Todd Osmundson
Graduate Student, NYBG Institute of Systematic Botany and the Lewis B. and Dorothy Cullman Program for Molecular Systematics Studies, and Columbia University Department of Ecology, Evolution and Environmental Biology
M.S., Montana State University
Bozeman, MT (2003)
Expertise: Systematics, Ecology and Conservation of Ectomycorrhizal Fungi
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My research interests are in the fields of ecology, evolution, and conservation of fungi, particularly ectomycorrhizal basidiomycetes. Fungal diversity and ecology (and microbial diversity and ecology in general) are poorly understood; however, knowledge about the evolution, dispersal, and interactions of these organisms is critical for understanding ecosystem function and predicting how diversity will be impacted by threats like climate change and habitat loss and fragmentation. As fungi are poorly-known organisms (only about 10% of the estimated 1.5 million fungal species have been described), their conservation requires work in a broad variety of areas, from the discovery and description of species to understanding the historical and environmental factors contributing to present species distributions, the function of fungal species in ecosystems, and the response of different fungal species to ecological perturbations. My past research experience includes work on a comparative study of fungal distributions in the eastern United States and China as an intern at the Field Museum of Natural History (Dr. Qiuxin Wu and Dr. Gregory M. Mueller, advisors), and M.S. thesis research on the systematics of the ectomycorrhizal genus Laccaria and the ecology of ectomycorrhizal host-fungus associations in the Rocky Mountain alpine zone at Montana State University (Dr. Cathy L. Cripps, advisor). I am currently a Ph.D. student in the Department of Ecology, Evolution and Environmental Biology at Columbia University (New York City) and the Institute of Systematic Botany and the Lewis B. and Dorothy Cullman Program for Molecular Systematics Studies at the New York Botanical Garden, working with Dr. Roy E. Halling.
My recent and current research projects include:
SYSTEMATICS OF TYLOPILUS
Tylopilus is a moderately large genus (150-200 described species) of ectomycorrhizal basidiomycetes in the family Boletaceae (the family that includes the porcini mushroom). A preliminary study by Manfred Binder and David Hibbett (see http://www.clarku.edu/faculty/dhibbett/boletales_stuff/Global_Boletales_2004_28S.gif) indicates that Tylopilus as currently circumscribed represents a polyphyletic assemblage of species. As a moderately large, broadly distributed genus (species are reported from the North temperate zone, montane Neotropics, northern South America, East Asia, Southeast Asia, Australia, New Zealand, and Africa) associated with diverse ectomycorrhizal host plants (including species in the Pinaceae, Fagaceae, Betulaceae, Myrtaceae, Casuarinaceae, and Caesalpinoid legumes) and having hypogeous (truffle-like) relatives, Tylopilus is a promising system for the study of character evolution and host specificity in the boletes. Our understanding of broader evolutionary patterns in the fungi is hampered by gaps in our knowledge of species, especially in tropical regions; therefore, this research involves an active field component including collecting expeditions in North America, Central America, Australia, and Southeast Asia. My systematic research includes macro- and micromorphological as well as molecular datasets.
ARBUTOID MYCORRHIZAE IN THE COSTA RICAN P¡RAMO
P·ramos are high mountain Neotropical ecosystems situated between treeline and the permanent snowline at elevations of approximately 3000 - 5000 m. Distributed discontinuously between 11° N and 8° S latitude, p·ramo occurrs predominantly in the northern Andes of Colombia and Ecuador, with scattered occurrences in Peru, Venezuela, and Costa Rica (Luteyn, 1999). P·ramo has the greatest degree of plant diversity of any high elevation ecosystem in the world and a high level of endemism, and plays a critical role in hydrological regulation, serving as a major water source for most Andean ecosystems, but these ecosystems face increasing degradation due to agriculture, grazing and recreation (Luteyn, 1999). Mutualistic interactions in these ecosystems are poorly characterized; a better understanding of high-elevation mutualisms, including levels of host specificity and the population and source-sink dynamics of high elevation and neighboring lower elevation populations, is important for better predicting the level of threat to species in these ecosystems. Based on field data, we hypothesized an arbutoid mycorrhizal association between Comarostaphylis arbutoides (Ericaceae) and the fungus Leccinum monticola (family Boletaceae) in the Costa Rican p·ramo; in this study, we applied a rigorous approach using anatomical and molecular data to uncover convincing evidence for this association. Results of this research are featured in the public exhibition "Plants and Fungi: Ten Current Research Stories," held in NYBG's Britton Science Rotunda & Gallery.
BIOGEOGRAPHY OF ECTOMYCORRHIZAL FUNGI
The distributions of ectomycorrhizal fungi are shaped by factors such as historical events and barriers to dispersal, abiotic conditions, and host distributions. Questions such as the influence of these factors on current distributions and the importance of long-distance spore dispersal in establishing populations (i.e., what constitutes a barrier to dispersal for ectomycorrhizal fungi) are not only intellectually interesting, but are important in understanding the impact of ecological perturbations (e.g., habitat fragmentation and climate change) on fungal diversity. With Dr. Roy Halling and Dr. Chuck Peters of NYBG, I am currently using geographic information systems to produce electronic distribution maps for ectomycorrhizal boletes in Costa Rica and plan to use ecological niche modeling to predict the distribution of specific mycorrhizal associations. I plan to use methods of historical biogeography to examine historical factors influencing the distribution of extant bolete species.
MICROBIAL DIVERSITY AND ECOSYSTEM FUNCTION:
Microbes such as fungi, bacteria, archaea are known to be critical in functions such as decomposition and nutrient cycling; the effect of global change on these organisms, however, is poorly understood. The BioCON experiment, conducted at the University of Minnesota's Cedar Creek Natural History Area, investigates the response of plant communities to 3 important global change factors: carbon dioxide enrichment, nitrogen deposition, and biodiversity loss. With Dr. Shahid Naeem of Columbia University, I am extending the study to examine the responses of microbial (bacteria and arbuscular mycorrhizal fungi) communities to these factors and to examine the effect of plant functional biodiversity on these responses. We are using Terminal Restriction Fragment Length Polymorphism (T-RFLP), a DNA-based approach, to assess microbial community diversity and statistically compare diversity between treatments.
CONSERVATION POLICY AND MICROBIAL CONSERVATION
I am also interested in the development of conservation policy that addresses the ecological importance of fungi and other soil microbes. My recent activities in this area include a preliminary analysis of economic rent capture for commercial harvests of edible mushrooms on public lands and the application of these rents to conservation finance, and an educational module on fungal conservation (currently in review) for the Network of Conservation Educators and Practitioners and the American Museum of Natural History.
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