I am an ecosystem ecologist and plant physiological ecologist. My primary research focus is investigating how processes that exchange carbon, water and energy between the land surface and the atmosphere vary across ecological gradients.   We use a tower-based micrometeorological technique called eddy covariance to measure whole ecosystem fluxes directly to develop a mechanistic understanding of the factors that control ecosystem processes such as carbon storage, water cycling and energy balance from a variety of biomes.  Increased societal attention to the goods and services provided by the biosphere increases the importance of being able to quantify variability in carbon and water fluxes at a wide range of spatial and temporal scales.  To do this, we not only need to understand ecosystem processes in intact, undisturbed ecosystems, but also how these processes change in response to large-scale disturbances (e.g. fire, insect outbreak, afforestation, deforestation, climate change, etc.).

My current research includes: 1) using measurements of ecosystem fluxes of carbon, water and energy in 6 biomes across an elevation gradient in New Mexico coupled with a model to predict which biomes are likely to be most sensitive to predicted climate change scenarios for the Southwest; 2) quantifying the consequences of large-scale piñon pine dieoff in piñon -juniper woodlands for ecosystem processes such as carbon storage and water availability; 3) investigating whether vegetation-microclimate feedbacks associated with the increase in creosote shrubs in desert grasslands promote shrub encroachment; and 4) quantifying how mesquite and juniper encroachment into grasslands in central Texas alters regional carbon and water cycling.