Addressing the diversity of Xylodon raduloides complex through integrative taxonomy.

In this study, the taxonomic diversity of the Xylodon raduloides species complex (Hymenochaetales, Basidiomycota) is examined. Specimens were studied using an integrative taxonomic approach that includes molecular phylogenetic and morphological analyses, and environmental niche comparisons. Four different species were found inside the Xylodon raduloides complex, with a biogeographic distribution pattern bound by geographic regions: Europe, North America, Patagonia, and Australia-New Zealand. Molecular, morphological, and environmental evidences delimit two lineages within this complex: a Northern Hemisphere clade with longer basidiospores and wider ranges in temperature and precipitation tolerance, and a Southern Hemisphere clade with smaller and more spherical basidiospores, and an isothermal and more humid climate preference. The integrative taxonomic approach used in this study demonstrates congruence between data sets and shows how morphological and environmental characteristics contribute to the differentiation of fungal species complexes. By combining various sources of taxonomic information, three new species are described: Xylodon laurentianus, X. novozelandicus, and X. patagonicus.

Priority effects are interactively regulated by top-down and bottom-up forces: evidence from wood decomposer communities.

Both top-down (grazing) and bottom-up (resource availability) forces can determine the strength of priority effects, or the effects of species arrival history on the structure and function of ecological communities, but their combined influences remain unresolved. To test for such influences, we assembled experimental communities of wood-decomposing fungi using a factorial manipulation of fungivore (Folsomia candida) presence, nitrogen availability, and fungal assembly history. We found interactive effects of all three factors on fungal species composition and wood decomposition 1 year after the fungi were introduced. The strength of priority effects on community structure was affected primarily by nitrogen availability, whereas the strength of priority effects on decomposition rate was interactively regulated by nitrogen and fungivores. These results demonstrate that top-down and bottom-up forces jointly determine how strongly assembly history affects community structure and function.

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.

The amsterdam declaration on fungal nomenclature.

The Amsterdam Declaration on Fungal Nomenclature was agreed at an international symposium convened in Amsterdam on 19-20 April 2011 under the auspices of the International Commission on the Taxonomy of Fungi (ICTF). The purpose of the symposium was to address the issue of whether or how the current system of naming pleomorphic fungi should be maintained or changed now that molecular data are routinely available. The issue is urgent as mycologists currently follow different practices, and no consensus was achieved by a Special Committee appointed in 2005 by the International Botanical Congress to advise on the problem. The Declaration recognizes the need for an orderly transitition to a single-name nomenclatural system for all fungi, and to provide mechanisms to protect names that otherwise then become endangered. That is, meaning that priority should be given to the first described name, except where that is a younger name in general use when the first author to select a name of a pleomorphic monophyletic genus is to be followed, and suggests controversial cases are referred to a body, such as the ICTF, which will report to the Committee for Fungi. If appropriate, the ICTF could be mandated to promote the implementation of the Declaration. In addition, but not forming part of the Declaration, are reports of discussions held during the symposium on the governance of the nomenclature of fungi, and the naming of fungi known only from an environmental nucleic acid sequence in particular. Possible amendments to the Draft BioCode (2011) to allow for the needs of mycologists are suggested for further consideration, and a possible example of how a fungus only known from the environment might be described is presented.

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.

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.

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.

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-alpha (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.