Although much of my research focuses on natural ecosystems, I am also very interested in systems dominated by human influence. My work in managed ecosystems includes highly disturbed or engineered urban and agricultural settings. In the US, 45 percent of the land surface is used in agriculture and nearly 5 percent is categorized as urban. These values are lower worldwide but still represent a significant change in the form and function of the critical zone/land surface.
My research at Colorado State University addressed remediation of highly salinized agricultural soils. This project incorporated laboratory and field soil physics techniques, and soil hydraulic modeling to provide management recommendations for irrigation water quality and gypsum amendments to mitigate further reductions in soil quality. I also made contributions to theory on salinity effects on unsaturated soil hydraulic properties.
My work in urban ecology with the Central Arizona-Phoenix Long-Term Ecological Research (CAP-LTER) site examined nitrogenous trace gas fluxes along urban-rural gradients and between land cover types. I also examined the affects of atmospheric carbon and nitrogen deposition on desert biogeochemistry and ecosystem function. Ongoing collaborations in Arizona examine how climate and land-cover changes alter urban soil development and the retention of anthropogenic nutrient inputs. I am also using stable isotope tracers to explore how pulses of water availability and edaphic soil properties influence nitrogen losses and transformations within urban watersheds.