Mutualist Communities

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What are the factors that structure AM fungal communities?

Although the AM fungal-plant mutualism is one of the oldest in nature, very few selective pressures on the fungus have been documented. My research explores the ecological and evolutionary responses within the AM fungal community in order to determine the nature of the plant-fungal interaction and the evolutionary pressures that can dissolve the mutualism. For example, I tested for trade-offs between host growth promotion and competitive ability in three fungal species, and found competitively superior fungi provided less host benefit (Bennett & Bever, 2009) (PDF). As a result, superior competitors appear to act almost as antagonists, but only in specific host-fungal pairs. My current and future research addresses this trade-off in fungal partners associated with monocultures (such as the invasive grass Holcus lanatus which does not exhibit growth responses to AMF infection).