Utilizing Existing Temperature and CO₂ Gradients Within Yellowstone National Park to Elucidate Symbiotic Plant-Fungal Responses to Global Environmental Change

PI: Catherine Zabinski, Montana State University

Global climate change will affect the majority of ecosystems on Earth.  While research to date has focused on responses of plants, their performance in isolation from other important components of the ecosystem may lead to erroneous conclusions.  We will take advantage of natural temperature and CO₂ gradients within Yellowstone National Park to investigate how a ubiquitous root/fungus symbiosis, arbuscular mycorrhiza, functions in varying temperature and CO₂ environments.  Preliminary data suggest that the fungus may possess a greater tolerance to high temperatures than the plant, and that more carbon is allocated from plant to fungus in high CO₂ environments.  Thus the functioning of the symbiosis, as well as responses of both plant and fungus, may be drastically different in a future climate.

Field observations and controlled greenhouse experiments will be combined to research the role of temperature and CO₂ concentration for plant and fungal community composition and biomass.  Changes in symbiotic functioning will be addressed by measuring belowground carbon allocation from plant to fungus and reciprocal nutrient transfers from fungus to plant in various CO₂ environments.  The importance of plant and fungal adaptation for experimental responses will be researched in a greenhouse experiment using seeds and fungi collected from areas of varying temperature and CO₂ environments.