Cheyenne, WY / Ft Collins, CO (RRRU) : Dr. Jack Morgan

Research interests in photosynthesis, plant/soil water relations, and physiological plant ecology of native grasslands. His major two areas of research are understanding the effects of global climate change on western rangelands, and evaluating the impacts of management practices on the health of rangelands, particularly in regards to C cycling. Increases in atmospheric CO₂ concentrations have important implications for rangelands as they are predicted to cause major changes in the global climate, and may already be affecting weather patterns and productivity of western rangelands. Increase in CO₂ will also impact rangelands through their direct effects of photosynthesis, growth, water relations, N metabolism and forage quality, and secondarily through effects on soil biology and mineral cycling. Dr. Morgan has been engaged in CO₂ enrichment research for several years with a cadre of scientists from other ARS research units and from Colorado State University, the University of Northern Colorado, and the University of Colorado. The goal of these studies is to better understand how future CO₂-enriched atmospheres will affect the ecology and sustainability of Great Plains grasslands, and to use that knowledge to develop management practices that will be appropriate for future environments. The C cycling work has been geared to evaluating how different grazing practices affect plant ecology, biodiversity, and ultimately, the C exchange and budget of rangelands. This work has been conducted in shortgrass steppe and northern mixed prairie, but plans are underway to take this work to sagebrush steppe regions in Wyoming.

Dr. Morgan is also the Research Leader of the USDA-ARS Rangeland Resources Research Unit, headquartered at the High Plains Grasslands Research Station in Cheyenne, Wyoming, with labs and offices at the Crops Research Lab in Fort Collins, CO and the Central Plains Experimental Range near Nunn, CO. This ARS research unit consists of an interdisciplinary group of scientists and support staff with expertise in plant and soil science, ecology, hydrology and range science, and is engaged in studies to understand various aspects of the ecology of western rangelands for purposes of providing ranchers, public land managers, state and federal governmental entities, other scientists and the public information on the functioning of these lands and tools for their wise management. Dr. Morgan is also a co-PI on the National Science Foundation funded Shortgrass Steppe Long Term Ecological Research Project, headquartered at Colorado State University, and is an affiliate faculty member in the Department of Renewable Resources at the University of Wyoming and the Crops and Soils Department at Colorado State University.

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Selected Publications:

Available on-line:

Morgan, J.A. 2002. Looking beneath the Surface. Science 298: 1903-1904.

Nelson, J.A., J.A. Morgan, D.R. LeCain, A.R. Mosier, D.G. Milchunas, and B.A. Parton. 2004. Elevated CO2 increases soil moisture and enhances plant water relations in a long-term field study in semi-arid shortgrass steppe of Colorado. Plant and Soil 259:169-179.

Other Publications:

Morgan, J.A., A.R. Mosier, D.G. Milchunas, D.R. LeCain, J.A. Nelson and W.J. Parton. 2004. CO2 enhances productivity, alters species composition, and reduces forage digestibility of shortgrass steppe vegetation. Ecological Applications 14:208-219.

Reeder, J.D., G.E. Schuman, J.A. Morgan, and D.R. LeCain. 2004. Response of organic and inorganic carbon and nitrogen stocks to long-term grazing of the shortgrass steppe. Environmental Management 10.1007/s00267-003-9106-5.

Pendall , A.R. Mosier, and J.A. Morgan. 2004. Rhizodeposition stimulated by elevated CO2 in a semi‑arid grassland. New Phytologist 162:447-458

Ferretti, D.F., E. Pendall, J.A. Morgan, J.A. Nelson, D.R. LeCain and A.R. Mosier. 2003. Partitioning evapotranspiration fluxes from a Colorado grassland using stabel isotopes: seasonal variations and implication for elevated atmospheric CO[1] 2. Plant and Soil 254:291-303.

Pendall, E., S. Del Grosso, J.Y. King, D.R. LeCain, D.G. Milchunas, J.A. Morgan, A.R. Mosier, D.S. Ojima, W.A. Parton, P.P. Tans, and J.W.C. White. 2003. Elevated atmospheric CO2 effects and soil water feedbacks on soil respiration components in a Colorado grassland. Global Biogeochemical Cycles 17:1-13.

LeCain, D.R., J.A. Morgan, A.R. Mosier and J.A. Nelson. 2003. Soil and plant water relations, not photosynthetic pathway, primarily influence photosynthetic responses in a semi-arid ecosystem under elevated CO2. Annals of Botany 92:41-52.

Mosier, A.R., E. Pendall, and J.A. Morgan. 2003. Soil-atmosphere exchange of CH4, CO2, NOx, and N2O in the Colorado Shortgrass steppe following five years of elevated CO2 and N fertilization. Atmospheric Chemistry and Physics Discussions 3:2691-2706.

Morgan, J.A., D.R. LeCain, A.R. Mosier, and D.G. Milchunas. 2001. Elevated CO2 enhances water relations and productivity and affects gas exchange in C3 and C4 grasses of the Colorado Shortgrass Steppe. Global Change Biology 7:1-16.

Schuman, G.E., D.R. LeCain, J.D. Reeder, and J.A. Morgan. 2001. Carbon dynamics and sequestration of a mixed-grass prairie as influenced by grazing. pp. 67-75. In: R. Lal (ed.)Soil Carbon Sequestration and the Greenhouse Effect. Soil Sci. Soc. Am., Special Publ. No. 57. Soil Science Society of America, Madison, WI

LeCain, D.R., J.A. Morgan, G.E. Schuman, J.D. Reeder, and R.H. Hart. 2000. Carbon exchange rates in grazed and ungrazed pastures of Wyoming. J. Range Management. 53: 199-206.