Research in my lab examines carbon, nitrogen, and water dynamics in terrestrial ecosystems, with an emphasis on responses to global change. Recent projects include: 1) the response of carbon and nitrogen cycles to elevated carbon dioxide in a Mojave Desert ecosystem, 2) the impact of invasive species on soil carbon and nitrogen dynamics, 3) mechanisms controlling plant nitrogen isotope composition, and 4) carbon isotope ratios of microbial communities to elucidate patterns of substrate use. Current research is focused on past and present patterns of atmospheric deposition and plant and ecosystem responses, and my students and I are part of the BioEarth (http://www.cereo.wsu.edu/bioearth/) and Nitrogen Systems: Policy-oriented Integrated Research and Education (NSPIRE) IGERT (http://igert.nspire.wsu.edu/) programs. Our research makes extensive use of both field and laboratory experiments, with emphasis on measurements of natural stable isotope ratios. I also direct the WSU stable isotope core laboratory (http://www.isotopes.wsu.edu/), and serve on the Executive Committee of the WSU Center for Environmental Research, Education and Outreach (CEREO) http://www.cereo.wsu.edu/.
Evans, R.D., A. Koyama*, D.L. Sonderegger*, T.N. Charlet, B.A. Newingham, L.F. Fenstermaker, B. Harlow, V.L. Jin*, K. Ogle, S.D. Smith and R.S. Nowak. 2014. Greater ecosystem carbon in the Mojave Desert after ten years exposure to elevated CO2. Nature Climate Change. 4:394-397.
Adam et al. . 2014. BioEarth: Envisioning and Developing a New Regional Earth System Model to Inform Natural and Agricultural Resource Management. Climatic Change. Published online April 2014.
*Sonderegger, D.L., K. Ogle, R.D. Evans, S. Ferguson and R.S. Nowak. 2013. Temporal dynamics of fine roots under long-term exposure to elevated CO2 in the Mojave Desert. New Phytologist. 198:127-138.
*Kelley, C.J., C.K. Keller, R.D. Evans, C.H. Orr, J.L. Smith and B.A. Harlow. 2013. Nitrate-nitrogen and oxygen isotope ratios for identification of nitrate sources and dominant nitrogen cycle processes in a tile-drained dryland agricultural field. Soil Biology and Biochemistry 57: 731-738.
*Schaeffer, S.M., S.E. Ziegler, J. Belnap and R.D. Evans. 2012. Effects of Bromus tectorum invasion on microbial carbon and nitrogen cycling in two adjacent undisturbed arid grassland communities. Biogeochemistry. 111:427-441.
*Jin, V.L.,. *Schaeffer, S.M. Ziegler, S.M. and R.D. Evans. 2011. Soil water availability and microsite mediate changes in phospholipid fatty acid biomarker abundances in Mojave Desert soils exposed to elevated atmospheric CO2. Journal of Geophysical Research – Biogeosciences. 116, G02001
*Jin, V.L. and Evans, R.D. 2010. Microbial 13C utilization patterns via stable isotope probing of phospholipid biomarkers in Mojave Desert soils exposed to ambient and elevated atmospheric CO2. Global Change Biology. 16:2334-2344.
Williams, D.G., R.D. Evans and J.R. Ehleringer. 2007. Applications of stable isotope measurements for early-warning detection of ecological change. In T.E. Dawson and R. Siegwolf (eds), Isotopes as tracers of ecological change.Elsevier Academic Press
Evans, R.D. 2007. Soil nitrogen isotope composition. In Michener, R.M. and K. Lajtha, (eds). Stable Isotopes in Ecology and Environmental Science 2nd Edition. Blackwell Scientific, Oxford.
*Sperry, L., J. Belnap and R.D. Evans. 2006. Bromus tectoruminvasion alters nitrogen dynamics in an undisturbed grassland ecosystem. Ecology. 87:603-615.
*Billings, S. A., S. M. *Schaeffer, and R. D. Evans. 2004. Soil microbial activity and N availability with elevated CO2 in Mojave desert soils. Global Biogeochemical Cycles 18: GB1011.
Walvoord, M.A., F.M. Phillips, D.A. Stonestrom, R.D. Evans, P.C. Hartsough, B.D. Newman and R.G. Striegl. 2003. A reservoir of nitrate beneath desert soils. Science. 302:1021-1024.
*Kolb, K.J. and R.D. Evans. 2003. Influence of nitrogen source and concentration on nitrogen isotopic discrimination in two barley genotypes (Hordeum vulgara L.). Plant, Cell and Environment. 26:1431-1440.
Evans, R.D., R. *Rimer, L.*Sperry and J. Belnap. 2001. Exotic plant invasion alters nitrogen dynamics in an arid grassland. Ecological Applications. 11:1301-1310.
Evans, R.D. 2001. Mechanisms controlling plant nitrogen isotope composition. Solicited review. Trends in Plant Sciences 6:121-126.
*Graduate students and post-doctoral research associates.