90% are native, with most of these being endemic. Six mycorrhizal agaric genera are especially well represented: Amanita (11 species), Cortinarius (57 speties), Democybe (11 species), Inocybe (13 species), Russula (23 species), and Thaxterogaster (13 species). Few pathogens have been recorded. The most conspicuous of these are three Cyttaria spp. (beech strawberries) found only on N. menziesii. Two mitosporic fungi, Nodulisporium sp. and Sporothrix sp., in association with various insects, may be partially responsible for beech forest decline. Sooty mould fungi, growing on honeydew secreted by scale insects, produce conspicuous black growth on beech trees. Such growth can be caused by representatives of 10 genera of ascomycetes and mitosporic fungi, many of which also grow on other host plants. Large numbers of saprobic fungi are recorded on beech wood or twigs and leaf litter, and some of these cause economically significant wood rots and sapstain.

Phylogeography and biogeography of fungi.

The rigorous study of processes shaping geographic distributions of lineages is a relatively new and emerging field in mycology. While it was previously generally believed that most fungi have wide distributions and largely unstructured populations, recent studies have shown that this is not the case. The study of distributions in tandem with molecular approaches to phylogeny has recently made substantial advances to our understanding of the diversity and biogeography of fungi. Comprehensive species inventories have provided a better picture of the actual distribution of these organisms, while robust phylogenies based on molecular characters have provided both data that allow interpretation of current distributions and testable hypotheses regarding the processes responsible for distribution patterns. This commentary provides an introduction to five papers in this issue of Mycological Research that focus on fungal phylogeography. These papers are based on oral contributions given at two symposia at the International Mycological Congress (IMC8) held in Cairns (Australia) in August 2006.

An annotated checklist of polypore and polypore‐like fungi recorded from New Zealand

Abstract A brief history of taxonomic research on New Zealand polypore fungi is given, followed by a checklist of published New Zealand records of these fungi. In total, 169 Poroid taxa a accepted, of which 48 have currently misapplied or uncertain names. A further 359 names used for New Zealand polypore fungi are cited as synonyms, and 33 names are treated as doubtful records. Twelve species are newly recorded from New Zealand: Anomoporia myceliosa, Australohydnum dregeanum, Ceriporiopsis rivulosa var. valdiviana, Coriolopsis strumosa, Junghuhnia separabilima, Phaeolus schweinitzii sens. str., Postia fragilis, Postia tephroleuca, Rigidoporus albostygius, Trechispora regularis, Tyromyces fissilis, and T. hypolateritius. The new combination Postia manuka is proposed. All names are indexed by epithet, followed by a bibliography.

A phylogenetic study of the genus Schizopora (Basidiomycota) based on ITS DNA sequences.

A phylogenetic analysis based on internal transcribed spacer regions of the nuclear ribosomal RNA region (ITS) sequences has been undertaken for species in the genus Schizopora. Four known species were studied, viz. S. radula, S. paradoxa, S. flavipora, S. nothofagi, and a hitherto undescribed species from Taiwan. Allopatric differentiation was apparent in S. radula, for which several geographically representive samples were available. Among these, ITS sequence data obtained from S. radula isolates from British Columbia and Australasia were identical. All previously recognised Schizopora species were well separated from each other with respect to their ITS sequences. Mating compatibility tests also showed complete reproductive separation between species, but intercompatibility between cultures from the same species, irrespective of geographical origin. Overall, the morphology of basidiomes of S. radula from New Zealand differs only in minor respects from those of European and Argentinean origin, but shows a higher degree of variability than described for European specimens.

Phylogenetic relationships of Japanese species of Heterobasidion--H. annosum sensu lato and an undetermined Heterobasidion sp.

The phylogenetic relationships of two Japanese Heterobasidion species, H. annosum sensu lato and an undetermined species, were revealed based on three gene loci, glyceraldehyde 3-phosphate dehydrogenase (gpd), heat shock protein (hsp) and elongation factor 1-α (ef). The tree, based on combined data of gpd, hsp and ef, showed that Japanese H. annosum s.l. was close to the European S-group, forming a subclade. The results of this study also provided strong support for the recognition of the undetermined Heterobasidion sp. as a distinct phylogenetic species closely related to H. araucariae.

NUTRIENT COMPOSITION OF EPIGEOUS FUNGAL SPOROCARPS GROWING ON DIFFERENT SUBSTRATES IN A NEW ZEALAND MOUNTAIN BEECH FOREST

Abstract Fungal sporocarps of selected species were collected from two substrates (standing dead spars and fallen logs, and the forest floor) in mountain beech (Nothofagus solandri var. cliffortioides) forest. Sporocarp C, N, P, Ca, K, Mg, Si, Al, andNa concentrations were determined. There was considerable variation in mineral element concentrations between species but this variation did not strongly relate to substrate, e.g., sporocarp N concentrations ranged from 12.1 mg g‐1 for Daldinia concentrica to 55.1 mg g‐1 for Pluteus cf. readii. Both species were found on decaying woody sustrates which had a mean N concentration of 1.5 mg g‐1. Except for Ca, nutrient concentrations were much higher in sporocarps than in substrates upon which they occurred. The high nutrient concentrations of sporocarps, particularly those found on standing dead spars and fallen logs, relative to their associated substrate, have important implications for ecosystem nutrient cycling.

Checklist of fungi on teatree (Kunzea and Leptospermum species) in New Zealand

Abstract An annotated list is provided of 450 taxa of fungi (including oomycetes and myxomycetes) that have been recorded in New Zealand in close association with teatree, that is, species of Kunzea and Leptospermum. Nearly all records refer to fungi growing with K. ericoides (kanuka) or L. scoparium (manuka), as ectomycorrhizal mycobionts, endophytes, pathogens, or as saprobes causing decay of wood and leaves. The only records of fungi specific to another taxon are those of the mycorrhizal genus Pisolithus, which grows in association with K. ericoides var. microflora in the central North Island thermal areas. The list has been compiled from data associated with specimens held in the New Zealand Fungal Herbarium (PDD) and in Herbarium NZ‐FRI‐M, and from the literature. Comments on the distribution of individual fungi within New Zealand, or on the occurrence of fungi on other plant substrata in New Zealand, are supported by information in the New Zealand Fungi website. Communities dominated by teatree are a widespread conservation resource, and an important habitat for New Zealand fungi, especially native species of ectomycorrhizal fungi. One hundred species of fungi have been described with teatree as the substrate for the type specimen. This figure is made up of 11 Ascomycota, 59 Agaricales, 20 Aphyllophorales, and 10 anamorphic taxa.