Current Research Areas

 
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Does drought frequency determine how nitrogen fixing plants respond to drought events?

Future climate is not only expected to be drier, but also more variable, with greater frequency of drought events. We investigated how increased drought frequency affects the growth and nitrogen fixation rate of Robinia pseudoacacia, or black locust, an important Eastern US tree species. We found that the frequency and duration of drought events determined the drought response strategy of black locust: prolonged drought triggered drought tolerance mechanisms, while short but frequent droughts promoted drought avoidance. Nitrogen fixation was important factor in facilitating both of these responses.

Jeffrey M. Minucci, Chelcy Ford Miniat, R.O. Teskey, and Nina Wurzburger. Tolerance or avoidance: drought frequency determines the response of an N2-fixing tree. New Phytologist, 215:434–442. doi:10.1111/nph.14558

 

 
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Does drought shift competition between nitrogen fixing plants and non-fixers?

Nitrogen fixing plants are a key source of nitrogen for forest ecosystems, yet they may be sensitive to drought due to their N acquisition strategy. We manipulated rainfall amounts for 3 years in a regenerating Southern Appalachian forest stand to test whether drought shifts competition between the N-fixer black locust (an important species in Eastern US forests) and its non-fixing competitors.

Jeffrey M. Minucci, Chelcy Ford Miniat and Nina Wurzburger. Drought sensitivity of N2-fixing trees may inhibit forest productivity. In prep

 

 

 
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Modeling current and future distribution of black locust in the eastern US

The N-fixing tree Robinia pseudoacacia, or black locust, drives nitrogen cycling and forest productivity in Appalachian forests, yet we know little about what factors control its range and abundance. Using USDA Forest Service Forest Inventory and Analysis data and machine learning algorithms (specifically gradient boosted geoadditive models), we are working to understand how climate, geology, forest structure, and soil factors interact to determine black locust distribution under current and future climate scenarios.

Jeffrey M. Minucci, J.P. Schmidt and Nina Wurzburger. Temperature sensitivity may drive northward migration of a key N2-fixing tree. In prep.

 

 

Are soil and microbial C:N patterns driven by differences in plant mycorrhizal type?

Recently, it has been suggested that global patterns in soil organic matter carbon:nitrogen ratio could be related to the type of mycorrhizal associations formed by an ecosystem's dominant plants, e.g., ectomycorrhizae or arbuscular mycorrhizae. We are using a global meta-analysis to model the effect of mycorrhizal type on the stoichiometry of soil organic matter and the microbial community.