Multiplicity of Fungal Form and Function in Arctic-Alpine Ecosystems
Davey, Marie L. , Nybakken, Line , Day, Melissa J. , Kauserud, Håvard , Ohlson, Mikael , Currah, Randolph S. .
Bryophilous mycota: A little known reservoir of pathogenic and degradative fungi.
Bryophytes are a dominant component of the vegetation in arctic, alpine, and boreal ecosystems; however little is known of the microbial communities they host. The fungal biomass associated with three common bryophytes (Hylocomium splendens, Pleurozium schreberi, Polytrichum commune) was estimated using the fungal biomarker ergosterol. The phyllosphere fungal community accounted for up to 4% of the dry mass of host gametophytes, a significantly greater proportion than that associated with co-occurring vascular plants. The fungal biomass associated with bryophytes varied both with host species and tissue type, and the observed differences in biomass may be a result of host anatomical and physiological attributes, including microniche availability and chemical host defenses, in addition to abiotic factors like moisture and nutrient availability. Culture-based investigations of the taxonomic diversity of bryophilous fungi associated with bryophytes indicate community composition also varies between host species, and high levels of previously unreported biodiversity exist among fungal associates of mosses, including a number of previously undescribed species. In vitro studies of the interactions between bryophilous fungi and their hosts suggest they play significant roles in ecosystem dynamics and function. Atradidymella muscivora, Kretzschmaria sp., and Acarosporium sympodiale have been identified as pathogens of mosses that may affect host population dynamics and create small-scale disturbances in ecosystems. Coniochaeta velutina, a known vascular plant pathogen, has been identified as a parasite of bryophytes, suggesting mosses may act as inoculum reservoirs for pathogens and parasites of vascular plants. In vitro decomposition studies indicate bryophilous fungi are capable of decomposing both polyphenolic and cellulose components of bryophyte cell walls underlining their role in carbon cycling in arctic, alpine, and boreal ecosystems.
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1 - Norwegian Unviersity of Life Sciences, Department of Ecology and Natural Resource Management , Postboks 5003, Ås, 1432, Norway
2 - University of Joensuu, Department of Biology, Box 111, Joensuu, 80101, Finland
3 - University of Alberta, Department of Biological Sciences, CW405 Biological Sciences Building, University of Alberta, Edmonton, AB, T6G 2E9, Canada
4 - University of Oslo, Department of Biology, Postboks 1066 Blindern, Oslo, 0316, Norway
5 - University of Alberta, Department of Biological Sciences, CW 405, Biological Sciences Centre, Edmonton, Alberta, T6G 2E9, Canada
Presentation Type: Symposium or Colloquium Presentation
Location: Ballroom 3/Cliff Lodge - Level B
Date: Tuesday, July 28th, 2009
Time: 10:15 AM